The influence of selected soil physical properties, soil type and site characteristics, soil temperature, and soil moisture on the response of small grains to potassium on Montana soils by Richard Harold Veeh A thesis submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE in Soils Montana State University © Copyright by Richard Harold Veeh (1981) Abstract: Two hundred twenty-two small grain experiments established on 127 site locations throughout Montana were selected to study the influence of pertain soil physical properties, soil classification parameters, soil moisture and temperature, and site and soil profile characteristics on crop response to applied K fertilizer. From 2 to 5 rates of K, ranging from 0 to 134 kg K/ha, were applied in the experiments studied. Rates of N and P were held constant within an experiment but varied from one experiment to another. A total of 48 independent variables in various combinations were inserted into multiple linear stepwise regression programs. The dependent variables were average and maximum percent yield response (to added K) as well as actual crop yield. The variable relationships were analyzed over the whole data set as well as over part of the data file subdivided according to: 1) crop; 2) crop and geographic location; 3) crop, geographic location, and percent response class; and 4) K rate at which maximum percent response occurred. Over 60 regression analyses were performed. Fifty-one of the resultant regression equations produced significant R^2 values ranging from the .10 to .005 significance level. The variables entering the regression equations most often (and the number of times each appeared) were elevation (19), latitude (17), dry consistence of the B horizon (17), dry consistence of the Cca horizon (15), textural class (15), moisture regime (14), dry consistence of the Ap horizon (14), and aspect (14). The most consistently correlated (Simple R) variables to the dependent variables were the K-treatment (rate) variables, mean annual soil temperature, dry consistence of the B horizon, elevation, slope, and moisture regime. These latter variables were consistently positively correlated to percent crop response to applied' K. The results of this study indicate that crops grown on the soils associated with the warmer and drier site locations responded to a greater degree to applied K. However, low spring soil temperatures were also associated with greater crop response to added K. Increased crop response to applied K was also associated with the more fine textured soils. Rainfall, although not consistently correlated (Simple R) to crop response, had a marked influence on the effect of applied K. STATEMENT OF PERMISSION TO COPY In presenting this thesis in partial fulfillment of the require­ ments for an advanced degree at Montana State University, I agrfee that the Library shall make it freely available for inspection. I. further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by my major professor, or, in his absence, by the Director of Libraries. It is understood that any copying or publication of this thesis for financial gain shall not be allowed without my written permission. Signature THE INFLUENCE OF SELECTED SOIL PHYSICAL PROPERTIES, SOIL TYPE AND SITE CHARACTERISTICS, SOIL TEMPERATURE, AND SOIL MOISTURE ON THE RESPONSE OF SMALL GRAINS TO POTASSIUM ON MONTANA SOILS ty . RICHARD HAROLD VEEH A thesis submitted in partial fulfillment . of the requirements for the degree of MASTER OF SCIENCE Soils ■I Approved: ittee Head, Major Department Graduate Dean MONTANA STATE UNIVERSITY • Bozeman, Montana December, 1981 ill ACKNOWLEDGEMENTS The author wishes to express his sincere gratitude.to Dr. Ear3. Skogley for his direction, inspiration,.and understanding during the development and preparation of this thesis. Appreciation is also extended to the thesis committee members. Dr. Larry Munn and Dr. Cliff Montague. Special thanks is extended to Bernard E-. Schaff, upon whose M.S. thesis this thesis seeks to build and without whose direct assistance this task could not have been completed. Also appreciation is extended to Dr. Gerald Nielsen I for his aid in obtaining soil mapping and soil series description information. Others whose assistance deserves recognition include: Dr. Richard Lund and Les Dover for their help in the necessary statistical analysis and computer programming, respectively; Montana Experiment Station personnel, who contributed to the location and sampling of the K-fertility plots; Soil Conservation Service personnel who pro­ vided soil series information for locations not previously mapped; the cooperators who provided, their land for the fertility plots; Evelyn Richard, typist. Finally, the author wishes to express sincere appreciation to his wife, Angela, for her understanding and support during this term of study and thesis preparation. TABLE OF CONTENTS Chapter Page Vita................... .. . . ............... ; . . ' Acknowledgements............................ . Table of Contents . . . ......................... . ■ List of Tables................................... . List of F i g u r e s ................................. . Abstract. ................... . . ................... ii iii iv vi viii ix 1 INTRODUCTION.......... I 2 LITERATURE REVIEW-................. . . ........... " Soil Texture and Clay Type..................... .. Soil Structure, Consistence, and Bulk Density . . Soil M o i s t u r e ............................... 12 Soil Temperature........................... * . . 5 5 8 3 4 MATERIALS AND METHODS ............................. Selection and Location of Plot Sites.......... .. Fertility Plot Sampling ......................... Dry Consistence and Bulk Density Determination. . Determination of Soil Series......... ......... Variables Determined from the Soil Series Description and Taxonomic Classification.. . . Variables Determined from the Montana Agri­ cultural Experiment Station. AnnualReports. . . Determination of Latitude, Elevation and Geographical Location ............... Determination of Percent K Response ............ Statistical M e t h o d s ....................... RESULTS AND DISCUSSION......................... 37 Regression No. I - No. 5: Yield as the Dependent Variable. . ......................... Regressions No. 6 - No. 10: Average Percent Yield Response (V42) as the Dependent Variable. Regressions No. 11 - No. 14: Maximum Percent Yield Response (V50) as the DependentVariable. Regressions No. 15 - No. 19: V50 or V42 as the Dependent Variable...................... . Regressions No. 20 - No. 31: V50 or V42 as the Dependent Variable............................. . Regressions No. 32 - No. 43: Average Percent Response (V42) as the Dependent Variable. . . . . . 15 18 18 19 20 22 22 27 29 30 34 40 47 . 53 59 65 74 V Chapter Page Regressions No. 44 - No. 47: Maximum Percent Response (V50) as the Dependent Variable . . Regression No. 48: Average Percent Response (V42) as the Dependent Variable . . . . . . . Regressions No. 49 or No. 50: Maximum (V50) and Average (V42) Percent Response as the Dependent Variable. . . .............. ; . Regression No. 51: MAST (V34) as the Dependent Variable........................... 91 Regression Equations - Summary......... . 5 SUMMARY AND CONCLUSIONS . . . . . ............... APPENDICES. ................................ Appendix 1 ..................................... Appendix I I ......................... Appendix III............................... . . . Appendix IV. . . . . . ................. LITERATURE CITED. ..... ..................... 83 87 89. 93 100 113 114 117 119 122 141 Vi ■ LIST OF TABLES Table Number Page 1 Coding 2 Coding Scheme for Temperature Regime. 3 Scheme for Moisture Regime . ............. . .24 24 ■ Coding Scheme for Structure ............... .. 25 4 Coding Scheme for Textural Class. ......... 5 Coding Scheme for Textural Family . . . . . . . . . 6 Coding Scheme for Crop Type . . . ........... ... 27 7 Variables used in Multiple Stepwise Linear Regression Analysis ............................. .35 Regression No. I - No. 5; Actual Crop Yield (V06 V10) as the Dependent Variable; Data File not Subdivided; Independent Variables not Restricted. 41 8 9 10 .11 12 .. . . Regressions Nb. 6 - No. 10; Average Percent Response (V42) as the Dependent Variable; Data File Subdivided on Crop, Independent Variables hot Restricted. ............. . . . . . . . . . . 26 , 26 . 48 Regressions No. 11 - No. 14; Maximum Percent Response (V50) as the Dependent Variable; Data ' File Subdivided on Crop; Independent Variables V01-V15 not Included............................. 54 Regression No. 15 - No. 19; Maximum (V50) and Average (V42) Percent Response as the Dependent Variables; Data File. Subdivided on Crop; VOl V15. and Soil Temperature, Rainfall, and Soil . Moisture Variables Not Included as Independent Variables ^ . 60 Regression No. 20 - No. 31; Maximum (V50) and Average (V42) Percent Response as. the Dependent Variables; Data File Subdivided on Crop and Geographic Location; Independent Variables Restricted as in Table 11 . . . . . . . . . . . . . . . 66 vii Table Number 13 14 15 16 ■ 17 18 19 20 Page Regression No. 32 - No. 43; Average Percent Response (V42) as the Dependent Variable; Data File Subdivided on Crop, Geographic Location, and Percent Response Class; Independent Variables as in Table 11. . . . . ............... 75 Regression No. 44 - No. 47; Maximum Percent Response (V50) as the Dependent Variable; Data File Subdivided on K-rate at Which Maximum Response Occurred (V51); Independent Variables as in Table 11.................................... 84 Regression No. 48; Average Percent Response (V42) as the Dependent Variable; Data File Restricted to Include Only Cases With Complete Data; Inde­ pendent Variables Restricted to. Soil Temperature, Rainfall, and Cumulative Soil Moisture Variables. 88 Regression No. 49 and No. 50; Maximum (V50) and Average (V42) Percent Response as the Dependent Variables; Data File Restricted to Include Only Cases With Complete Data; Independent Variables as in Table 11 and Table 15 Combined........ .. . 90 Regression No. 51; MAST (V34) as the. Dependent Variable; Data File Subdivided on Crop; Inde­ pendent Variables Restricted as in Table 11 . . . 92 Overall Correlations of the Independent Variables with the Dependent Variables - Yield (V06 - V10) and Maximum (V50) and Average (V42) Percent Yield Response. . ...................................... 9.4 Summary of Small Grain Response to Applied K Fertilizer, Montana Statewide Study, 1968-1980. . 97 Number of Experiments at the Various Rates of Applied K at Which Maximum Percent K Response Occurred..................... .................... 98 vi.ii .LIST OF FIGURES. Figure Number Page 1 Coding Scheme for Aspect. ............. . „ 2 Delineation of geographic location (V27) and the number of experiments according to crop in, each. W = winter wheat, S = spring wheat, B = barley, 0 = oats. . . . . ............. .. . 20 . 31 ix ABSTRACT ■ Two hundred twenty-two small grain experiments established on 127. site locations throughout Montana were selected to study the influence of pertain soil physical propertiesi soil classification parameters, soil moisture and temperature, and site and soil profile characteristics on crop response to applied K .fertilizer. From 2 to 5 rates of K, ranging from 0 to 134 kg K /ha, were applied in the experiments studied. Rates of N and P were held constant within an experiment but varied from one experiment to another; A total of 48 independent variables in various combinations were inserted into multiple linear stepwise regression programs. The dependent variables were average and maximum percent yield response (to added K) as well as actual crop yield. The variable relationships were analyzed over the whole data set as well as over part of the data file subdivided according to: I) crop; 2) crop and geographic location; 3) crop, geographic location, and percent response class; and 4) K rate at which maximum percent response occurred. Over 60 regression analyses were performed. Fifty-one of the resultant regression equations produced significant R^ values ranging from the .10 to .00.5 significance level. The variables entering the regression equations most often (and the number of times each appeared) were elevation (19), latitude (17), dry consistence of the B horizon (17), dry consistence of the Cca horizon (15), textural class (15), moisture regime (14), dry consistence of the Ap horizon (14), and aspect (14); The most consistently correlated (Simple R) variables to the dependent variables were, the K-treatment (rate) variables, mean annual soil temperature, dry consistence of the B horizon, elevation, slope, and moisture regime. These latter variables were consistently, positively correlated to percent crop response to applied' K. The results of this study indicate that crops grown on the soils associated .with the warmer and drier site locations responded to a greater degree to applied K. However, low spring soil temperatures were also associated with greater crop response .to added K. Increased crop response to applied K was also associated with the more fine textured soils. Rainfall, although not consistently correlated (Simple R) to crop response, had a marked influence on the effect of applied K. Chapter I INTRODUCTION Accurately predicting K-fertilizer recommendations for crops grown on Montana soils has been a recognized problem for several years. Research during, the past decade has shown K-response by various crops to be unpredictable, and poorly related to soil test K ratings. Although a soil may test "high" in extractable K, a yield response to added K frequently occurs. Significant crop response also occurs regardless of yield level; this suggests that K may be yield-limiting independent of the status of other growing conditions (Skogley, 1976). A coordinated statewide research effort was begun in 1971 to try to determine what factors were contributing to the variability in K-response. That K-fixation had long been associated with the presence of micaceous clays (particularly illite) led to a study in which clay type and amount of clay were related to crop response (Phillips, 1973). No significant relationships existed upon which a K-soil test could be based. Wang (1975) also studied K-fixation and release potential of selected soils incubated over various time periods. This research showed that after small additions of K, the level of extractable K could be greatly increased; this suggests that a type of K-release mechanism is operative in some soils. Haby (1975) investigated the possibility of using a more reliable extraction procedure than the standard NHyOAc extractable .2 'K-soil, test; Fifteen different extraction techniques were studied on a wide range of soil types. The results of this investigation showed that soil test values could at best, only account for 40 percent of the variation in crop response. This strongly suggests the lack of a close functional relationship between extractable K (regardless of extraction procedure or method of expressing the results) and K availability to plants grown.under the climatic and soils conditions of Montana. Some system which relates more closely to factors controlling K availability over time will need to be developed as a K soil test. Uptake of K by plant roots has been shown to be governed primarily by ion diffusion, accounting for a minimum of 80 percent of the K-supply. Mass flow and direct root contact can account for no more than 15r20 percent of the K supply (Barber, 1962; Beckett, 1964). Massee (1973) found a very good correlation between K-diffusibn in . a variety of soil types and crop response to added K under controlled conditions. Developing a K soil test based on factors that influence K diffusion presents a complex problem. Not only is K diffusion related to numerous soil physical properties (e.g.- texture and structure) but also to various climatic and weather-related factors such as moisture availability and temperature. These are extremely variable from year to year,in Montana, as well as during any one growing season. Shrader, et al (1957) hypothesized that soils should possess 3 inherent characteristics which influence crop growth and are defined and/or expressed by the parameters used in soil classification. Schaff (1979) investigated this hypothesis on a number of soils which, had been used during two years of soil fertility field research experiments with winter wheat. The soils were characterized as to their p h y s i c a l c h e m i c a l , and climatic properties and then correlated to winter wheat response to added K-fertilizer. Variables with the highest correlation (soil and site combined regression analysis) with percent yeild response were: I) mean annual soil temperature at 50 cm.; 2) moist consistence of the Ap horizon; 3) moist consistence of the B horizon; 4) dry consistence of the B horizon; and 5) the clay / content of the Ca horizon. • . : 2 These five variables produced an R value of .88. These results were very encouraging. Td further investigate the hypothesis that genetic soil characteristics influence crop response to added K 9 the present study was conceived. The data base would be expanded to determine if significant correlations could be observed statewide, and for additional crops. Soils and sites were classified according to Soil Taxonomy (U.S.D.A., 1975) at selected locations at previous small grain soil fertility experiments (127 sites). The soil samples were analyzed by horizon (Ap9 B 9 and Cca) to determine dry consistence and bulk density values; other selected soil and site properties which could be determined from the SCS 4 soil series description for a particular, site and for which a coding scheme could be devised were also included. The objectives of this research project were to I) determine if known or easily determined soil and site characteristics were significantly correlated to crop response to K fertilizer when a large number of sites from,past experiments throughout the state was included, arid 2) investigate the^feasibility of developing a system for predicting future crop responses to K-fertilizer based on selected soil and site classification parameters. Chapter 2 LITERATURE REVIEW - Crop responses to applied fertilizers and yield differences have been associated with soil type differences (Shrader et al., 1957; Olsen, 1977). Dass and Shankhayan (1979) reported that the dry matter production of wheat and response to added K differed signifi­ cantly when the crop was grown on different soil types. Some of the soil and site properties which have been reported to be most important in this regard are discussed below. Soil Texture and Clay Type Liebhardt and Cotnoir (1979) studied 28 Delaware soil series ranging in texture from silt loam to loamy sand.. Soils higher in sand content did not need as much K added to raise the soil test values as soils higher in silt and clay. Von Braunschweig (1980) found similar effects of clay content upon K-availability. On coarse textured soils with clay contents up to 12 percent, a K-saturation of the clay minerals, from 1.7 to 2.5 mg. K/percent clay was necessary for adequate plant uptake of K. Soils, with clay contents from 12 to 25 percent and greater than 25 percent required 1.2 - 1.7 mg K/percent clay and 1.11.4 mg K/percent clay, respectively, for adequate K uptake - Calculating these values in terms of mg K/100 g soil, it was apparent that the more clay the soil contained, the higher the exchangeable K content 6 should be for adequate K nutrition. The level of K available at the plant root is the critical factor governing plant K uptake. aspects. . This involves a number of soil Potassium-fixing.soils may show extreme, variability in their K-supplying power. In one study it was observed that K-fixation. values were relatively constant on the plots without or with low K-fertilization; after high K application, fixation values fluctuated much more (Burkart and Amberger, 1978). Also, the rise in the level of available K by fertilization was negatively correlated to soil clay content. In a similar study, the K concentration of a saturated paste extract was inversely related to soil clay content (Mengel and Aksoy, 1971). ■ These experimental data support the concept that the K concentration of. the soil solution influences the K-supply. for plants and that the K concentration of the soil solution is influenced by the degree of K saturation of the clay minerals. In a study of four Ohio.soils with a wide range of K release capability, it was observed that the two soils highest in clay and total K content reacted in a significantly different manner to added K than did soils with less clay (Munn and McLean, 1975). Initial cropping decreased exchangeable K in all K-treated soils eliminating the effect.of K treatments on exchangeable K. However, after initial cropping where no K was added, exchangeable K varied sixfold from.the lowest (least, percent clay) to the highest .(greatest percent clay). 7 In the two soils highest in clay content, there was a tendency for prior cropping to increase K fixation and reduce the plant recovery of subsequently applied K. Sparks et a l . (1980) reported that soils with sandy surface horizons and clayey subsoils had a pronounced accumulation of K in the subsoil layers. The K in the clayey subsoil, probably a result of leaching of both applied K and that of genetic origin, was avail­ able to plants depending upon the ease of root, penetration. The ability, of the plant to extract subsoil K caused a lack of response to surface applied K. Singh et al. (1977) observed higher K uptake by dryland wheat grown on a clay loam soil than oh a loamy sand, soil in a year of normal rainfall and profile storage. This difference was attributed to the higher water storage capacity of the clay loam soil. It is probable that the increased water supply in the clay loam soil is related to a greater potential, for K ion diffusion. Particle size within the clay fraction has been observed to influence the rate of weathering and K fixation and release of clay minerals. Potassium release has been shown to be more rapid as the particle size becomes smaller. However, at a certain point in decomposition at which the diameter and thickness of the clay particles approach equality, little or no K release is observed. This is probably due to the stable overall charge of the clay particle 8 (Sawhney, 1972). Particle size was also related to K-selectivity and to ease of collapse of the frayed edges of the particle. A greater area of collapsed central core relative to the edges of the particle was associated with greater ease of collapse of the edges. Beckett and Nafady (1967) also associated specific K sites with the edges or peripheral interstices of stacks of clay plates and the non-specific (Gapon) sites to their planar surfaces. Soil Structure, Consistence, and Bulk Density Soil structure can influence the pgrceptage of total soil volume that can be utilized by roots. Soil consistence as well as perme­ ability can be interrelated with many other physical properties. A hard dry consistence commonly implies slow permeability, low porosity, and high bulk density (Niekerk and Lambrechts, 1977). In a study of some Singapore soils. Wells and Leamy (1977) observed that the physical properties of the soils were different and could be related to the nature of the parent rock. For intensive market gardening, the moist soil consistence and grade of structure were both determined to be of major importance. Soil consistence is a soil parameter which measures the force . required to crush a soil ped. Consistence is probably an important parameter in that it is dependent upon various soil physical properties such as porosity, bulk density, arid texture as they interrelate. Cone 9 index (Cl) ] defined as the force required to push a penetrometer into the soil divided by the cross-sectional area of the penetrometer cone, is a similar type of measurement. In a study fo determine those factors which influence the Cl value, it was observed that Cl for each texture increased monotonically with decreasing soil water pressure, but no simple relationship between Cl and texture was found (Byrd and Cassel, 1980). Regression equations relating Cl to water content, percentage of sand, and the volume of pores greater than 150 pm in diameter explained 67 - 72 percent of the observed variation (.0001 probability level.). It was pointed out that the importance of roots in natural systems should not be overlooked as an influence, in determining soil physical properties. Reddy et al. (1978) observed that the hydraulic conductivity and water holding capacity of the soil had increased by 25 - 30 percent and 10 - 16 percent, respectively, under all of the cropped plots (42 ikg. K/ha level) at the full flowering stage as compared to the control. The root weight of all crops had also increased by 25-40 percent with the increased K application. Root growth has been shown to be one.of the most important factors for improving soil structure; bulk density can be used as a sensitive index of soil structure. This suggests that the higher rates of hydraulic conductivity (associated with the lower bulk density values) 10 observed under the 42 and 83 kg. K/ha treatments might be attributed to better root growth. The relationship between root growth, bulk density and soil structure has been shown to be important. Schuurman (1971) observed that root weights, numbers, and rooting depth decreased with increasing soil density. In addition, uptake of water and minerals, particularly P and K, decreased. The yield of dry matter of wheat decreased in all soil series except one as the bulk density was increased from 1.02 3 to 1.52 g/cm (Sharma and Verma, 1971). A similar trend was also observed for root growth, grain yield, and uptake of N, P, and K. In a related study, the compaction of soil to create a bulk density 3 greater than 1.40 g/cm proved harmful for plant growth in all soil series observed (Verma and Sharma, 1972). The harmful effect of compaction was again directly related to decreased nutrient uptake. It is probable that decreased nutrient uptake is related to decreased ion diffusion and increased soil matric potential associated with the higher bulk densities. Soil physical parameters may also be important in the way that they can modify the biological-chemical nature of the soil environment. Samra and Goswami (1978) found that grain yield increased up to a bulk density of 1.6 and 1.75 at the 0 - 1 5 cm depth and 15 - 30 cm depth, respectively, after which yield dropped off. The interaction of bulk density and moisture content was observed to significantly 11 affect the oxygen diffusion rate. Oxygen diffusion rate increased as yield increased to a point after which yield decreased. The same kind of parabolic relationship was observed between bulk density and grain yield and between soil resistance to penetration and grain yield. In another study soil compaction was observed to decrease total porosity and the amount of macropores (> 50 n). However, the amount of water holding pores (.20 -.10 y) and fine capillary pores (< .20 p) increased (Talha et a l ., 1979). Total dry matter production of maize and barley as well as. K concentration and uptake was higher at all levels of fertilization in the compact soil and increased as K fertilization level increased. By compacting the soil an equilibrium was reached among water and air-filled pores. The potential existed for a negative effect on plant.growth during moist years because the plants would suffer from an excessive COg/Og ratio (0^ deficiency). Tillage practices have been found to significantly affect K ' concentration and uptake of K. These effects have variously been associated with increased compaction of high moisture content (Fisher et al., 1975),. differences in concentration gradients of K (Drew and Saker, 1978; Hodgson, et al., 1977), differences in moisture content and depth and abundance of rooting (Cannell et al., 1980; Drew and Saker, 1980), and differences in physical and chemical properties and activity of earthworms (Lai, 1976), 12 Soil Moisture Sharda and Gupta (1975) point out that soil moisture affects the growth of plants by modifying soil aeration, mechanical impedance of the soil, the concentration of readily soluble nutrients and the heat conductivity of the soil. In their investigation an increase in oxygen diffusion rate with increasing soil moisture tension was indicated. Uptake of nutrients was found to decrease with increased moisture stress. The interaction between soil moisture regime and nitrogen level has been found to be significant in respect to N, P, and K uptake (Varma et a l ., 1976; Varma, 1976). As soil moisture increased, the higher rates of nitrogen increased general growth and dry matter production. Better root growth, in particular, allowed the plants access to more soil which resulted in better water use efficiency. ■. ' The influence of increasing moisture levels on N, P , and K uptake has been similarly observed in two other studies (Bajpai and Mertia, 1977; Fedak and Mack, 1977). Increasing moisture levels increased ash content of the grain and straw, increased grain and protein yield, and decreased grain protein content. Hoyt and Rice (1977) found that efficiency of moisture use was generally more than doubled by the fertilizer and fertilizer plus manure treatments, versus the control (no applied fertilizer or manure) Petinov et al. (1977) also observed that the higher the level of N, P, 13 and K, the more pronounced the positive response of the plants to soil moisture. Soil moisture, as it fluctuates, may also affect exchange relations and, therefore, soil solution concentrations of. K. Raney and Hoover. (1946) reported that alternate wetting and drying of some soils caused a rapid fixation of K in a non-replaceable form and that very little fixation of this kind took place under the soils kept continually moist. However, Scott and Smith (1957) found that the exchangeable K in the surface and subsoil was doubled upon drying and that K uptake by plants was always less on soils kept continually moist than from soils that had been dried and rewetted. uptake, in particular, from the non-exchangeable Potassium K fraction, was impaired by a dry soil medium (Mengel and Wiechens, 1979). The release rate of non-exchangeable K was more important for crop production than the level of exchangeable soil K. Beckett and Nafady (1967) also observed that the rate of release of, K from a non-labile pool decreased as the non-labile pool became exhausted. Soil moisture will influence the concentration of ions in the soil solution both by the effect of dilution and by the relative effect on ions of different charge. Karlen et al. (1978) found that as soil moisture was increased, Ca and Mg concentrations in leaf tissues Were depressed while K concentrations increased or remained unchanged. It was felt that this differential change in cation composition of 14 wheat grown under wet soil conditions could be explained by changes in ion activities in accord with Donnan Equilibrium Theory. .This theory shows that t h e 'availability of monovalent ions increases while the availability of divalent ions decreases as soils become more nearly saturated with water. There is much evidence that K concentrations in soil solutions are decreased and that K absorption on exchange sites is increased by. liming. These Ca:K interactions explained the decreased yield of potatoes in a study conducted at Rothamsted (Bolton, 1977). Jankovic and Nemeth (1978) observed that owing to K and P fertilization, the Ca concentration of the soil solution increased as a result of exchange processes in the soil. Simple ion concentrations were determined to be more suitable than the potentials for defining nutrient dynamics changed by fertilizer application. The concentration of cations in solution and pH have also been shown to influence K release from micaceous clays. Marked complementary ion effects on K and Ca displacement occurred when the exchange was from pH-dependent charges. At 30 percent K saturation (70 percent Ca), complementary ion effects were small. However, at 10 percent K saturation (90 percent Ca), the different complementary cations caused more than a fourfold difference in the K displaced from illite ■ (McLean and Bittencourt, 1974). Mattson (1973) found that the uptake . of P and K was lowest, and the.uptake of Ga highest toward the dry end 15 of the treated soils. Again, the implication here is that moisture is important in that it modifies both the relative ionic concentrations and ion diffusion. Soil Temperature At any one moment, temperature varies from soil horizon to soil horizon. It fluctuates with the hour of the day and with the season of the year, and the fluctuations may be large or small according to the environment. Seasonal fluctuations in soil temperature are affected by latitude, soil moisture, groundwater, air movement near . ■ i. the ground, clouds, rain, and ground cover. The influence of latitude is dominant over most of the United States. Daily fluctuations are affected by all of these except latitude, arid the influence of moisture is dominant (Smith and Newhall, 1964). The importance of slope and ■■ aspect can also be very pronounced on adjacent soils, especially in .. the higher latitudes. Daily changes in air temperature have a significant effect on the temperature of surface-soil horizons to a depth of about 50 cm. This is particularly so in soils of dry climates where moisture can be exceedingly important in reducing fluctuations in soil temperature. Oliveira et al. (1979), in attempting to estimate soil temperature at 2 cm from air temperatures, found that on rainy days the measured soil temperature was always lower than the estimated soil temperature because the rainwater cooled the soil surface more rapidly than the air 16 Willis and Power (1975) point out that water viscosity and sur­ face tension are inversely related to temperature, and relative hydraulic conductivity increases as temperature increases. A dry soil will freeze more quickly and to a greater depth than a wet soil, and thawing of the dry soil occurs much more rapidly in the spring. As the soil profile cools or warms, the water table drops or rises in response to the known fact that a cold soil holds more water than a warm soil and loses water more slowly. Frost may remain in the soil profile for a significant time after the surface has thawed, thus forcing plant roots to grow into soil colder than the surface. Soil temperature has been shown to significantly affect K-uptake and the K-requirement. Boatwright et al. (1976) found that fertiliza­ tion of spring wheat with N-, P , and K appeared to partially alleviate the detrimental effect of low surface soil temperatures. In. a similar study, N, P, and K concentrations were observed to be higher in grain.from plants grown under reduced soil aeration and 25° C soil temperature than in grain produced at lower soil temperatures (Labanauskas et al., 1975). Wicke (1973) also observed that the K requirement was greatest at the lower soil temperature and that the response to added K was smaller at high root-zone temperatures than at low root-zone temperatures. Kabli and Toop (1970) found that high soil temperature (23.9° C and higher) could be contributing to the problem of K-induced 17 Mg deficiency by increasing the potassium uptake. Mack (1971) confirms this in his report op yields of bromegfass.. An increase in concentration of the major nutrients (N, P, K) in the plants coincided with the. greater herbage growth on the warm soil. The changes in uptake for N,. P, and K per I 0 C change of seasonal temperature were 8.7, 10.4, and 7.1 percent, respectively, and the associated values were 1.5, 1.6, and 1.4 at 9.2° C. • Temperature influences may also be related to different exchange relations which exist among potassium-bearing micas. The heating of various micas caused marked differences in K-exchangeability. Although the maximum degree of K exchange was generally unaltered by heating, major changes in the rate of exchange occurred (Scott, et a l ., 1972). Heat treated muscovite showed a marked increase in the rate of exchange, whereas biotite and lepidomelane showed a decrease in the rate of K release. Chapter 3 MATERIALS AND METHODS Selection and Location of Pldt Sites Between 1968 and 1980, numerous field soil fertility research studies were conducted by Montana Agricultural Experiment Station researchers, Extension Service Soil Scientists, and USDA-ARS scientists in Montana. . Results of recent research.suggested that these sites could provide valuable information for developing a system for predicting crop response to K fertilizer. Because crop yield and response data were already available from previously conducted research, only the site and soil characteristics (which are basically constant over the years) needed to be obtained. To do this, only - those research sites, which included small grains (winter wheat, spring wheat, barley, and oats) as the experimental crop and upon which various rates of K fertilizer were applied as a variable in the experiment were selected. The total number of sites sampled based on these criteria was 127. Because many of the sites had several experimental plots established on them oyer the years, the site data \ • 1 ' could be applied to more than one set of experimental data (i.e. yield data, etc.). For this reason, the total number of experiments (cases) included in this study was 222, In most cases site location was determined from the legal descriptions as reported by the various researchers in the Montana 19 Agricultural Experiment Station Annual Report. Actual location in the field of the old plot sites was accomplished with the aid of someone who was directly involved in the research when, the plot was established and/or with the, help, of the cooperatofs themselves. In all cases, care was taken to insure that the sample taken was in close, proximity to the old fertility plot site to insure the same soil type (series, level). See Appendix I for site numbers, cooperators, legal descriptions, and soil series names; Fertility Plot Sampling Soil samples were taken as near the center of the old fertility plot as could be determined. A Giddings probe,was used to take soil samples to a depth of approximately four feet. The core sample was then divided into plow layer (Ap) horizon, B horizon, based on structural and textural differences induced by clay accumulation, and a Cca horizon, as determined by reaction with dilute hydrochloric acid. Samples from each horizon at each site were then placed in a sampling bag labelled as to cooperator, years in which the plot was., used, and horizon name and depth. In several cases, because of the method of sampling, soil type differences, or previous erosion, it was not possible to distinguish three distinct horizohs. In a few cases, the presence of a Cca horizon was not detected to the maximum depth of sampling. 20 Percent slope and aspect of the plot area were also recorded. Aspect was introduced into the analysis by the following coding scheme in which a number from I to 8 was assigned to correspond with the general site aspect (Figure I). 315-360 45-90 270-315 225-270 180-225 \ 90-135 Coding Scheme for Aspect 135-180 Dry Consistence and Bulk Density Determination Traditionally, dry consistence in the field is determined by placing a soil ped between the thumb and forefinger (and/or between the hands) and exerting a force sufficient to crush the ped. On the basis of the force applied, one of six semi-quantitative values is assigned, ranging from loose to extremely hard. 21 To obtain a more quantitative .(less subjective) measure of dry consistence, a pocket penetrometer (CL-700; Soiltest1 Inc.) with the foot attached was used to determine the point of failure or force required to.crush the ped. Five peds from each horizon at each site ‘ 2 were sampled and the dry consistence measurements recorded in kg/cm . In addition to the latter measurements, the thickness of each ped was measured and recorded. This was done to subsequently determine if a significant relationship.existed between ped thickness and the consistence measurement, itself. If necessary, corrections could then be made later for those horizons with either small or large average ped thicknesses. However, care was taken to try to eliminate this potential problem by selecting five peds of similar range in size for each horizon at each site. Ped thicknesses ranged from 10 - 25 mm; 2 If the force required to crush the ped exceeded 4.5 kg/cm (maximum value on the penetrometer scale), a value of 5.0 was recorded. . Bulk density determination was accomplished by using the clod method (Black., 1965) . medium. Saran was used as the water seal or coating This method was chosen because in many cases an intact core was not preserved through handling. Three large-sized peds were sampled from each horizon for each site. The average bulk density of the three peds sampled was entered as the value used in the statistical analysis. , 22 Determination of Soil,Series The soil series present at a site was determined in one of two" ways. The soil series name was obtained in many cases from the researcher as reported in the Montana Agricultural Experiment Station Annual Report. If not given, then the legal description of the fertility plot was used in conjunction with the appropriate Soil Conservation Service county soil survey to determine the soil.series present at a site. Not all counties in Montana have been mapped, so the soil series present at some site's is not known. The inclusion ■ of the variables derived from the soil series description was not possible for these sites (See Appendix II). " Variables Determined from the Soil Series Description and Taxonomic Classification '' ' The soil classification and profile description system (H.S.D.A., . . ■ , . , 1951; U.S.D.A., 1975) used in the United States makes use of soil physical criteria as well as climatic parameters to distinguish one soil type from another. .In the present study, some of the variables used in the statistical analysis were derived from these physical and climatic criteria. These include: I).mean annual soil tempera­ ture (MAST); 2) soil structure; 3) textural class; 4) textural family; 5) temperature regime; and 6) moisture regime. Mean annual soil temperature was introduced as a variable in the , 23 analysis by calculating the average of the range of values presented in the soil series description for a given site. If a specific tempera ture was obtainable as the MAST in the soil series description, then that value was used in the analysis. Soil structure, textural class, textural family, temperature regime, and moisture regime were all introduced as variables in the regression analysis according to various coding schemes. The coding schemes were devised so that the number sequence would reflect a logical order. For example, textural family determination was coded from coarse-textured to fine-textured; structural grade was coded from weak to strong. Moisture regime determination for a given soil series was derived from the classification of that series at the subgroup level. A soil with a cryic temperature regime was assumed to possess a udic moisture regime in that the ustic moisture regime could not technically apply at the subgroup level of classification (U.S.D.A., 1975). A soil with a frigid temperature was considered to have an ustic moisture regime unless the subgroup modifier indicated some other moisture regime (intergrade). Any soil series in this study classified as an aridisol always possessed an ustic intergrade in the subgroup modifier. See Table I and Table 2, respectively, for moisture regime and temperature regime coding schemes. Soil structure was introduced as a three-digit variable in the 24 Table I Coding Scheme for Moisture Regime Moisture Regime Coded Value Udic I 2 . Ustic Ustic - aridic Aridic - ustic 3 . 4 . Table 2 Coding Scheme for Temperature Regime Temperature Regime Coded Value Cryic I Frigid 2 Mesic - .3 '' ' ' .25- analysis-composed of three coded 1-digit numbers for grade, size,, and type, respectively (Table 3). . Table 3 Coding Scheme for Structure Coded Value Grade Size Coded Value Coded Value Type Weak I '' Fine I . Platy I Moderate 2 Medium 2 Prismatic 2 Strong 3 . Coarse 3 Columnar 3 Angular blocky 4 Sub-angular blocky 5 Granular 6 Massive 7 Single grain 8 '- ■ ; Textural class always refers to that texture dominant at the sur­ face of a given soil series and is that texture usually associated with the soil series name. Textural family is that parameter associated with the control section of a particular soil series at the family level of classification (Hopkins, 1979; U.-S.D.A., 1975). Table 4 and Table 5 contain the coding schemes for textural class and textural family, respectively. Soil series names and their respective moisture 26 Table 4 Coding Scheme for Textural Class ' Textural Class. Coded Value Fine-sandy loam I Loam 2 Silt loam 3 Silty clay loam 4 Clay loam 5 Clay 6 Table 5 Coding Scheme for Textural Family Textural Family Coded Value Coarse-loamy I Fine-loamy 2 Fine-silty 3 Fine-montmofillonitic . 4 - 27 and temperature regimes, as well as textural classifications can be found in Appendix II. Variables Determined, from the Montana Agricultural Experiment Station Annual Reports Variables obtained from the annual reports that were used in the statistical analysis included: I) type of crop; 3) year of the experiment; 3) yield data; 4) K-rates applied; 5) rainfall; 6) soil ■ temperature data; and .7) soil moisture data. The coding scheme for crop type is given in Table 6. Table 6 Coding Scheme for Crop Type Crop Type Coded V a l u e . Winter Wheat I Spring Wheat 2 Barley 3 Oats 4 "Year" was introduced as a variable in the analysis by recording the last two digits of the year the experiment was conducted. Yield data ('kg/ha) were obtained from the annual reports only for those 28 treatments in which nitrogen and phosphorus were considered to be adequate and in which the N and P rates were constant across the various rates of K, Thus, N and P rates were constant within an experiment for the yield data recorded but were variable from one experiment to another. Rates of applied K varied from .experiment to experiment. In some cases, only two rates of K were applied (e.g. 0 and 56 kg K/ha). a number of cases, five rates of K were applied. In In all cases, the number of yield variables corresponded to the number of rate variables. The control was always the same at 0 kg K/ha. Rainfall (cm.) was introduced as a single variable in the analysis. The value recorded, was that of total rainfall reported during the growing season with no regard being given to the distribution. Temperature data taken throughout the growing season were used in calculating an average monthly temperature for April, May, June, and July. Four variables were thus introduced into the analysis. Spring soil moisture was introduced to the analysis in the form of seven variables. content to 183 cm. These variables represented the total moisture(V43) as well as the moisture content of the soil profile taken in 30 cm. increments from the surface to 183 cm. (6 variables - V44 through V49). At a later date, sixe more variables were introduced from these data as a modification of the six variables just mentioned. Whereas the first six variables (V44 through V49) 29 measured soil moisture within a given 30 cm. increment, the latter six variables (V52 through V57) measured the cumulative soil moisture from the surface to a specified depth (e.g. 0-30cm., 0-60cm., 9-90cm,etc.). Temperature, moisture, and rainfall data were missing from the annual reports in many cases, complicating the statistical analysis. Because of the missing data for these variables, care must be taken in interpreting the significance of some of the regression results, particularly those in which the dependent variable was a yield variable (V6 through V10). More will be said about this problem in the section on statistical methods. Table 7, which presents all of the variables used in the analysis, also details the severity of. missing data for each variable. Determination of Latitude, Elevation, and Geographical Location Latitude and elevation of each site were both determined by obtaining the appropriate topographical map which could be used in conjunction with the legal description of a particular site. Latitude was introduced into the analysis as a four-digit number recorded to the nearest minute. Elevation, in most cases, was determined ± 7.5 meters. Geographical location was an arbitrarily derived variable used in the analysis. Its derivation originated from the desire to separate the plot sites according to the area of the state of Montana 30 in which they were established. These areas were defined on the basis of the proximity of the sites to one another and according to known growing season differences, such as usual time of harvest and general climatic conditions. Four areas were thus delineated and a number (1-4) used as the assigned coded value for the variable (Figure 2). Determination of Percent K Response For those experiments with five treatments of applied K fertilizer including the control (0 kg K/ha), a quadratic multiple regression analysis was used to obtain the calculated maximum percent K response. This method of percent response determination was described by Schaff (1979). The equation obtained from the regression analysis is as follows: Y = a + b 1 X + b 2 X2 where; Y = calculated maximum yield a = intercept of the Y axis; X = O b^ = linear regression coefficient bg = quadratic regression coefficient X = rate of applied K fertilizer If the derivative of the original equation is calculated, the rate of K fertilizer needed for maximum yield can be determined. The W-4 4 W-U W - 14 Figure 2. VV- 64 Delineation of geographic location (V27) and the number of experiments according to crop in each. W = winter wheat, S = spring wheat, B = barley, 0 = oats. 32 equation becomes: Y » b1 + 2 b2 X By setting.Y = 0 and solving for X: 2 b 2 X + b1 = 0 where; X = rate of K fertilizer to obtain maximum yield response.. By substituting this value of X into the original equation, one can then solve for maximum yield (Y). After the maximum yield is determined, then a simple ratio (Y/a) provides Y, or the percent change in yield (response). For those sites with only 2, 3, or 4 treatments of K fertilizer including the control (0 kg/ha K ) , a second method was used to calculate percent K response. This method was used as an alternative because quadratic multiple regression analysis becomes more meaningless as the number of points to which a curve is adjusted decreases. In other words, a perfect-fit quadratic curve will always result in instances of the presence of only three points. This second method of determining percent K response is less involved. The yield at each rate of K application (other than the control) was divided by the yield at the control rate (0 kg K/ha). These percent response values were then added together and divided by the number of values so determined. percent K response. This value conveys the average 33 The following equation describes the procedure. Assume an experiment in which 0, 22, and 48 kg/ha added K were the treatments used, then: where: = yield at 22 kg/ha K Y^g = yield at 48 kg/ha K Yg = yield of the control %K = average percent K response res These two methods of percent K response determination were assumed to provide similar values and were used as the same dependent variable (V42) in the subsequent multiple stepwise linear regression analysis. A third determination of percent K response utilized a method similar to the second. In this case, the greatest yield value for a given experiment (other than the control yield) was divided by the yield value of the control. K response." This value was termed "maximum percent This method was used over all of the experiments (222) and the results introduced into the analysis as a second dependent variable (V50). Appendix III presents site number, experiment number, average percent K response, maximum percent K response, and the K rate corresponding to maximum percent K response. 34 Statistical Methods The variables used in the analysis (Table 7) were inserted into an SPSS multiple stepwise linear regression program (Nie et a l ., 1975). This regression program was chosen because it contained an option which could manage cases with missing data for a given variable. Therefore, a case (experiment) with missing data for certain variables was not completely eliminated from the analysis; and the data base was pre­ served for those variables for which data were present. I Because of the large amount of missing spring soil moisture, soil temperature, and rainfall data, for example, the data base would have been reduced drastically had not this approach been taken. However, because this approach was chosen, care must be taken in interpreting the results with regard to variables for which only minimum data existed. The analysis of R 2 values and the interpretation of significant F-values should be based on the number of sites with complete data. Results including variables with missing values will tend to inflate the R 2 value for the equation; the degrees of freedom used in deter­ mining the significance of the F-value will also tend to be inflated. For example, if data are missing for a given variable at "n" number of sites, then the R of sites minus "n." 2 for that variable is based on the total number The overall regression equation R is based on the total number of sites analyzed. 2 value, however, More restrictive 35 Table 7. Variable Number I 2 3 4 5i/ 6T/ 7I/ 4/ 4/ 10ii 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41i/ 4243 44 45 46 47 48 49i/ SOi' 51 52 53 54 55 56 57 ~ y Variables used in Multiple Stepwise Linear Regression Analysis Variable Name Site Site-Experiment Separation Number Crop Year Card Number Yield I Yield 2 Yield 3 Yield 4 Yield 5 K-Trt. I K-Trt. 2 K-Trt. 3 K-Trt. 4 K-Trt. 5 Dry Consistence A Dry Consistence B Dry consistence Cca Bulk Density A Bulk Density B Bulk Density Cca Structure A Structure B Structure Cca Textural class Textural family Geographic Location Thickness of B Depth to Ca Elevation Slope Aspect Latltude Mean annual soil Temperature (MAST) Temperature Regime Temperature (April) Temperature (May) Temperature (June) Temperature (July) Rainfall Water Regime Average Z K response Total Spring Soil H O Spring Soil H 1O (O-M) Spring Soil H M (30-60) Spring Soil H M (60-90) Spring Soil H,0 (90-122) Spring Soil H1O (122-152) Spring Soil H M (152-183) Maximum Z K response K-rate for max. response Spring Soil H 1O (0-30) Spring Soil H M (0-60) Spring Soil H M (0-90) Spring Soil H M (0-122) Spring Soil H M (0-152 Spring Soil HjO (0-183) Units Card // a number (1-127) 1,2,3 a number (1-4) Coded Value-a number (68-80) a number (1-3) Kg/ha Kg/ha Kg/ha Kg/ha Kg/ha Kg/ha Kg/ha Kg/ha KgZha Kg/haKg/cm KgZ cm. KgZ gZ ClDj g/cm3 g/cm . Coded value^y Coded valuery Coded value%y Coded valuery Coded valuery Coded value-' 1,2. 1,2, 1.2, 1,2. I I I I I I I I I I I I I I I I I I I I I I I I 2 2 2 cm meters percent _y Coded value— ' degrees (°) and minutes (’) °C 2/ Coded value— ^ •c eC eC eC cm. 2/ Coded valuepercent cm. cm. cm. cm. cm. percent KgZha cm. cm. cm. cm. Format F 3.0 & i 6 & 3 3 3 3 F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F I .0 1.0 2.0 I .0 4.0 4.0 4.0 4.0 4.0 1.0 2.0 3.0 2.0 3.0 2.1 2.1 2.1 3.2 3.2 3.2 3.0 3.0 3.0 2.0 2.0 1.0 2.0 2.0 4.0 2.1 2.0 2 F 4.2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 3 3 3 3 3 3 3 3 F F F F F F F F F F F F F F F F F F F F F F F F 3.1 1.0 2.0 2.0 2.0 2.0 3.1 2.0 3.0 4.1 3.1 3.1 3.1 3.1 3.1 3.1 3.0 3.0 4.0 4.0 4.0 4.0 4.0 4.0 Cases with Missing Data 0 0 0 0 0 0 0 16 135 119 0 0 16 135 119 0 20 4 0 20 4 42 56 42 36 37 0 20 4 0 0 10 0 36 0 194 179 176 177 150 37 0 94 99 99 100 107 145 172 0 0 99 99 99 99 99 99 Used as a dependent variable in the regression analysis. Coded value; See Tables 1-7 for coding schemes used to Introduce the variables into the analysis. 36 options of analysis were used later in the investigation to try to remedy this situation and to insure statistical validity in the results. These are described in the Results and Discussion section. Due to the fact that over 60 separate regressions were conducted and because of the large number of independent variables, the number of variables allowed to enter the equation, the F-value, and tolerance level were set at 5, 1.0, and .10, respectively. This was done in order to restrict the length of the resulting regression equation and to give some assurance of the significance of the results. level of statistical significance was determined from standard F-tables (Steel and Torrie, 1960). The Chapter 4 RESULTS AND DISCUSSION Two preliminary investigations were performed prior to the multiple regression analyses which involved yield and percent response as the dependent variables. First, an analysis of variance (ANOV) was conducted, with bulk density as the dependent variable. The bulk density values were grouped both on site and horizons within a site. This analysis was done to determine if statistically signifi­ cant differences between plot locations existed for one of the variables (bulk density) that would be used later as an independent variable in the regression analyses. The ANOV produced an F-value of 9.15 when comparing one site to another. At I and 126 degrees of freedom, these results are significant at the .005 significance level. An F-value of .20 resulted when comparing horizon bulk densities at a given site. At ■■ I and 2 degrees of freedom, this was not statistically significant. These results establish that horizon differences at a site are not apparent, but that differences in bulk density between sites are pronounced. The second preliminary investigation was conducted to establish if ped thickness was an important, factor influencing the dry consistence measurements. This was done to establish whether or not corrections in the dry consistence values would have to be made for 38 horizons with either low or high mean values for ped thickness. A regression analysis was performed using consistence values as the dependent variable and ped thickness.as the independent variable. The F-value produced from this regression was 130.8, significant at the .005 level. However, the R equation was only .07. value resulting from the regression These results indicate that ped thickness does influence the consistence measurement but that it does not ■ account for a very large amount of the observed variability. If the pocket, penetrometer was to be used in the field to measure consistence, uniform ped thickness would be desirable. Because care was taken to ,select ped sizes of a comparable range of thicknesses for each horizon and because other factors obviously influence the consistence values, it was determined that correction of the dry consistence data because of ped thickness was not necessary. The discussion of results which follows in this chapter is organized by the order in which the regression analyses were run. In each regression analysis, data were organized differently to reveal independent variable relationships with different dependent variables. Divisions of the data file by crop, geographical location (see Figure 2), percent response class, and by K-rate at which maximum response occurred are. explained at the beginning of each discussion section dealing with a. specific group of regression equations. Each group of regression equations was organized and separated on the. basis .of how 39 the data file divisions were made. Each regression table presented in the following discussion sections was organized in a similar mariner. In the column located ori the extreme left of each table (refer to Table 8, pg 41), the regression number and the dependent variable and .the independent variables used in the analysis were given,. Also, when it applied, the part,of the data file included in the regression analysis was identified in this column. The coding schemes used for crop (Table 6, p g . 27) and geographical location (Figure 2, pg. 31) were used to identify the .part of the data file in which the regression equation applied. The division of the data into percent response classes and according to K-rate at which maximum response occurred (V51), when applicable, were also designated in the extreme left hand column of the. table. Also included in this column in some instances are the number of cases (experiments) to which the regression equation applies. A complete list of.the variables used in the analyses can be found in Table 7 (pg. 35). It will need to be referred to in interpreting the regression analysis results, presented in Table 8 through Table 17 and the summary tables (Table 18 through 20) . Because of the large number of variables used in this study, some: limitations were applied to each regression analysis. One of these limitations was to allow only a set number of variables to 40 enter each regression equation. ; In regression No. I through No. 14, ten variables were allowed to enter the equation. In regression No. 15 through No. 5.1, a maximum of five variables were allowed to enter the equation. It was felt that this limitation would still allow for identification of all important relationships. ■ ,Table No. 11, Regression No. 15 (pg. 60), can be used as an example of how the actual regression equation would be constructed from the table using step number, constant, and beta values. This equation would read: . Y - 78.82 - .186 + .145X2 + .164X +..i47X^ where: Y = maximum percent yield response (V50) X1 ,= value of V28 1 X \ ’ = value of V17 2 ' X^ = value of V30 X. = value of V19 4 Regressions.N o . I - No. 5: Yield as the Dependent Variable The following regression analyses were conducted using V06 . through VlO (actual crop yield at the various K rates) as the depend­ ent variables. In this group of analyses,. ten variables were allowed to enter each of the regression equations. The independent variables for each analysis were the same and included those variables which were listed in the table of the regression results (Table 8). The Table &. R e g r e s s i o n No. I - No. 5; A c t u a l Crop Y i e l d (V06-V10) as the Depend e n t Variable; D a t a fi l e n o t Subdivided; Independent Variables not R e s t r i c t e d . . Regression No..Dependent Var. VO6 . Independent Vars. V O l , ' V03, V04, V H , V16, to V41, V43 to V49: ■ .2 Dependent • Var. V07 Independent Vars. VOlj V03» V04, Vi2, Vl6 to V 4 l , V43 to V49 Step Variable into eq. Name I 2 3 4 5 6 7 8 . 9 10 Variable Number Constant V23 Strue. B .V34 ,'MAST V03 Crop ■ Vl 6 ' Dry Con. A 2450.19 V35 Temp.cls. Temp.(May) V3.7 V18 Dry Con. C ■ Bulk Den.C ■-V21- Rainfall V40 Soil H 2O (90-122) .V47 ' Struc. B V23 ■ I Vl 6 Dry Coru. A 2 V03 3 ' Crop . V34 MAST 4 . Vl 2 2306.73 K-trt. 2 5 6 . Thickness , V28 of B Soil H 2O '7., >44 (0-30) 8 . Temp.(May) V37 9 Temp. cls. - V35 10 Soil H 2O (152-183) V49 Beta Simple R R F-sig. level .161 ' .41 .005 .17 ' ,21 .353 • .39 ■ .005 -.217. -.27 .24 ' .005 .100 .16 ' .26 .005 -.01 ■ .28 -.248 . .005 -;288 ' -.04 . .30 .005 , ..13 ■ .235 .31 .005 -.160 .03 .33 . .005 .121 , .21 .34 .005 .133 .129 .201 -.172 • .288 -.181 ' ' .06 .35 .005 ..43 ■ .18 .22 .20 -.29 . .26 .39 .29 -.22 .30 .005 .005 .005 .005 .005 .095 .13 .32 . -005 .303 -.300 : -.167 .16 -.09 .04 .34.36 .37 .005 .005 .005 ■-.145 -.04 .38 .005 Table 8, Continued. R e g r e s s i o n Np. I - No. 5; A c t u a l Crop Y i e l d (V06-V10) as the Depend e n t V a r i a b l e ; D a t a Fi l e not Subdivided; I n d ependent Variables not Restricted. Regression No. V49 Dependent Var. V09 Independent Vars. VOl, V03, V04, V14, V16 to V41, V43 to V49 ■ I 2 3 ■4: 5 67 8 9 10 Bulk Den.A Struc. B ■ Crop Rainfall Dry Con.A Temp. (June) MAST ' Tex. cls. • Year Site I. • K-trt-4 2 ■ Bulk Den.A Water Reg. 3 Dry Con.A 4 Temp.(June) 5 Site 6 Geog. Ioc. "7 Struc.C 8 Dry Con.B 9 Year 10 Constant Vl 9 V23 . V03 ■ ■ V40 ' Vl6 ■ -1386.72 . V38 V34 V25 V04 VOl V14 .V19 V41 . V16 V38 VOl V27 V24 .. Vl 7. V04 Beta -.611 . -. 44 .30 .172 -.251 -.26 .22 .238 .210 -.10 .03 -.191 .29 .234 -.181 .13 .231 .14 - .165 ' . — .03 .844 -.251 .089 .103 4285.93 -.080 .150 ■ -.093. .062 .061 . -.074 2 R . Simple R .84 — .18 . .16 .01 -.32. .04 .. -.15 • .02 ■ -.01 .06 ■ .19; .30 .36 .40 .42. .44 .46 .47 .48 .49 F-sig. level .005 .005 ,005 .005 .005 .005 .005 .005 .005 . .005 .70 .005 .76 .005 .77 ■ .005 .78 ■ .005 .79 .005 .79 .005 .80 .005 .80 .005 ' .005 .81 .005 . .81 42 3 Dependent Var. VO8 Independent Vars. VOl, V03, V04, V13, Vl6 to V41, V43 to Step . Variable . Variable into eq. Name Number Table 8, Continued. R e g r e s s i o n No I. - No. 5; A c t u a l Crop Y i e l d (V06-V10) as the Depend e n t Variable; D a t a Fi l e no t Subdivided; Independent Var i a b l e not Restricted. Regression No. 5 Dependent Var. VlO .Independent Vars. VOl, V03, V04, V15, Vl6 to V41, V43 to V49 Step Variable into eq. Name I 2 3 4 5 ■6 7 8 9 10 Variable Number K-t'rt.5 Bulk Den. A Water Reg, Aspect . Rainfall ■ Temp.(May) Dry Con.A. Soil H 9O(152-183) Soil H O (90-122) Soil H O (0-30) Constant Beta R^ F^sig. level .664 — .468 .180 -,.080 •.135 -.278 '.124 .69 -,42 •.29' .01 .03. -.05 . -.09 -.184 .07 V47 .267 .19 .76 .005 V44 -.111 -.10 .76 . .005 V15 V19 V41 V32 V40 V37 Vl 6 V49 . ' Simple R 3932.32 '' . •48 .68 .70 . .' .72 .73 .73 .74 .005 .005 .005 .005 .005 .005 .005 .005 44 analyses were conducted over the entire data set so that the results were based on 222 cases, the total number of experiments included in this study. Regression No'. 4 and No. 5 (actual crop yield as the dependent variable) produced the highest R 2 values, .81 and .76, respectively. The F-signif.icance level of the results was .005 at each step in all five of the regression equations. and probably misleading. Methods section that R 2 This was somewhat surprising It was pointed out in the Materials and values and F-signif icanc.e levels tend to. be inflated by including variables with missing data into the regression analysis. The variables for which this was particularly true were those associated with the seasonal temperature data (V36, V 37, V28, V39), rainfall data (V40), and spring soil moisture data (V43 through V49). Although other variables which appeared in the regression equations also had missing data, the severity was not. as pronounced (See Table 7 for the number of missing cases for each variable. Simple correlations (Simple R ) , however, for each of the variables in the equation indicated valid relationships to the dependent variable. It is important to note the strong positive correlation between structure of the B horizon (V23) and yield in regression No. I, No. 2, and No. 3. This indicated.that higher yields were associated with the more strongly structured soils. Thickness of the B horizon (V28) was also positively correlated with yield in regression No. 2. 45 Mean annual soil temperature (MAST) was positively correlated to yield in regression No. I, No. 2, and No. 3. This suggested that lower soil temperatures associated with some soils may have been yield-limiting. Yield (V09 and V10) in regression No. 4 and No. 5 showed a strong positive correlation to the rate of applied K (V14 and V15, respectively). This indicates that availability of native soil K and/ or low rates of applied K are not adequate in many cases. Dry consistence of the Ap horizon (V16) was the only variable to appear in all five of the regression equations. Its correlation (Simple R) to yield ranged from slightly positive to slightly negative. However, bulk density of the Ap horizon (V19) showed a consistently strong negative correlation to yield in regression No. 3, No. 4, and No. 5. The literature generally supported this observation in that increased bulk densities were associated with decreased root penetration and nutrient uptake. In the surface horizon (Ap) high bulk densities may also have been associated with increased difficulty of seedling emergence. Rainfall (V40) was positively associated with yield in regression No. I 1 No. 3, and No. 5; yet moisture regime (V41), which was coded wet to dry, was also positively correlated to yield in regression No. 4 and No. 5. This latter relationship of moisture regime to yield seems to be in agreement with the positive association between 46 MAST and yield. In regression No. 51, MAST and moisture regime were highly positively correlated to one another. The warmer soils (> MAST) would be expected to be associated with the drier moisture regimes in that soil moisture would have exerted a profound buffering influence on soil temperature. Temperature in May (V37) in regression No. I, Nb. 3, and No. 5 as well as temperature in June (V38) in regression No. 4 showed a strong negative correlation with yield. This at first seemed to. have contradicted the relationship between MAST and yield. However, the value of the MAST whs determined from long-term temperatue data and so was an average. That low early growing season temperatures are correlated with greater yields could be explained by the fact that low soil temperatures have been associated with greater stored soil moisture. Crop differences existed with regard to yield. This was shown by the fact that crop (V03) was an important variable in regresison No. I, No. 2, and No. 3. Varietal and crop differences with regard to nutrient uptake may, be due to differences in root membrane activity; the selectivity for certain ion absorption may be an inherited trait (Mattson, 1974). Lal and Sharma (1974) found that two varieties of dwarf wheat differed significantly in their ability to extract .N, P, and K. , Their experimental results were consistent 47 over three levels' of soil moisture and five rates of applied N- Regressions No. 6 - No. 10: Average Percent Yield Response (V42) as the Dependent Variable.* 2 The regression analyses were performed separately for each crop (regression No. 6 for winter wheat, Nb. 7 for spring wheat, No. 8 for barley and No. 10 for winter wheat) and combined over all crops (regression No. 9). The data subfile for oats was not analyzed ■ separately throughout the regression analysis because there were only four experiments with oats as the experimental crop. Regression No. 6 and No. 10 differ only in that VOl and V04 (site and year) were removed as independent variables in regression No. 10. The removal of VOl and V04 from regression No. 10 and subsequent regression analyses was done because it was decided that no explicit meaningful information could be derived from their inclusion in the regression equation. Crop (V03) was also removed as an independent variable from these and subsequent regression analyses as the data were divided and analyzed according to crop. The highest R 2 values were obtained for spring, wheat and barley 2 (regression No. 7 and No; 8). respectively. The R values were .57 and .45, However, the highest .F-significance level (.005) was attained for winter wheat (regression No. 6 and No. 10) and in Regression No. Regressions No. 6 — No. 10; A v e r a g e P e r c e n t R e s p o n s e (V42) as the Dependent Variable; D a t a Fi l e Subdivided on C r o p ; Independent Va r i a b l e s not Restricted, Step into eq. 6 Dependent I Var. V42 2 Independent 3 Vars. VOl, 4 V04, Vll to 5 V41, V43 to 6 V49 7 Subfiles: 8 Divided on 9 crop; winter 10 wheat (133 cases) 7 Dependent I V a r . V42 2 Independent Vars. VOl, 3 V04, Vll to 4 V41, V43 to 5 V49 6 Subfiles: Divided on 7 crop; spring 8 wheat (36 9 cases) 10. Variable Name Latitude Rainfall Dry Con.B Bulk Den.B Site Struc.A Struc.B Slope Temp.(May) K-trt.2 Variable Number V27 V40 Vl 7 V20 VOl V22 V23 V31 V37 Vl 2 Constant 93.03 Beta Simple R R2 .241 .210 .313 -.244 -.285 .285 -.196 -.099 -.207 .264 .26 .20 .14 .04 -.01 .13 .06 -.04 .01 .09 .07 .08 .10 .11 .13 .14 .15 .16 .17 .19 F-sig. level . .005 .005 .005 .005 .005 .005 .005 .005 .005 .005 oo Latitude Soil H O (30-60) Dry Con.A Slope . Bulk Den.C Thickness of B Rainfall K-trt.4 Bulk Den.A Soil H O (90-122) -.23 .05 -1.461 -.566 .713 -. 380 -.15 -.16 .06 . -.14 .09 .14 .20 .25 V28 V40 Vl 4 Vl 9 .458 -1.058 .916 .627 .10 -.17 .04 -.10 .31 .33 .39 .48 .10 .10 .10 .025 V47 .885 i O kO Table 9. .57 .01 V33 -.163 V45 V16 V31 V21 284.78 — — ---- — — — — ■ Table 9, Continued. Regressions No. 6 - No. 10; Average Percent Response (V42) Dependent Variable; Data File Subdivided on Crop; Independent Variable Restricted 2 R Simple Regression Step Variable• Variable Constant Beta Name No. Number R into eq. 8 Dependent I V a r . V42 2 •Independent 3 Vars. V01, 4 V04, Vll to .5 V41, V43 to 6 V49 7 Subfiles: 8 Divided on 9 crop; barley (49 cases) 10 9 Dependent I Var. V42 2 Independent 3 Vars. VOl, 4 V04, Vll to V41, V43 to . 5 V49 Subfiles: 6 Divided on 7 crop: over­ 8 all (222 cases) 9 10 . as the not F-sig. level .540 .380 .486 .151 .238 -.347 .235 -.173 .29 .26 .13 .05 .10 -.17 -.19 .07 .08 .15 .25 .29 .31 .34 .38 .39 V48 -.547 -.10 .41 .01 V49 .471 .10 .45 .01 V15 Vl 3 Vl 7 .371 .254 .241 .13 .11 .11 .02 .06 .08 .10 .005 .005 V44 .376 .08 .09 .005 -.486 -.165 -.157 -.04 -.03 .08 .12 .14 .14 .005 .005 .005 V46 .632 .02 .15 .005 V45 V39 — .483 .091 .002 .04 . .16 .17 .005 .005 K-trt.3 K-trt.5 Temp.(July) Dry Con.B Elevation Year Site Aspect Soil H O (122-152) Soil H O (152-183) V13 V15 V39 V17 V30 V04 VOl V32 K-trt.5 K-trt.3 Dry Con.B Soil H O (0-30) Soil H„0 . (90-122) Year Bulk Den.B Soil H 9O (60-90) Soil H O (30-60) Temp.(July) V47 V04 V20 221.47 141.19 .05 .025 .005 .005 . .01 .01 .005 .01 Table 9, Continued. Regressions No. 6 - No. 10; A v e r a g e Percent Response (V42) as the Dependent Variable; Date Fi l e S ubdivided on Crop; Independent V a r i a b l e n o t Restricted. Step into Variable Name Variable ' Number Constant . Beta ' 2 Simple R R .162 .356 -.167 -.121 '.19 .19 .08 -.07 .04 .06 .08 .09 .05 ■ .025 .01 .025 .079 -.997 .738 .15 .02 .09 .10 .11 .15 .025 .025 ■ .005 O CM CO Regression No;. ,F-sig. level -.06 ■ .16 - .005 .335 .192 -.008 ; ■ .14 .18 .19 .005 .005 10 10 Geog. Ioc. Dry Con.B Bulk Den.B Depth to Ca Soil H-O (0-30) Temp.(May) Temp.(June) Soil. H 9O ' (152-183) Soil H 9O ■ (122-152) K-trt.2 . V27 Vl 7 V20 V29 V44 V37 V38 . 92.99 V49 I Dependent I V a r . V42 2 Independent 3 Vars. Vll to .4 V41, V43 to 5 V49. Subfiles: 6 Divided on 7 winter wheat. 8 . (133 cases) 9 - V48 Vl 2 51 the case of the overall regression analysis (regression No. 9). Again, it is stressed that when variables with missing data are included in the analysis the R 2 and F values are probably inflated. Spring soil moisture (V43 to V49), rainfall (V40), and temperature (V36 to V39) variables appeared in all the regression equations. The presence of these variables in the regression equations meant they were subject to misinterpretations. It was somewhat contradictory that rainfall (V40) was positively correlated to percent yield response in regression No. 6 and nega­ tively correlated in regression No. 7. This difference could possibly be explained by assuming that the addition of water to the soil may have produced variable influences op crop response to added K under different soil conditions. If the soil was dry so that no K diffusion could take place, then rainfall should have had a positive influence on crop response. Under adequate soil moisture conditions in which diffusion of native K to the plant root is sufficient, the general cooler climatic conditions (cloud.cover, etc.) associated with rainfall may possibly have acted to depress crop response to added K. Distribution of rainfall and soil perme­ ability may also have been important factors in the explanation of these results. Both dry consistence of the B horizon (V17) and bulk density of the B horizon (V20) were positively correlated to percent 52 response in all cases in which they appeared in the regression, equations. High bulk densities are usually associated with less plant available water.. This is due to the increased raatric potential. If high bulk densities were restricting diffusion of native K, one would have expected the observed positive correlation between bulk density, and crop response to added K. increases as clay content increases. zone of clay accumulation; Dry consistence probably The B horizon is the major ■ The higher CEC values associated with increasing clay content (especially considering that 2:1 clays are dominant in Montana soils) may also be associated with restricting diffusion of native K. These results were in accord with observations presented in the Literature Review section. In the one'case in which thickness p f ■the B horizon.(V28) was . included in the regression equation (regression Ho. 7), it was also positively correlated to crop response. Structure of the B horizon (V23) was also positively correlated to winter wheat response ■(regression No. 6). This relationship between strongly structured soils and positive crop response to added K may be due to the fact that strongly structured soils are.usually associated with soils that have an abundance of clay and experience a definite dry period during any given year. Both of these factors would tend to cause slower or more tortuous diffusion of K in the soil. The K-rate variables (Vl2, V13, V15) were positively correlated 53 to crop response, in regression No. 6 through No. 10. This again suggested that, in many cases, the availability of native K was not adequate. Although subsoil moisture was somewhat variable in its correla tion to crop response, spring soil moisture in the surface 30 cm. (V44) was positively correlated with crop response (regression No. 9 and No. 10). This indicated that adequate' surface soil, moisture may have been a prerequisite in order for added. K to have had a positive effect. The strong negative correlation of latitude (V33) to crop response is of interest in regression No. 7. Soils in the higher latitudes generally warm up more slowly in the spring; The potassium requirement of small grains is high early in the growing season. If temperature was the limiting factor, a positive correlation between latitude and crop response would be expected. . However, other factors may have influenced the effect of latitude. Perhaps low temperature was still the limiting factor in that the effects of applied K were not realized, in the colder soils. Also, higher rates of K application may have been required in colder soils to provide a crop yield increase. Regressions No. 11 No. 14; Maximum Percent Yield Response (V50) as the Dependent Variable. These regression analyses were conducted separately for each Table 10. Regressions No. 11 - No. 14; Maximum Percent Response (V50) as the Dependent Variable; Data File Subdivided on Crop; Independent Variable VOl-VlS Not Included. Regression No. Step into eq. Rainfall Elevation K-rate for max. res. Struc. B Soil H O (90-122) Thickness of B . Dry Con.B Bulk Den.B Temp.(May) Temp.(June) Variable Number Constant Beta Simple. R . R2 F-sig. level V40 V 30 .182 .093 .20 .16 .04 .06 .025 .025 V5I •V23 .189 -.155 .14 -.10 .08 .10 .025 .01 -.158 -.04 .12 .005 V28 Vl 7 V20 V37 V38 -.116 .221 -.168 -.802 .789 -.17 .08 -.02 .03 .10 .14 .15 .15 .16 .19 .005 . .01 .01 .01 .005 V38 V31 V 30 V41 V25 V16 V19 -1.803 -.011 -.245 1.508 -1.436 .837 -.805 -.29 .26 . -.20 .15 -.08 .03 -.15 .08 . .21 .28 .31 .39 .46 .55 .005 .005 V51 V39 .306 1.671 .20 -.28 .61 .64 .005 .005 V45 -.176 O i—i I 11 I Dependent „ 2 Var. V50 3 Independent Vars. V16 4 ■ to V41, V43 5 . to V49, V51 Subfiles: 6 Divided on crop; winter 7 wheat 8 (133 cases) 9 10 Variable Name .66 .005 V47 101.48 12 Dependent I V a r . V50 2 Independent 3 Vars. V16 4 to V41, V43 5 to V49, V51 6 Subfiles: 7 Divided on 8 crop: spring wheat . 9 (36 cases) 10 Temp.(June) Slope Elevation Water Reg. Tex.cls. Dry Con.A Bulk Den.A K-rate for max. res. Temp.(July) Soil H 9O (30-60) 184.17 .10 .025 .025 .025 .01 2 Table 10, Continued. Regressions No. 11 - No. 14; Maximum Percent Response (V50) as the Dependent Variable; Data File Subdivided on Crop; Independent Variable V01-V15 Not Included. n Regression No. Step into eq. 13 Dependent Var. V50 Independent Vars. Vll to V41, V43 to V49, V51 Subfiles: Divided on crop: barley (49 cases) I 2 3 4 5 6 7 8 9 10 14 Dependent Var. V50 Independent Vars Vl6 to V41, V43 to V49, V51 Subfiles: Divided on crop: overall (222 cases) I 2 3 4 5 6 7 8 9 10 . Variable Name ' Variable Number K-trt.5 K-trt.3 ' Elevation K-trt.2 K-rate for max. res. ■ Temp.(June) Geog. Ioc. Latitude Soil H„0 (122-152) Soil H O (152-183) Constant R F-sig. level .40 .31 . .19 -.04 .16 .26 .32 .41 .005 .005 .005 .005 .207 .242 .220 .219 .33 .01 -.19 .13 .45 .49 .49 .50 .005 .005 .005 .005 V48 -.373 .04 .51 .005 V49 .355 .25 .53 . .005 .251 -.154 .295 .130 .21 ■ -.12 .11 .07 .04 .06 .08 .09 .005 .005 .005 .005 -.196 WV04 .10 .005 . .116 .104 .233 .151 .03 .03 — .01 -.03 .11 .11 .12 .12 .005 .005 .005 .005 -.051 — .08 .13 .005 V15 Vl 3 V30 V12 V51 V38 •V27 . V33 K-rate for max. res. . V51 Struc. B V23 V 30 Elevation V40 Rainfall Soil H 9O (90-122) V47 Soil H 9O V49 (152-183) V18 Dry Con.C V33 Latitude Geog. Loc. V27 Thickness V28 of B . Beta .491 .389 . .460 .326 -155.51 -50.16 Simple R • 56 crop as in t.he previous section (regression Mo. .11 for winter wheat,.. Mo. 12 for. spring wheat,, and. N o . 13 for barley). Regression No. 14-. was the combined overall regression and corresponded to regression No. 9 in the previous group of regressions. The inclusion of V51 (the K'-rate at which maximum response occurred) into these regression analyses was done because the dependent variable (V50) was the one with which it was associated. The other Krrate variables were excluded from these regressions except for in regression No. 13, Regression No. 12 (spring wheat) and No, 13 (barley) produced 2 the highest R values, . 66 and ‘ .53, respectively. were higher than the corresponding regression. R group (regression No. 7 and No. 8). values in the prior The F-significance levels of these regressions were also higher overall being significant at the .005 level. 2 These values each regression equation Care must be taken in inter- preting the significance of these results as the R 2 and F-values were probably inflated due to. the inclusion of variables with missing data into the analysis. However, results indicated a good potential for utilizing certain of these independent variables to predict crop , response to K fertilizer. The K-rate variables (V51, V13, V15) again showed a pronounced positive correlation to the dependent variable. Variable 51 (K rate. at which maximum response occurred) was postively correlated in all four regressions. Variable 15 and V13 (high and moderate rates of • . . 57 . K application) in regression No. 13 had Sinple-R values of .40 and .31, respectively, with the dependent variable (V50). Rainfall was positively correlated to maximum percent response in both cases in which it appeared in the regression equation (regression No. 11 arid No. 14). Elevation (V30) was also positively correlated to percent response.in three of the four regression equations. Elevation may have been an important factor with regard to crop response to added K in the way that it may have modified the climatic environment. Elevation may have influenced soil moisture and soil temperature in that wind, rain, and storm patterns may have been affected. Average temperature in May (V37.) and Jurie (V38) were only slightly positively correlated to percent response in regression No. 11 and No. 13. There was a much stronger negative correlation between V38 and average temperature in July (V39) in regression No. 12.. Soil temperature probably.influenced crop response to added K differently depending on other existing soil conditions. correlation would be expected to exist, A positive between soil temperature and crop response under conditions of adequate soil moisture. Iricreasing soil temperature in this case would have probably increased ion diffusion of applied K. On the other hand, a negative correlafion would have existed between soil temperature and crop response 58 (particularly later in the growing season); if soil moisture was inadequate. In this case, greater soil temperatures could have been associated with drying of the soil profile so that diffusion was reduced. Another aspect of soil temperature is that diffusion oj:." ; K would normally increase with increasing temperature, allowing native soil K to be more available, thus decreasing the response to . ... ' ■ ■■ ■ . supplemental K. 'I, .I fIt' Spring soil moisture (V45, V47, V48, V49) was not consistently ■ correlated to crop response. The greatest correlation, which was .25 between deep soil moisture (V49) and maximum percent response, appeared in regression No. 13. Although snring soil moisture variables appeared in all of the regression equations, they generally . 2 entered toward the end of the equation, and increased the R values very little. Structure of the B horizon (V23) was negatively correlated to crop response in regression No. 11 and No. 14. results from previous regression groups. This.contradicted It was. difficult to explain.the effect of soil structure on crop responses, especially considering the way in which the soil structure variables were derived and coded. First, it was impossible to know if grade, size, or type of structure was the dominant influence on crop response. Second, because the structure variables were derived from the SCS soil series description, it was possible that the coding scheme was 59 misleading for these particular soil sites. Horizon depths and designations in the soil series description usually did not correspond to the method of horizon naming and sampling that was done in the.field during this study. Also, the soil series description usually described horizon soil structures in terms of a. range of structures (e.g. moderate medium angular blocky to strong medium prismatic). It was doubtful that a meaningful interpretation could be derived from the structure variables as they were used in. these analyses. For these reasons, structure as an independent variable was removed from subsequent analyses. Adams and Wilde (1976) added some insight into this problem. -■ . ' : They studied the variability in 16 morphological soil properties in a soil mapping unit mapped as one soil series. Maximum variability was observed in structure grade and size and wet consistence. Data showing the variability within soil mapping units should be included in all soil surveys to give users a better understanding of the limits of their ability to generalize. This may be very important when making fertilizer recommendations for areas where limited sampling has led to generalized soil mapping. Regressions Mo. 15 r No. 19; V50 or V42 as the Dependent Variable.. Regression No. 15 through No. 19 were different from the previous regressions in that the three structure variables, the average Table 11 Regression No; Regression No. 15 - No. 19; Maximum (V50) and Average (V42) Percent Response as the Dependent Variables; Data File Subdivided on Crop; VOl - V15 and Soil Temperature , Rainfall , and Soil Moisture Variables Not Included as Independent Variables. Step into eq. 15 Dependent I V a r . V50 Subfiles: 2 .Divided on 3 crop: Winter 4 Wheat (133) • Independent Var.V16 to V21, V25, V26, V28 to V35, V41 16 Dependent I . 2 Var. V42 Subfiles: 3 Divided on crop: Winter wheat (133) Independent Vars. Vl6 to V21, V25, V26, V28 to V35, V41 Variable Name Thickness of B Dry Con.B Elevation Bulk Den.A Variable Number V28 . Vl 7 V30 , V19 Constant . 73.82 Beta -.186 .145 .164 .147 Simple R -.17 .08 .16 .12 R2 F-sig. level .03 ..05 .07 .09 .05 .05. .05 .025 § Dry Con.B Bulk Den.B Latitude V17 V20 V33 153.89 .436 -,312 -.122 .19 .08 -.15 .03 .06 . .07 .05 .025 .025 Table 11, Continued. R e g r e s s i o n No. 15- No. 19; M a x i m u m (V50) and A v e r a g e (V52) Percent Response as the D e p e n d e n t Variables; D a t a F i l e S ubdivided on Crop; V Ol - V15 and Soil Temperature, Rainfall, and Soil M o i s t u r e V a r i ables Not Included as Independent Variables. Regression No. Step into eq. .17. Dependent I 2 Var V50 Subfiles: 3. Divided on 4 crop; Spring 5 wheat (36) Independnet. Vars. V16 to V21, V25, V26, V28 to V 3 5 , V41 18 . Dependent I V a r . 42 Subfiles: 2 Divided, on 3 crop: Spring 4 Wheat (36) Independent . Vars: V16 to V21, V25, V26, V28 to V35, . V41 . Variable Name • ■ Slope Elevation ■ Water Reg. Tex. cls. . Dry Con.A Variable Number V31 V30 V41 V25-' V16 ■ •' Constant 94.62 Beta . .276 -.003 1.256 -1.086 .330 Simple R .26 r-.20 .15 -.08 .03 R 2 .07 ..12 , .19 .28 .36 • ' F-sig. level . . --- : — .10 .05 .025 2- ’ Thickness of B Aspect Water Reg. Slope V28 V32 ' V41 V3l 99.46 i485 -.511 .293 .219 .32 -.31 .12 .03 .10 .26 .32 . .36 .10 .01 .01 .01 Table 11, Continued. R e g r e s s i o n No. 15- No. 19; M a x i m u m (V50) and A v e r a g e ( V 4 2 ) .Percent Response as the D e p e n d e n t Variables; Da t a File Subdivided on Crop; VOl - V l 5 and Soil Temperature, Rainfall, and Soil M o i s t u r e Va r i a b l e s Not Included as. - Independent Variables. Regression No. Step into eq. 19 Dependent I Va r . V42 '2 Subfiles:. Divided on crop; overall (22%) Independent Vars: V16 to V21, V25, V26, V28 to V35; V41 Variable Name • Dry Con.B Latitude ' Variable .Number V17 V33 - Constant 145.09 Beta .100 ' -.094 Simple R .11 . -.11 R2 F-sig. level .01 .02 .10 .10 o> NS 63 monthly temperature data, the spring soil moisture data, and the rainfall data were excluded from the analyses.. This was done to try to increase the statistical validity of the subsequent regression equations, due to extensive missing data in each of these parameters. Regression No. 15 and No. 16 differ only in that the dependent variable was V50 (maximum percent K response) in the first case and V42 (average percent K response) in the second, case for winter wheat. The R 2 and F-significance level indicated very little difference in using V50 or V42. as the dependent variables. Only ■four variables in the first case and three in the second were, signifi­ cantly (P = .10) related to crop yield responses. Dry consistence . of the B horizon (VI7), however, was the only variable common to both equations. Of. the seven variables included in both equations; four of them are related to B horizon characteristics. In both equations and in regression No. 19 as well, bulk density and dry consistence were positively correlated to percent yield response. Increased, bulk density probably resulted in a reduction of plant available water, reduced root proliferation, and restriction of native K diffusion. Higher values of dry consistence can be associated with decreased root penetration and utilization of native K, so that a positive resnonse to added K resulted. A higher R 2value■'(.36) . ■vwas ■ . " ■ .. obtained from the spring wheat sites (regression No. 17 and No. 18). But, in regression No. 18 64 the F-value was more highly significant (.01) than that for regression No. 17 (.025) with V50 ,as the dependent variable. Thickness of the B horizon (V28) was positively correlated to crop response in regression No. 18 and negatively correlated in regression No. 15. Again, the effect of the thickness of the B horizon.on crop, response to added K may have been determined by other factors which modified its effect (e.g. clay content,. stored soil moisture). - , Water regime was positively correlated to crop response in both cases in which it appeared in the regression equation. This suggests that the soil types which are normally associated with the. drier sites tend to show a greater crop response to added K. ' Elevation was positively correlated to crop response in regression No. 15 and negatively correlated in regression No. 17. This indicated that elevation, by itself, was not a good parameter . for predicting crop response. ' . : Its effect on crop response was probably realized by the way in which it interrelated with other-, factors. The negative correlation of latitude to crop response in regression No. 16 and No. 19 suggests that temperature in the more northern latitudes may be limiting crop response to added K. Slope w a s .positively correlated to crop response in regression No. 17 and No. 18. Areas with greater slopes are usually associated with drier. 65 sites in that groundwater tends to move downslope^ If the site aspect was oriented to the south, this drying effect associated with greater.slope would be maximized. Regressions No. 20 - Mo,. 31: V50 or V42 as the Dependent Variable.,. Geographic location (V27) appeared as a variable in several of the previously discussed regression groups. It was not clear, however, because of the coding scheme employed, exactly for w h a t . reason this variable was important to crop responsei In order to try to determine this ’’reason", the data for the present set of regressions was divided and analyzed both in terms of crop type (V03) and geographic location (V27). ... The regression equations for this analysis were grouped in pairs so that each pair concerned the same data set (identified in the regression tables). The only difference was that in the ' first case of a given pair the dependent variable was maximum percent response (V50), and in the second case it was average percent response (V42). Regression No. 30 and No. 31 yielded the highest R .86.and L72, respectively. 2 values, For regression No. 30 (maximum percent response as the. dependent variable) the F-statistic was more highly significant at the .01 level.. Both.equations concerned barley experiments in the southeastern part of Montana. Generally, these soils tend to. be warmer during the growing season, and this is' the Table 12. Regression No. Regression No. 20 - No. 31; Maximum (V50) and Average (V42) Percent Response as the Dependent Variables; Data File Subdivided on Crop and Geographic Location; Independent Variables Restricted as in Table 11. Step Variable into e q . . Name 20 Dependent I . Var. V50 2 Subfiles: 3 Divided on: 4 Crop -I Geog. loc.-l (44) Independent Vars: - same as Regression #15 Variable Number Bulk Den.C Aspect Dry Con.A Depth to Ca V21 V32 V16 V29 Bulk Den.C Dry Con.A Aspect Depth to Ca Dry Con.B V21 V16 V32 V29 Vl 7 Constant 168.73 Beta Simple R . R2 - F-sig. level -.319 -.267 -.274 -.251 -.37 -.17 -.01 -.33 .14 .18 .21 .25 .025 .025 .025 .025 -.317 -.431 -.185 -.287 .221 -.35 -.14 -.09 -.26 .12 .12 .17 .22 .25 .29 - .025 .025 .025 .05 .025 21 Dependent. I V a r . V42 .2 Subfiles: 3 Divided on: 4 ^ Crop - I 5 Geog. loc.-l (44) Independent Vars: - same as Regression #15 159.27 Table 12, Continued. R e g r e s s i o n No. 20 - No. 31; M a x i m u m (V50) and. Average (V42) Percent R e s p o n s e as the Dependent Variables; Da t a File Subdivided on Crop a n d . G eographic Location; Indep e n d e n t Va r i a b l e s R e s t r i c t e d as in Table 11. Regression No. ' Step into eq. 22 Dependent I Var. V50 2 Subfiles: 3 Divided on: ■4 Crop-2 •5 Geog.loe.-l (25) Independent Vars: same as Regression #15 23 Dependent I Var. V42 2 Subfiles: 3 4 Divided on: Crop —2 5 Geog.loc.-l (25) Independent Vars.: same as Regression #15 ■ Variable Name Latitude Dry Con.C Bulk Den.A Aspect Water Reg. . Variable Number V33 . Vl 8 V19 V32 V41 Constant -306.00 Beta .434 -.764 -.899 -.657 -.431 Simple R. .33 . -.32 -.30 -.27 ..13 R 2 . .11 .27 .44 .73 .79 F-sig. level . --.05 .01 .005 .005 O' Aspect .Bulk Den.A Dry Con.C Depth to Ca Slope V32. . Vl 9 Vl 8 V29 V31 121.34 -.829 . — .40 -.01 -.037 -.31 . -.749 .781 .07 .347 : -.02 .16 .28 .39 . .54 .60 .05 .025 .025 .005 .005 Table 12, Continued. Re g r e s s i o n No. 20 - No. 31; M a x i m u m (V50) an d Average (V42) . Percent Response as the D e p endent Variables; D a t a File Subdivided on Crop and Geographic Location; Independent Va r i a b l e s R e s t r i c t e d as in Table 11. Regression Step No. into e q . 24 Dependent I V a r . V50 2 ■ Subfiles: 3. Divided on: Crop - 1,2,3 . Geog. loc.-3 (26) . Independent Vars.: same as Regression #15 25 Dependent -I Var. V42 .2 Subfiles: 3 Divided on: ■ 4 crop - 1,2,3 Geog. Ioc. - 3 (26) Independent Vars: same as Regression #15 Variable Name Bulk Den.C Latitude Aspect Variable Number V21 V33 V32 Constant 978.91 Beta . . . Simple R .655 -.434 .231 .32 -.07 .OS R ■ 2 .10 .21 .26 F-sig. level — .10 .10 CTi 00 MAST Tex.F a m , Bulk Den.A Slope V34 V26 V19 V31 -39.99 .745 .474 .231 .331 .30. .13 .11 . .07 .08 .25 . .30 .33 .05 .05 .10 \ Table 12, Continued. Regression No. 20 - No. .31; Maximum (V50) and Average (V42) ercent Response as the. Dependent Variables; Data File Subdivided on Crop and Geographic Location; Independent Variables Restricted as in Table 11. Regression Step No. . into eq. 26 Dependent I ■ Va r . V50 2 Subfiles: 3 Divided on: Crop - 1,3 Geog. Ioc. -4 (77) Independent Vars: same as Regression #15 2.7 Dependent I Vars. V42 2 Subfiles: 3 . Divided on: 4 Crop - 1,3 Geog. loc.-4 (77) . . Independent Vars: same as Regression #15 Variable Name Elevation ■ Tex. cls„ Dry Con.B Variable Number V30. V25 Vl 7 Constant 93.93 Beta Simple R R^ ' .385 -.265 .154 .23 -.002 .03 .05 " .07 .09 F-sig. level . .05 .10 .10 o Elevation Tex. cls. Dry Con.B Latitude V30 V25 Vl 7 . V33. ■ -71.15 .448 -.355 .358 .151 .15 -.05 .14 — .06 .02 .05 .11 .13 •------------ — — .05 .05 Table 12, Continued. Re g r e s s i o n No. 20 - No. 31; M a x i m u m (V50) and Average (V42). Percent Response as the De p e n d e n t V a r i a b l e s ; Date File Subdivided on Crop and Geographic Location; I n d ependent Va r i a b l e s R e s t r i c t e d as in Table 11. Regression Step Nb. into e q . Variable Name. Variable . Number Constant Elevation Tex. els. Dry Con.B .V30 ■725 Vl 7 ■ 92.79 .421 -.307 .208 Elevation Dry Con.B Tex. cls, V30 . Vl 7 V25 89.54 .396 .336 . -.374 Beta Simple R R^ F-sig. level .24 . -.01 . .05 .06 .08 .11 .10 .10 .10 .17 .15 -.04 .03 .06 .13 .05 28 Dependent I Vars. V50 2 Subfiles: 3 Divided on: Crop - I Geog.loc.-4 (64) Independent. Vars: same as Regression #15 29 Dependent I Var. V42 2 Subfiles: 3 . Divided on: Crop - I Geog. Ioc. - 4 . (64) Independent Vars: same as Regression #15 /- a e Continued. Reg r e s s i o n No. 20 - N o . .31; M a x i m u m (V50) and A v e r a g e (V42) Percent Response as the Dependent Variables; Data File Subdivided on Crop and Geographic Location; I n d ependent V a r i a b l e s Restr i c t e d as in Table 11. O Regression Step Variable No.. into eq. . Name 30 Dependent I . Va r . V50 2 Subfiles: 3 Divided on: 4 Crop - 3 5 ■ Geog. loc.-4 (13) Independent Vars: same as Regression #15 31 Dependent I V a r . V42 2 Subfiles: 3 Divided o n : 4 Crop - 3 5 Geog. Ioc. -4 (13) Independent Vars: same as Regression #15 ' .Variable Number Latitude Aspect Depth to Ca ' Tex. cls. . Bulk Den.B V33 V32 V29 V25 V20 Depth to Ga Temp. Reg. Latitude ' Dry Con.B Water Reg. V29 V35 V33 Vl 7 V41 Constant . Beta Simple R R -403.72 .603 -.392 .555 .392 -.258 .63 -.52 .40 .06 -.11 .39 .64 .73 .80 .86 98.30 .181 -.954 -.014 .500 .845 .47 -.43 ,37 .41 .03 .22 .40 .57 .63 .72 F-sig. level .025 .01 .01 .01 .01 — .10 .05 •10 •10 72 only part of Montana that has soil, types with a mesic temperature regime. Depth to the ca (V29) was positively correlated to crop response in these equations. This indicated that as the horizon of calcium accumulation approached the surface, there was a decreased response to applied K. Perhaps the greater calcium concentration associated with a ca horizon was interfering in some way with K uptake. The literature supports this as a.possibility. Elevation (V30) was a very important variable in this group of regression equations. It was positively correlated to crop response in regression No. 26 through No.. 29, which deal with winter wheat and barley and winter.wheat alone in geographic location 4. Because elevation did not enter regression No. 30 and No. 31 (barley alone), this effect can be attributed to the winter wheat sites. The possible effects of elevation have already been discussed. Textural class (V25) entered the regression equations five times (regression No. 26 through No. 30). No.consistent correlation to crop response appeared to exist. Dry consistence of the B horizon (V17) was positively correlated to crop response in all cases in which it appeared in an equation; it also appeared most often in the regression equations. However, dry consistence and bulk density of the Ap (V16 and V19) a n d .Cca horizons (.Vl8 and V21) were most often negatively correlated to crop 73 response, Ttiiis negative correlation of the Ap horizon to crop response could have involved the possibility that textural differ­ ences at the surface of a soil could have governed the effectiveness of broadcast application of K; Hard dry consistence and high bulk densities may not have allowed penetration of surface-applied K. Aspect (V32) also appeared in six of the regression equations and was negatively correlated to crop response in all cases except one. The interpretation of the effect of aspect on crop response was difficult because of the coding scheme devised. The effect of aspect was no doubt related to how it modified the effect of slope and incidence of incoming radiation (soil temperature). If this was the relationship that existed, then one would have expected a positive correlation between aspect and crop response if most of the experimental sites pertaining to the regression equation had northeast to southeast exposures, One would have expected the opposite correlation if most of the experimental sites had northwest to southwest exposures. This was due to the coding scheme employed (see Figure I). Regression No. 22 and No. 23 (spring wheat in geographic ' • V location I) produced the most highly significant results (.005 level). It is interesting to note that the equations have only three variables in common and they appear in a different order. This points out that the nature of the dependent variable exerts some kind 74 of unexplainable influence on the factors which relate to the variability in crop response. Regressions No. 32 - No. 43: Average Percent Response (V42) as the Dependent Variable. Some of the percent response (V42) data clearly indicated that a negative response to added K occurred. In some cases there was clearly a strong positive response to applied K . In order to determine what, factors might be responsible for this variation in response to added K, the data file for the present set of regressions was divided riot only by crop type and geographic location but also be response class (V42). the following basis: Three response classes were created on Subfile I) 95 percent response and less = negative response; Subfile 2) 96 - .105 percent response = no response; Subfile 3) 106 percent response and greater = positive response. Regression No. 41, which described the analysis of the spring wheat experiments in geographic locations I, 2, and 3 in the "no response" class, yielded the highest R 2 value (.93). This was 2 2 significant at the .005 level. Regression No. 33 produced an R value of .20, also significant at the .005 level. This latter equation described the analysis for all crops in subfile 2 (no response) over all of the geographic locations. Response class 2 (no response) was described by regressions No. 33, No. 36, No. 39, and No. 41. All of the regression equations Table 13. Regression No. Regres s i o n No. 32 - No. 43; A v e r a g e Percent R e s p o n s e (V42) as the Dependent Variable; D a t a File Subdivided on Crop, Geogr a p h i c Location, and Percent Response Class; Independent V a r i ables as in Table 11. ’ Step into eq. 32 Dependent I Var. V42 2 Subfiles: 3 Divided on: ,4 Crop - 1,2, 3 l l _ Geog.Ioc-I,2,3,4 %—ras. — I (45) Independent Vars: same as Regression #15 33 Dependent I V a r . V42 2 Subfiles: 3 Divided on: 4 Crop, 1,2,3, 5 4. Geog. Ioc. - I,2,3,4 % res.-2 (85) Independent Vars: Same as Regression #15 Variable Name Depth to Ca Latitude Tex. Earn. Aspect Elevation Variable Number V29 V33 V26 V32 . V30 . Constant 231.56 Beta •.171 -.503 -.340 .240 -.234 Simple R R2 .24 -.16 -.13 .14 -.08 .06 .09 .15 .18 .22 ■ F-sig. level — .10 .10 .10 . ^i "" Elevation Slope Dry Con.C . Water Reg. Tex. cls. V30 V31 V18 V41 V25 97.05 .202 .239 .148 -.295 .253 .32 .23 .11 -.11 .11 .10 •13 .16 .18 .20 .005 .005 .005 .005 .005 Table 13, Continued. R e g r e s s i o n No. 32 - No. 43; A v e r a g e Per c e n t R e sponse (V42) as the D e p e ndent Variable: D a t a File Subdiv i d e d o n Crop, G eographic Location, and Percent Respons e Class; Independent V a r i a b l e s as i n Table 11. Regression No. 34 Dependent Va r . V42 ' Subfiles: Divided on: Crop-1,2,3 Geog.Loc- Step into eq. I 2 3 4 5 6 Variable Name Tex. cls. Tex. Fam. Water Reg. MAST Dry Con.C Bulk Den.C Variable Number V25 V26 V41 V 34 V18 V21 Constant .116;59 Beta .536 -.493 .553 . T-.448 .278 -.198 2 Simple R R . .13 .06 .13 .02 .11 -.05 . .02 .04 .06 .10 .12 .15 F-sig. level ---- — — — — -------------- .10 .10 .05 I,2,3,4 % res.-3 (89) Independent Vars: Same as Regression #15 35 Dependent Var. V42 Subfiles: Divided on Crop-1 Geog.Loc. I 2 3 4 5 I,2,3,4 %res. -I (24) Independent Vars:Same as Regression #15 '-j ON Elevation Aspect Bulk Den.A Temp.Reg. Water Reg. V30 . V32 Vl 9 V35 V41 119.31 -.571 -.366 -.251 -.318 .230 . -.43 -.31 -.14 -.05 .09 . .19 .25 .35 .39 .43 .05 .05 .05 .05 .10 Table 13, Continued. Reg r e s s i o n No, 32 - No. 43; A v e r a g e Per c e n t Res p o n s e (V42) as the Dependent Variable; D a t a File Subdiv i d e d o n Crop, G eographic Location, and Percent R e s p o n s e Class; Independent V a r i a b l e s as i n Table 11. Regression Step No. into eq. 36 . I Dependent Var. V42 2 Subfiles: 3 Divided on: 4 Crop - I 5 Geog.loc.-l,2,3,4 % res.-2 (57) Independent Vars: Same as Regression #15 Variable Name Depth to Ca Latitude Water Reg. Dry Con,C Dry Con.A 37 Dependent I Water Reg. Va r. V42 2 MAST Subfiles 3 Dry Con.B Divided on: 4 Bulk Den.A Crop -I 5 Latitude Geog. Ioc.1 ,2 ,3,4 % res.-3 (52) Independent Vars: Same as Regression #15 Variable Number V29 V33 V41 V18 V16 V41 V34 Vl 7 Vl 9 V33 Constant Beta Simple R R^ F-sig. level 143.01 -.292 -.303 -.279 .240 -.187 -.23 -.22 -.15 .02 -.06 .05 .09 .13 .16 .19 .10 .10 .10 .10 .10 153.41 .581 -.514 .219 .201 -.201 .20 .07 .19 .19 -.15 .04 .08 .13 .17 . .19 — — — . — — — ' .10 .10 .10 Table 13, Continued. R e g r e s s i o n No. 32 - No. 43; A v e r a g e Per c e n t R e sponse (V42) as the Dependent Variable; D a t a File S ubdivided on Crop, Geographic Location, and Percent R e s pon s e Class; I n d ependent V a r i a b l e s as in Table 11. Regression No. Step Variable into e q . Name 38 Dry Con.B Dependent I Var. V42 2 Tex. Fam. Dry Con.A Subfiles: 3 Dry Con.C Divided on: 4 Crop-1 5 Tex.cls. Geog.loc.-l % res.-3 (18) Independent Vars: Same as Regression #15 39 Dependent Latitude I. V a r . V42 2 Dry Con.A Water Reg. Subfiles: 3 Divided on: 4 Dry Con.C Crop - I Geog. loc.-4 A res.—2 (31) Independent Vars: Same as Regression #15 Variable Number Vl 7 V26 Vl 6 V18 V25 Constant 123.95 Beta .534 .008 -.247 -.546 -.703 Simple R .45 -.40 -.08 -.13 -.32 F-sig. level .20 .30 .41 .47 .55 .10 .10 .10 .10 .10 oo V33 Vl 6 V41 V18 253.04 -.615 -.432 -.334 -.255 -.27 -.18 -.14 -.03 .08 .16 .25 .30 — .10 .05 .05 a e 13, Continued. Re g r e s s i o n No. 32 - No. .43; Ave r a g e Percent R e s p o n s e (V42) as the Dependent Variable; Da t a File S ubdivided on Crop, G eographic Location, and Percent R e s pon s e Class; Independent V a r i a b l e s as in Table 11. Regression No; Step Variable into eq. Name 40 Dependent Dry Con.C .I Va r. V42 2 Latitude Subfiles: 3 Dry Con.B Divided on: 4 . Elevation Crop - I 5 Tex. cls. Geog.loc.-4 . % res.-3 (27) .Independ. Vars . r Same as Regression #15 41 Dependent I Dry Con.C Var. V42 2 Elevation Subfiles: 3 Bulk Den.B Divided on: 4 Bulk Den.C Crop - 2 5 Water Reg. Gepg.loc.-l,2,3 % res. - 2 (16) Independent Vars.: Same as Regression #15 n Variable Constant Beta ■Number_____________;___________ V18 V33 Vl 7 V30 . V25 V18 V30 V20 V21 V41 Simple R ______ R p-sig. ■ level -972.77 .521 .888 1.599 1.728 -1.400, .27 .15 .13 .04 .05 .07 .11 .16 .28 .48 — — — --- — .025 96.33 .649 .246 -.589 .319 .157 .78 .75 -.31 . .34 -.33 .61 .79 .89 .91 . .93 .005 . .005 .005 .005 .005 T able 13, C o n t i n u e d . R e g r e s s i o n No. 32 - No. 43; A v e r a g e P e r c e n t Re s p o n s e (V42) as the Dependent Variable; D a t a File S ubdivided o n Crop, G eographic Location, and P e rcent R e s pon s e Class; Independent V a r i a b l e s as in Table 11. Regression Step No. into eq. Variable ' Name 42 Dependent I Depth to Ca Va r. V42 2 Elevation Subfiles: Aspect 3 Divided on: Crop -3 Geog.loc.-l,3,4 % res.-3 (25) Independ. Vars.: Sames as Regression #15 43 Dependent I Thickness V a r. V42 of B Subfiles: Divided on: Crop - 3 Geog. loc.-l % res. - 3 (16) Independ. Vars.: Same as Regression #15 Variable Number Constant Beta Simple R R 2 F-sig. level V29 V30 V32 99.33 -.482 .359 .307 -.51 .34 .22 .26 .34 .43 .01 .01 .01 V28 130.03 -.551 -.55 .30 -05 81 included dry consistence of regime (V41). the Cca horizon (V18) and moisture Moisture regime was consistently negatively correlated to crop response. This suggests that added K may not produce as great a response on soils that normally are of the drier regimes. Dry consistence of the Cca horizon was positively.correlated to crop response in three of the four regressions. In regression No. 41., bulk density of the Cca horizon was also positively correlated to crop response. Perhaps this indicates that in soils with more easily penetrable subsoils, a response to added K is not likely to occur. This may be due to the fact that native soil K was utilized more readily.from the subsoil horizons. Latitude (V33) was negatively correlated to crop response in regression No. 36 and No. 39. The reason that the ''no response" class is negatively correlated to latitude is open for speculation. It could be that the effect of latitude was temperature related. At any rate, it was interesting that latitude was more negatively correlated in the Hno response1' 1 ' class (regression No: 36 and No. 39) and negative response class (regression No. 32) and positively correlated in the positive response class (regression No. 40). Another trend appeared with respect to the depth to the Cca horizon CV29). In the negative response class (regression No. 32), V29- was strongly positively correlated to crop response. However, in the no response class (regression No. 36) and positive response class 82 (regression No.42), there was a strong negative correlation between crop response and depth to the Cca. This relationship suggested that added K fertilizer was more likely to cause a positive response under conditions of high C a C O ^ accumulation nearer to the soil surface. The positive response class was described by regression No, 34, No. 37, No. 38, No, 40, No. 42, and No. 43. In this, class, moisture regime (V41) and MAST (V34) were both positively correlated to crop response. This again indicated that soils which tended to be warmer and drier throughout the year showed a greater positive response to added K. 1 . ■ Textural class (V25) and textural family (V26) appeared to be inconsistently correlated to crop response between regression equations in response class 3 (e.g. regression No. 34 vs. No. 38), However, both variables were consistently correlated within a regression equation. This perhaps indicated that other factors were responsible for modifying the effects of texture and that crop response was dependent on these other factors as well, Dry consis­ tence of the B horizon 0/17) was again positively correlated to crop response in all three regression equations (No. 37, No. 38, and No. 40) in which it appeared. The implications of this relationship have already been discussed. Regression No. 43 included only one significant variable (V28). 83 Thickness of the B horizon was strongly negatively correlated to crop (barley) response, and this variable alone accounted for 30 percent of the observed variation in response. Regressions. No. 44 - No. 47: Maximum Response (V50) as the Dependent Variable.* 2 The data file for regressions No. 44 through No. 47 was divided according to the K rate at which 'fhe maximum crop response occurred. This was done to investigate whether different factors were important to response depending on rate of applied K. The data subfiles were created as follows : Subfile I) 11^39 kg K/ha; Subfile 2) 45-67 kg K/ha; Subfile 3) 81-96 kg K/ha; Subfile 4) 112-128 kg K/ha; and Subfile 5) 134 kg K/ha. None of the. regres­ sion equations corresponded to subfile 2 (which included only those experiments in which maximum percent response was attained at 45-67 kg K/ha applied K) since no significant results were obtained. . The regression equation (No. 47) dealing with the highest rate of added K produced the highest R 2 .value (.40). The highest F- significance level (.025) in this equation was actually achieved in Step 4 (R 2 = .36). 'Regression No. 45 and No. 46, which dealt with subfile 3 and subfile 4, respectively, as explained above, also were significant at the ,025 level. Textural class (V25) appeared in three of the four regression Table 14. R e g r e s s i o n No. 44 - No. 47; M a x i m u m P e r c e n t R e s p o n s e (V50) as the Dependent Variable; Data F i l e Subdi v i d e d on K - r a t e at W h i c h M a x i m u m Re s p o n s e Occurred (V51); Independent V a r i a b l e s as in T able 11. Regression Step No. into eq. 44 ' Dependent I Va r . V50 2 Subfiles: 3 Divided on V51 (SI) 4 cases: 43 5 Independent Vars: V16 to V21, V25, V26, V28 to V 3 5 , V 4 1 45 Dependent I 2 V a r . V50 Subfiles: 3 4 Divided on 5 V51 (S3) cases: :41 Independent Vars: V16 to V21, V25, V26, V28 to V 3 5 , V41 Variable Name Variable Number Elevation Dry Con.C Thickness of B Tex. cls. Bulk Den.C. V30 V18 Latitude Tex.cls. Aspect Bulk Den.C Dry Con.A V33 V25 V32 V21 V16 V28 V25 V21 Constant 37.26 -323.36 R 2 Beta Simple F-sig. level .453 .115 .34 .05 .12 .18 .05 .025 -.354 -.274 .242 -.26 .06 .15 .21 .25 .27 .05 .05 .05 .631 .592 -.305 .312 .203 .31 .05 -.14 .12 .03 .10 .16 - .22 .28 .31 .05 .05 .05 .025 .025 Table 14, Continued. R e g r e s s i o n No. 44 - No. 47; M a x i m u m P e r c e n t R e s p o n s e (V50) as the Dependent Variable; Da t a F i l e S u b d i v i d e d on K-rate at W h i c h M a x i m u m R esponse Occur r e d (V51); I n d ependent V a r i a b l e s as in Table 11. Regression Step No. into eq. 46 Dependent I V a r . V50 2 Subfiles: 3 Divided on 4 V51 (S4) 5 cases: 42 ■ Independnet Vars: V16 to V21, V25, V26, V28 to .V35, V41 47 Dependent I V a r . V50 2 Subfiles: 3 Divided on 4 V51.(S5) . 5 cases: 29 Independent Vars: V16 to V21, V25, V26, V28 -to V35, V41 Variable Name Water Reg. Temp. Reg. Aspect Tex. Fam. Dry Con.C Variable Number V41 V35 V32 V26 V18 Constant 101.50 2 Beta Simple R R .242 -.020 .208 .349 -.290 .38 .003 .19 .36 -.15 .15 .20 .23 .26 .30 F-slg. level .025 .025 .025 .025 .025 co Ln Latitude Tex. cls. Tex. fam. Temp. Reg. Slope V33 V25 V26 V35 V31 -29.70 .270 1.282 -1.036 .224 .205 .27 .21 -.03 .14 .02 . .07 .17 .33 .36 .40 — .10 .025 .025 .05 86 equations and was most strongly positively correlated to crop response at the highest rate of applied K. Textural family (V26) was also strongly positively correlated to crop response in regression No. 46 which was also concerned with the higher rates of applied K. This indicates that {the more finely textured soils show a more positive response to high rates of applied K „ Bulk density and dry consistence of the Cca horizon appeared in regression No. 44, No. 45 and No. 46.. Both of these variables seemed to be more positively correlated to crop response at the lower rates, of applied K. In regression No. 46 (higher K rate class), dry consistence of the Cca was negatively correlated to response. This suggests that perhaps the lower rates of applied K have more of a positive effect on response as the subsoil horizons become more impenetrable. Temperature regime (V35) and moisture regime (V41) appeared in : ' ■ the regression equations (No. 46 and No. 47) at the higher rates of applied K. The general positive correlation of these variables to crop response indicates that the higher rates of K are more effective on the warmer and drier soil types. . Aspect (V32) appeared in regression No. 45 and No. 46 (maximum percent response as the dependent variable) as ah important variable. It was negatively correlated to crop response in one case and positively correlated in the other. The problem, as discussed 87 earlier, with regard to the coding scheme for aspect, could explain this phenomenon, It should be pointed out that one class or rate of applied. K did not dominate the determination of the maximum response variable (V50). This indicates that factors such as soil type and/or soil conditions may dictate the most effective rate of K application. Regression No, 48; Average Percent Response (V42) as the Dependent Variable.* 2 The fact that much of the growing season temperature data, rain~ fall data, and spring soil moisture data were missing, indicated that statistical validity of previous results in which they were included in the regression equation was questionable. To determine a more accurate interpretation of the importance of these variables to crop response, a regression analysis option was used to include only those cases which had a complete set of data for these variables. Only growing season temperature data (V37, 738* V39), rainfall (V40), and cumulative spring soil moisture to 122 cm. (V52), V53), 754, 755) were included as independent variables in the analyses. The results showed that only average temperature in May (737) and rainfall (740) entered the regression equation. May by itself produced an R 2 correlated to crop response. Temperature in value of ,17 and was strongly negatively This indicated that low soil temperatures early in the growing season may have limited uptake of native K. One Table 15. Regression No. 48; Average Percent Response (V42) as the Dependent Variable; Data File-Restricted to Include Only Cases With Complete Data; Independent Variables Restricted to Soil Temperature, Rainfall, and Cumulative Soil Moisture Variables. , Regression No. I 2 Variable Name Temp.(May) Rainfall Variable Number V37 V40 Constant 126.37 . Beta -.467 -.172 Simple R . -.42 -.03 R .17 .20 F-sig. level .01 .025 88 48 Dependent Var. V42 Subfiles: All;cases: 41 ' Independent Vars: V37 to V40, V52 to V55 Step into eq. 89 would probably have observed a positive response to added K if this was the case, These results were in accord with observations discussed earlier by Boatwright et^ jal. (1976) . Regressions No, 49 or No. 50; Maximum (V50) and Average (V42). Percent Response as the Dependent Variable. The same regression analysis was performed.with a different dependent variable in each case (V50 and V42, respectively). set of independent variables was the same in both cases. The The independent variable set included all of those variables used.in regression No. 48 with the addition of those variables (V16 to V21, i V25, V26, and V28 to V35) used in the majority of the regression analyses. A more statistically valid regression analysis option was again used to only include those cases for which there was a complete data set for the variables included. Dry consistence of the Cca horizon (V18),.temperature in May (V37), and rainfall (V40) appeared in both regression equations. Both equations were significant at the .05 level. The R 2 values for both equations were similar at .33 and .34, respectively. All of the variables that entered the two equations which were related to soil physical properties, dry consistence of the Cca horizon, bulk density of the Ap horizon, textural family, and thickness of the B horizon (V18, V 1 9 , V26, and V28, respectively) were all positively correlated to percent response. These results Table 16 , Regression No. 49 and No. 50; Maximum (V50) and Average (V42) Percent Response - as the Dependent Variables; Data File Restricted to Include Only Cases With ■ Complete Data; Independent Variables as in Table 11 and Table 15 Combined. Regression No. ■ Step into eq. 49 Dependent I Var. V50 . 2 Subfiles: 3, All^cases: 32 .4 Independent Vars i-1 V16 to. 5 V21, V25, V26, V28 to V35, V37 to V40, ' V41, V52 to V55 . ■■ 50Dependent Var. V42 Subfiles All»cases: 32 Independent Vars. - Vl6 to V21, V25, V26, V28 to V35, . V37 to V40, I 2 3 4 ’ 5 Variable ■ Name Variable Number Constant Befa Simple • R 2 . • R FXsig. level -Dry Con.C. Bulk Den.A Rainfall Thickness of B Temp.(May) ■ V18 . Vl 9 ■ V40 . V28 V37 • 53.12 .317 . . ,37 .367 .11 -.05 -.315 . .278 -.240 .29 -.33 .13 .17 • .23 . .05 .10 ,10 .29 , .33 . .05 .05 .■ ' Dry Con.C Tex.- Fam. Temp.(May) .) Rainfall Soil H O (0-90) .Vl 8 V26 V37 V40 .596 -.380 102.36 -.223 , -.344 V54 .244 . . •41 .17 .11 . .22 -.41 .26 -.03 .30. .12 .34 .025 .05 .05 .05 .05 V 0 o 91 suggest that as clay content Increases (associated with hard consistence of the Cca, greater thickness of the B horizon, and a positive correlation to textural family as coded coarse to fine), a more positive response to added K results. The negative correlation of temperature in May (V37) to percent response was consistent with regression No. 48 and has been dis­ cussed. The fact that cumulative soil moisture to 90 cm. (V54) appeared in regression No. 50 indicated that soil moisture was important with regard to crop response to added K. The positive correlation of this moisture variable to response suggests that without adequate moisture diffusion of applied K to the plant root will not occur. Rainfall, another moisture variable, was not clearly correlated to crop response; but its appearance in both equations proved that it did account for some of the variability in response to added K. Regression No. 51; MAST (V34) as the Dependent Variable. Schaff (1979) determined that MAST was the most important variable in relating to percent change in yield of winter wheat to applied K fertilizer. This factor alone accounted for 56 percent of the observed variability in percent change in yield. Because of the importance of this variable in Schaff's .regression analyses, it was of interest to try to determine why MAST did not Table 17. Regression No. 51; MAST (V34) as the Dependent Variable; Data File on Crop; Independent Variables Restricted as in Table 11. Regression No. Step into eq. 51 . Dependent Var.. V34 Subfiles: Divided on: Crop - I Cases ;133 Independent Vars. Same as Regression #15 I 2 3 4 5 Variable Name Water Reg. Latitude Tex. Fam ■Temp. Reg. Dry Con. C Variable Constant Number • V41 V33 V26 V35 V18 15.56 Beta .511 -.133 .299 .243 -.162 Simple R .82 -.51 .65 .47 .03 Subdivided R2 F-sig. level .68 .73 '.75 .77 .79 .005 .005 .005 .005 .005 93 appear more often in the regression equations in this study. Regression No, 51 was performed with MAST (V34) as the dependent variable. The independent variable set was that utilized in the . majority of the regression analyses, in other words, that set which excluded variables with a large amount of missing data. MAST was highly positvely correlated with moisture regime (V41), textural family (V26), and temperature regime (V35). highly negatively correlated to latitude (V33). It was also The regression equation showed that these four variables alone accounted for 77 percent of the observed variability in MAST (.005 significance, level). Because of this relationship, it was not surprising that MAST did not appear more often in the regression equations. Other independent variables, particularly water regime (V41), probably accounted for the same variability in crop response as MAST. Regression Equations - Summary Table 18 summarizes the correlations (Simple R) of each independent variable used in the regression equations with the dependent, variables,which are yield (V06 to VlO) and average (V42) and maximum (V50) percent response. Table 18 also summarizes the relative overall importance of each independent variable, based on the number of times that each of them enters a regression equation and the frequency of entry (number of times included as an independent variable divided by the number of times of entry into, the equation). Table 18. V a r ia b l e Name S ite C ro p Year -K -ra te 2 K -ra te 3 K -ra te 4 K -ra te 5 D ry C o n . A D ry C o n . B D ry C o n . Cca B u lk D e n . A B u lk D e n . B . B u lk D e n .Cca S tru c . A S tru c . B S t r u c . Cca T e x . e ls . T e x . Fam. Geog. L o c . T h ic k n e s s B D e p th t o Ca E le v a t io n S lo p e A spect L a t it u d e MAST Tem p. R eg im e Tem p. (M a y) Tem p. (J u n e ) Tem p. ( J u l y ) R a in fa ll W a te r R egim e S o il H O (0 -3 0 ; S o i l H2 O (3 0 -6 0 ) S o i l H-O (6 0 -9 0 ) S o i l H -o ,(9 0 -1 2 2 ) Overall Correlations of the Independent Variables with the Dependent Variables - Yield (V06 - V10) and Maximum (V50) . and Average (V42) Percent Yield Response. S im p le R (+ ) - V a r ia b l e N um ber • VOl ' V03 V04 V12 V13 V14 V15 V16 ■ Vl7 V18 V19 V20 V21 V22 . V 23 ■ V24 V25 V26 . V27 V28 V29 V 30 V31 V 32 V33 V34 V35 V37 V38 V39 V40 ’ V41 •(-)- • . I 9 ' 4 2 4 ' 4 15 7 ' 6 • 7. 6 3 ■ 3 4 2 6 • ■ 11 N o. o f R e g r e s s io n s i in c lu d e d a s a V a r ia b l e 9 3 3 2 '.■2. i 2 2 3 2 4 6 16 10 4 ■ 4 5 I 4 S im p le R . 8 I • 5 8 3 , 4 2 6 3 3 5 5 ■4 2 8 10 3 6 2 I 4 4 5 9 7 7 7 7 . 50 50 50 50 50 50 15 15 15 50 50 15 50 50 50 ' 50 50 50 ' 49 .50 18 18 18 18 • 50 N o . T im e s V a r ia b l e E n te r e d . R e g r e s s io n .. ' 4 . 3 4 '■ 4 . 3 . 2 4 14 17 15 12 ' 7 9 . I ' 6 I 15 7 5 9 9 19 .9 14 17 ■ 6. 6 9 6 3 10 15 E n t r y F re q u e n c y i n t o R e g r e s s io n E q u a t io n . (%) • 44 ' 60 . 44 57 43 29 57 28 34 30 24 14 ' 18 7 ■ 40 7 30 14 33 18 18 38 18 28 34 12 12 50 • 33 17 56 30 V44 3 I, 15 4 27 V45 • I 2 15 3 , 20 V46 I 15 I V47 2 .4 15 6 I. ■■2 15 3 ■ 20 4 4 . . 2 .1 5 • 4 6 4 40 100 3 I 33 S o i l H-O (1 2 2 -1 5 2 ) V48 S o il H O (1 5 2 -1 8 3 ) V49 K -ra te o f V51 M a x . R e sp o n se S o i l H-O (0 -9 0 ) • V54 ' I' ■ 7 \ The' variables entering the regression equations most often were elevation (V30 - 19 times), latitude (V33) and dry consistence of the B horizon (V17 17 times), dry consistence of the Cca horizon (V18), textural class (V25), and dry consistence of the Ap horizon (V16) and aspect (V32 - 14 times). , The most consistently.correlated variables in the regression equations were the K-4ate variables (V13, V14, V15, V5l), MAST (V34), dry consistence of the B horizon . (V17), elevation (V30),, slope (V31), and moisture regime (V41). The. K-rate variables were consistently positively correlated to crop response, indicating that applied K generally caused increased .yields. MAST and moisture regime were also consistently positively correlated to crop response, suggesting that, applied K was generally more effective on soil types associated.with the warmer and drier sites. Slope was also consistently positively correlated to crop response, This relationship may be related to moisture availability, (drier sites) or to a slope-aspect interaction in which the incidence of incoming radiation may have affected soil temperature trends. Overall, dry consistence and. bulk density throughout the soil profile seemed to be very important with regard to crop response to added K, Dry consistence of the B horizon (V17) was the most important factor relating to crop response and was also the most 96 . consistently correlated variable (Simple R) to crop response. Dry consistence of the B and Cca horizons are generally positively . correlated to crop response whereas dry consistence and bulk density of the A horizon appear slightly negatively correlated to crop response. . If one assumes that increased dry consistence values can be associated with greater clay contents and decreased ease of K diffusion, root penetration, and exploitation of native soil K reserves, then the positive correlation between crop response and the harder subsoil horizons seems reasonable. The fact that bulk density and dry consistence of the Ap horizon appeared more negatively correlated to crop response perhaps suggests that the effectiveness of applied K (usually broadcast) was limited by compacted surface horizons which would have retarded diffusion of applied K into the soil profile. Table 19 summarizes the responses to applied K by crop and geographic location for all of the experiments included in this study. Although oats showed the highest percentage of experiments with a positive response to applied K, there were only four experiments which used pats as the experimental crop. The other three crops are similar in the percentage of experiments of each which responded positively to applied R, Winter wheat experiments in geographic location 4 had the Table 19. Crop Winter Wheat Spring Wheat Barley Oats ■ Sunnnary of Small Grain Response to Applied K Fertilizer; Montana Statewide Study, 1968-1980. No. of Experiments 133 36 49 . 4 No. with Positive K-Response 90 22 31 4 % Positive Response 68 61 63 100 No. with Negative K-Response 43 14 18 0 ■ % Negative Response 32 39 37 0 Range of % K Response 81-122 85-121 • 88-117 83-153 Geo. Average Lo g . % K (V27) Response I 2 ■3 4 .102 101 .101 . 106 80-115 HO 96-120 I 100 2 HO 106 61-146 I 3 4 106 2 90-118 89-118 102-109 108-110 3 4 104 104 ’I 106 109 2 3 VO 98 Table 20. Number of Experiments at the Various Rates o f Applied K at Which Maximum Percent K Response Occurred. Rate at Which Maximum K-^Response Occurred (V51) Number o f ■ Experiments -■ kg K/ha - 11 3 13 2 22 12 27 2 28 22 ■ 34 I 39 1 45 37 48 11 54 2 56 11 57 4 67 2 81 2 90 32 96 7 112 32 115 9 128 I 134 29 222 99 highest average percent K response (106 percent) for that crop. Spring wheat showed a higher average percent response in geographic location 3 (106 percent) than in geographic location I (100 percent). Barley showed a.greater average percent response in geographic locatipn I (106 percent) yet also showed a much greater variability in response in this area (61 - 146 percent). Table 20 shows the number of experiments which produced maximum percent K response at each rate of applied K. It was interesting to note that in about half of the experiments the crops responsed to their maximum at applied K rate of 90 kg K/ha and above. This is conclusive evidence that in many cases availability of native soil K is not adequate for the nutrition of small grains. It further points odt that crop responses to added K fertilizers may not be measured in many field experiments due to inadequate rates of application in the experiments. Chapter 5 SUMMARY AND CONCLUSIONS From 1968 to 1980, numerous small grain soil fertility experiments in which applied K fertilizer treatments were involved were establish­ ed around the State of Montana. Two hundred twenty-two of these experiments established on 127 different site locations were selected to study the influence of soil profile and site characteristics and soil classification parameters on yield and crop response to applied K fertilizer. From two to five rates of K, ranging from 0 (control), to 134 Kg K/ha, were applied in the experiments studied. Sites were classified as to their soil series using the legal description of the site along with the appropriate SCS county soil survey, or by using the series name associated with an experiment as reported in the Montana Agricultural Experiment Station Annual Report. Eight variables (classification parameters) were included in the regression analyses as determined from the SCS soil series description. Soil samples from each of three horizons identified as the A p , B, and Cca horizons were taken at each of the 127 sites. Dry consistence and bulk density measurements were obtained for each soil horizon sample. Site characteristics including slope, aspect, elevation and latitude were also recorded and introduced as variables in the regression analyses. Spring soil moisture data, rainfall data, and soil temperature 101 data were obtained from the Montana Agricultural Experiment Station Annual Report and introduced as variables in the regression analyses. However, many of the experiments did not include soil moisture and temperature data.. A total of 48 independent variables iri varying combinations were inserted into multiple linear stepwise regression programs with actual crop yield dr percent change in yield as the dependent variable.. Percent change in yield was determined both as an average and maximum percent figure. Over 60 regression analyses were performed with varying combin- ■ ations of independent and dependent variables. The data file was divided in many cases so that the regression equations usually only pertained to a selected part of the data file. subdivided according to: The data file was I) crop (winter wheat, spring wheat, barley, and oats ) ; 2) crop and four geographic locations (see Figure 2); 3) .crop, geographic location and percent response class (see Results and Discussion section - page 74 under Regressions No. 32 - No. 43); and 4) K rate at which maximum response occurred (V51). Fifty-one of these regression equations produced significant results ranging from .10 to .005 significance level. These.regression equations are presented in the Results and Discussion Section of this thesis in Table No. 8 through Table No. 17. Regression equations No. I through No. 5, which utilized actual 102 crop yield as the dependent variable and included ten variables each, all produced R 2 values significant at the ,005 level. Regression equations No. 6 through No. 10 (average percent response as the dependent variable) and regression equations No. 11 through No. 15 (maximum percent response as the dependent variable) also included ten variables each; and the regression equations also all produced R 2 values significant at the .005 level. The significance of these results is probably inflated due to the inclusion of spring soil moisture, rainfall, and soil temperature variables which had extensive amounts of missing data. Regression No. 4 and No. 5 (actual crop yield as the dependent variable) are of special interest, though, in that the first two variables into the equation (K-treatment and bulk density of the Ap horizon) by themselves produced R 2 values of ,76 and .6 8 , respectively. Regression No. 15 through No. 17 are similar in that the same restricted set of independent variables was used in these analyses. The set of independent variables was restricted in that soil moisture (V43 - V49 and V52 ^ V55), soil temperature (V36 - V39) and rainfall (V40) variables were removed from the analyses due to the large amount of missing data for these variables. The dependent variables used in these analyses were either the average (V42) or maximum (V50) percent response, The most significant results (,005 level) were produced by regression equations: No. 22, which measured the 103 relationship of maximum percent response of spring wheat in geographic location 1— No. 23, which measured the relationship of average percent response of spring wheat in geographic location I; No. 33, which measured the relationship of average percent response in experiments which included all four crops over all four geographic locations and that had average percent response values between 96 and 105; and No. 41, which measured the relationship of average percent response in experiments which dealt with winter wheat in geographic locations I, 2, and 3 that had average percent response values between 96 and 105. These regression equations 2. produced R values of .79, .60, .20, and .93, respectively, with five variables included in each equation. The only variable to appear in all of these equations was dry consistence of the Cca horizon (VIS). Regression No. 49 and No. 50 (V50 and V42 as the dependent variable, respectively) were produced with a restricted regression program option in which only those cases (experiments) with a complete data set were included in the analysis. The independent variable set was again expanded to include soil temperature, rain-fall, and cumulative spring soil moisture variables, equations produced R — See Figure 2. 2 These regression values of ,33 and .34 respectively (.05 V 104 significance level). Dry consistence of the Cca horizon (V18), rainfall (V40), and average soil temperature in May (V37) were the only variables to appear in both regression equations. Elevation (V30) entered the regression equations more than any other variable and was most often positively correlated to crop response to applied K.- The effect of elevation on crop response may be related to its influence on climatic factors such as moisture and temperature, but ascertaining its importance at this point is merely speculative. Dry consistence of the B horizon (VI7) is consistently positively correlated to crop response to added K. This relationship may have to do with the decreased ability of roots to penetrate into subsoil horizons with a hard dry consistence or for native soil K to readily diffuse to crop roots. If this is so, then the plant's ability to utilize native soil K would be limited and a response to added K would be likely. Consistence is no doubt a measurement that integrates the effects of other factors such as clay content, clay type, and bulk density. It will be important in the future to quantitatively determine exactly how these various factors interact to influence the consistence measurement. Schaff .(.1979) determined that clay content of the ca horizon was one of the five most important factors influencing winter wheat 105 response to added K. The importance of the dry consistence of the Cca horizon (VlS) in the present study corroborates his observation and gives credence to the idea that clay content and consistence are directly related to one another. The relationship of soil structure to crop response to added K is not clearly defined in this study. However, the structure of the B horizon (V23) appears to be very important with regard to yield variability. In regression No. I, No. 2 and No. 3, it is strongly positively correlated to actual crop yield, which was the dependent variable in these regression equations. Because of the coding scheme used for the soil structure variables, it was difficult to ascertain the exact effect of soil structure on yield; but the indication was that greater yields were associated with the stronger, more coarsely structured soils. Perhaps this effect was related to better root penetration and exploitation of the soil environment along the planes of separation between adjacent peds associated with well structured soils. Other soil classification parameters accounted for much of the variability in crop response to added K. Moisture regime and mean annual soil temperature were two classification parameters that.were consistently positively correlated to crop response. That is, the warmer and drier soils were associated with greater response to added K, Temperature regime was also an important soil classification 106 parameter that appeared in the regression equations, but it was not as consistently correlated to crop response. Textural class and textural family both were significantly related to crop response to applied K in a number of the regression equations. The general trend was for the fine textured soils to respond to a greater degree than the more coarse textured soils. This was consistent with most o f .the literature which indicated that as clay content of the soil increased, more total soil K was required for adequate supply to the plant to be maintained. The above soil classification parameters may be easily determined in the field or from a soil series description. The indication was that all or some of these parameters could be incorporated into a reliable K soil test procedure. The K rate variables were the most consistently correlated variables to crop response. The high positive correlation of K rate to crop response indicated that, in many soils, adequate availability of native soil K did not exist. However, approximately one-third of the total number of experiments in this study either showed no response or a negative response to applied K. cases the negative response was pronounced; In some This suggested that for a given set of existing soil conditions, there was an optimum rate of K which should be applied to achieve maximum crop response. Tf the availability of native soil K was adequate, it is possible 107 that added K may have interfered with the uptake of some other nutrient. It is important to know when arid where this type of adverse effect is likely to occur. Schaff (1979) found a positive correlation between the con- ++ centration of extractable Ca percent yield response. in both the 1st and 2nd horizons and It was the most highly related chemical factor to percent yield response of winter wheat to K fertilizer. In the present study, depth to the Cca horizon (V29) was an important factor relating to crop response to applied K. It is possible that the calcium concentration in the soil solution may have affected diffusion of soil K by influencing the ionic concentration of K. A high calcium concentration may have interfered with other pri­ mary nutrients also. Phosphorus, for example is considered to be more limiting for small grains than potassium. Calcium is known to convert phosphorus into forms unavailable to plants and, thus, could indirectly influence plant K needs as well. This indirect influence may be related to decreased demand and uptake of K with decreased phosphorus avail­ ability. Rainfall during the growing season was also important with regard to crop response to applied K. Rainfall was not consistently correlated to yield response because its influence was probably modified by other existing soil conditions, such as amount of spring soil moisture. The time and distribution of rainfall was also 108 probably important and could explain variations in response to applied K. These considerations were not part of this study. Soil temperature and moisture were important with regard to crop response to added K. Temperature in May (V37) was most often negative­ ly correlated to crop response, suggesting that low spring temperatures controlled and probably retarded diffusion of native soil K to the plant root. Added K would have increased the soil solution K con­ centration and increased K diffusion under these circumstances. Rather than soil moisture or temperature being the primary influence on crop response by itself, it was probably an inter­ action of these two factors which partially governed the effect of added K. An abundance of soil moisture would tend to prolong low spring soil temperatures by increasing the specific heat of the soil. On the other hand, the absence of adequate soil water would allow the positive effect of temperature on diffusion to be realized yet may have adversely affected the K concentration in the soil solution and limited K diffusion. This study has shown the importance of soil temperature and moisture upon crop response to added K. However, significance of these relationships were limited by the fact that many of the experiments did not include soil moisture, rainfall, and soil temperature data collection. All future experiments should include the collection of these data as part of the standard experimental 109 procedure. These factors are critical to dryland agriculture in Montana,and indications are that these factors highly influence crop response to added K fertilizer. The effects of soil moisture and temperature on crop response will undoubtedly also be influenced by soil texture and other soil physical properties. Clay content, clay type, and bulk density are known to influence ion diffusion in soils. It is the interaction of all of these factors which will ultimately determine crop response to added K. It is essential that future studies be directed toward quantitatively determining the nature of these interrelationships. The relative importance of each of these factors will vary, and each of them could probably be considered to be limiting K diffusion and crop response depending on a given set of soil conditions. The regression equations substantiate this conclusion in that the correlation (simple R) between crop response and these climatic and physical factors varied from one regression to another in many cases. Pt is important to realize that this study was limited in that many factors which could affect crop response to added K were not considered or included as variables. Management techniques, for example, may have a direct influence on crop response. The fact that bulk density of the Ap horizon was an important variable in many of the regression equations suggested that compaction problems HO on some soils may have existed as a result of time, amount, and kind of cultivation employed. Also; time of fertilizer application (spring vs. fall) and seeding date are two important variables which ■ were not considered in this study. .. .1. Raychaudhuri (1976) found that in high potassium-fixing soils, recovery of applied K by the crop was appreciably lower from broad­ cast than from band application. Application of K in two or three split doses was found to. be superior to a single basal dressing, depending on the soil texture and predominant clay type. Method and time of K fertiliser application, as well as type of K fertilizer applied (e.g. KCl vs. KgSO^), were variables not included in this, study. • + Kowalenko and Rpss (1980) observed that the presence of K 4* depresses ' . fixation, and that fixed ammonium established some + kind of equilibrium with exchangeable NH^ over time. 4“ 4“ It. is known that NH^ and K act similarly in the soil environment under certain circumstances. This is due to the fact that the ions are of equal valence and approximate ion size. The type and amount of N ferti­ lizer was variable from one experiment to another in this study, and the influence of this difference was unknown. McLean (1976) made some interesting observations with regard to K fixation and release; Potassium release, which became progressively smaller in magnitude with time, was eventually exceeded greatly by Ill the capacity of the clay to fix added K in non-exchangeable form. He believed both processes occurred simultaneously, and it was not always known which predominated for a 'given soil. Therefore, there was always uncertainty as to how to take them into account when making a K recommendation based on soil tests. He concluded that it was particularly the fine textured alluvial or lakebed soils with a predominance of micaceous illitic clay that varied the most in K release and fixation, depending on the degree of original weathering and recent cropping conditions. The weathering of clay particles probably varies from year to year in Montana in that soil moisture, snow cover, and the depth to which a soil freezes vary. Temperature effects have been shown to be important with regard to K fixation and release. A better under­ standing of these mechanisms will enhance the predictability of crop response to added K. Willis and Power (1975) point out that soil temperature has a dominant influence on plant growth, both directly and indirectly. Whether temperature has a direct or indirect effect is, however, a moot question, particularly because we are primarily interested in some yield function; and the plant acts as an integrator of many individual factors. Diffusion is the primary mechanism by which K reaches the plant root. Diffusion of K in the soil environment is no doubt governed . 112 by the interaction of many important factors. This study has established that known or easily determined soil and site character­ istics are significantly correlated to crop response to K fertilizer and do indeed influence the process of diffusion. The results of this study indicate that many of the significant variables could be incorporated for use in a K soil test. The parameters which accounted for much of the variation in crop response to applied K fertilizer can be easily determined in the field, from a soil series description, or from a soil sample taken for limited laboratory analysis. Moisture content and soil temperature are known to influence diffusion. The way in which site characteristics (e.g. slope and aspect) and soil physical properties, such as bulk density, con­ sistence, structure, and texture, modify the influence of moisture and temperature will allow for better understanding the soil environment in which K diffusion must occur. APPENDICES APPENDIX I 115 Site Numbers, Cooperators, County, Legal Descriptions, and Soil Series for the 127 Small Grain Sites, 1968-1980. Site No. Fertility Experiments Legal Description Cooperator County Stevenson Berkrum Benge Kelly Rowland Hill Glacier Powder River Bighorn Carbon I I I 2 2 S * . Sec. 12, T MN , RlOE SEll of SW,, Sec. 20, T M N , R5W NVfI,, Sec. 7, TlS, R50E SVR, of SMI, Sec. 26, TlS, R M E NVf,, Sec. 10, T4S, R22E Absorokee 6 7 8 9 10 Wieler Bates Daum Toreke, W. Erickson, L. Stillwater Gallatin Yellowstone Bighorn Bighorn I I I 2 2 NEl, of SVRi, Sec. 18, TIN, R20E SEl,. Sec. 32, TIN, RlE NVf, of NEtl1 Sec. 7, T4S, R26E SEI,, Sec. 7, T2S, RllE SE!, of NVf,. Sec. 11, T4N, R23E Amsterdam Shaak Gilt Edge Bainville 11 12 13 14 15 Cooper Franeen Bros. Lakey Filing Relnoweki Gallatin Liberty Hill Hill I I I 8 2 SVf,, Sec. 27, TIN, RlE NVf, of NEl,, Sec. 24.T32N, RlM SE), of NE!,, Sec. 10, T U N , R5E SMliof NVf,, Sec. 5. T32N, R9E NEl, of NVf,, Sec. 4, T U N , R U E 16 17 18 19 20 Warnick Gregoire Rolston Redekopp Coulter Hill Hill Hill Valley Garfield I I 6 2 3 SE), of SE),. Sec. 19, TU N , R U E NVf,, Sec. 18, T U N . RISE NVf,, Sec. 21, T32N, R U E SMI,, Sec. 30, T U N , R45E SVf,, Sec. 4. T19N, R M E Williams Telstad Dooley Cherry 21 22 23 24 25 Erickson, K. Nissley Fadhl Halside Obergfell McCone Dawson Rosebud Roosevelt Richland 2 I 2 2 2 NVf, SE), NVf, sEl, NE!, Vida Farnuf Ghamn Williams Chama 26 27 28 29 30 Mocassin Sta. Metcalf Nemec Lee Bates Judith Basin 11 Judith Basin 3 Fergus I Judith Basin I Gallatin I SVf1 of S E V Sec. 16, TU N , R14E SE!, of SVf,, Sec. 14. T16N, R14E NVf,, Sec. 6, T18N, R U E SEl, of SM!,, Sec. 7. T17N, R U E S E V Sec. 32, TIN, RlE Judith Judith Danvers Winifred Amsterdam 31 32 33 34 35 Toreke Wieler Daum Benge Erpelding Bighorn Stillwater Yellowstone Powder River Rosebud I I I I I SVfl, SVf,. SVf,, SHI,, SEV Absarokee Farland Fort Collins 36 37 38 39 40 Dyk Patterson Holland Holland Miklovich Gallatin Stillwater Rosebud Rosebud Bighorn 2 I 3 I I NW*, Sec. 6, TlS, R3E SW* of SW*, Sec. 23, T4S, RlOE NElllSec. 20, T6N, R42E N E V Sec. 20. T6N, R32E NEl,. Sec. 33. TSS, RISE Manhattan . Absarokee 41 42 43 44 45 Torske, L. Dyk Herzog Erpelding Brinkman Bighorn Gallatin Stillwater Rosebud Fergus I I I I I SHV SHV NVf1, SEV NWV Gilt Edge Manhattan Tanna Fort Collins Danvers 46 47 48 49 50 Boling Cash Daura Pidwerbeckl Redekopp Fergus Musselshell Yellowstone Valley Valley 2 2 I I I SW*, Sec. 33, TlSN, R14E NHl,. Sec. 30, TSN, R25E SVf,. Sec. 18, T4S, R26E SW*, Sec. 14, T27N, R40E Nlj of NVf,, Sec. 32. T U N , R45E Coffee Creek Bainville Absarokee Evanston Martinsdale 51 52 53 54 55 Erpelding Erpelding Helm Hauks Perry Rosebud Rosebud Garfield Gallatin Choteau I I I I I S E V Sec. 15, T6N, R41E NEk. Sec. 15, T6N, R41E NEl,, Sec. 32, TlTN, R43E SE), of SHl,, sec. 32, T2S, RSE SE), of S E V Sec. 31, T23N, RlOE Fort Collins Fort Collins Cherry Amsterdam Gerber 56 57 58 59 60 Works Miklovich Pehl Schaff Sime, Inc. Choteau Bighorn Prairie Golden Valley Gallatin 2 I 3 I I SVfi of SEl,. Sec. 24, T28N, R9E NVf, of SVf,, Sec. 27, T6S, R36E SE), of SVf,. Sec. 20, T12N. R52E E*! of NE V Sec. 6, T5N, R22E SVfl. Sec. 31, T2S, RSE Evanston Savage Chauta Wormser Bozemae I 2 3 4 5 of of of of of NVfll SEV NVf,, SEV SHV Sec. Sec. Sec. Sec. Sec. Sec. Sec. Sec. Sec. Sec. Sec. Sec. Sec. Sec. Sec. I, T24N, R49E 12, T19N, RSlE 28, T12N, R44E 19, T U N . R55E 13. T23N, R57E 7, T2S, R U E 18, TIN, R20I 18, T4S, R26E 6, TlS, RSOE 16, T6N, R41E 7, T2S, R U E 7, TlS, R3E 21, TIN, R20E 15, T6N, R41E 31. T19N, R U E Soil Series Kevin Vona Unanmed loam Gilt Edge Edgar Richfield 116 Site Numbers, Cooperators, County, Legal Descriptions, and Soil Series for the 127 Small Grain Sites, 1968-1980. 61 62 63 64 65 Lasella Visaer Works Dralne Holland Cascade Madison Choteau 66 67 68 69 70 Dahlman Koch-Pox Todd Kronebusch Kronebusch 71 72 73 74 75 Rosebud I 2 I I I Still. Sec. 33, 12IN, RSE NE**, Sec. 9, T3S, RlW SE*!, Sec. 24. T28N, R9E NE1I1 Sec. 8, T7S, RSSE SVA of NWS, Sec. 21, T6N, R43E GcirKnr Evanston Evanston Kremlin Ploweree Rosebud Gallatin Gallatin Pondera Pondera I I I I I NWS, Sec. 13, T6N, R41E S * of NEll. Sec. 22, T2S. R6E NWiI , Sec. 21, T2S, R4E NWiI, Sec. 8. T29N, R2U SEiI of SEiI, Sec. 16, TION1 R3W Unwrn Bozeman Amerstdam Kevin Kevin DeStaffany DeStaffany Hufflne Kell Gettel Pondera Pondera Gallatin Pondera Cascade I I I I 2 StiiI, Sec. 29, T28N, Rlti ES of SES. Sec. 30, T28N, Rlti NES, Sec. 7, T2N, RSE StiS. Sec. 23. T30N, R2W SES, Sec. 8 T22N, RlE Scobey Amsterdam 76 77 78 79 80 Sommerfeldt Swlnland Swinland Goldenstein Huffine Cascade Park Park Gallat in Gallatin I I I I I NES. Sec. 17, T22N, RlE StiS. Sec. 17, TSN, R9E SES, Sec. 27, T SN. R9E StiS of SES, Sec. 27, T2S, RSE NWS, Sec. 7, T2N.RSE 81 82 83 84 85 Teymoes McOmber pPsrson Bros. Barber, L. Martens Teton Teton I I I I 3 NES, Sec. 25, T23N, R3W SUS, Sec. 14, T21N, RSti NWS, Sec. 32, T21N, Rlti NEH, Sec. 18, T19N, R14K NtiS of SVA, Sec. 33, T28N, R12E 86 87 88 89 90 Jurenka Hill Bltz Hill Spicher Hill Res.Site Hingham Hill Res.Site Rudyard Hill I 5 I 2 3 SES, Sec. 27, T35N, R9E StiS of StiS, Sec. 10, TlON, Rl2E NtiS of NES, Sec. 12, TI2N. RlOE SES of SES. Sec. 6, T32N, RlOE NWS of NWS, Sec. 27, T2SN, R9E Assinniboine 91 92 91 94 95 Vermulum Vermulum Johnson Lakey Kaimnerzell Glacier Glacier Glacier Liberty Liberty ? 5 3 2 I NES of SES, Sec. I, StiS of NWS, Sec. 6, StiS of NWS,Sec. 26, SES, Sec. 35, T13N, SES of NES, Sec. 5, Pendroy Pendroy Brockway 96 97 98 99 100 Cady Kaercher Donovan Tviet Chrlstofferson Liberty Hill Hill Richland Roosevelt 2 10 3 2 2 NtiS StiS NtiS StiS NWS of of of of of StiS. Sec. 26, T34N, R7E StiS, Sec. 2, T12N, R14F. SES. Sec. 13, T34N, R13E SES.Gec. 25, T25N, R57E StiS, Sec. 17, T29N, R56E Vida Williams 101 102 103 104 105 Iloye Benson Waters Holland Hansen Roosevelt Roosevelt Roosevelt Rosebud Sweetgrass 2 4 2 I 4 SES NES SES NES StiS of of ol of of SlA, SES, StiS1 NES, SES, Sec. Sec. Sec. Sec. Sec. 12, 22, 16, 19. 36, Williams Parshall Williams Floweree Floweree 106 107 108 109 HO Mosdal Larsen Herzog McFarland Stillwater Rosebud Bighorn Stillwater Yellowstone 2 I I I I NES SES NtiS StiS StiS of of of of of StiS, SES, StiS, StiS, SES, Sec. Sec. Sec. Sec. Sec. 12, TIN, R22E 24, T6N, R41E 7, T2S, R34E 21, TIN, R20E 10, TIN, R24E 111 112 113 114 115 Becker Warren Sire Larsen Eastlick Yellowstone Bighorn Yellowstone Rosebud Stillwater I I 2 I 1 NES of StiS. Sec. 26, T2S, R26E SES, Sec. 18, T2S, R34E StiS. Sec. 22. TIN, R29E SES of NWS, Sec. 24, T6N, R41E NWS of NWS, Sec. 11, TIN, R22E Absorokee Richfield Danvers 116 117 118 119 120 Lee Larsen Keller Logan Warren Yellowstone Rosebud Yellowstone Yellowstone Bighorn I 2 I I 3 NWS of NWS, Sec. 3, T IS. R26E StiS of SES, Sec. 24, T6N, R4I# NWS, Sec. 29, T4N, R32E SWt. Sec. 36, TIN, R28E StiS1 Sec. IR, T25, R34E Absarokee Degrand Kobar Shaak Richfield 121 122 123 124 125 126 127 Haines Keller 2 I I 2 I I i ____ - 222 StiS of NWS, Sec. 16, TON, R38E SUS, Sec. 21. T4N, R32E NES of NWS, Sec. 36, TIN, R38E NWS of SVA, Sec. 24, T6N, R21E SVA of NWS, Sec. 15, T2N, R28E NES of NES, Sec. 30, T2N, R28E NWS of StiS, Sec. 17. T12N. Rl3E Vanstel Lonna Choteau Rosebud Yellowstone Yellowstone Schaff Golden Valley Huntley Sta. Yellowstone Michael Yellowstone Rolston "Hi . Total Experiments w/Yleld Data T14N, T14N, T32N, RSE T31N, RSti RSti RSti Cargill Cargill Bridget Bozeman Amsterdam Rothiemay Rothiemay Rothiemay Marias R6E T ION, R56E TlON1 RSSE TION1 RS6E T6N, R43E T SN, R22E Evanston Yaraac Bainville Marias Thurlow APPENDIX II 118 Soil Series, Textural Class, Textural Family, Classification, Water Regime, and Temperature Regime of the 127 Experimental Sites. Series Name Textural Class Absarokee Amsterdam Assinniboine Bainville Bozeman Bridger Brockway Cargill Chama Chanta Cherry Coffee Creek Danvers Degrand Dooley Edgar Evanston Farland Farnuf Floweree Fort Collins Gerber Gilt Edge Havre Joplin Judith Reiser Kevin Kobar Kremlin Lonna Manhattan Marias Martinsdale Marvan Parshall Pendroy Richfield Rothiemay Savage Scobey Shaak Tanna Telstad Thwrlow Unnamed Vanstel Vida Vona Wages Williams Winifred Wormser Yamac clay loam silt loam fine-sandy clay loam silt loam loam silt loam silty-clay silt loam loam silty-clay clay loam clay loam loam fine-sandy Textural Family fine-raontmorillonitic fine-silty fine-loamy fine-silty fine-silty fine-loamy fine-silty fine-silty loam fine-silty fine-loamy loam fine-silty fine-montroorlllonitic fine-montaorillonitic fine-loamy loam fine-loamy fine-loamy fine-loamy loam fine-silty silt loam fine-loamy loam fine-silty silt loam fine-loamy loam silty-clay loam fine-roontmorilIoni tic fine-montmorilIonitic silty-clay loam fine-loamy loam fine-loamy loam gravelly-clay loam fine-loamy silty-clay loam fine-silty clay loam fine-loamy silty-clay loam fine-montmorilIonitic fine-loamy loam silt loam fine-silty coarse-loamy fine-sandy loam fine-raontmorillonitic clay fine-loamy loam fine-montmorillonltic clay loam coarse-laomy fine-sandy loam clay fine-montmorillonitic silty-clay loam fine-montmorillonitic fine-loamy loam fine-montmorillonitic silty-clay loam clay loam fine-montmorillonitic fine-montmorillonitic silty-clay loam fine-montmorillonitic clay loam fine-loamy fine-montmorillonitic clay loam fine-loamy clay loam fine-montmorillonitic fine-loamy fine-sandy loam coarse-loamy fine-loamy fine-loamy loam clay loam fine-montmorillonitic clay loam fine-montmorillonitic fine-loamy loam loam Classification Typic Argiboroll Typic Cryoboroll Arldic Argiboroll Ustic Torriorthent Argic Pachic Cryoboroll Argic Cryoboroll Borolllc Calclorthld Borollic Calclorthld Typic Haploboroll Aridic Haploboroll Typic Ustochrept Typic Haploboroll Typic Arglboroll Aridig Argiboroll Typic Argiboroll Ustolllc Camborthid Aridic Argiboroll Typic Argiboroll Typic Argiboroll Aridic Haploboroll Ustollic Haplargid Vertic Argiboroll Haplustollic Natrargid Uatic Torrifluvent Aridic Argiboroll Typic Calciboroll Ustollic Haplargid Aridic Argiboroll Borollic Camborthid Aridic Haploboroll Borollic Camborthid Typic Calciboroll Ustertic Torriorthent Typic Argiboroll Ustertic Torriorthent Pachic Haploboroll Ustertic Torriorthent Aridic Arglustoll Aridic Calciboroll Typic Argiboroll Aridic Argiboroll Abruptic Argiboroll Aricid Argiboroll Arldic Argiboroll Ustolllc Haplargid Typic Cryoboroll Ustolllc Haplargld Typic Argiboroll Ustollic Haplargid Aridic Argiustoll Typic Argiboroll Typic Haploboroll Aridic Argiustoll Borollic Caraborthid Water Regime Temperature Regime UBtic udic ustic— ssridic aridic— kistic udic udic aridic— fustic aridic— ♦ustic ustlc ustic— xiridic ustic ustlc ustlc ustic— +aridic ustic aridic—*ustic ustic— +aridic ustic frigid cryic frigid mesic cryic cryic frigid frigid frigid frigid frigid frigid frigid frigid frigid ustic-+aridic aridic— +ustic ustic aridic— +ustic aridic— Rustic ustic-*aridic ustlc aridic— +ustic ustlc-»aridic aridic-'+ustic ustic— +aridic aridic-+ustic ustic aridic— +ustic ustic aridic— +ustic ustic aridic-tustic ustic-+aridic ustic-^aridic ustic-aaridic ustic-taridic ustic ustic— +aridic ustic— +aridic aridic-+uatic udic aridic-*ustic ustic aridic-+u8tic ustic— +aridic ustic ustic ustic— +aridic aridic-»ustic frigid frigid frigid frigid frigid frigid frigid frigid frigid frigid frigid frigid frigid frigid frigid frigid frigid frigid frigid frigid frigid frigid frigid frigid mesic cryic frigid frigid frigid frigid frigid APPENDIX III 120 Site Number, Experiment Number, Average I K response. Maximum % K Response, and K Rate at Which Maximum Crop Response Occurred. Slti No. I 2 3 4 5 5 6 7 8 9 10 10 11 12 13 14 14 14 14 14 14 14 14 15 15 16 17 18 18 18 18 18 18 19 19 20 20 20 21 21 22 23 23 24 24 25 25 26 26 26 26 26 26 26 26 26 26 26 27 27 27 28 29 30 31 32 33 34 35 36 36 37 38 38 38 39 40 No. I 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 SI 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 X K res. 101 107 103 103 94 107 124 111 104 104 107 101 100 102 101 111 83 107 95 109 107 103 103 108 95 103 90 98 112 105 HO 121 123 101 108 99 97 103 89 118 HO 102 107 107 105 113 96 102 99 111 106 95 94 102 144 102 109 111 105 116 111 121 100 104 106 104 104 104 120 108 104 98 104 85 98 111 134 102 Maximum % K ree. 120 107 111 107 101 111 124 119 106 109 108 107 102 103 106 115 86 HO 109 126 114 109 HO 117 96 113 95 98 115 109 HO 129 127 104 109 99 101 105 90 118 HO 107 109 108 109 114 100 104 101 111 107 96 97 102 146 103 109 111 108 121 114 133 114 HO 106 106 106 105 124 109 106 100 106 95 100 116 127 104 K rate of Max. res. 112 112 28 28 112 28 112 28 112 112 112 28 28 28 112 28 112 45 45 45 . 134 134 134 45 28 28 112 112 28 28 56 134 90 134 112 28 112 28 112 90 112 112 112 112 28 112 112 112 28 90 45 112 90 34 134 28 90 90 22 112 112 90 134 112 28 28 28 112 28 112 112 28 28 112 22 45 134 134 Site No. 41 42 43 44 45 46 46 47 47 48 49 50 51 52 53 54 55 56 56 57 58 58 58 59 60 61 62 62 63 64 65 66 67 68 69 70 71 72 73 74 75 75 76 77 78 79 80 81 82 83 84 85 85 85 86 87 87 87 87 87 88 89 89 90 90 90 91 91 92 92 92 92 92 93 93 93 94 94 Exper. Z K ree. 79 80 81 82 83 84 85 86 87 88 89 90 91 93 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 HO 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 Average X K res. Maximum K rate of X K res. Max. res. 103 100 116 109 115 102 107 HO 89 119 115 96 124 112 92 93 104 114 100 118 98 114 97 83 109 106 121 85 117 107 98 101 HO 86 98 90 107 93 104 101 96 130 103 HO 108 107 97 89 90 87 81 102 94 61 112 97 99 109 90 93 93 122 90 107 80 81 120 146 86 70 100 92 103 108 106 107 102 105 HO 112 120 113 115 J03 108 HO 107 119 115 105 124 122 106 105 103 113 101 116 99 120 98 101 112 112 124 98 119 108 100 105 HO 99 104 107 116 102 112 104 100 133 108 HO 109 105 HO 97 100 95 88 104 101 62 130 99 101 115 95 95 95 138 100 116 95 96 143 173 92 70 104 112 115 117 127 114 121 114 134 134 134 90 134 90 45 90 134 45 90 22 45 90 134 45 134 134 45 90 134 90 45 134 22 22 45 45 22 22 90 112 11 134 56 90 134 134 22 22 11 56 56 56 45 90 45 90 45 45 90 67 67 45 45 45 134 90 45 45 56 56 56 134 45 45 134 90 121 Site Number, Experiment Number, Average % K Response, Maximum % K Response, and K Rate at Which Maximum Crop Response Occurred site No. 95 96 96 97 97 97 97 97 97 97 97 97 97 98 98 98 99 99 100 100 101 IOi 102 102 102 102 103 103 104 105 105 105 105 106 106 107 108 109 HO 111 112 113 113 114 115 115 HS 116 117 117 118 119 119 119 Exper. No. 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 107 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 X Average K res. 95 87 132 93 100 101 100 109 115 90 100 118 107 109 90 133 88 116 120 108 107 HO 97 90 100 97 97 117 91 HO 120 99 112 153 118 111 112 100 99 107 HO 100 111 102 111 122 117 104 105 101 95 103 97 99 Maximum % K res. 98 91 162 106 102 105 106 111 116 100 102 126 107 120 111 139 92 115 128 113 109 HO 112 98 104 97 108 135 98 111 135 100 114 160 118 117 116 101 101 116 115 102 111 103 113 123 117 105 105 106 97 105 100 100 K rate of Max. res. 56 45 45 45 56 90 56 45 90 90 45 45 45 134 45 90 22 90 134 90 112 112 134 45 22 112 134 45 115 115 115 48 48 57 54 115 57 115 57 96 115 115 54 57 115 48 48 96 48 48 48 48 27 127 Site No. Exper. No. 120 120 120 121 121 122 123 124 124 125 126 127 211 212 213 214 215 216 217 218 219 220 221 222 Average Maximum % K Res. % K res. 103 93 95 104 95 118 108 96 105 104 97 92 107 98 100 104 102 122 HO 96 106 109 98 96 K rate of Max res. 96 81 81 96 96 96 48 48 48 115 96 39 APPENDIX IV 123 COMPLETE DATA SET USED IN THESIS PREPARATION FORMAT STATEMENT (CP6 -SPSS) INPUT FORMAT NOTE: FIXED (F3.0, F1.0, F1.0, F2.0, X, FI.O 5 X 5 5F4.0, X 5 FI.O 5 F2.0, F3.0, F2.0, F3.0, X 5 3F2.1, 3F3.2, X 3F3.0, F2.0., F2.0, F.1.0, X 5 F2.0, F2.0 / IOX 5 F4.0, X 5 F2.1, F2.0, X 5 F4.2. F3.I 5 X 5 FI.O 5 X 5 F2.0, X 5 F2.0, X 5 F2.0X, F2.0, X 5 F3.1, F2.0, F3.0, F4.1, X 5 F3.1, X 5 F3.1, X 5 F3.1, X, F3.1, X 5 F3.1, X 5 F3.1 / IOX f3.0, F3.0, 6F4.0) Refer to the next page. Format statement begins in column I 5 located 2 columns after the dash mark. It ends for each card 2 columns before the column with all number ones. The column with all number ones and the next two digit column (beginning with number 81) are not part of the data file. The numbers in these columns are values for V27 and V42 and are located elsewhere in the data file. They were also moved to the end of each line for the creation of subfiles for manipulation of the data. Table 8 may be used as a cross reference. It includes the variable names, numbers, and format for each one. i 1 34 I I 68 I 375632892767 2 8 4 I I 71 8 4 I I 71 2 1082 5 3 4725 88 11 252020292164 967 15 8 4 8 3 4 86 112 J 4 3 I 141171 14 1 1 7 1 5 2 3 I 141171 8 3 1 I 78 831178 2 3 I 11 811177 I 2 I 3 I 4 SI I I 77 1 6 1 I 71 2 3 I 161171 2 I 5 161171 16 I 7 821178 821173 8 2 1 I 78 872177 3 I 2 3 I 872177 872177 973172 2 3 I 973172 973172 2 I 5 I 9 20 21 22 23 24 25 26 27 I 271 I 80 1271130 1271130 873177 873177 3 I 2 3 I 28 29 - 30 31 32 33 34 - 873177 971172 2 3 I 971172 971 I 72 151 I 7J 2 3 I 35 - 151170 2 36 37 - 151170 751176 3 I 38 39 - 751176 751 I 76 2 3 22 443933 178157158 2 81 2 2 028112 1 1 1 3 1 6 242632 24602332221821302265 I 181 70 4 4731 67 2 95 22 022 36093508319932733515 1213 10 8 4 7 4 3 6 7 2 97 134 022 202917071935 028112 14 1 7 1 7 392829 50335047469746574549 1295 30 4 4 7 3 4 6 7 2 1 00 22 022 401619 313229842648 812 10 5 4 8 2 2 95 45 045 876 10 95 112 3 4825 2 72 798 106 00 45 4590134 4593134 045 90 243923452292 853 10 S 4834 96 28 2 23592292209723652285 1146 10 8 4 7 4 0 58 2 100 90 166156177 89 374328 43 41 23 38 I 46 66 39 216222125 72 2 21 15 25 216222125 2 77 74 75 21 15 25 297 71 166144154 90 3 337 57 153140146 79 73 I 13 75 54 216222125 2 21 5 039 00 39 362824 3 90 I 92638 3 I 57160168 I I 6222 8 I 160152133 66 76 I 13 28 216222224 2 21 IS 30 116222 I 21 66 76 92 I 57160168 8 93 028112 283540 163166162 4 254 64 I 20132139 96 I 83 83 87 87 I I I 5 21 I 7 51 4 9 1 38 I 75 1 4 9 1 3 8 93 I 5281 5 81 83 I I I I I I 90 3 74328 4590134 I I I I 90 022 81 81 I I I 90 95 I I I I I I 25 90 045 2 76 I 92638 2 4834 3 3 90 150138163 62 5 87 383136 I 23 045 72 151734 3 2 126310011263 798 00 4834 2 1 00 90 21842097 21571908 876 10 8 4 8 3 2 69 2 96 39 340032393105 812 10 5 4 2 2 2 95 45 12101284 961 4590134 142158155 83 2 7 9 63 316212122 294 85 I 66 68 216222 85 70 51 7 4 54 13 28 I 30 55 51 31 15 30 I I I I I I I I 87 89 89 89 90 90 90 90 90 90 90 90 90 90 90 90 92 92 92 93 I I 93 93 93 93 93 95 I I 95 95 I 96 96 96 I I I I 124 10 8 3 1 I 78 81 I I 7 7 011 67 40 41 42 - 43 44 - - - 2 3 I 871177 871177 - 11170 2 3 I 237924062312 812 10 5 4 8 2 2 101 45 I 24310081492 - I I I 70 11173 121171 121171 2 3 I 902 5 7 4843 120 112 I 774 I 7 1 4 1 8 8 2 72 2 69 1 2 1 I 71 3 I 1008 15 106 112 55 - 56 57 - 58 59 - 60 61 - 461174 4 6 1 I 74 - 151171 151171 151171 - 761 I 68 761 I 68 - 761 I 68 2 8 1 I 71 281171 2 8 1 I 71 551 551 551 181 181 I I 1 I I 73 73 73 71 71 4822 72 2 67 2 72 2 201619691982 914 10 98 112 I 2 4827 4831 11 045 2 3 I 1 1 4 6 10 8 4 7 4 0 108 11 I 7671 7341 949 58 2 3 I 1 1 27 5 H O 112 64 2 - 262175 262175 78 79 - 262175 261 I 75 3 I 80 - 261175 2 3 I 2 35 28 7 4831 69 2 28963138311129972869 1295 108 5 22 8 4704 65 116222 68 57 8 I 59 21 49 15 2 21 75 13 I I I 46 I I I 022 4590134 028112 12 14 022 19 4590134 022 4590134 371 I 58 101 46 145 294 60 15 I 64 101 338 151 61 216222224 91 71 39 66 1 I 233745 163155161 7 0 3 101 369 63 216222115 2 81 66 65 21 293419 316212122 41 15 30 I 30 51 64 156142136 163166102 353 40 I 281 3 3 1 4 0 60 66 216222 102 7 216212232 233843 157145154 85 2 1 0 4 1 64 43 316222224 333833 216222224 3 4 5 50 4 35 31 15 30 103 314634 163164163 2 104 91 5 30 102 103 4 2 27152856291028432849 I 295 5 8 4704 65 2 25 282029 028112 32633129329933763268 1 0 4 8 20 8 4741 64 2 103 90 194221241969 880 109 26 I I I I 2 2 98 98 98 99 99 76 98 283540 22 97 97 21 2 O il 97 I I I 3 16 143153165 I S 36 76 028112 13 16 76 116222 19 2 66 I 92638 I 57160168 3 99 028112 12 17 862 10 I 4834 113 28 383341223767 21 I I I 2 2 3 I I 20 3 4590134 8 21 10 96 2 I 95 4590134 116222 216324225 2 68 76 84 86 21 022 2 3 I 90 I 57160168 97 214022 18 2 31183205311132123152 1173 5 8 4 7 1 7 67 2 103 90 I 794 20291 848 4720 15 028112 11 1 7 2 3 I 4 192638 028112 022 2 3 I 90 3 35823730359536363636 1 0 4 8 80 2 4 8 2 0 64 2 104 22 75 76 77 1 8 1 I 71 5 160157152 105 262 48 41 5 213121 149146143 2 106 2162221 I 5 216222115 15 30 21 10 65 20 4 27 2 44 213121 149146143 2 105 41 OO Kl 73 74 74 I I 7 6 461174 10 90 OO r\j 70 71 72 741176 74 I I 7 6 876 99 5 5 21 21 10 10 99 101 101 101 101 101 101 101 I I I I 101 101 102 I 02 I 02 103 I I 103 103 I I 103 I I 103 103 104 I I 104 104 I I I I I I 04 I 04 I 04 25 I I I 25 I I I 105 105 105 105 105 105 106 106 125 68 69 045 171171 171171 8 7 1 I 77 48 49 65 66 67 229822112265 *71176 171171 45 46 47 62 63 64 I 2 3 I - 50 51 52 53 54 871176 371176 81 - 82 - 83 84 - 85 - 261 I 75 291171 291171 2 9 1 I 71 87 - 61 I I 74 61 I I 7 4 6 1 I I 74 88 - 21 I 70 21 I 70 21 I 70 86 89 - 90 91 - 92 - 71 I I 7 5 71 I I 75 93 94 - 95 - 96 97 3 I 2 3 I 2 3 I 2 107 45 143815251525 1264 10 8 4 7 1 5 106 28 64 2 1 2 0 6 6 0 2 4 8 5 7 58 2 107 112 29532904341929392937 2 1075 71 I I 75 9 0 1 I 75 3 I - 9 0 1 I 75 9 0 1 I 75 872176 3 I 116 45 1546178815721599 899 10 2 4 8 4 6 116 45 I 821 I 8 8 2 2 0 9 7 98 99 - 872176 872176 I 00 101 - 972172 972172 102 - I 03 104 - 972172 131171 3 I 131171 2 1 3 1 I 71 2 6 1 I 72 3 I 261 I 72 261172 262172 2 3 I 262172 262172 2 7 1 I 71 2 7 1 I 71 2 105 - 106 107 - I 08 I 09 - 110 - 111 - 112 - 1 1 3 - 114 - 1 1 5 1 1 6 1 1 7 - 271171 151 I 70 181170 181 I 70 1 1 8 119 - 561 I 73 561173 I 20 - 561 I 73 631174 I 21 - 2 2 3 I 2 3 I 2 3 I 876 115 10 90 5 4809 4822 67 72 022 4590134 I 20 023112 IC I 3 022 4590134 5 41 I 54149 1 34 316222224 4 94 41 216222135 5 73 72 73 21 316322132 5 79 72 73 41 045 90 2 045 25802738274828762580 1295 5 8 47 0 4 65 2 111 90 022 25832621278228562688 I 295 5 8 4 7 0 4 65 2 111 90 022 229225002607 1242 5 I 4709 114 112 028112 65 2 69 2 192222182083 874 15 4 4 8 3 2 3 I 115 28 16171540182917751614 2 893 113 72 022 I 8 4590134 I 9 4590134 2 20312131241722982162 022 77 147152129 107 34 402 167 107 396 66 96 105 151 I 5 66 4590134 334036 143170158 45 111 306 58 97 15 30 156 10 I 106 I I I 06 106 I 06 18 56 89 69 116222 58 8 I 58 21 I 58 54 59 15 I I 13 I 15 77 30 213121 149146143 2 111 2162221 I 5 5 21 10 25 283917 I 50142 1 56 2 111 216222115 5 21 13 25 333833 I 6 0 1 5 71 5 2 133 3 112 322 77 216222224 I 72617 I 5 9 1 501 5 C 91 3 114 167 25 216222 33 42 7 304324 216222 7 147144137 10 28 216222115 61 21 76 213121 149146143 2 111 58 5 33 56 56 66 I I I I I I I I 20 68 I 374328 175149138 109 4 5 90 1 34 028112 11 16 625 192638 I 57160168 3 109 90 028112 12 14 106 331920 I 99 2 207623862211 1013 10 8 4 8 3 8 115 28 4810 216222224 393523 164151140 I 35 3 107 360 74 33 6790 2 2 8 I 5 2 3 045 I 0 0 1 I 1 0 9 1 0 75 798 00 4834 111 45 10 45 137 106 3 2 3 4 36 2 2 3 I 2 I 53 25 I 06 I 06 106 107 I 07 107 107 107 I I I 07 107 107 107 I I I I I 09 109 109 I I I I 109 109 I I I I I I I I I I I I I I I I 109 I I I I I I I I I I I I I I I I I I I I 1 I I I I I I I 2 I I 2 I I I I I I 2 64 21 10 62 20 2 21 2 8 I 4 43 I I I I 2 I I 4 I I 4 21 36 I I I 53 2 23 114 I I 7 126 3 I 8 15 I 25272789276226482822 1027 2 0 8 4 7 3 2 64 2 1 1 2 I 34 240625672574 15 17 028112 I 22 - 631174 2 I 23 I 24 - 631174 974172 3 I 974172 974172 2 7 1 I 74 2 3 I 2 7 1 I 74 2 271174 891175 891 I 75 3 I - I 25 I 26 I 27 I 28 I 29 I 30 131 I 32 I 33 I 34 I 35 I 36 I 37 I 38 I 39 143 I 44 145 I 46 147 I 48 149 I 50 I 51 I I I I 52 53 54 55 I 56 157 I 58 159 I 60 161 I 62 - 2 891175 621 I 75 621175 3 I - 621175 681175 3 I 681 I 75 6 8 1 1 75 2 - 541173 - 541173 541173 801177 801177 801177 361171 361171 2 3 I 2 3 I 2 3 I 2 3 6 1 I 71 421172 3 I 421 I 72 421172 11 I I 7 0 2 3 I 111170 11 I I 7 0 71 I 7 0 71 I 70 71 I 70 2 3 I - 3 0 1 I 71 301171 - 3 0 1 I 71 - 362171 2 3 I 362171 362171 2 3 - 2 3 I 798 126 00 45 72 045 4834 8 4539 90 64 022 4590134 04 5 6790 14 2 0 4590134 283917 54 48 50 I 751491 38 I 501421 56 216222115 5 203127 157156132 I 97 122 4 4 7 71 84 81 79 022 4590134 I 276527702646 1 4 2 9 30 2 4 5 4 7 028112 103 28 231923652455 I 3 7 9 10 7 4 5 4 8 106 112 312933083175 1379 20 2 4 5 4 8 64 64 28 4 5 90 1 34 4590134 2425 172187 216222 7 216222 2 I I 8 121 121 121 I 22 122 13 25 I I 23 58 I I I I I 74 8 30 2 2 2 90 103 7 3 I I 3 32 10 23 109 90 2 2 32 2 2 323128 142127131 111 I 93 2 3 3 52 216222 40 37 7 373015 148133130 99 I 97 342 51 216222 56 58 7 231613 126124 7 I 126124 7 I 74 2 022 4590134 22 124121124 3 35 4 57 23 36 38 33 32 30 46 59 61 12 20 33 98 452307 74 2 149137134 1 00 470 83 86 77 023112 I 50406 1 451 341 4 0 101 I 102 028112 242209 142138135 114 I 1 04 216222 028112 222305 I 371 201 23 I 104 216222 231613 I 24121124 2 104 126124 I I 2 I I 8 I I 8 21 85 114225 144141135 I 86 5 8 7 82 2 028112 67 I I 28 12 23 38 75 75 2 22 28 38 7 3 32 8 20 7 3 32 18 33 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 28 212222532181 1 4 2 9 30 2 4 5 4 7 I I 7 13 28 33043359338934223709 1455 50 I 4 5 4 6 67 2 112 134 158716321609 1371 10 I 4 5 4 9 64 I I I I 121 3 022 106 I 52 I 022 15521324142516061700 I 4 62 20 I 4 5 5 6 64 I 110 134 106 374328 2 022 67 117 118 31812717334126883072 I I 5 6 9 4 0 3 4 5 3 8 64 105 45 100 3 2 I 7 0 0 1 9 7 6 2 0 5 0 2 2 5 8 2 1 71 1242 5 I 4 7 0 9 65 2 133 90 1962205027082419 9 3 7 50 8 4 8 3 3 2 138 67 34263308292329943341 72 2 1523 30 2 4 5 3 7 98 134 43854345386338834357 1554 50 99 134 I 50 2 7 I 12 20 33 2 2 2 I I 7 122 85 85 85 86 86 86 93 93 93 97 97 97 98 98 98 I 00 I 00 I 00 102 102 102 104 I 04 104 I 04 104 104 I 04 104 I 04 127 I 40 I 41 142 - 893 10 2 4 8 1 0 119 45 8871122 968 - 163 164 I 65 I 66 167 I I I I - 68 69 70 71 - I 72 I 73 I 74 - I 75 I 76 I 77 I 78 I 79 I 80 181 I 86 187 I 88 I 99 I 90 I 91 192 I 93 I 94 I 95 I 96 197 198 I 99 2 3 I 791 I 77 791 I 77 601174 2 3 I 601174 601174 2 991172 2 0 1 I 71 2 0 1 I 71 - 531173 531 I 73 - 200 201 202 - 203 - - 2 0 1 I 71 531173 2 4 1 I 71 241171 2 4 1 I 71 1 0 3 1 I 72 1031172 1031 I 7? 211171 21 I I 71 211171 201170 201 I 70 201 I 70 2 2 1 I 71 221171 2 2 1 I 71 21 I I 7 0 022 52624805539655245000 1520 5 2 4 53 9 67 I 105 90 39744256408644514257 022 1569 112 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 20 90 I 4537 67 124 30 134 2 4536 72 4590134 022 4 59 01 34 022 265423522392 1 0 0 5 60 6 4 7 2 6 90 112 0281 12 53 4590134 298427692984 625 10 4 4 8 2 6 10 11 0281 1 2 4590134 2 022 164015991747 028112 2 235924862365 60 6 4 7 2 6 28 53 2 2 3 245926072668 800 20 5 4 7 2 5 109 112 67 2 I 277124932507 64 2 67 2 2 1005 3 105 21 I I 7 0 2 1 11 70 2 701 35 3 I 10 112 24 I I 70 24 I I 7 0 2 2 4752 10 4 4826 4590134 363315 I 4213 61 26 71 I 1 09 4 50 87 2425 3 172187 1 21 23 26 31 028112 37 1 36 92 98 136 93 74 26 3 71 32 3 32 78 226222135 3 76 74 72 216222 80 134 560 78 7 68 7 75 2 91 225232215 3 33 225232215 22 21 4 64 30 3 3 88 89 3 3 3 3 89 89 92 92 3 3 92 96 38 3 3 3 96 96 97 97 97 28 3 3 3 373727 216324225 23 2 23 97 2 3 2 3 1 8 1 561491 4 5 2 102 510 93 216232232 23 225232215 3 93 98 67 33 243524 146133131 2 1 07 5 0 3 78 216222134 78 23 23 38 77 77 232318 99 216232232 2 101 88 82 23 15 28 85 83 182822 145146136 2 113 5 70 115 216324225 2 108 77 101 2 3 3 6 51 84 85 26 1 48 103 502 134 92 156149145 1 10 538 91 97 89 96 2 83 2 23 73 70 15 121 88 88 2 3 3 6 51 79 81 I 69160162 109 109 3 3 46 15 2 9 107 107 109 121 121 76 33 2 2 I 04 I 04 104 107 2 2 216324225 2 84 85 76 2 2 2 2 2 2 13 79 13 2 2 2 22 30 104 23 93 33 3 2 3 0 51 74 67 2 111 36 67 82 216232232 103 25 70 182822 145146136 2 96 511 106 2 028112 148 89 2 2 023112 417 332928 161148160 264 2 88 268 028112 I 9 0 2 2 1 1 0 2 1 71 625 226222135 111 37303609365637094045 625 10 4 4821 67 2 108 134 2 454645 I 25157142 102 I 107 373 61 2 022 701 35 107 112 216222 85 81 2 234 I 248 421 7 3 2 2 1 0 2 4 0 6 7 7 7 20 8 471 I 53 2 106 22 67 292117 153137138 161 1 104 462 88 96 40923770370935883662 695 30 3 4 7 5 3 64 2 92 22 64 I 4590134 2 4752 I 022 4 59 0 1 34 I 15371751190018041911 2 1523 991 I 72 - - 3 I 621174 621174 621174 9 9 1 I 72 32793683354134143562 1 4 6 2 20 3 4 5 5 7 64 I 112 22 81 13 82 3 3 3 3 3 3 3 3 102 102 I 02 103 103 103 107 107 107 3 I I 0 3 3 3 H O I I O 3 I I 3 I I 3 128 I 82 183 I 84 I 85 I 731 I 76 731 I 76 731176 791 I 77 - 208 209 - 210 241 I 70 1032172 3 I 1032172 1032172 5 91 I 74 2 591174 591174 3 7 1 I 71 2 2 3 I 2 3 I 1 0 4 1 I 76 - 21 8 219 - 1041176 41171 4 1171 41171 220 221 222 223 224 - I 181 I 73 1181173 1181178 - 121 I 1 3 0 I 21 I I 3 0 121 I I 3 0 - 1241173 I 2 4 1 I 73 124117% 225 226 227 228 229 230 231 232 233 234 - 581175 581175 - I 2 6 1 I SO I 261 I 30 235 236 237 - 238 239 240 241 242 - 243 244 - 581175 I 261 381 381 381 581 I I I I I 80 71 71 71 73 581173 581 I 7J 651175 6 5 1 I 75 6 5 1 I 75 2 5 1 I 71 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 8 4613103 305427732900 1 3 5 6 10 4 4 5 3 4 3 2 69 2 279824262838 990 15 2 4 5 3 2 1 0 6 101 112 3 424141173963 899 IC 4 4605 97 48 997 8761017 20 96 4 4617 232722452223 1 1 2 7 30 8 4 6 1 6 96 48 3 364250 2 057115 8 12 17 69 2 0 4 8 96 7 10 16 67 2 0 4 8 96 9 1 9 21 048 64 411818 23 028112 2 35073275332534353351 7 7 7 10 4 4 6 4 7 58 2 98 90 292428042669 929 20 7 4 5 5 5 92 3 98 96 309030752994 23 5 44 49 111314232 I 9 147185192 121314214 5 44 28 48 5 34 I 3 25 147 83 131 68 23 38 20 85 5 022 20 25 13 I 5 21 45 30272757288629862901 777 10 4 4 6 4 7 58 2 99 90 022 4590134 34193214329033733413 820 10 5 4 6 1 6 6 9 2 I 0 0 I 34 336034073279 022 20 22 6 4616 94 3 4590134 028112 I 5 0 1 34 1 3 4 91 246 107 382241 149161171 1 9 3 4 9 5 2 4 5 1 4 9 86 4 154744 4590134 0 4 8 96 6 15 16 3 1 73624 96 9 117 303936 149176170 4 94 022 792 100 16 2 112 2 9 0 6 2 4 3 9 2 8 53 8 2 3 20 4 4 6 1 6 98 115 838 102 19 I 33 023112 58 95 4590134 216324225 212 4 I 381491 57 95 312 76 118178167 96 309 164 433428 I 701 381 3 8 3 97 305 80 323630 138150149 131 4 97 312 79 322338 162155148 4 98 4 3 3 4 28 I 7 0 1 3 8 1 3 8 I 49 3 98 79 9 373340 I 521451 5 I 3 98 4 96 69 192426 128134121 216322234 62 42 35 7 5 34 25 41 326222325 4 44 25 46 1 1 6322 38 22 316224 36 7 5 44 I 5 28 316334334 6 44 33 46 126224225 24 25 46 111222132 5 83 81 69 44 8 23 211224 2 24 I 5 25 2 24 25 46 89 100 7 126224225 42 28 216322234 91 2 36 72 125222225 3 3 3 4 3 3 34 18 100 34 10 36 7' 4 23 I I 7 4 4 83 83 83 4 4 4 4 85 85 85 9 I 4 4 4 4 91 91 4 4 4 4 94 94 94 95 95 95 4 4 95 95 4 4 95 96 4 4 96 96 9 7 97 4 4 4 4 4 4 4 4 4 4 4 90 I I 3 I I 7 I I 7 4 4 4 4 4 97 97 97 97 98 98 98 98 98 98 98 98 98 99 129 - 35 45 022 373727 169160162 268 2 117 •o O 215 216 217 1213 101 4590134 rxi - 3 7 1 I 71 371171 I 04 I I 7 6 3 I 3 022 00 - 112 21642446292322982406 625 10 4 4821 67 2 1 35 45 14851320150410971359 OO OO 211 212 213 214 3 I 114 LW - IW - 205 205 207 OO I* 204 245 - 251171 2 246 247 - 251171 - 1 0 5 1 I 78 3 I 248 249 - 250 251 - 1051178 1051173 I 101 I 76 2 3 I 11011?6 I 101 I 76 101171 3 I 101171 2 101171 3 I 252 253 254 255 256 257 258 259 260 261 262 263 264 3 I 661175 661175 I 171 I 30 1171130 2 3 I 1171180 2 5 1 I 70 3 I 251 I 70 2 3 I - 270 271 - 275 276 277 278 279 - 282 - 283 284 - 285 - 280 281 251 I 70 1141177 I 14 I I 7 7 2 2 2 I 14 I I 7 7 3 1 I 70 3 T l 70 2 31 I 70 41170 3 I 4 1170 2 41 I 70 1191178 I 191 I 73 1191173 3 I 3 I 2 3 69 1158 20 4 4 5 5 1 1 0 6 101 57 252525682501 1158 10 2 4 6 0 7 1 0 6 102 28 306230193095 I 2 4 9 40 I 4600 101 115 318131523238 1181 10 4 4 5 4 9 102 115 61 64 2 2 0 4 8 96 2 8 13 3 057115 0 3 9 212021842120 326 10 4 4 6 1 6 60 103 57 229325462157 I 0 3 6 80 6 454 5108 111 28 205521922055 990 15 2 4 5 3 2 1 0 6 107 28 384240393888 1194 5 4 4548 1 05 48 67 95 83 216322234 165160165 I 3 90 34 10 52 131224135 54 3 84 81 5 34 I 3 25 49 028112 203833 I 55160166 4 I 00 131224135 5 34 20 30 342527 216222132 2 24 13 25 2 0571 I 5 5 9 14 2 057115 I 8 14 2 022 203833 I 58160166 I 7 2 4 1 01 4590134 0 4 8 96 11 17 21 22 436 75 168154159 4 99 4 99 99 99 4 4 4 4 4 41 131224135 34 20 30 7 4 24 55 63 192426 128134121 2 102 520 86 125222225 3 94 89 87 34 10 23 84 434526 116222125 24 169156156 86 4 149134149 32 2 80 25 46 4 4 4 4 4 4 4 4 4 4 4 4 4 4 22 99 99 99 99 I 00 I 00 100 I 00 I 00 I 00 I 00 I 00 I 00 101 101 101 101 101 101 101 101 101 102 102 102 102 216132135 I 14 15 30 116322 5 34 25 41 4 4 4 I 02 102 103 103 103 103 103 30 4 4 103 103 4 103 103 103 166168159 4 4 4 4 63 1 5 6 3 1 0 1 2 5 2 474641 I 9 23 41 303936 149176170 I 50 4 103 3 44 28 181 028112 216212232 5 94 89 67 5 4 4 4 4 4 4 24 171824 028112 84 116222125 2 71 64 54 23 3 0 4 8 96 4 7 17 101 292421 27 75 126 4 15 I 551 571 6 0 I 8 057115 2 82 3 3 4 1 34 2 2 163148158 I 7 0 2 8 H 2 61 I 57 107 92 443534 028112 60 114 I 7 3 1158 10 2 4 6 0 7 1 0 6 3 107 28 34883453337736543543 801 10 8 4 6 1 7 6 7 2 105 90 257425802681 701 10 4 4 7 4 5 104 112 30 564 4 277529772648 149915821453 829 20 5 4 6 1 6 I 06 48 99 7 221322122 75 85 4 94 44 15 4 4 4 130 101 I 70 6 6 I I 75 61 O oo - 4745 OO 101170 101 I 70 - 273 274 1131177 2 3 I - 268 269 272 1131177 2 3 I 4 O 266 267 - 1091176 1091176 1 0 9 1 I 76 1131177 10 OO 265 - 2 701 101 28 239023872360 1 4 0 9 45 8 4 6 0 8 100 48 236823912314 - 286 287 288 289 290 291 292 81 I 70 31 I I 71 3 I 31 I I 71 31 I I 71 2 3 I - 296 297 - 298 299 - 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 - 321171 3 2 1 I 71 321171 351171 3 5 1 I 71 351171 1161178 I 161 I 78 1161178 1211179 I 21 I I 7 9 I 2 1 1 I 79 1251177 I 25 I I 77 1 2 5 1 I 77 2 3 1 I 71 2 3 1 I 71 2 3 1 I 71 2 23 344742 028112 67 2 377639843896 935 15 2 4 5 4 0 1 0 6 106 28 3 363236953828 253642 163159164 97 3 103 172 87 220 25 283725 162148141 4 104 216222125 33 4 4 4 4 364444 121314214 30 4 4 4 2 0 4 8 96 7 12 17 22 63 350035043775 920 10 I 4556 109 115 92 3 61 2 2 3 I 2 3 I 2 3 I 2 I 90720161 976 I I 27 30 8 4616 106 48 267729712747 1249 10 4 4 5 3 0 11 I 28 2 I 58 2 2 I 7 0 4 8 96 6 10 15 4 8 96 14 028112 3 183 207 73 322335 155141140 1 1 0 4 1 0 4 4 4 6 21 2 201 3 4 462 96 168154159 1 05 I 54744 72 141137145 105 292421 I 9 443 I 381491 57 I 04 142327 19 163177185 104 1 73624 2 028112 4540106 368339453965 884 45 5 46 4 7 057115 6 7 11 048 187619872033 935 15 108 112 96 10 028112 64 104 15 67 2 4 4 4 44 048 oO 30 5 228121152378 838 20 4 4 6 1 7 104 96 3 0 3 9 3 1 9 2 3 1 83 829 20 5 461 6 105 48 15 216222232 398 4647 44 423923 164151149 3 104 I 8 5 103 104 I 04 104 4 028112 14 45 28 4 221322122 4 4 4 6 884 109 103 103 51 0281 I 2 163317741667 4 4 30 2 2 3 I 33 44 58 2 3 I 13 4 316832363335 1274 10 8 4 5 3 7 105 96 2 3 I 44 25 216313224 3 4550 23 414242 164159148 4 104 297430433158 827 20 8 4 6 1 6 1 1 4 106 112 2 3 I 4 2 I 45161166 4 37 028112 I 1241179 I 24 I I 7 9 9 1 I 70 04 8 96 11 1 6 2 2 3 I 231 I 70 2 3 1 I 70 2 2 6 4 2 2 6 1 24 70 1302 25 2 4 5 3 0 109 112 3 67 1171178 1171178 I 24 I I 7 9 70 70 70 70 70 4539106 1 508 50 105 112 I 171 1 7 8 I I I I I 8 2 I 2 3 I 51 51 51 91 91 30 96 290 148 I 18178167 105 141 59 404626 166157155 117 107 354141 I 32 4 157171171 93 87 316224 50 2 S 24 44 18 20 80 7 36 5 44 15 28 48 1 1 1 2 2 2 1 32 5 84 89 61 44 125222225 3 85 81 77 34 18 30 64 59 116222125 24 55 62 2 8 28 23 41 25 4 4 4 4 4 4 4 4 4 4 4 4 4 4 316334334 6 29 33 20 44 33 46 121314214 5 44 5 15 216313224 4 44 20 30 125222225 3 34 18 30 107 4 4 4 4 4 4 4 4 4 028112 61 2 142327 2 141137145 107 536 99 102 97 88 83 67 104 104 104 I 04 I 04 104 I 04 104 I 04 I 04 104 I 04 104 I 04 104 I 04 104 104 105 105 105 105 105 105 105 105 105 I 07 107 107 107 107 4 107 107 4 107 131 308 309 996 107 - 295 305 306 307 219221662349 S I I 70 81 I 70 - 303 304 I 2 3 I - 293 294 300 301 302 I 201 I 79 1201179 1201179 327 231170 3 108 328 329 1111179 111 1 1 79 I 2 228222412645 121 I 20 8 4 5 3 8 330 331 332 I 11 I I 7 9 34 1 1 7 i 3 i I 16 96 1 58717071 722 3 4 1 I 71 3 4 1 1 71 2 3 1 0 3 6 30 1 09 112 333 334 335 336 337 • 338 339 340 ■ • • 343 344 • ■ 345 ■ 346 347 ■ - 34 8 349 - 350 351 - 352 353 354 - 35 5 356 357 - 358 359 - S 4545 048 58 2 67 2 64 2 6 96 9 16 0 4 8 96 6 7 16 2 9 4 141 I 38156163 85 2 108 145 50 216212232 5 13 53 29 44 I 5 33 4 4 4 21 2 8 3 7 131224135 34 13 28 25802467247428372689 I 2 0 3 20 4 4 6 0 9 1 0 6 3 I 10 90 022 1051176 I 388442404308 0 5 7 1 15 1 051 I 76 1051 I 76 1121177 2 3 I 1 4 0 9 45 8 4 6 0 8 111 115 257227032957 1121177 1 121 I 77 2 3 9 9 6 20 1 15 1 15 3 251629932609 381173 381 I 73 I 2 32473691375335463471 7 9 2 20 6 4 6 1 6 94 3 381 I 7 3 1071176 3 I 1 I 6 45 230624022704 1071176 1071176 1151177 1151177 2 3 I 2 829 10 4 4 6 ' 6 117 115 I 70218351931 1211 20 8 4 SS1 1151177 3 113 36 0 361 1051179 1051179 — 1051179 1081 I 76 I 2 3 229426242510 1 4 0 9 45 3 4 6 0 8 114 48 I I 81 3 2 1 1 2 1 9 5 9 362 363 364 — 2 3 967 116 581174 I 20352316225122752447 365 - 3 66 367 - 581174 581 1 74 2 3 7 7 7 10 120 1 34 1151179 I 210524662458 1081176 1081176 4 4550 5 7 I 10 30 3 154 I 57 110 505 50 158 113 22 474542 I 63150161 1 1 3 3 I 10 3 6 2 1 72 216 223718 145168163 9 9 3 111 2 022 I 39150163 12 023112 67 4 39 0571 1 5 6 13 20 1 508 119 40 28 43 0 I 20 4 59 0 1 34 2 2 3 I 08 108 4 4 4 I 2 3 61170 107 107 46 471173 47 1 1 73 471 1 73 6 1 I 70 611/0 4 4 4 28 209722972253 4539106 67 38 34 1 1 88 110 8 161 23 3 I 69 107 44 115222235 2 3 4548 2 121314214 5 33 34 27 383525 I 50166162 2 108 1231179 3 70 I 36167149 028112 1 2 3 1 1>9 1231179 10 48 264224 4590134 72 2 0 5 71 1 5 8 '3 20 75 2 0571 15 7 10 1 6 69 2 96 8 1 4 2 0 3 0571 1 5 6 11 1 5 2 1 322338 162155148 1 2 6 4 1 1 1 94 15 27 132918 I 59163172 97 3 111 274 126 18 424039 I 571631 73 1 0 7 4 I I I 384 171 55 5 49 4 216322234 3 110 89 90 34 4 44 73 60 10 I 3 33 57 5 44 20 30 211224 2 24 I 5 25 7 23 216222 61 63 31 2 24 24 20 30 215 5 87 89 44 I 5 25 216322234 3 25 24 21 34 216122 64 61 2 70 24 13 33 126224225 2 67 44 17 24 25 46 216 37 7 115 25 57 I 048 4540100 39 30 I 57 9 2 3 1 1 2 1 4 7 158 77 403233 I 59158168 237 3 112 332 137 7 4 4 4 4 4 4 4 216222232 26 4 4 10 4647 58 022 4 59 0 1 34 2 4 3 3 4 28 3 I 701 3 8 1 3 8 I 14 200 51 21 96 424039 I 571631 73 216 215 5 44 25 H O I I O I I O I I O n o I I O H O 4 4 111 111 4 111 111 4 4 4 4 4 4 4 4 4 4 4 4 4 4 I 5 I C8 108 108 108 4 4 4 048 107 I I O I I O 111 111 4 4 107 4 111 111 111 111 111 111 I I 2 I I 2 I I 2 I I 2 I I 2 I I 2 I I 4 I I 4 I I 4 I I 7 132 341 342 112 1151179 - 1151179 57 1 1 7 3 571173 571 I 73 - 1221179 - 1221179 - 1221179 481173 48 I I 73 481173 331171 33 1171 331171 - I 051 I 77 - 1051177 - I OS I I 77 - 1151178 - 11 51178 - I 151 I 78 5117 1 5117 1 51 I 71 51 I I 73 51 I I 73 51 1173 391 I 74 39 1 1 7 4 39 1 1 7 4 - I 061 I 76 - 1061 I 76 - 1061176 901275 901275 901275 921272 921272 921272 701275 70 1 2 7 5 701275 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 121 I 20 8 4551 75 2 117 48 25582603296329432771 1 0 6 0 30 6 451 7 69 2 116 45 235926672889 896 10 4 4 6 0 5 64 2 122 96 I 61 7 1 4 3 9 1 9 2 1 I 801 I 697 1 2 64 25 I 4 5 2 9 58 2 119 45 134016631549 12 64 30 2 4 5 2 9 58 2 I 24 I 28 182919042470 1 4 0 9 45 8 4 6 0 8 69 2 I 35 115 225827882721 1211 20 8 4551 75 2 1 23 48 246130433050 1 249 10 4 4 5 3 0 58 2 I 24 112 31663473373839203725 827 10 3 4 6 1 6 1 1 4 3 I 24 90 28732697348135403662 792 20 6 4 6 1 6 94 3 127 I 34 135121671975 I 2 8 0 10 5 4601 67 2 160 57 2439231215661989 899 10 2 4 8 4 6 2 95 45 23921908 27552540 1161 5 8 4 8 44 69 2 92 45 30553259300927422901 1 1 3 3 20 8 4 8 1 9 58 2 107 22 5 9 14 20 58 4 117 210 80 41 47 42 3 4 4 5 4 3 I 541 5 5 1 6 9 47 2 113 233 28 1 3 1 2 2 2 1 3 2 4 44 23 43 64 46 SC 45 0 4 8 96 7 14 18 22 274138 151161159 93 4 118 175 67 215215 34 40 022 3 7 3 9 3 9 I 561581 60 47 2 119 123 23 121314214 71 29 5 44 28 43 364630 153157159 2 120 121314214 5 44 13 25 022 45901 34 45901 34 028112 057115 6 10 16 18 39 I 10 0 4 8 96 5 7 1 51 6 424039 157163173 2 7 4 4 1 22 47 8 201 028112 30 I 57 3 I 20 351 158 1 37 7 3 34 41 34 61 2 1 6 3 2 2 2 3 4 3 34 68 70 76 10 2 1 5 5 44 94 76 I 5 25 216 107 404626 166157155 2 I 24 121314214 5 44 2 24 9 5 I 5 022 4590134 1 43037 I 70159165 I 26 4 I 24 90 22 216212232 38 21 022 4590134 2 9 3 3 2 4 I 58 I 4 8 1 5 0 I 46 4 I 34 28 6 48 211224 7 2 24 13 25 74 52 56 56 057115 O 5 10 15 354346 148165163 1 38 3 I 53 31 0 1 72 216222232 72 66 045 33 I 99 6790 34 167 151 80 396 66 89 69 I 34 5 44 58 I 58 6 41 23 33 38 53 15 56 045 00 45 4C4521 1 6 7 1 6 0 1 4 7 4 86 214 022 4590134 27 35 30 I 35134162 3 90 4 8 2 87 2 1 6 2 2 2 1 3 2 5 21 25 41 91 88 76 72 I58 10 20 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 I I I I I I I I I I I 7 I I 7 I I 8 I I 8 I I 8 I I 8 I I 8 118 I I9 I I 9 I I9 I 20 I 20 I 20 I 20 I 20 I 20 122 I 22 I 22 I 24 I 24 I 24 I 24 I 24 124 I 34 134 I 34 153 I 53 153 80 80 80 86 86 86 90 90 90 133 368 36 9 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 383 38 9 390 391 392 393 394 395 396 397 398 399 4 00 401 402 403 404 405 406 407 408 - 89 1 2 7 5 89 1 2 7 5 891275 881275 881275 381275 26 1 272 261272 261272 141273 14 1 2 7 3 141273 261271 261 2 71 261271 561273 56 1 2 7 3 56 1 2 7 3 92 1271 92 1271 9 2 12 71 971271 97 1 2 7 1 971271 973272 973272 973272 971272 971272 971272 85 1271 85 1271 851271 941273 941273 941273 14 22 72 14 2 2 7 2 142272 142273 14 2 2 7 3 I 2 3 1 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 1633147816261304 937 50 8 4 8 3 3 2 100 67 2500223823652386 90 2 30 6 4 8 3 3 2 95 90 28362486251327622728 1295 5 8 4704 65 2 97 90 8 2 0 894 692 746 975 15 8 4834 2 109 45 148513841425 1 295 5 8 4 7 04 65 2 96 112 892 853 890 88? 897 893 10 8 4 8 10 72 2 101 1 34 18351908 20161962 1161 5 8 4844 69 2 104 56 21372097 I 7471 788 79 3 00 48 34 2 102 56 9 8 3 1 0 0 8 995 79 8 00 4834 2 1 02 45 108210551136 798 00 4834 2 105 90 20972097 23252412 8 3 0 10 I 4 8 0 8 64 2 104 56 128 128 I 08 155 1 0 0 5 80 3 4 8 34 2 121 134 974 9 0 7 1 0 4 2 1062 9 7 5 15 8 4834 2 109 13 887 80 6 840 773 9 7 5 15 8 48 34 2 045 6790 14 20 022 4 5 9 0 19 21 203127 157156132 I 97 90 4 4 7 71 84 81 79 35 237 66 66 74 36 I 64 93 399 148 61 022 4590134 213121 149146 143 2 94 045 90 242632 I 34 028112 142158155 95 328 64 2162 22 1 I 5 5 41 30 51 213121 149146143 2 95 2162221 I 5 5 022 4590134 1 7261 7 I 591501 50 91 3 100 I 54 33 21 6 2 2 2 7 2 38 48 25 056 00 56 404521 167160147 4 I 00 214 056 00 56 374328 175149138 100 I 34 6 2 9 4 3 2 6 I 541491 4 5 2 1 6 3 3 4 3 3 4 4 102 345 6 045 90 374 328 1 751491 38 100 04 5 90 3 7 4 3 2 8 I 751491 38 101 05 6 045 OC 56 90 I 34 353430 I 49150157 102 364 66 045 90 I 34 242632 142158155 103 045 90 I 34 2 4 26 32 142158155 103 328 64 71 66 64 41 30 51 8 23 I 58 I I I 15 I 66 66 I I 21 10 25 I I I I 46 66 I 71 71 I I 21 10 25 I I I 21 28 43 I I 10 I 41 10 20 I I I I 13 28 I I I i 13 28 1 I I I 13 28 I I I I I 1 I 5 20 I I 46 51 I 1 46 66 I I I I 46 66 I 71 71 I I 74 O f\> * - 90 90 90 93 93 93 94 94 94 95 95 95 95 95 95 I 00 I 00 I 00 I 00 I 00 I 00 I 00 I 00 I 00 I 00 I 00 I 00 101 101 101 102 102 102 I 02 102 102 103 103 103 103 103 134 409 410 4I I 4I 2 41 3 414 41 5 4I 6 4I 7 418 4I 9 4 20 421 422 423 424 425 426 427 428 42 9 4 30 431 432 4 33 434 435 436 4 37 438 439 440 441 442 443 444 445 446 44 7 448 449 14 22 73 942273 942273 942273 931273 931273 931273 14 1 2 7 2 1 4 12 72 14 12 72 93 2273 932273 93 2273 974272 974272 974272 931272 931277 931272 86 1 2 7 2 86 1 2 7 2 861272 972272 972272 972272 671275 671275 671275 501273 501273 501273 192271 192271 192271 1021272 1021272 1021272 191271 191271 191271 1022272 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 110 134 141 128 161 155 1 005 80 3 4834 2 114 90 110914111122 ions 1 1 0 7 20 4 4 8 30 64 2 1 27 45 1142 114212571250 975 15 8 4834 2 110 45 116913371149 1 2 57 1 1 0 7 20 4 4 8 30 64 2 114 45 9 0 7 9 7 4 961 7 9 8 00 4834 2 1 07 45 161316871673 1 8 88 1 1 0 7 20 4 4 8 30 64 2 117 134 531 692 47 7 437 853 5 I 4846 72 2 130 45 98811161149 7 9 8 00 4 8 34 2 I 16 90 43574689481247344650 1 5 5 4 20 4 4 5 3 9 67 I 110 45 20592155208919632138 865 20 7 4 8 2 3 64 2 105 22 9 0 0 833 907 868 10 2 48 24 64 2 101 112 32262473320531523622 603 5 5 4 8 2 0 64 2 112 134 167316601653 8 6 8 10 2 4 8 2 4 64 2 99 28 35623716349435823420 04 5 90 134 353430 149150157 105 364 66 71 216 36 I 22 3 74 74 I 22 3 74 74 045 90 I 34 233713 150143148 4 1 0 6 413 71 045 90 I 34 242632 142158155 107 04 5 90 I 34 2 337 1 3 I 5014 31 4 8 216 4 107 4 1 3 71 36 04 5 90 045 90 045 66 64 374328 I 75149138 107 I 34 233713 150143148 4 108 216 30 216222 17 I 55 3 112 130 I 22 3 7 2 045 90 3 7 4 3 2 8 I 7 51491 38 115 022 4590134 4 13947 I 42166164 I I 10 465 I 29 226222135 3 I I 7 113 106 022 4590134 214616 I 38161144 80 2 96 169 34 316322121 2 47 23 SI 153025 160183163 2 97 2 2 9 82 216222122 I 34 29 46 023112 022 4590134 20 22 30 165173151 578 2 97 135132135 I 0231 I 2 I 53025 160183 163 2 99 366 73 216222122 I 79 37 68 02 2 202230 135132135 4590134 165173151 I I I 5 20 I 46 51 I I 31 5 15 I 79 79 I I I 46 66 I I I 31 5 15 I 79 79 I I I 13 28 I I I 31 5 15 I I I 21 15 I I I I 13 28 I I I 32 74 99 2 2 2 23 41 56 3 I4 3 3 23 43 56 3 38 CO 3 3 13 13 28 3 3 3 23 43 56 3 50 49 3 3 13 13 28 3 103 105 105 105 I 06 106 106 107 107 107 107 107 107 107 107 107 108 108 108 I I 2 I I 2 I I 2 I I 5 I I 5 11 5 I I O HO I IO 96 96 96 97 97 97 97 97 97 99 99 99 100 135 * * - O O 450 451 4 52 4 53 454 45 5 4 56 457 45 8 459 460 461 462 463 464 465 466 467 468 469 470 4 71 47 2 4 73 4 74 475 4 76 477 4 78 4 79 480 481 482 483 484 485 486 487 488 489 490 - 10 22272 10 22272 19127] 1 9 12 70 191 2 7Q 1002272 1002272 1002272 491273 49 1273 491273 991272 99127? 991272 1001272 1001272 I 001 2 72 852371 85 2371 85 2371 921373 921373 921373 901375 90 1 3 7 5 901375 961 373 961373 961373 982372 982372 982372 92 13 71 92 13 71 92 1371 72 13 75 72 1 3 7 5 721375 85 1371 85 1 3 7 1 851371 2 3 I 2 3 I 2 3 I 2 3 I 2 3 1 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 603 5 5 4 8 2 0 64 2 104 22 I 9 2 2 2 0 5 0 2 1 03 868 10 2 4 8 2 4 64 2 I 09 112 20762258207623392215 625 1 5 7 4 8 1 5 6 7 2 113 90 I 881 21 0421 0 4 2 1 6 8 1 91 £ 6 5 5 20 I 4 8 0 6 72 2 115 90 29703185338734073084 695 30 3 4 7 5 3 64 2 115 90 32053709385737364106 6 2 5 15 7 4 8 1 5 67 2 128 I 34 1 9251 199 1 7531043 8 3 0 10 I 4 8 0 8 64 2 62 56 28552000 1161 5 8 4 8 44 69 2 70 45 1935184912531591 899 10 2 4 8 4 6 2 96 45 1 83 167 I 51 I 61 1002 5 8 4840 2 91 45 112912581016 769 8 1 0 15 3 4 8 4 0 2 111 45 22201613 21562425 1161 5 8 4 8 4 4 69 2 112 56 37993775386535013617 1 0 8 2 30 8 4 8 0 9 67 2 102 45 27042339 25752613 830 10 I 4 8 0 8 64 2 101 56 373 2 100 153025 160133163 2 103 4 3 6 68 028112 216222122 I 91 71 95 23 43 56 66 45 022 4590134 3 3 4 4 39 I 721581 63 2 7 6 2 108 216324225 022 4 5 9 C 1 34 1 0 0 6 1 9 I 46 1651 64 1033115140 38 2 1 62 22 7 2 23 41 4 40 38 20 02 2 4590134 332928 161148160 264 2 I 16 21 62 32232 2 23 022 45 90134 3 3 4 4 39 I 721 581 63 2 7 6 2 I 20 21 63 24225 2 23 48 056 00 56 294326 154149145 4 61 3 5 3 69 3 1 6 3 3 4 3 3 4 6 41 10 25 67 67 70 80 404521 167160147 4 70 214 045 045 045 045 6790 90 90 I 34 I 34 33 I 99 34 44 26 203030 I 67 81 396 I 34 2 23 48 64 6 41 56 30 46 64 10 20 151 66 89 69 58 I 58 15 56 I 57 142 37 300 43 43 33 48 I 71 15 61 155154164 90 1 25 4 1 056 00 56 404521 167160147 4 92 214 022 45 90134 404127 142135159 3 93 425 79 3 1 6 3 2 2 1 3 2 5 41 18 33 71 72 69 59 75 056 00 56 I 34 6 41 10 20 2 9 4 3 2 6 I 54 1491 4 5 3 1 6 3 3 4 3 3 4 6 41 10 25 4 94 316 61 47 90 55 63 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 I I I I I I I I I I I I I I I I I I I I 1 I I I I 00 I 00 I 08 108 108 108 I 08 108 11 5 I I 5 I I 5 I I 6 I I 6 I I 6 I 20 120 120 61 61 61 70 70 70 81 81 81 87 87 87 90 90 90 92 92 92 93 93 93 94 94 94 136 491 492 49 3 494 495 496 49 7 498 499 50 0 501 502 503 504 505 506 507 508 509 510 51 I 512 51 3 514 515 516 517 518 51 9 52 0 521 522 523 524 525 526 527 528 52 9 530 531 532 533 534 535 536 5 37 - 535 539 - 540 541 542 - 543 544 - 545 - 54 6 - - 550 551 - 5 52 - 5 53 554 - 555 5 56 557 - 558 559 - 560 561 562 5 63 564 - 565 5 66 567 — - 568 569 - 570 571 5 72 - I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 26612607 26772451 951 25 6 4 8 2 8 2 98 56 49825181511348405038 1 0 8 3 15 2 4 8 1 8 58 2 104 22 16241769173616401855 I 24 2 5 I 4 7 0 9 65 2 114 134 23822258 22582398 798 00 48 34 2 106 56 185517691903 1 9 30 84 7 35 7 4831 69 2 104 I 34 213421772161 1 2 95 5 8 47 04 65 2 102 34 18821710 19192204 1161 5 8 4844 69 2 115 56 505 564 4 8 9 575 975 15 8 4834 2 114 I 34 20592204222621832107 1173 5 I 4 7 1 7 67 2 108 45 484 564 468 532 9 7 5 15 8 4834 2 117 45 171021611887 1532 975 15 8 4834 2 126 45 7 6 9 758 83 9 925 810 15 8 4 8 4 0 2 120 134 26402914 8 8 0 35 7 4831 69 2 110 56 12531285131713871441 1143 5 8 4 7 22 64 2 05 6 00 56 95 02 2 4590134 02 2 4590134 314 216222132 141 2 100 056 00 56 100 045 90 134 3 101 034112 056 213121 149146143 2 102 00 56 4 103 04 5 90 134 107 022 300 64 300 64 4590134 I 4 5 2 I 07 045 90 I 34 I 08 045 90 I 34 109 045 90 I 34 109 056 12 14 19 02 2 I 46 41 61 333833 4590134 I I 601 571 52 56 I I I 5 21 15 I I I 21 13 25 I I I I 13 28 I I I 21 10 20 I I I 21 10 25 I I I 41 10 20 I I I I 46 66 I 48 51 I I 41 15 30 I I I I 46 66 I 48 51 I I I 46 66 I I I I 25 41 I I I 21 10 20 I 61 I I 41 28 43 I I 95 95 95 98 98 98 I 00 I 00 I 00 I 00 I 00 I 00 101 101 101 102 102 102 103 103 103 107 107 107 107 107 107 108 108 108 109 10 9 109 I 09 109 109 I 10 HO I 10 I I 5 I I 5 137 54 7 548 549 95 13 71 951371 95 13 71 691375 691375 691375 271372 271372 271372 97 13 71 971371 97 13 71 183372 183372 183372 261371 261371 261371 92 2 3 7 1 92 23 71 922371 141373 141373 141373 461372 461372 461372 14 2 3 7 3 142373 142373 141372 141372 141372 981372 981 3 72 981372 181371 181371 181371 451372 451372 - - - - - - - 451372 262371 262371 2623 71 91 I 373 91 1373 91 I 373 181372 1 8 13 72 18 13 72 1 8 23 72 18 2372 1 8 23 72 751371 751371 751371 962373 962373 962373 983372 983372 983372 2 6 13 72 261372 26 1 3 7 2 91 23 73 91 2 3 7 3 912373 1021373 1021373 1021373 1022373 1022373 1022373 1011373 10 11373 1011373 1012373 10 12373 10 12373 201 3 72 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 2 3 I 115 134 122613551484 1 295 5 8 4 7 0 4 65 2 121 112 559 39 2 446 403 1161 20 4 4844 69 2 143 134 155917851876 20 16 8 4 7 35 7 4831 69 2 129 134 2038 160718552038 8 4 7 35 7 4831 69 2 I 27 90 84910751129 I 1 46 10 8 4 7 4 0 58 2 133 112 183 296 210 220 1002 5 8 48 40 2 162 45 731 7 9 6 1 0 1 6 1113 2 8 1 0 15 8 48 40 1 39 90 22582446279629033306 1295 5 8 47 04 65 2 146 134 387 2 3 7 242 40 9 1161 20 4 4 8 44 69 2 1 73 90 278527362279 603 5 5 4 8 20 64 2 98 45 322031073113 603 5 5 4 8 2 0 64 2 97 112 160216611753 6 3 2 15 6 4 8 2 2 67 2 109 112 195721402156 6 3 2 15 6 48 22 67 2 I 10 112 24532770284528842876 034112 213121 14 9146143 2 116 2162221 I 5 5 21 10 25 045 90 I 34 403437 162157150 4 I 20 404 58 214 64 045 90 I 34 333833 160157152 3 I 21 216222224 2 21 10 04 5 90 I 34 333833 160157152 3 I 23 216222224 2 21 10 20 1 52815 I 20132139 4 I 30 21 62 22 4 31 15 028112 045 90 134 44 26 157 142 1 32 300 43 43 1 34 6 41 10 20 69 48 66 99 7 33 48 I 71 20 30 15 61 04 5 90 134 2 0 3 0 3 0 I 551 5 4 1 6 4 I 33 022 4590134 213121 14 9146143 2 144 216222115 04 5 90 4 0 34 37 162157150 4 146 404 58 214 64 045112 2 0 2 2 3 0 16 51 73151 77 2 90 254 13 51 32135 I 13 13 28 045112 20 22 30 165173151 77 2 97 287 135132135 I 13 13 28 045112 0 7 3 5 1 7 151159162 I 35 2 107 272 216324225 2 23 18 33 045112 073517 151159162 1 3 5 2 110 328 216324225 2 23 18 33 225232215 3 33 022 I 34 45901 34 23 26 1 48 1 34 I 5 21 25 41 10 25 1 34 6 41 10 20 69 4 8 66 99 13 I I I I I I I I I I I I I I I I I I I I I I I I I I I I 3 3 3 3 3 3 3 3 3 3 3 3 3 I I 5 116 116 116 I 20 I 20 120 121 121 121 123 123 123 I 30 I 30 130 132 I 32 132 I 33 I 33 I 33 144 144 144 146 146 146 90 90 90 97 97 97 107 107 107 I I 0 I 10 I I 0 11 8 138 573 574 575 576 577 578 579 580 581 582 583 584 585 586 5-8 7 588 58 9 59 0 591 592 593 594 595 596 59 7 598 59 9 600 601 602 603 604 605 606 607 608 60 9 610 611 612 61 3 619 619 620 621 622 625 624 625 626 627 628 629 630 631 632 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 2C1372 201372 - 471373 - 471373 471373 I 201 3 8 0 I I I I 2 0 1 3 90 2 0 1 3 80 202390 202380 I 20 2 3 8 0 1191380 1191380 1191380 2 1005 3 I 118 90 10671100 60 2 3 I 1 203 107 20 13 6 4726 988 4 53 9741137 4609106 027 3 2 98 81 178215891782 9 96 30 8 4 5 3 9 1 0 6 3 3 I 100 81 217621822049 3 I 2 1194 I 00 27 217121692139 5 4 4548 1194 I 192380 I 192380 1192330 401372 2 3 I - 401372 401372 411372 411372 2 100 27 40124111413340644156 1036 5 2 4521106 3 3 I 104 134 I 7 0 4 1 581 I 785 I 7 6 3 1 8 7 1 2 411372 641375 641375 3 I 2 935 20 2 4 5 4 0 1 0 6 3 110 134 29412929294531693046 1 0 3 6 10 2 4 5 1 5 69 2 641375 441372 3 I 108 90 27692875274031182880 - 441372 - 441372 I 131376 1131376 I 131376 521373 521373 2 3 I - - 2 3 I - 521373 431372 2 3 I - 431372 2 431372 1061376 3 I 1061376 1061376 2 3 - 827 10 4 4 4616114 2 4590134 022 4590134 022 022 022 4590134 29263171329832643503 1249 35 I 4 60 0 67 2 124 135 131224135 5 56 39 15 I 63159164 4 144 34 144 13 28 12 44 13 33 163159164 4 44 13 33 I 66168159 221322122 4 44 15 30 97 474641 81 3 113 90 35053903 1181 10 4 4 5 4 9 64 2 111 54 23362411251426222576 827 10 4 4 6 1 6 1 1 4 3 112 90 120 474641 2 108 95 2 027 4 5 4 8 6 7 78 93 3 81 733 212837 139150163 43 4 89 I 78 57 253642 81 2 - 118 3 027 67 2 253642 SI 027 3 I 5 4590134 022 3 191516931882 996 30 8 4 5 3 9 1 0 6 2 117 2 166168159 221322122 4 44 4 4 4 2 3 41 103 115 15 30 99 445041 I 51168156 87 3 102 619 98 106 100 97 463340 I 73171 I I 6 63 4 103 513 87 216313224 383236 150139158 3 1 0 7 511 86 226322132 2 105 87 75 24 4 3 58 79 79 374739 168178180 I 70 4 109 267 65 216222125 2 78 72 52 24 92 94 4 80 44 30 62 46 103 46 66 054 3 3 4 1 34 67 2 118 89 4 4 89 4 4 4 4 93 93 95 95 4 4 95 97 4 97 97 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4590134 022 4590134 022 I 551 5 7 1 6 0 216212232 5 98 72 66 44 274543 I 63147164 1 2 6 4 112 112 54 216212232 33 19 2 5 24 404242 160154163 1 0 8 3 I 16 3 3 6 84 216222232 5 44 354346 148165163 I 3 8 3 1 18 2 7 7 1 5 6 216222232 69 52 2 054 4601 I I 8 3 4 4 4 I I I 422 186 81 58 60 23 41 0 5 10 15 5 4 4 18 33 10 30 I 53 I 34 24352882 1280 10 5 118 54 3 44 33 53 4 4 4 4 4 4 4 4 4 4 89 93 99 99 99 102 102 102 103 103 103 107 107 107 109 I 09 109 I I I I I I I I I I I 2 I I 2 I I 2 I I 6 I 16 I I 6 I I 8 I I 8 I I 8 139 633 634 - W 615 616 617 ■T* m O O 614 655 656 657 - 261471 I 203220932054 2 - 261471 261471 261472 I 295 103 658 659 - 660 - 661 6 62 665 664 66 5 666 - 261472 261472 781477 781477 5 I 2 3 I 781 4 7 7 771 4 77 2 3 I 771477 7 71 4 77 2 3 5 28 8 4704 028112 65 2 25162362240127422566 I 295 5 8 4 7 0 4 65 2 109 90 022 313634303347 I 721 5 5 4609 109 56 056112 3380 67 I 25702537279926702831 1721 5 5 4639 67 I I 10 I 34 022 4590134 224 4590134 213121 149146143 2 I 02 216222115 213121 149146143 2 109 216222115 5 21 I o 3935 I 147153 108 216222 2 22 61 2 4039 I 132163 I 10 216222 6 1 2 2 2 5 21 10 25 102 102 7 7 2 22 25 2 102 109 109 109 108 108 108 II0 II 0 I I0 140 LITERATURE CITED 142 LITERATURE CITED Adams, J . A. and R.H. Wilde. 1976. Variability within a soil mapping unit mapped at the soil type level in the Wanganui district. I. Morphological variation. New Zealand Journ. Agric. Res. 19(2): 165-76. Bajpai, M. R. and H . S. Mertia. 1977. A note on the irrigation and fertility levels on the yield and nutrient uptake of dwarf barley cultivar RDB-I. Annuals of Arid Zone 16(1): 153-6. Barber, S. A. 1962. A diffusion and mass-flow concept of soil nutrient availability. Soil Science 93:39-49. Beckett, P . H . T. 1964. Studies on soil potassium. II. The immediate Q/l relations of labile potassium in the soil. J. Soil Science 15:9-23. Beckett, P. H. T. and M. H. M. Nafady. 1967. Studies on soil potassium. IV. The effect of K-fixation and release on the form of K:(Ca + Mg) exchange isotherm. J . Soil Science 18(2): 233-43. Black, C. A. (ed.). 1965. Methods of Soil Analysis - Part I. pgs. 381-3. American Society of Agronomy, Inc.; Madison, W i s . Boatwright, G. O., H . Ferguson, and J. R. Sims. 1976. Soil tempera­ ture around the crown node as it influences early growth, nutrient uptake, and nutrient translocation of spring wheat. Agron. Journ. 68(2):227-31. Bolton, J. 1977. Liming effects on the response of potatoes and oats to phosphorus, potassium, and magnesium fertilizers. .J. Agric. Sci. 89:87-93. Burkart, N. and A. Amberger. 1978. Effect of potassium fertilization on K-availability in potassium fixing soils over the vegetative period. Z. Pflangenernaehr. Bodenkd. 141:167-79. Byrd, C. W. and D. K. Cassel. 1980. The effect of sand content upon cone index and selected physical properties. Soil Science 129(4):197-204. 143 Cannell, R. Q., F. B . Ellis, D. G. Christian, J. P. Graham, and J. T. Douglas. 1980. The growth and yield of winter cereals after direct drilling, shallow cultivation, and ploughing on noncalcareous clay soils, 1974-1978. J . Agric. Sci. 94:345-59. Dass, G. and S. D. Shankhayan. 1979. Forms of soil potassium in acid soils of Palam Valley of Himachal Pradesh and the response of wheat to application of potassium. Indian J. Agric. Sci. 49(6): 434—40. Drew, M. C. and L. ,R. Saker. 1978. Effects of driect drilling and ploughing on the root distributipn in spring barley, and pn the concentrations of extractable phosphate and potassium in the upper horizons of a clay soil. J. Sci. F d . Agric. 29:201-6. Drew, M. C. and L. R. Saker. 1980. Direct drilling and ploughing: their effects on the distribution of extractable phosphorous and potassium, and of roots, in the upper horizons of two clay soils under winter wheat and spring barley. J. Agric. Sci. 94: 411-23. Fedak, G. and A. R. Mack. 1977. Influence of soil moisture levels and planting dates on yield and chemical fractions in two barley cultivars. Can. J. Plant Science 57:261-7. . Fisher, N. M., P. T. Gooderham, and J. Ingram. 1975. The effect on the yields of barley and kale on soil conditions induced by cultivation at high moisture content. J. Agric. Sci. 85:385-93. Haby, V. A. 1975. Evaluation of soil test methods and development of a potassium fertilizer recommendation system for Montana. Ph.D. dissertation. Plant and Soil Science Dept., Montana State Univ., Bozeman. Hodgson, D. R. ,. J. R. Proud, and S. Browne. 1977. Cultivation systems for spring barley with special reference to direct drilling (1971-1974). J. Agric. Sci. 88:631-44. Hopkins, D. G. (ed.). 1979. Soil series of Montana: A key to taxonomic classification. Montana Agric. Exp. Sta. and SCS. Miscellaneous Report 16. Hoyt, P. B. and. W. A. Rice. 1977 . Effects of high rates of chemical fertilizer and barnyard manure on yield and moisture use of six successive barley crops grown on three Gray Luvisolic soils. Can. J. Soil Sci. 57:425-35. 144 Jankovic, V. M. and K. Nemeth. 1979. Influence of long-term ferti­ lizer trials with increasing K and P levels on K and P dynamics in the soil and on yidld. Landwirtsch. Forsch 32(3):283-91. Kahn, K. L. and E. W. Toop. 1970. Influence of soil temperature and potassium fertilization on magnesium content of tomato plants. Can. J. Plant Sci. 50:740-2. Karlen, D. L., R. Ellis, Jr., D. A. Whiteny, and D. L. Grunes. 1978. Influence of soil moisture and plant cultivar on cation uptake by wheat with respect to grass tetany. Agron. Journ. 70(6);918- 21. Kowalenko, C. G. and C. J. Ross. 1980. Studies on the dynamics of "recently" clay-fixed NH^ using N^-*. Can. J. Soil Sci. 60:61-70. Labanauskas, C. K., L. H. Stolzy, and R. J. Luxmoore. 1975. Soil temperature and soil aeration effects on concentrations and total amounts of nutrients in 'Yecora' wheat grain. Soil Science 120(6):450-4. Lai, P . and K. C. Sharma. 1974. Uptake of N, P, and K in two varieties of dward wheat grown at different levels of soil moisture and nitrogen. Indian J . Agric. Sci. 44(8):499-503. Lai, R. 1976. No-tillage effects on soil properties under different crops in Western Nigeria. Soil Sci. Soc. Am. J . 40:76208. Liebhardt, W. C. and L. Cotnoir. 1979. Potassium fertilizer recommendations and changes in potassium soil test values as influenced by additions of potassium. Commun. in Soil Science and Plant Analysis 10(5):831-40. Mack, A. R. 1971. Yield of bromegrass and removal of nitrogen, phosphorus, and potassium under modified soil-temperature field conditions. Can. J. Soil Sci. 51:195-309. Massee, T. W. 1973. Soil characterization by diffusion measurements. Ph.D, dissertation. Plant and Soil Science Dept., Montana State Univ., Bozeman. Mattson, S. 1973. Ionic relationships of soil, and plant. IV. uptake in relation to membrane activity and soil moisture. Agricultures Scandinavica 23:11-16. Ion Acta 145 Mattson, S . 1974. Ionic relationships of soil and plant. V. Ion uptake in relation to valence, membrane activity, and soil moisture. Acta Agriculturae Scandinavica 24:33-6. McLean, E. 0. and V. C. Bittencourt. 1974. Complementary ion effects on potassium and calcium displacement from triionic bentonite and illite systems as affected by pH dependent charges. 'jjpil Science 117(2):103-9. McLean, E. 0. 1976. Exchangeable K levels for maximum crop yields on soils of different cation exchange capacities. Commun. i p , Soil Science and Plant Analysis 7(9):823-38. Mengel, K. and T. Aksoy. 1971. The potassium concentration of the soil solution and its effect on the yield of spring wheat. Z.Pflanzenernaehr Bodenk. 128(1):28-41. Mengel, K. and B. Wiechens. 1979. Effect of non-exchangeable soil K fraction on the yield and production of rye-grass. Z. Pflan­ zenernaehr Bodenk. 142(6):836-47. Munn, D . A. and E . 0. McLean. 1975. Soil potassium relationships as indicated by solution equilibriums and plant uptake. Soil Sci. Soc. Am. P r o c 39:1072-76. Nie, -N. H., C. H. Hull, J . G. Jenkins, K. Steinbrener, and D. H. Bent. 1975. Statistical Package for the Social Sciences. McGraw-Hill Book Company; New York, N.Y. Niekerk, B. J. and J. J. N. Lambrechts. 1977. Morphological criteria and their interpretation for agriculture in terms of soil, behavior and land quality. Technical Comm. No. 146, p. pgs. Dept, of Agricultural Technical Services, Republic of South Africa. Oliveira, F. R. de., G. C . Vieira, M. Pinheiro, and J. B. Filho. 1979. Soil temperature at a depth of 2 cm. as a response to air tempera­ ture. Revista Ceres 26(144):205-15. Olsen, G. W. (Chairman of Committee 6 ). 1977. Status of evaluation of interactions between soils and fertilizer responses in the United States and some other areas. Cornell Agronomy Memio 77-2. Cornell Univ., Ithaca, N.Y. 146 Petinov, N. S., V. P. Ivanov, V. I. Kirillina, V. G. Golovatyi, and K. K. Kalimulina. 1977. Dynamics of dry matter and plastic compound accumulation in barley plants as a function of soil moisture and mineral nutrition. Soviet Plant Phys. 24(3):479-85. Phillips, S . J. 1973. Potassium availability and mineralogical relationships of selected Montana soil clays and silts. M.S. Thesis. Plant and Soil Science Dept., Montana State Uhiv., Bozeman. Raney, R. A. and G. D. C . Hoover. 1946. The release of artifically fixed potassium from a kaolinitic and a montmorillonitic soil. Soil Sci. Soc. Am. Proc. 11:231-3. Raychaudhuri, S . P . 1976. Potassium fertilizers for increased crop, production. Bulletin Indian Soc. Soil Sci. 10:306-16. Reddy, D. S., D. R. Reddy, and G. V. N. Chary. 1978. A note on the effect of sulphate of potash on the hydraulic conductivity, water holding capacity, and crop yields under rainfed agriculture at Anantapur. Annals of Arid Zone 17(2):236-8. Samra, J. S . and N. N. Goswami. 1978. Response of wheat to soil ■ physical parameters at. varying levels of soil fertility. J. Indian Soc. Soil Sci. 26(1):38-43. Sawhney, B . L. 1972. Selective sorption and fixation of cations by clay minerals: A review. Clays Clay M i n . 20:93-100. Schaff, B . E. 1979. Influence of soil profile and site character­ istics on the response of winter wheat to K on Montana soils. M.S. Thesis. Plant and Soil Science Dept., Montana State Univ., Bozeman. Schuurman, J . J . 1971. Relation between soil density, root growth, and uptake of minerals and water by oats. In Structure and Fucntion of Primary Root Tissues: Proceedings of a Symposium. Tatranska Lomnica, Czechoslavakia. Ed. by Joseph Kolek, pgs. 351-56. Scott, T. W. and F. W. Smith. 1957. Effect of drying upon avail­ ability of potassium to soil moisture. . Soil Sci. Soc. Am. Proc. 20:45-50. 147 Scott, A. D . , F. T. Ismail, and R. R. Locatis. 1972. Changes in interlayer potassium exchangeability induced by heating micas. Proc. Intr. Clay Con., Madrid, 1972. pgs. 467-79. Sharda, A. K. and J. P. Gupta. 1975. Influence of different water regimes on oxygen diffusion rates, nutrient uptake, growth and yield of wheat. Annals of Arid Zone 14(4):373-5. Sharma, R. B . and G. P. Verma. 1971. Effect of compaction of black cotton soils on the uptake of N, P , and K by wheat. Indian J . Agric. Res. 5(3):165-71. Shrader, W. D., F.l'F. Riecken, and A. J. Englehorn. 1957. Effect of soil type differences on crop yields on Clarion-Webster soil in Iowa. Agron, Journ. 49:254-7. Singh, Y., R. Singh, and G. S . Sekhon, 1977. Uptake of primary nutrients by dryland wheat as influenced by N fertilization in relation to soil type, profile water storage, and rainfall. J. Indian Soc. Soil Sci. 25(2):175-811. Skogley, E. 0. 1976. Potassium in Montana soils and crop require­ ments. Montana Agric. Exp. Sta. Res. Rept. 8 8 , Bozeman. Smith, G. D., F. Newhall, L. H. Robinson, and D. Swanson. 1964. Soil-temperature regimes - their characteristics and predict­ ability. U.S.D.A. Bulletin, Soil Conservation Service, SCS-TP144, 14 pgs. Sparks, D. L., D . C . Martens, and L. W. Zelayny. 1980. Plant uptake and leaching of applied and indigenous potassium in Dothan soils Agron. Journ. 72:551-5. Steel, R. G. D. and J. H. Touie. 1960. Principles and Procedures of Statistics. McGraw-Hill Book Company, Inc. Talha, M., A. Amberger, and M. Burkart. 1979. Effect of soil compaction and soil moisture level on plant growth and potassium uptake. Z . Acker-und Pflanzenbau 148:156-64. U.S.D.A. 1951. Soil Survey Manual. Agriculture Handbook No. 18. Soil Conservation Service. 148 U.S.D.A. 1975. Soil Taxonomy. ture Handbook No. 436. Soil Conservation Service. Agricul­ I V a r m a , S . K. 1976. Nutrient absoprtion under soil moisture stress and nitrogen deficiency in wheat (Triticum aestivum). Indian J. Agric . Res. 10(3):174-8. Varma, S. K . , B. S . Malik, and M. C. Agarwal. 1976. Effect of . nitrogen application under varying soil moisture regimes on the uptake of nutrients in barley. Indian Journ. Agton. 21(3): 318-20. Verma, G. P . and R. B . Sharma. 1972. Effect of compaction on yield and uptake of N, P, and K by maize (Zea mays L.). J N K W Res. Journ. 6(1):16-20. , j I Von Braunschweig, L. - Chr. 1980. K availability in relation to clay content - results of field experiments. Potash Review; Commun.. by the International Potash Institute. Subject 16, No. 2. Wang, J. S . 1975. Potassium availability as influenced by application rates and incubation time in Montana soils. M.S. Thesis. Plant and Soil Science Dept. , Montana State Univ., Bozeman. Wells, N. and M. L. Leamy. 1977. Genetic-properties of Singapore soils and their implications for soil management. Malaysian Society of Soil Science, Conference of Classification and Management of Tropical Soils, Kuala Lumpur, 1977. Wicke, H. J . 1973. On the potassium requirement of cereals. The dependence of the potassium effect on light and temperature as well as on soil potassium content. Archiv fur Acker - und Pflanzenbau und Bodenkunde 17(I):55-63. Willis, W. 0. and J . F. Power. 1975. Soil temperature and plant growth in the Northern Great Plains. In Prairie: A multiple view. (M. K. W ali, editor). Northern Plains Research Center, Univ. of North Dakota Press, Mandan, N.D. N378 V518 cop.2 DATE 118. Veeh, R. H. The influence of selected soil physical properties, soil type and site characteristics, soil temperature, and... ISSUED TO N A W UBL I/ C W A _