AN ABSTRACT OF THE THESIS OF
in
GERALYN MARIE WEST
for the degreeef M4STER OF SCIENCE
CROP SCIENCE
presented on 3.ALk<11(1-7-7
Title:
FOLIAR VS. ROOT UPTAKE OF THE HERBICIDE HOE 23408 IN
ITALIAN RYEGRASS AND WILD OATS
Abstract approved:
Redacted for Privacy
Arnold P. Appleb,r
'.1
HOE 23408 [methyl 2-[ 4-( 2, 4- dichlorophenoxy )phenoxy]propanoate]
is a herbicide used to selectively-control Italian ryegrass
(Lolium muitiflorum Lam.) and wild oats (Avena fatua L.) in wheat.
The objective of this research was to compare the relative importance of foliar and root uptake of the herbicide in these two weed
species.
Factors such as plant biotype, stage of plant growth, soil
type, irrigation type, and amount of soil moisture were examined.
Plants were grown in plastic pots in the greenhouse with a 12hour day, 12-hour night schedule.
HOE 23408 (38% a.i. emulsifiable
concentrate) was applied using an overhead variable-speed sprayer
calibrated to deliver 309 L/ha.
placement sites:
The herbicide was applied at three
foliage only, soil only, and foliage plus soil.
Foliar placement was accomplished by protecting the soil with a
1.5 cm layer of perlite prior to spraying.
when dry.
This layer was removed
Soil only application was administered by pouring a 25 ml
solution of the herbicide directly onto the soil.
The combination
treatment was sprayed with neither area protected.
Symptoms de-
veloped within 2 to 4 weeks from the day of treatment.
Fresh weights,
visual ratings of injury, and dry weights were obtained to assess
injury.
Fresh weights gave the best injury estimate and were con-
verted to percent fresh weight reduction prior to analysis.
Five
replications were used in each experiment.
Both foliar only and soil only applications of the herbicide
caused injury to both species.
to HOE 23408 than wild oats.
Italian ryegrass was more sensitive
HOE 23408 was applied at rates of .56,
Injury increased with increasing rate
1.12, 1.68, and 2.24 kg/ha.
in all placement treatments.
The effect of the herbicide on ryegrass and wild oats was
examined under conditions of New Zealand and western Oregon.
In
New Zealand, the high organic matter Canterbury Plains silt loam
greatly reduced soil activity of the herbicide.
'Tama' ryegrass, a
rapidly growing New Zealand variety, was found to be more sensitive
to foliar application than the western Oregon biotype.
Ryegrass was
slightly more susceptible to the herbicide at the one- to two-leaf
stage than at the three- to four-leaf stage.
Ryegrass and wild oats were grown in western Oregon using
Woodburn silt loam (3.5% 0.M.), Newberg sandy loam (1.7% O.M.), and
silica sand (0.5% O.M.).
Injury from a 1.12 kg/ha application of
the herbicide decreased with increasing organic matter content.
No
differences were noted for foliar applications of the herbicide in
the different soil types.
Placement effects were examined under two irrigation types:
No placement x irrigation interaction was
subsurface and overhead.
noted.
Plants subjected to subsurface irrigation grew more rapidly,
and consequently, the overall injury was greatest in these plants.
Two studies were conducted with ryegrass grown under various
soil moisture conditions:
60% F.C., and 32% F.C.
120% Field Capacity (F.C.), 96% F.C.,
Neither foliage only nor soil only place-
ments were affected by soil moisture.
However, HOE 23408 activity
in the combination treatment was significantly reduced under low
soil moisture conditions.
Ryegrass and wheat were grown in quart size glass Mason jars
filled with nutrient solution.
The objective of this study was to
determine if root inhibition could be caused by either placement of
HOE 23408.
The herbicide was applied either to the foliage or to
the nutrient solution.
daily.
Measurements of the longest root were taken
Root growth was severely inhibited only when the roots were
exposed to the herbicide, not when the foliage was treated.
FOLIAR VS. ROOT UPTAKE
OF THE HERBICIDE HOE 23408 IN ITALIAN RYEGRASS
AND WILD OATS
by
Geralyn Marie West
A THESIS
submitted to
Oregon State University
in partial fulfillment of
the requirements for the
degree of
Master of Science
June 1978
APPROVED:
Redacted for Privacy
Professor of Agronomf) U
in charge of major
Redacted for Privacy
Head of Department of Crop Science
Redacted for Privacy
Dean of Graduate School
Date thesis is presented
July 19, 1977
Typed by Gloria M. Foster for Geralyn Marie West
ACKNOWLEDGMENTS
My most sincere appreciation to Dr. Arnold P. Appleby
for his guidance and patience throughout my graduate program.
My thanks to Dr. Ralph E. Berry and Dr. David 0. Chilcote
for serving on my graduate committee.
My deepest gratitude to Dr. Roger J. Field for his understanding and assistance during my stay at Lincoln College in
Canterbury, New Zealand.
DEDICATION
This thesis is dedicated to my husband, Randy, and
to my parents, for their love and support throughout my
education.
TABLE OF CONTENTS
Page
INTRODUCTION
1
LITERATURE REVIEW
3
HOE 23408
Italian Ryegrass
Wild Oats
Factors Affecting Foliar and Soil Uptake
Foliar Uptake
Uptake From the Soil Solution
The Role of Water Stress
GENERAL MATERIALS AND METHODS
FOLIAR VS. ROOT UPTAKE OF HOE 23408 AT DIFFERENT
RATES OF APPLICATION
Oregon Placement Studies
Materials and Methods
Results and Discussion
New Zealand Placement Studies
Materials and Methods - New Zealand Experiment
No.
1
Results and Discussion
Materials and Methods - New Zealand Experiment
No. 2
Results and Discussion
3
5
6
7
7
10
11
14
17
17
17
18
20
20
22
24
25
FOLIAR VS. SOIL UPTAKE OF HOE 23408 BY RYEGRASS
AT TWO GROWTH STAGES
Materials and Methods
Results and Discussion
28
28
28
FOLIAR VS. SOIL UPTAKE OF HOE 23408 BY RYEGRASS
AND WILD OATS GROWN IN THREE SOIL TYPES
Materials and Methods
Results and Discussion
32
32
34
FOLIAR VS. SOIL UPTAKE OF HOE 23408 BY RYEGRASS
AND WILD OATS GROWN UNDER TWO TYPES OF IRRIGATION
Materials and Methods
Results and Discussion
45
45
46
SOIL MOISTURE AND HOE 23408 EFFICACY
Materials and Methods
Water Stress Study
Soil Moisture Studies
Results and Discussion
Water Stress Study
Soil Moisture Studies
50
50
50
51
53
53
55
Table of Contents (continued)
Page
ROOT GROWTH INHIBITION BY HOE 23408
Materials and Methods
Results and Discussion
CONCLUSION
.
.
0
G
a
Gt
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0 .....
57
57
59
0
......
63
REFERENCES
66
APPENDIX
70
LIST OF TABLES
Page
Table
1
2
3
4
5
6
7
8
9
10
11
Analysis of soils used in experiments
15
Response of wild oats and ryegrass at three sites of
placement and three rates of HOE 23408
19
Response of New Zealand varieties of wild oats and
ryegrass at three sites of placement and three rates
of HOE 23408
23
The effect of placement of HOE 23408 on New Zealand
biotypes of ryegrass and wild oats
24
Response of 'Tama' ryegrass to HOE 23408 when grown
in silica sand
26
Percent dry weight reductions and visual ratings for
'Tama' ryegrass treated with 1.68 kg/ha HOE 23408 at
two growth stages
30
A detailed description of growing conditions for
five soil type experiments
33
Response of ryegrass and wild oats to 1.12 kg/ha
application of HOE 23408 at three sites of placement in three soil types
35
Response of ryegrass to 1.12 kg/ha soil application of HOE 23408 in three soil types
36
Response of wild oats to 1/12 kg/ha soil application of HOE 23408 in three soil types
36
The range of visual injury ratings for soil only
herbicide treatments in soil type experiments
42
12
Placement means for type of irrigation studies
.
.
.
48
13
Irrigation means for type of irrigation studies.
.
.
48
14
Placement x irrigation type means for wild oats
grown in silica sand
49
Fresh weights of controls in type of irrigation
studies
49
A description of growing conditions for ryegrass in
two soil moisture experiments
52
15
16
Page
Table
17
18
19
20
Percent dry reduction weights of ryegrass subjected
to two levels of water stress
54
Fresh weight reduction and visual ratings of ryegrass
injury at different soil moisture levels
56
Rates in ppm (w/vol) of HOE 23408 applied to either
the root or the foliage of two species: wheat and
ryegrass
62
Dry weights (g) of wheat and ryegrass root growth
from foliar or nutrient solution applications of
HOE 23408
62
LIST OF FIGURES
Page
Figure
1
HOE 23408 [methyl 2-[4-(2,4-dichlorophenoxy)
phenoxy]propanoate]
4
.
2
3
4
5
6
7
8
9
Percent injury from three HOE 23408 placement
sites on two ryegrass biotypes grown in soils
with various organic matter levels
27
A comparison of injury when HOE 23408 is applied
at dtfferent placement sites on ryegrass
29
Injury of two growth stages of 'Tama' ryegrass
from 1.12 kg/ha application of HOE 23408
31
Injury from various placements of HOE 23408 on
ryegrass grown in three soil types (subirrigation
study)
37
Injury from various placements of HOE 23408 on
ryegrass grown in three soil types (overhead
irrigation study)
38
Injury from various placement of HOE 23408 on
wild oats grown in three soil types (subirrigation
study)
39
Injury from various placements of HOE 23408 on
wild oats grown in three soil types (overhead
irrigation study)
40
The effect of 1.12 kg/ha of HOE 23408 applied at
three placement sites to wild oats grown in silica
1. Foliage
Plants were overhead irrigated.
sand.
only, 2. soil only, 3. foliage + soil, 4 control
.
10
11
The effect of 1.12 kg/ha of HOE 23408 applied at
three placement sites to wild oats grown in sandy
1. Foliage
Plants were subirrigated.
loam soil.
only, 2. soil only, 3. foliage + soil, 4. control.
.
.
.
.
43
43
The effect of 1.12 kg/ha of HOE 23408 applied at
three placement-sites to wild oats grown in silt
loam soil. Plants were overhead irrigated.
1. Foliage only; 2. soil only; 3. foliage + soil;
4. control
44
Page
Figure
12
13
14
An illustration of materials used for the root
Ryegrass foliage is shown
inhibition studies.
10 days after HOE 23408 application. A. Control;
B. foliage only, low rate; C. foliage only, high
rate; D. solution only, low rate; E. solution only,
high rate
58
Root and shoot appearance of wheat plants 10 days
after treatment with HOE 23408. A. Control;
B. foliage only, low rate; C. foliage only, high
rate; D. solution only, low rate; E. solution
only, high rate
58
Influence of root or foliar applications of
HOE 23408 on the root growth of wheat or
ryegrass
61
FOLIAR VS. ROOT UPTAKE
OF THE HERBICIDE HOE 23408 IN ITALIAN RYEGRASS
AND WILD OATS
INTRODUCTION
Ryegrass (Laium multiflorum Lam.) and wild oats (Avena fatua
L.) are two of the most serious weed problems facing Oregon wheat
growers.
Both are winter annuals and .have life cycles so similar
to winter wheat that they are difficult to control in that crop.
Wild oats may also emerge as a summer annual to cause problems in
spring wheat fields.
Control of Italian ryegrass is hampered by the fact that it is
also grown as a seed crop in the Willamette Valley.
This insures a
plentiful source of seed for infestation in wheat fields.
Wild oat
control is also hard to achieve because of the dormancy of wild oat
seeds (Black, 1959).
Forbes (1963) showed that dormant seeds could
remain in the soil for as long as 8-9 years, although most seeds
germinated within a 5-year period.
Current herbicides available for control of these two weeds in
small grains are:
zoquat.
triallate, diallate, diuron, barban, and difen-
Each of these materials has advantages and disadvantages.
Up to the present time, chemical control of both weeds has met with
limited success.
HOE 23408
[ methyl- [4 -(2,4- dichlorophenoxy) phenoxy] propa-
noate] is an experimental herbicide which shows great promise for
the control of ryegrass and wild oats.
Ryegrass is highly suscep-
tible to HOE 23408 while wild oats is moderately susceptible (Wu and
2
Santelmann, 1976).
Barley is moderately tolerant (Lee and Alley,
1975) and wheat is highly tolerant (Miller and Nalewaja, 1974).
HOE 23408 is the first herbicide to show such a margin of selectivity
for ryegrass and wild oat control in small grains.
Although little
is known regarding the mode of action of HOE 23408, there is evidence that absorption can occur from both foliar and soil applications.
This research was undertaken to examine the relative impor-
tance of foliar vs. root uptake from postemergence applications of
HOE 23408 to two species of wild oats and ryegrass.
The objectives
of the research were the following:
1.
To examine factors such as rate of herbicide, stage
of plant growth, soil type, and type and amount of
irrigation, and to assess how these factors affect
the relative importance of foliar vs. root uptake.
2.
To examine how injury occurs when the herbicide is
applied to the foliage or to the root.
3
LITERATURE REVIEW
HOE 23408
HOE 23408 controls many annual grass species of agronomic importance such as barnyardgrass (Echinochloa crusgalli (L.) Beauv.) the
foxtails (Setaria sp. Beauv.), fall panicum (Panicum dichotomiflorum
Michx.), large crabgrass (Digitaria sanguinalis(L.) Scop),Italian ryegrass (Lolium multiflorum Lam.), and wild oats (Avena fatua L.).
Downy brome (Bromus tectorum L.) and annual bluegrass (Boa annua
L.) are more tolerant and can be partially controlled only by
preemergence treatments.
HOE 23408 has exhibited an antagonistic response to tank mixes
with many other herbicides.
It may be necessary to apply HOE 23408
alone and allow at least 3 days before application of other chemicals to the field.
Antagonism has been noted with broadleaf herbi-
cides such as 2,4-D LV ester, MCPA LV ester, and dicamba amine
(Ivackovich, 1976).
Many crop plants are tolerant to HOE 23408.
The potential use
of the chemical is great in vegetable crops (Putnam
et al., 1974)
as well as in such agronamic crops as barley, wheat, soybean, and
peanuts (Wu and Santelmann, 1976).
HOE 23408 is active when applied either preplant incorporated,
preemergence, or postemergence.
The structural formula of HOE 23408
is shown in Figure 1.
HOE 23408 is formulated as an emulsifiable concentrate ( 3 lb/
gal a.i.).
Recent work with surfactants has revealed many
4
CH
3
0-CH-C-OCH
3
0
Figure 1.
HOE 23408 [methyl 2-[4-(2,4-dichlorophenoxy)
phenoxy] propanoate],
possibilities for increased activity through the use of such compounds.
The mode of action is not yet understood.
One study found
that HOE 23408 was not translocated to an appreciable extent in
either sensitive or tolerant species (Brezeanu
Brezeanu
et al., 1976).
et al. (1976) also noted ultrastructural modifications.
Chloroplasts were the most damaged organelles.
In susceptible
plants, utilization of carbon dioxide is drastically reduced.
There appears to be a latent period of 4-7 days after treatment
where carbon dioxide reduction is only slight and no injury symptoms are present (American Hbechst Technical Information Bulletin).
Following this latent period, injury manifests itself by chlorotic
mottling and necrosis of the foliage.
species.
Symptoms vary according to
Wild oat injury begins with chlorotic mottling and a
slight reddening at the leaf blade tips.
Ryegrass injury may begin
with a chlorotic mottling or a whitening of whole leaf areas followed
by a rusty color throughout.
Necrosis follows.
Severe root inhi-
bition has been noted in treated species such as ryegrass, wild
5
oats, and corn.
Treated plants can be easily pulled from the soil.
Postemergence treatments of HOE 23408 are most effective at
early growth stages.
Much better control of wild oats was noted
at the one- to three-leaf stage than at the four- to five-leaf stage
(American Hoechst Technical Information Bulletin).
American Hoechst
has determined the order of increasing sensitivity of wild oat plant
parts as growing point, coleoptile, crown sheath, leaf sheath, first
leaf, and third leaf.
Studies have indicated that HOE 23408 is not very mobile in
the soil.
Wu and Santelmann (1976) have indicated that HOE 23408
has the same degree of mobility as trifluralin.
Most herbicides
remained in the upper 7.6 cm of soil in the field and leachability
studies indicateda leaching of only 0 to 1 cm.
Higher rates of
HOE 23408 appear to be necessary in soils high in organic matter.
Ample soil moisture may increase effectiveness.
High relative
humidity and low air temperature also appear to favor HOE 23408
Studies
injury (American Hoechst Technical Information Bulletin).
indicate that HOE 23408 applied at rates less than 2 lb/A persists
in soils for a maximum of 8-9 weeks (Ivackovich, 1976).
Wu and
Santelmann (1976) attributed breakdown primarily to microbial
degradation.
Italian Ryegrass
Italian ryegrass has a growth habit very similar to wheat.
It
emerges early and is one of the major weeds in Willamette Valley
small grains because it is also grown here for a seed crop.
Up to
6
this time, it has been difficult to control because herbicides
which would kill it without injuring wheat were not available or
were inconsistent in their effectiveness.
Wild Oats
Wild oats germinate over a wide range of temperatures from 2
The optimum temperature for germination is 15°C (Koch,
to 35°C.
1968).
Since temperatures near 15°C are prevalent in Oregon in
both spring and fall, the climate here is well suited to its development.
Wild oats begin with a poor root system.
One study found that
5 days after emergence, they had less roots than six out of nine
dicots studied and had much less root growth than all but one
cereal (Pavlychenko, 1934).
The average wild oat plant has 3-4
seminal roots while wheat has 4-5, rye has 5-6, and barley has 6-13.
Cohen and Tadmor (1969) determined that root elongation was between
2 and 7 cm per day for large-seeded wild oats and .5 to 2 cm per
day for small-seeded wild oats.
Elongation was positively corre-
lated with seed weight and increased 2-3 times when the temperature
increased from 10 to 20°C.
Thurston (1959) pointed out that this
slow initial root growth makes it a poor early competitor, but
once established, it has a higher net assimilation rate than other
weeds, it grows more rapidly, and it grows taller.
This may be one
reason why HOE 23408 is much more effective at the smaller growth
stages.
Odgaard (1972) surveyed wild oat growth habit under
different soil types:
fen, sandy soil, loam, and heavy marsh soil.
He found that wild oats developed panicles earlier on the sand and
loam soils than on the marsh or fen.
Straw was longest and flowering
continued longer on the fen (the most fertile soil).
Factors Affecting Foliar and Soil Uptake
Foliar Uptake
Regardless of what type of molecule is present on the leaf surface, all must pass through the same leaf layers to reach the symplast.
These layers are the wax layer, the cuticle, the pectin
layer, the cell wall, and the plasma membrane (Franke, 1967).
The
wax layer is made of hydrocarbons, unsaturated ketones, and longchain aldehydes.
According to Crafts and Foy (1962), they are
frequently packed in groups perpendicular to the membrane.
The
cuticle is made up of cutic and cutinic acid (Bayer and Lumb,
1973) and covers all external portions of the shoot (van Overbeek,
1956).
A thinner cuticle lines the stomatal cavities (Yamada
al., 1966).
1967).
et.
As a whole, cuticle is negatively charged (Franke,
Pectin is composed of long chain polygalacturonic acid
molecules having side carboxyl groups.
Pectin is a polar substance,
having base exchange properties and capable of forming salts
(Crafts and Foy, 1962).
The cell wall is composed of hexoses,
pentoses, and uronic acid (Frey-Wyssling and Muhlethaler, 1965).
This structure is thickened by cellulose and impregnated with wax
and cutin (Bayer and Lumb, 1973).
The presence of hydroxy and
carboxylic acid groups causes the cell wall to be hydrophilic.
Most investigators consider the plasma membrane to have a protein-
8
lipid-protein or lipid-protein-lipid structure (Branton, 1969).
Although knowledge is incomplete as to how penetration of the plasma
membrane is accomplished, most investigators consider it a metabolic,
energy-requiring process (Prasad and Blackman, 1965).
These layers
collectively form a highly non-polar waxy surface on the outside
with a gradient to the highly polar cell wall on the inside.
More sites of preferential absorption are on the lower leaf
surface than are on the upper leaf surface (Goodman and Addy, 1962).
Some of the preferential absorption sites are:
guard cells (Franke,
1967), veins (Currier and Dybing, 1959), trichomes, anticlinal
walls, and areas surrounding hairs (Franke, 1967).
Crafts (1956)
proposed two distinct pathways for herbicide entry -- one aqueous
and the other lipoidal.
Lipoidal, non-polar substances, such as
HOE 23408, enter the wax and cuticle layer easily by diffusion.
If
a substance is too lipophilic, it may remain embedded in the cuticle.
Most continue diffusing through the leaf following embedded waxes
and cutinized areas through the more polar layers.
Hydrophilic
herbicides are absorbed via the alternate aqueous route.
The most
impenetrable layer to hydrophilic compounds is the waxy layer and
absorption of polar compounds is greatly enhanced by a hydrated
atmosphere (Clor
et al., 1962).
Under high humidity, the em-
bedded waxes become separated by water and the molecules diffuse
along with the water to the polar leaf regions.
Once the polar
substance enters the pectinaceous and cellulose layers, it moves
freely by diffusion.
Once inside the leaf cells, the herbicide may
cause immediate damage (contact action) or it may translocate to
9
another part of the plant where it exerts its action (systemic
action).
Recent research would tend to place HOE 23408 in the first
category (Brezeanu
et al., 1976),
The efficacy of uptake is governed by varying factors related
to the plant'; the environment, and the molecule itself,
Gross mor-
phology of a species is one of the most important plant factors.
Italian ryegrass has a thin cuticle and is easily wet.
Wild oats
Wax and cuticle deposition increase with
has a thicker cuticle.
age, giving old plants a surface that is less easily wet (Franke,
1967).
Herbicide absorption tends to decrease with increasing age
(Sargent, 1965).
Regarding environmental effects on absorption, a few general
statements can be made.
Anything which serves to break down the
cuticle will enhance absorption.
Included in this category are
weathering, insect punctures, and disease (Linskens et al., 1965).
Absorption of a substance generally increases linearly with increasing concentration.
High temperatures often increase the rate
of penetration (Sargent and Blackman, 1965).
A higher light in-
tensity may increase penetration in some cases.
Sargent and
Blackman (1965) studied 2,4-D absorption as affected by concentration and light intensity.
They found that more 2,4-D could be ab-
sorbed from application of 400 mg applied under light than 1000 mg
applied in darkness,
Time of day may also either promote or decrease
absorption by changes in relative humidity or changes in the plant's
contact angle (Linskens et al., 1965).
Herbicide formulation and adjuvants may affect the herbicide's
10
performance.
Norris and Freed (1966) looked at how side chains
affect absorption,
Propionic side chain molecules were absorbed
better than acetic acid types which in turn were absorbed better than
butyric groups.
Surfactants may increase herbicide effectiveness by lowering
the surface tension (Bayer and Lumb, 1973).
No additional surfac-
tants, however, were used in our study.
Uptake From the Soil Solution
Herbicide is taken up by plant roots along with water.
types of passive uptake are performed by the root:
mass flow.
Two
diffusion and
In addition, active uptake takes place at the plasma-
lemma in root tissue at the point where the molecule enters the
symplast,
Mass flow is primarily a function of herbicide concen-
tration in the soil solution and of the amount of water absorbed by
the plant.
Diffusion depends on the magnitude of the concentration
gradient which in turn is regulated by the rate of removal of molecules from the soil-root interface by absorption and transport processes in the plant (Scott and Phillips, 1973).
Uptake of either
type would be influenced by the age of the plant and the degree of
differentiation and suberization (Walker; 1973).
A herbicide may lose activity in a soil because of several
factors:
(1) microbial decomposition, (2) chemical decomposition,
(3) adsorption on soil colloids, (4) leaching, (5) volatility, and
(6) photodecomposition.
be photodecomposed.
HOE 23408 is not very volatile or likely to
It is low in water solubility and is relatively
11
immobile in the soil, remaining in the uppermost layer (Wu and
Santelmann, 1976),
It is believed to be largely broken down by
microbial decomposition (Wu and Santlemann, 1976).
Higher rates
must be applied in soils higher in organic matter.
Therefore, the
factors which appear most relevant in their effect on HOE 23408
activity are (1) microbial decomposition and (2) adsorption on soil
colloids.
Chemical decomposition may be an additional factor.
If a herbicide is chiefly inactivated by microbial decomposi-
tion, any environmental factors which favor the microbe population
will tend to hasten breakdown.
Conversely, the herbicide is likely
to remain intact longer under conditions unfavorable to the microbes.
The herbicide is likely to remain active longer if the soil
is cold, dry, or poorly aerated, or if it has a pH less than 5.5
(Klingman and Ashton, 1975).
Adsorption on soil colloids will be higher in soils high in
cation exchange capacity and organic matter, or low in soil moisture.
For most soil-applied herbicides, the amount which must be
applied to cause injury increases with increasing soil organic
matter content (Upchurch et al., 1966),
The Role of Water Stress
Water stress affects the plant by disrupting vital
physiologi-
cal functions such as photosynthesis, respiration, and transpiration, changing the growth rate and favoring some plant parts over
others (Hsiao, 1973).
These changes affect the uptake of compounds
in the soil solution and alter the translocation of the compounds.
12
The rate of plant growth is directly dependent on water poten.
tial (Gates, 1968),
Green et al.(1971) quantified the relationship
of growth to water potential ( 'p) in the following equation:
Growth rate
Eg (gip
T
)
Where Eg . gross extensibility of the cell
T
= water potential due to pressure
T th = threshold turgor water potential
Water stress does not affect all plant parts equally.
Gates
(1968) determined that the most actively growing plant parts
suffered greatest inhibition.
Generally speaking, during water
stress, reproductive growth is favored while vegetative growth is
reduced (Hagen et al., 1959; Salter and Goode, 1967; Kramer, 1969).
Water stress may also affect the morphology of the plant, causing
it to deposit a heavier cuticle (Kramer, 1969).
Both net photosynthesis and respiration decrease at increasing
levels of water stress.
One study (Brix, 1962) indicated an in-
crease in respiration but most studies indicate a reduction although
the reduction is not as great as that indicated for photosynthesis
(Hsiao, 1973).
The rate of photosynthesis is seldom limited by lack
of water for reagent purposes (Kramer, 1969).
If water stress is
severe enough to cause stomatal closure, carbon dioxide becomes
limiting.
Barrs (1968) found that photosynthesis and transpiration
decreased at the same rate and concluded that stomatal
of great importance.
closure was
Boyer (1965) obtained conflicting results as
he noted much photosynthesis reduction while stomata were open.
13
The balance between absorption and transpiration largely determines the degree of stress.
Kramer (1969) termed transpiration the
dominant factor in plant water relations.
When water evaporates from
the leaf surface, an energy gradient is established which causes
movement of water into the plant.
Transpiration rate is controlled
by (1) leaf area and structure, (2) stomatal opening, and (3) the
steepness of the vapor pressure gradient of water to air (Kramer,
1969).
Herbicides may also affect the rate of transpiration.
Studies
involving 2,4-D, atrazine, and amitrole have shown that these herbicides significantly reduce transpiration rate as well as photosynthesis (Smith and Buchholz, 1964; Gill et al., 1972).
Herbicide movement to and into the plant is affected by soil
moisture and transpiration rate.
Many studies have found that the
amount of a herbicide absorbed from the soil solution is proportional to the transpiration rate (Schreiber et al., 1975).
As a
decrease in soil moisture levels causes a reduction in transpiration
rate, herbicidal uptake and, hence injury, may be reduced under
water stress conditions (Cox and Boersma, 1967; Babalola et al.,
1968).
Sedgeley and Boersma (1969) found that wheat sustained
diuron damage more easily under conditions of high soil moisture
than of low.
Schreiber
et al. (1975) found that bromacil uptake
was affected by changes in soil moisture and that low soil moisture
reduced uptake.
An excellent review of the effect of soil water
potential on herbicide uptake is provided by Crafts and Crisp
(1971).
14
GENERAL MATERIALS AND METHODS
Studies were conducted in Oregon and New.Zealand-using ryegrass
(Lolium multiflorum Lam.) and wild oats (Avena fatua L.).
In Oregon,
ryegrass biotypes found in Oregon and Canadian wild oat seed were used.
New Zealand biotypes were used for both species for studies conducted
in that country.
Plastic pots, 10 by 10 by 10 cm, were used through-
out the studies.
The soil types used in various experiments are given
in Table 1.
Prior to use, the soil was prepared by straining it
through a coarse -mesh sieve-to eliminate large chunks of organic
matter, debris, or soil.
Ryegrass seeds were planted 0.5 cm deep
(deeper in the silica sand) and wild oats were planted 1 cm deep.
The plants were sprayed at the two- to four-leaf stage.
Those plants in growth chambers were grown under a light intensity of 21.5 lux provided by fluorescent and incandescent illumination.
Relative humidity was 70% and a 12-hour day, 12-hour night
schedule was maintained.
Day temperature was 20°C and night tempera-
ture was 10°C unless otherwise noted.
Plants grown in the greenhouse were also on a 12-hour day, 12hour night schedule provided by fluorescent lights suspended 31 cm
above the rims of the pots and sunlight when available.
studies were conducted under two temperature regimes:
day and 18°
Greenhouse
(1) 24° ± 3°C
2°C night, or (2) 20' ± 4°C day and 12° ± 2°C night.
HOE 23408, formulated as a 38% a.i. emulsifiable concentrate,
was used.
For Oregon, the plants were sprayed using an overhead
variable speed sprayer calibrated to deliver 309 L/ha.
flat fan even nozzle tip was used for spraying.
An 8001
In New Zealand
15
a backpack sprayer was used, also calibrated to deliver 309 L/ha.
Analysis of soils used in experiments.
Table 1.
Organic Matter %
CEC
Soil Type
pH
Woodburn silt loam
5.0
3.5
15.1
Newberg sandy loam
5.0
1,7
15.5
Silica sand
7.1
0.5
9.4
Sandy clay loam
6.6
1.4
18.0
Canterbury plains silt loam
Undetermined
4.5
Undetermined
The herbicide was applied at three different placement sites.
The foliar placement was accomplished by protecting the soil with a
1.5 cm layer of perlite applied to the surface just prior to spraying.
The perlite was allowed to remain on the surface until dry
and then removed.
was not used.
In the soil application, the overhead sprayer
The soil treatment was prepared by adding the proper
amount of active ingredient to 25 ml of water/pot.
To give the pre-
scribed rate, this solution was poured directly on the soil surface
in a manner which provided even distribution.
The foliar plus soil
placement was accomplished by using the overhead sprayer without
protecting either portion of the plant.
The pots were watered
within 1 hour prior to spraying and not watered for 24 hours after
treatment.
Two to four weeks after herbicide treatment, the plants were
harvested.
In Oregon, the foliage was dried in glass weighing
bottles in an oven at 80°C and weighed on a Mettler balance.
16
In New Zealand, foliage was placed in paper bags and dried in an
oven at 80°C.
A Mettler balance was again used for weighing.
weights were obtained for each experiment.
Dry
In many cases, fresh
weights were also obtained before the foliage was dried.
17
FOLIAR VS. ROOT UPTAKE OF HOE 23408
AT DIFFERENT RATES OF APPLICATION
Oregon Placement Studies
An experiment was undertaken to determine the extent of injury
resulting from various placement sites of HOE 23408:
or foliar plus soil.
Three rates were chosen:
foliar, soil,
1.12, 1.68, and
2.24 kg/ha, to see if the relative effectiveness of each placement
site remained constant over varying herbicide concentrations.
Materials and Methods
A sandy clay loam soil was prepared by mixing greenhouse potting
soil with silica sand, a 60:40.ratio.
The resulting soil had a pH of
6.6 and organic matter-content of 1.39% (Table 1).
Wild oats and rye-
grass were the bioassay species.
The pots were placed.in a growth chamber and grown for 14 to 16
days prior to treatment.
Overhead irrigation was supplied every other
day throughout the growth period.
When plants reached the two- to
three-leaf stage, three rates of herbicide were applied at three
placement sites.
Ryegrass pots were-harvested 3 weeks after spraying.
Wild oats grew 5,weeks-from treatment to harvest because they were
slower to develop injury symptoms.
Visual ratings of injury, fresh
weights, and dry weights were obtained.
Fresh weights were converted
to percent of control and percent fresh weight reduction was obtained.
These data were-transformed using the-Arcsin / transformation as suggested in Steel and Torrie (1960).
The data were then analyzed as a
randomized block design with a 3 x 3 factorial arrangement (Appendix
Tables 1 and 2).
18
Results and Discussion
Injury symptoms developed within 2 weeks on ryegrass.
Symptoms
began with a whitening and chlorotic mottling of foliage parts
followed by necrosis.
Symptoms on wild oats developed later and in
general were less severe.
Symptoms on wild oats began with a
yellowing of the tips of the leaf blades, followed by overall
chlorotic mottling and necrosis.
Visual ratings were made on a
percent-injury basis (Table 2 and Appendix Tables 3 and 4).
Injury
ratings are based on reduction in the height and vigor of the plants
and foliar desiccation.
Tables 3 and 4.
Plant fresh weights are given in Appendix
Dry weights are given in Appendix Table 5.
The
results expressed as percent fresh weight reduction are given in
Table 2.
The two evaluation methods, ratings and percent fresh
weight reduction, yielded similar conclusions.
Although differences were not always statistically significant,
there was a consistent trend.
For all three rates and for both
species, injury increased in the order;
combination.
foliage only < soil only <
Within each placement, there was a slight increase in
herbicide activity with increasing rate.
Without exception, ryegrass was more severely injured than wild
oats.
Wild oats was not only injured to a lesser extent in most
cases, but also took much longer to develop injury symptoms.
Throughout the experiment, wild oats was plagued with a disease
problem which caused some chlorosis even in the control treatments.
This condition may have produced a stress situation which resulted
in a diminished herbicide uptake.
In addition, wild oats may be
Table 2.
Response of wild oats and ryegrass at three sites of placement and three rates of HOE 23408.
Wild Oats
Treatment
kg/ha
Placement
Ryegrass
Fresh wt.b
% reduc.
HOE 23408
1.12
Foliar
49.7 (45,1)
36
13.7 (19.0)
10
HOE 23408
1,12
Soil
81,3 (65,5)
69
67.1 (55.5)
74
HOE 23408
1,12
Combination
93.3 (75,0)
91
76.9 (62.9)
87
HOE 23408
1.68
Foliar
75.8 (61,4)
52
55.6 (48.4)
57
HOE 23408
1.68
Soil
88,2 (70.0)
79
74.2 (60.6)
75
HOE 23408
1.68
Combination
94.4 (76.6)
96
86.7 (69.1)
93
HOE 23408
2.24
Foliar
89.0 (70.9)
76
53.2 (51.7)
73
HOE 23408
2.21
Soil
91.5 (72,8)
85
86.5 (68.8)
90
HOE 23408
2.24
Combination
95.0 (77.1)
99
93.4 (75.4)
99
LSD
LSD
a
b
Injurya
ratings
Fresh wt.
% reduc.
(12.4)
(11.1)
(16.7)
(14.9)
.05
.01
Ratings average of two independent evaluators expressed on a percent injury basis.
Arcsin / transformations are in parentheses.
Injury
ratings
20
inherently a more tolerant species than ryegrass.
We can conclude from this study that both foliar and root uptake
of HOE 23408 may produce injury.
Under the conditions of this experi-
ment, root uptake exerted a stronger role than did foliar uptake.
New Zealand Placement Studies
'Tama' ryegrass, a heavy tillering, rapidly growing New Zealand
variety, and wild oats from the Canterbury Plains of New Zealand
were selected as bioassay species in a study which was conducted in
New Zealand.
The soil type was a Canterbury Plains silt loam soil
with an organic matter content of approximately 4.5%.
The Canterbury
Plains is an area characterized by well-drained fertile soil and low
rainfall (52 cm/yr).
occupation.
Sheep farming is the principal agricultural
Cropping is done usually in rotation with pasture,
and wheat is the main cash crop.
The purpose of this study was to determine if the same placement and rate effects obtained in Oregon could be repeated with the
different soils, biotypes, and environmental conditions present in
New Zealand.
Materials and Methods
New Zealand Experiment No,
I
Wild oats are difficult to grow uniformly in the greenhouse
because of the dormancy of wild oat seed.
If planted without pre-
germinating, seedlings may emerge at very different times, or in
some cases, fail to emerge at all.
was found to be dormant.
The biotype found in New Zealand
A germination study.of-50 seeds without
21
the hulls removed resulted in no germination after 1 week incubation
in moistened petri dishes at 15°C.
A similar test with'the hulls
removed improved germination 10%, while a study where the hulls were
removed and the seeds were treated with gibberellic acid resulted in
Many investigators have reported that germinating
100% germination.
is increased if the hulls of wild oats are removed (Hay and Cumming,
Likewise, the stimulatory effect of gibberellic acid has
1959).
been noted by many workers (Hay and Cumming, 1959; Simpson, 1965).
The New Zealand wild oat seeds were pre-germinated with the husks
removed in a solution of 10-3M gibberellic acid.
After 3 days,
those with most uniform radical emergence were selected and 12 seeds
were planted per pot.
pot.
Seedlings were later thinned to 10 plants per
The ryegrass in this case was planted and thinned in the same
way as the previous experiment.
Both species were grown in the
growth chamber with conditions as given in the General Materials and
Methods section.
The plants attained the two- to three-leaf stage
prior to treatment.
This took 15 days for the ryegrass and only 10
days for the wild oats, probably because of the pre-germination
period.
days.
Plants were watered by overhead irrigation on alternate
They were watered within 1 hour before spraying and not for
24 hours after spraying.
A backpack sprayer was used for the treat-
ments and was calibrated to deliver 309 L /ha,
The same rates (1.12,
1.68, and 2.24 kg/ha) were used to treat wild oats in this experiment.
Because ryegrass was found in previous experiments to be more
sensitive than wild oats, a lower rate was employed, giving the
following rates for ryegrass treatment:
0.56, 1.12, and 1.68 kg/ha.
22
In this study, both species developed injury symptoms within 3 weeks
and were harvested 3.5 weeks after treatment.
Because all of the
plants were grown in the same growth chamber and appeared to be
sufficiently uniform, the experiment was set up using the completely
randomized design with nine treatments and five replications per
treatment.
Dry
Fresh weights were not obtained in this study.
weights and visual ratings were taken.
The treatments included
three rates x three sites of placement plus one control.
The visual
ratings were transformed using the Arcsin iTtransformation and
analyzed (Steel and Torrie, 1960).
These were analyzed with a
3 x 3 factorial arrangement (Appendix Tables 7 and 8).
Results and Discussion
The results are presented in Table 3 and Appendix Tables 9,
10, and 11.
Although the differences were not significant, there
were slight increases in visible injury with increasing rate
(Appendix Tables 7 and 8).
Since no placement x rate interaction
was apparent, the placement effects were summed across rates
(Table 4).
For both species, the order of injury according to placement
was:
soil only < foliar only < combination.
These results con-
tradict the Oregon study which showed that the soil placement provided more injury than the foliar placement in most cases.
Since
both experiments were done in growth chambers under identical environmental conditions, it is unlikely that such factors as temperature, light, or moisture could account for the differences.
The
Table 3.
Response of New Zealand varieties of wild oats and ryegrass at three sites of placement
and three rates of HOE 23408.
Ryegrass
Treatment
Rate
kg/ha
HOE 23408
HOE 23408
HOE 23408
0.56
0.56
0.56
HOE 23408
HOE 23408
HOE 23408
1.12
1,12
1.12
Soil
HOE 23408
HOE 23408
HOE 23408
1.68
1.68
1.68
Soil
HOE 23408
HOE 23408
HOE 23408
2.24
2.24
2.24
Control
0
LSD
LSD
a
b
.05
.01
Placement
Foliar
Soil
Combination
Foliar
Combination
Foliar
Combination
Wild Oats
% Dry wt.
reduction
Injury
ratingsa
87.3 (69.1)
5.7 (14.0)
94.6 (76,5)
80 (66.0)
12 (20.1)
99 (87.4)
89,3 (71.0)
30.4 (33.5)
93,2 (74,9)
82 (68.4)
29 (28.9)
98 (84.8)
78.5 (62.38)
0.0 (0)
78.8 (62.6)
68 (55.7)
28 (31.8)
95 (80.0)
93.9 (75,8)
51.3 (45.8)
95.1 (77.2)
88 (72.3)
38 (36.8)
99 (87.4)
74.0 (59.3)
0.0 (0)
75.8 (60.5)
73 (58.8)
34 (35.5)
93 (78.3)
75.9 (60.6)
80 (64.1)
35 (36.2)
96 (82.6)
Foliar
Soil
-
-
Combination
-
-
0.0
0
Injury
ratingsa
% Dry wt.
reduction
-
1.1
( 6.0)
80.5 (63.8)
0.0
0
(8.0)
(16.8)
(7.0)
(9.3)
(10.7)
(22.4)
(9.4)
(12.4)
Ratings average of two independent evaluators expressed on a percent injury basis.
Arcsin A- transformations are in parentheses.
24
differences could have been due to biotype effects, soil effects, or
a combination of the two.
Biotype effects might include different
preferential sites of absorption, different growth rates, cuticular
differences, or tillering differences.
Edaphic factors which could
affect the amount of uptake from the soil would include cation exchange capacity, soil pH, organic matter content, and type of soil
microorganisms present.
In the New Zealand study, differences in the injury level of
wild oats and ryegrass were much less pronounced than in the Oregon
However, ryegrass was injured in a shorter time than wild
study.
Ryegrass developed symptoms within 1 week of spraying, while
oats.
in the case of wild oats, 2 weeks were required.
Table 4.
The effect of placement of HOE 23408 on New
Zealand biotypes of ryegrass and wild oatsa.
Placementb
Soil only
Combination
Species
Foliar only
Ryegrass
83.3 (65.9)
26.3 (30.8)
98.7 (83.4)
Wild oats
73.7 (59.2)
32.3 (34.6)
94.7 (76.7)
= (1.68) for ryegrass means
LSD
LSD.01 = (12.95) for ryegrass means
LSD.05 = (5.35) for wild oat means
LSD
a
b
= (7.15) for wild oat means
.01
Data are visual ratings expressed on a percent injury basis, each
is a mean of 15 ratings.
Arcsin IT transformations are in parentheses.
Materials and Methods - New Zealand Experiment No. 2
'Tama' ryegrass seeds were planted and grown in an identical
25
The only differences were the
manner to the previous experiment.
As the plants were grown in
soil type and amount of fertilization,
a silica sand with few available nutrients (Table 1), it was
necessary to supplement the watering with fertilizer twice per week.
A nutrient solution containing both macronutrients and micronutrients
(Hewitt, 1952) was prepared and used for this purpose.
were treated at the two- to three-leaf stage.
The plants
The plants were
harvested and the data were analyzed in the same manner as before.
Results and Discussion
Injury was so severe on 'Tama' ryegrass grown in silica sand
that all treatments were visually rated at 100% injury (Table 5).
Analysis of variance was conducted on the dry weights (Appendix
Tables 12 and 13) and some significant differences were noted.
At
the two lower rates, the combination treatment was more effective
than either of the protected treatments.
At the highest rate, all
placements provided equal injury.
Sensitivity of the two biotypes to a foliar application of
HOE 23408 was markedly different.
A comparison of the results of
the first three experiments is given in Figure 2.
'Tama' ryegrass
grew more rapidly and tillered more profusely than the Oregon biotype and these factors could make 'Tama' ryegrass more sensitive.
Many investigators have noted that fast-growing plants are much more
susceptible to herbicide injury (Klingman and Ashton, 1975).
Sensitivity of ryegrass to HOE 23408 also differed according
to the type of soil used (Figure 2).
Injury from soil only
26
Table 5.
Response of 'Tama' ryegrass to HOE 23408 when
grown in silica sand.
Injury
ratinga
Treatment
kg/ ha
Placement
% Dry wt.,
reduction°
HOE 23408
HOE 23408
HOE 23408
0.56
0.56
0.56
Foliar only
Soil only
Combination
90.9 (72.4)
92.8 (74.4)
96.7 (79.5)
100
100
100
HOE 23408
HOE 23408
HOE 23408
1.12
1.12
1.12
Foliar only
Soil only
Combination
94,6 (76.6)
92.1 (73.7)
96.2 (78.8)
100
100
100
HOE 23408
HOE 23408
HOE 23408
1.68
1.68
1.68
Foliar only
Soil only
Combination
96.7 (79.5)
95.3 (77.5)
95.4 (77.6)
100
100
100
Rate
LSD
LSD
(3.2)
.05
(4.3)
.01
aRatings expressed on percent injury basis.
b
Arcsin /T transformations are in parentheses.
placements coincides well with organic matter content in the various
soils (Table 1).
Ryegrass grown in the high organic matter soil
was injured least by the soil treatment while ryegrass grown in the
low organic matter sand was injured most.
In each case, the combination treatment caused a high level of
injury.
Environmental conditions which maximize both foliar and
soil uptake would be likely to achieve the most severe injury.
27
100
.90
80
70
60
% Injury*
50
40
30
20
10
0
Foliage
only
Soil
Combination
only
Placement
biotype from Oregon (medium O.M. soil)
biotype from New Zealand (high O.M. soil)
biotype from New Zealand (low O.M. sand)
Figure 2.
Percent injury from three HOE 23408 placement
sites on two ryegrass bid-types grown in soils
with various organic matter levels.
*Percent injury obtained from visual ratings made by two
Ratings given here are the mean
independent evaluators.
of five replications.
28
FOLIAR VS. SOIL UPTAKE OF HOE 23408
BY RYEGRASS AT TWO GROWTH STAGES
The objectives of this study were:
(1) to determine if ryegrass
is more sensitive to HOE 23408 at the one- to two-leaf stage or the
three- to four-leaf stage, and (2) to determine if a placement x
growth stage interaction exists.
Materials and Methods
'Tama' ryegrass grown in a Canterbury Plains silt loam soil,
was prepared as described in General Materials and Methods.
Plants
were grown in a growth chamber and overhead irrigated in all experiments.
The herbicide treatment was applied when plants reached either the
one-to two-leaf or three-to four-leaf stage.
15 days after treatment.
were obtained,
Plants were harvested
Dry weights and visual ratings of injury
Visual ratings were transformed to Arcsin VT and
analyzed as a randomized complete block design with a factorial
arrangement of treatments (Appendix Table 14).
Results and Discussion
Results are presented in Table 6 and Appendix Table 15.
placement x growth stage interaction was found,
No
'Tama' ryegrass at
both growth stages suffered more injury from foliar placement than
from soil placement of the herbicide (Figure 3).
These data agree
with those obtained in a previous experiment using the same ryegrass
biotype, the same soil type, and the same environmental conditions
(Table 4),
Although injury from each placement was greater in the
29
100
90
80
70
Injury
60
50
40
30
= LSD
20
.05
10
0
Foliar
of
Foliar +
soil
Placement Site
Figure 3.
A comparison of injury when HOE 23408 is applied
at different placement sites on ryegrass.
30
Table 6.
Percent dry weight reductions and visual ratings
for 'Tama' ryegrass treated with 1.68 kg/ha
HOE 23408 at two growth stages.
Placement
% Dry wt, reduction
Stage 2
Stage 1
Foliar only
61.4 (51.6)
Soil only
Combination
Control
LSD
LSD
a
0.0 (0)
52.3 (46.3)
05
.01
(49.7)
74 (59.3)
58.5 (49.9)
7.2 (15.6)
18 (25.1)
7.0 (15.3)
54.3 (47.5)
80 (63.4)
57.5 (49.3)
58.1
0.0
0.0
Visual ratinga b
Stage 1
Stage 2
0.0
0
(18.3)
(11.1)
(24.6)
(15.2)
Visual ratings on percent injury basis and are means of ratings
taken by two independent evaluators.
b
Arcsin )5( transformations are in parentheses.
first experiment (Table 4), this is probably due to the fact that in
the first case, ryegrass was allowed to grow for a longer period
after treatment.
For each placement site, the older plants developed less
chlorosis than the younger plants.
The results are presented as
growth stage means summed across placements (Figure 4), and indicate
that plants treated at the one-to two-leaf stage were more sensitive,
according to visual appearance.
Reasons for this, could include:
(1) the higher proportion of meristematic tissue in younger plants,
and (2) less cuticle deposition in younger plants.
Although there
were no differences in dry weight reduction at the two growth stages
(Table 6), the younger plants appeared to be more sensitive.
31
100^
90
80
70
= LSD
% Injury
.05
60
50
40
30
20
10
0
Stage 1
Stage 2
Growth Stage
Figure 4.
Injury of two growth stages of 'Tama' ryegrass
from 1,12 kg/ha application of HOE 23408.
32
FOLIAR VS. SOIL UPTAKE OF HOE 23408 BY
RYEGRASS AND WILD OATS GROWN IN THREE SOIL TYPES
A study was undertaken to determine the influence of soil type
on the activity of HOE 23408.
In previous experiments, the amount
of injury resulting from various placements of HOE 23408 varied
greatly from one experiment to another.
The experiments in this
section were designed to clarify the role of soil type in bringing
about such variability.
Materials and Methods
Ryegrass and wild oats were grown in three soil types for
these experiments.
The soil types were selected to provide a range
of organic matter levels.
Woodburn silt loam (3.5% 0.M.), Newberg
sandy loam (1.7% O.M.) and silica sand (0.5% O.M.) were employed
for these experiments (Table 1).
Five studies were conducted and the growing conditions for each
experiment are described in Table 7.
Each experiment was set up
as outlined in the General Materials and Methods section.
Pots
were fertilized at weekly intervals with a 4000 ppm solution of
12-6-6 Ortho-Gro fertilizer.
Wild oats used in these studies were
-3
pre-germinated for 2 days in a 10
prior to planting.
M solution of gibberellic acid
Plants were treated at the three-to four-leaf
stage.
In experiments 1-4, there were four treatments for each soil
type:
Treatment 1:
1.12 kg/ha HOE 23408 applied to foliage only.
A detailed description of growing conditions for five soil type experiments.
Table 7.
Experiment
1
Species
Site of
Experiment
Ryegrass
Greenhouse
Temperature
No. of
Period of
seeds _.Growth Prior
per pot
to Treatment
24° ± 3°C day
18° ± 2°C night
10
Peilod of
Growth from
Trt. to Harv.
Type of
Irrigation
3 weeks
2 weeks
Subirrigation
(Thinned
20 to 10)
2
Ryegrass
Greenhouse
24° ± 3°C day
18° ± 2°C night
10
3 weeks
2 weeks
Overhead
irrigation
3
Wild oats
Greenhouse
24° ± 3°C day
18° ± 2° night
8
2.5 weeks
2.3 weeks
Subirrigation
(Thinned
12 to 8)
4
Wild oats
Greenhouse
24° ± 3°C day
18° ± 2°C night
8
2.5 weeks
2.3 weeks
Overhead
irrigation
5
Ryegrass
Growth
chamber
20°C day
10°C night
10
3 weeks
3 weeks
Subirrigation
34
Treatment 2:
1.12 kg/ha HOE 23408 applied to soil only.
Treatment 3:
1.12 kg/ha HOE 23408 applied to foliage and soil.
Treatment 4:
Control
Each treatment was replicated five times.
Fresh weights and
dry weights were obtained (Appendix Tables 16, 17, 18, and 19) but
fresh weights were used for analysis as they gave a better estimate
of injury.
Fresh weights were converted to % fresh weight reduction
and transformed to Arcsin v for analysis as recommended by Steel
and Torrie (1960).
The data were analyzed as a randomized complete
block design with a factorial arrangement of treatments (Appendix
Tables 20, 21, 22, and 23).
(1)
Experiment 5 had only two treatments for each soil type:
control and (2) soil only placement.
Data for this study are pre-
sented in Appendix Tables 24 and 25.
Results and Discussion
A summary of the data from experiments 1-4 is presented in
Table 8.
In the ryegrass studies, the foZiar only placement
Soil
caused slightly less injury than the combination placement.
type was not found to affect the amount of injury from foliar
applications of HOE 23408.
For the soil only treatment, great differences in injury level
were noted in the different soil types
(Tables 9 and 10).
species were injured most when grown in sand.
Both
These differences
were more pronounced for wild oats than for ryegrass.
Differences
were greater for both species when they were overhead irrigated.
Table 8.
Response of ryegrass and wild oats to 1.12 kg/ha application of HOE 23408 at three sites
of placement in three soil types.b
Placement
Soil Type
Irrigation
Foliage only
Sand
Sandy loam
Silt loam
Subsurface
Sand
Sandy loam
Silt loam
Soil only
Combination
foliage and
soil
LSD
LSD
.05
.01
Ryegrass
Fresh wt,
% Reductionc Visual Ratings
Wild Oats
Fresh Wt.
Visual Rating
% Reduction
82.3 (65.3)
89.6 (71.5)
92.1 (73.9)
75.6
89.6
90.0
45.2 (42.1)
62.5 (52.2)
55.9 (48.5)
49.0
Overhead
87.5 (69.5)
86.6 (69.2)
85.2 (67.5)
86.8
82.6
77.6
36.9 (37.2)
49.4 (44.7)
54.9 (47.9)
51.7
68.0
67.5
Sand
Sandy loam
Silt loam
Subsurface
86.9 (69.2)
76.4 (61.5)
77.5 (62,1)
80.6
68.4
69.0
74.9 (60.3)
47.8 (43.8)
30.6 (33.4)
80.5
48.9
43.0
Sand
Sandy loam
Silt loam
Overhead
85.9 (68,3)
58.1 (49.8)
64.5 (53.5)
94.0
51.0
60.0
68.1 (55.9)
24.0 (26.4)
46.9 (44.2)
85.4
38.6
37.0
Sand
Sandy loam
Silt loam
Subsurface
88.8 (70.6)
89.8 (71.5)
94.6 (76.82)
91.0
83.8
85.0
54.6 (47.6)
65.2 (54.3)
73.6 (56.9)
62.5
79.6
81.8
Sand
Sandy loam
Silt loam
Overhead
87.0 (69.2)
87.7 (70.0)
90.1 (71.7)
89.4
84.6
80.2
73.3 (59.4)
64.1 (53.4)
67.6 (55.5)
93.1
Subsurface
Overhead
Subsurface
Overhead
(8.1)
(2.9)
(10.9)
(3.9)
(9.4)
(10.9)
(12.6)
(14.7)
aRatings the average of two independent evaluators. Expressed on a percent injury basis.
All data are expressed as a mean of five replications.
c
Arcsin A- transformation are in parentheses.
74.1
70.4
72.5
72.0
36
Table 9.
Response of ryegrass to 1.12 kg/ha soil application
of HOE 23408 in three soil types.
Soil Type
% Fresh Wt. Reduction - Arcsin A-Transformation
Sand
Sandy Loam
Silt Loam
LSD.05
LSD
Experiment 1
69.16
61.47
62.13
5.09
7.40
Experiment 2
68.29
49.78
53.53
8.22
11.96
Experiment 5
61.14
59,00
50.56
12.97
Table 10.
01
Response-of* wild oats to 1,12 kg/ha soil application
of HOE 23408 in three soil types.
Soil Type
% Fresh Wt. Reduction - Arcsin A- Transformation
Sand
Sandy Loam
Silt Loam
LSD
LSD
Experiment 3
60.34
43.76
33.44
9.38
12.64
Experiment 4
55.93
26.40
44.20
10.92
14.70
.05
.01
The relative importance of foliar or soil placement also varied
according to soil type.
In the case of ryegrass, all placements
provided nearly equal injury in sand (Figures 5 and 6), while in the
silt loam and sandy loam soils, the soil only treatment caused much
less injury than the other two placements.
When wild oats were used,
the soil only placement surpassed the foliar in sand, while in the
other soils, foliar treatment was more injurious than soil treatment (Figures 7 and 8).
A comparison of the various placement sites
is shown in Figures 9, 10, and 11.
In addition to the soil treatment being most effective in sand,
it is also most consistent in sand.
This is apparent in experiment 5
37
100
90
80
% Fresh wt
reduction
ezki
#t1
ii:
-
LSD
N
f5
7 0
.05
it.1
`
1
6 0
5 0
A ,
u.
_
Xf
0
4
14
iV
iAl
...w
tV
fe
N.
144
40 --
30 -
20 -
..,-,
4.
F
i
4
10
44°
t
4
P1
do
0
.'.;:
4%,
itt
Foliage only Soil on y Combination
Placement
Sandy loam
Silt loam
Silica sand
Figure 5,
Injury from various placements of HOE 23408
on ryegrass grown in three soil types
(subirrigation study).
38
100_
90
80
% Fresh wt
reduction
70
1=
60
LSD.05
50
40
30
20
10
0
Foliage only
Soil only
Placement
Combination
FR Sandy loam
Silt loam
rr-7
Figure 6.
Silica sand
Injury from various placements of HOE 23408
on ryegrass grown in three soil types
(overhead irrigation study).
39
100
90
80
% Fresh wt 70
reduction
Ii
,toit
60
Iiit
At
I'
.05
P
tit
241
50
= LSD
14'
1
40
,%
?:4
sp.
I 1'
30
....
5
0,
o.
20
41
Ar
Ns
-03
10
:
1
0
Fb
g-
nly 'cl-I
It
or4 combination
Placement
Sandy loam
LA Silt loam
E;1
Figure 7.
Silica sand
Injury from various placement of HOE 23408
on wild oats grown in three soil types
(subirrigation study).
40
70
% Fresh wt
reduction
= LSD
60
.05
10`
rai
Foliage only
Soil only Combination
Placement
Sandy loam
Silt loam
Silica sand
Figure 8.
Injury from various placements of HOE 23408
on wild oats grown in three soil types
(overhead irrigation study).
41
where the visual injury ratings ranged from 90% to 99% in sand, 30%
to 78% in sandy loam, and 10% to 80% in silt loam (Table 11).
The
increasing variability in the higher organic matter soils could be
due to the inherent variability in soil microorganisms which may
inactivate the herbicide.
In summary, for both species a soil application of HOE 23408
is affected by soil type.
Soils which are high in organic matter
may affect herbicide efficacy by causing less severe or less consistent injury.
In these experiments, wild oats were less sensi-
tive to HOE 23408 than ryegrass.
This is illustrated by the
smaller weight reduction in wild oats (Table 8).
Table 11,
soil
The range of visual injury ratings for soil only herbicide treatments in
type experiments,
Experiment
Sandy Loam
Range
Visual Rating
Range
70-95
25
55-75
20
55-75
20
90-95
5
45-60
15
50-70
20
90-95
5
30-78
48
10-80
70
90-63
27
25-80
55
13-70
57
70-95
25
20-60
40
10-70
60
1
Ryegrasssubirrigation
2
Ryegrass -
Silt Loam
Visual Rating
Sand
Visual Rating
Range
overhead
5
Ryegrassgrowth chamber
3
Wild oatssubirrigation
4
Wild oatsoverhead irrigation
Figure 9.
Figure 10.
The effect of 1.12 kg/ha of HOE 23408 applied at
three placement sites to wild oats grown in silica
1. Foliage
Plants were overhead irrigated.
sand.
only, 2. soil only, 3. foliage + soil, 4. control.
The effect of 1.12 kg/ha of HOE 23408 applied at
three placement sites to wild oats grown in sandy
1. Foliage
Plants were subirrigated.
loam soil.
only, 2. soil only, 3. foliage + soil, 4. control.
44
Figure 11,
The effect of 1,12 kg/ha of HOE 23408 applied at
three placement sites to wild oats grown in silt
Plants were overhead irrigated.
loam soil.
1. Foliage only; 2. soil only; 3. foliage + soil;
4. control.
4'5
FOLIAR VS. SOIL UPTAKE OF HOE 23408 BY
RYEGRASS AND WILD OATS GROWN UNDER
TWO TYPES OF IRRIGATION
Some investigators have noted that herbicide efficacy may be
increased or decreased depending on irrigation type.
This is es-
pecially true of relatively non-mobile compounds such as HOE 23408
which may depend on soil moisture to move them within reach of the
plant.
Stanger and Appleby (1971) determined that lateral movement
and toxicity of cycloate increased with increased soil moisture
when cycloate was applied by subsurface line injection.
Materials and Methods
Data from the four greenhouse experiments reported in the previous study were divided into data groups and analyzed using a
statistical arrangement designed to observe the differences in
overhead vs. subirrigation.
Three soil types and two species were
Each
used to give the total of six combinations for data analysis.
group was analyzed as a randomized complete block design with six
treatments and five replications.
The treatments were analyzed as
foliar
a 3 x 2 factorial arrangement with three sites of placement:
only, soil only, and a combination of the two, and two irrigation
types:
overhead and subirrigation.
Analysis was conducted on the
Arcsin VT transformation of percent fresh weight reduction data as
in the previous experiments (Appendix Tables 27 and 28).
Data from
the ryegrass experiments are presented in Table 8 and Appendix
Tables 29, 30, and 31.
Data for the wild oat experiments are given
in Table 8 and Appendix Tables 32, 33, and 34.
:46
Results and Discussion
In general, no placement x irrigation type interactions were
noted.
Placement means summed across irrigation types are given in
Table 12.
Placement effects also have been discussed in the pre-
vious section.
Irrigation
type was found to be a factor in determining
toxicity of HOE 23408.
In sand, nearly equal injury was observed
One
for both species grown under both irrigation types (Table 13).
exception was the combination placement on wild oats (Table 14)
which caused much greater injury when the pots were overhead irrigated.
Overhead irrigation could increase toxicity by providing
good conditions for maximum uptake from both foliar and root areas.
Also, with this type of irrigation, the herbicide may be washed
down in the soil to the meristematic area of the root where it may
be most effective.
Root uptake would acquire a greater importance
than foliar uptake in this case.
As noted in the previous study
(Figures 7 and 8), soil application in sand may cause greater injury than foliar applications on wild oats.
In a sandy loam soil, greater toxicity was observed for both
species when they were grown under subirrigation.
Subirrigation
also led to greater toxicity for ryegrass grown in silt loam
(Table 13).
Many studies have indicated that a plant which is growing
rapidly may be injured more severely than one which is not
(Klingman and Ashton, 1975).
Plants grown in silica sand grew
poorly under both irrigation types.
Although nutrients were added
47
weekly, nutrients became a limiting factor for their growth in
silica sand.
In the other soil types, ryegrass grew much better
under subirrigation.
The control in overhead irrigation treatments
reached only 75% of the subirrigated control in sandy loam and only
66% of the control in silt loam (Table 15).
The growth trends
closely agree with the differences in toxicity under the two irrigation types.
Table 12.
Soil Type
Placement means for type
Species
of
irrigation studies.**
Foliar Only
Placement
Soil Only
Combination
Soil Type
.05
LSD
-
7'.2
6.4
70.8
53.9
74.3
56.2
.01
4.4
9.8
8.7
3.2
69.9
68.7
67.4
Ryegrass
Sand
Wild oats*
Sand
54.0
70.4
Ryegrass
Sandy loam
48.5
35.1
Wild oats
Sandy loam
57.8
70.7
Ryegrass
Silt loam
38.3
48.2
Wild oats
Silt loam
*See Table 4.
**Arcsin VT) for average percent fresh weight reduction.
Table 13.
LSD
11.1
5.0
8.1
3.7
6.4
8.7
Irrigation means for type of irrigation studies.**
Species
Type of Irrigation
Overhead Irrigation
Subirrigation
68.4
Ryegrass
Sand
Wild oats*
Sand
68.2
Ryegrass
Sandy loam
50.1
Wild oats
Sandy loam
70.9
Ryegrass
Silt loam
46.3
Wild oats
Silt loam
*See Table 4.
**Arcsin A- for average percent fresh weight reduction.
69.0
-
62.0
41.5
64.2
49.2
LSD
.05
2.6
5.9
5.2
6.7
3.0
5.2
LSD
.01
3.6
8.0
7.1
9.1
4.1
7.1
Table 14.
Placement
Placement x irrigation type means for wild oats grown in silica sand.*
Irrigation Type
Subirrigation
Overhead Irrigation
LSD
.05
LSD
.01
Foliar only
42.1
37.2
10.16
13.9
Soil only
60.3
55,9
10.16
13.9
Combination
47.6
59.4
10.16
13.9
*Arcsin IT
Table 15.
Soil Type
for average percent fresh weight reduction
Fresh weights of controls in type of irrigation studies.
Species
Ryegrass
Wild Oats
Subirrigation
Overhead Irrigation
Subirrigation
Overhead Irrigation
Sand
2.1056
2.1580
2.5493
1.5893
Sandy loam
3.7850
2.8157
4.1727
4.1694
Silt loam
4.0045
2.6514
4.6578
5.5488
50
SOIL MOISTURE AND HOE 23408 EFFICACY
The following three studies were designed to observe the relationship of soil moisture to HOE 23408 toxicity.
Uptake from a soil
solution has been shown to be proportional to the transpiration rate
(Schreiber et al., 1975).
Many investigators have shown that her-
bicide uptake may be restricted under low soil moisture conditions
(Cox and Boersma, 1967; Balbalola et al., 1968).
Materials and Methods
Water Stress Study.
Pre-germinated 'Tama' ryegrass seedlings
were chosen for the bioassay species.
0.5 cm deep in 92mm x 85mm pots.
Ten seedlings were planted
A standard greenhouse potting
soil mixture of sand, soil, and vermiculite was used.
Plants were
thinned at the one-to two-leaf stage to five plants per pot.
Plants were grown in a growth chamber for a period of 18 days
prior to treatment.
During this period, watering was by subirriga-
Plants, were treated at the six-to seven-leaf stage.
tion.
On the day of treatment
pots were placed inside beakers and
grown in this manner for the duration of the experiment.
were treated with four rates of herbicide;
(w/vol).
The plants
0, 10, 100, 1000 ppm
This was accomplished by pouring the appropriate herbi-
cide solution in a 1000 ml beaker and placing one pot of ryegrass
plants in each beaker.
A prescribed amount of mannitol was also
added to the beaker solution to obtain the desired level of water
stress:
-0.3 bars or -2.5 bars.
The first level, -0.3 bars,
corresponded to field moisture capacity and the second level,
51
-2.5 bars, corresponded to a 50% reduction in available moisture.
Four rates of herbicide and two levels of water stress led to the
use of eight beakers for.alj,possible treatment combinations.
These
eight combinations were replicated four times and the data were
analyzed according to a randomized complete block design.
Injury was assessed by harvesting the top growth 7 days after
treatment and obtaining dry weights for each treatment.
Soil Moisture Studies.
Plants in these two studies were pre-
pared and grown in the greenhouse as described in General Materials
and Methods.
studies.
A western Oregon ryegrass biotype was used in these
The soil was prepared by mixing greenhouse potting soil
with silica sand in a 60:40 ratio to yield a sandy clay loam soil
with organic matter content of 1.4% (Table 1).
Both studies involved three soil moisture levels and three
sites of placement:
foliar only, soil only, and a combination.
A control pot was included for each soil moisture level.
The pots
were arranged in the greenhouse according to a randomized complete
block design.
Soil moisture levels and details which differ in the
two experiments are given in Table 16.
The various moisture levels
were computed by the following method.
The same amount of soil
(650 g oven dry weight) was placed in each pot to bring the weight
of the pot to field moisture capacity.
It was necessary to add
240 g of water for a total pot weight of 890 g.
Various percentages
of the 240 g of water were added to obtain different moisture levels
(Table 16).
Table 16.
A description of growing conditions for ryegrass in two soil moisture experiments.
No. of
Experiment
1
Reps
5
Temperature
20' ± 4°C day
Time Prior
to Treatment
Time, Trmt
to Harvest
6
24° ± 3°C day
10° ± 2°C night
Wt(g) Soil +
Water/Pot
4 weeks
3 weeks
96% F.C.
60% F.C.
32% F.C.
880 g
795 g
730 g
5 weeks
2 weeks
112% F.C.
96% F.C.
60% F.C.
940 g
880 g
795 g
12° ± 2 °C night
2
Moisture
Levels
53
All pots were subirrigated with the same amount of water prior
to treatment.
Plants were treated with .56 kg/ha HOE 23408 at the
In experiment 1, pots were allowed to dry
five to six-leaf stage.
down to the appropriate moisture level after treatment.
To main-
tain water at the appropriate moisture level, the prescribed amount
of water was applied to the soil surface.
tained after harvest.
Visual ratings were ob-
In the second experiment, the appropriate
moisture levels were maintained 3 days prior to treatment,
Pots
were weighed daily and water was added as necessary to maintain the
moisture levels.
Fresh weights and visual ratings were obtained.
Data were converted to percent fresh weight reduction and the Arcsin
transformation was used to analyze the data.
Results and Discussion
Water Stress Study.
to 4 days after treatment.
followed by necrosis.
Treated plants began to show symptoms 3
Symptoms began with chiorotic mottling
At the time of harvest, virtually all top
growth of the herbicide-treated plants was dead.
The plants sub-
jected to water stress without herbicide were flaccid and the leaves
were wilted.
The dry weights of the top growth for the various treatments
are given in Table 17 and Appendix Table 35.
Analysis of variance
was conducted according to a 4 x 2 factorial arrangement to test for
interaction between herbicide rate and level of water stress.
No
significant interaction was noted, although changes in the rate of
herbicide produced highly significant changes in degree of injury
54
Percent dry reduction weights of ryegrass subjected
to two levels of water stress.a
Table 17.
Stress
Level
(bars)
0 ppm
Level of Herbicide Concentration (w/vol)
LSD.05
1000 ppm
100 ppm
10 ppm
- 0.3
0.0
38.2 (38.2)
41.6 (40.2)
65.4 (54.0)
- 2.5
0.0
6.8 (15.1)
11.1 (19.5)
27.7 (31.8)
a
LSCI01
(15.7)
(21.2)
Arcsin A-transformations in parentheses.
(Appendix Table 36).
With either high or low moisture stress, a
trend of increasing injury was evident for 0 ppm to 1000 ppm of the
herbicide (Table 17).
Use of the LSD test determined that at a
given rate of herbicide, high moisture stress conditions produced
significantly less injury (Table 17) than -did low moisture stress
conditions.
Many investigators have detected more herbicide damage at high
soil moisture levels (Sedgeley and Boersma, 1969).
this are:
Reasons for
(1) less herbicide may reach the plant due to a decrease
in hydraulic conductivity of the soil (Kramer, 1969) and (2) transpiration is decreased, therefore uptake is decreased (Crafts and
Crisp, 1971).
More definitive results could be obtained with radioactivelylabeled materials to determine the amount of HOE 23408 being taken
up by the plant under different levels of soil moisture.
Although
the results of this study are not conclusive, they tend to suggest
that a high level of water stress may limit HOE 23408 efficacy on
ryegrass by restricting herbicidal uptake.
55
Soil Moisture Studies.
In both soil moisture studies, the
combination treatment provided the greatest injury at the highest
moisture level and the least injury at the lowest moisture level
(Table 18).
The results from the combination treatment agree with
those from the water stress study (Table 17) and indicate that
injury from HOE 23408 may be decreased when there is little available soil moisture.
Neither the foliar only nor the soil only treatments exhibited
a response to soil moisture.
The soil only treatment caused nearly
complete control even at the low soil moisture levels and this high
degree of effectiveness may explain the lack of moisture response.
In every case, the order of toxicity was:
nation > foliage only.
soil only > combi-
It is not known why the soil only treatment
was more effective than the combination treatment.
However, similar
results were obtained in an earlier study using the same soil type,
the same ryegrass biotype, and similar environmental
(Table 2).
conditions
Fresh weight reduction and visual ratings of ryegrass injury at different soil
moisture levels.
Table 18.
Experiment 2
Experiment 1
Visual Ratinga
Placement
Moisture Level
Foliage only
120% field capacity
96% field capacity
60% field capacity
32% field capacity
59.2 (50.31)
56.6 (48.84)
54.2 (47.45)
120% field capacity
96% field capacity
60% field capacity
32% field capacity
100.0 (90.00)
100.0 (90.00)
100.0 (90.00)
120% field capacity
96% field capacity
60% field capacity
32% field capacity
93.0 (78.30)
71.0 (58.30)
65.8 (54.29)
Soil only
Combination
LSD
LSD
a
.05
.01
Arcsin v given in parentheses.
--
--
Visual Rating
% Fresh Wt. Reduction
43.8
34.6
39.6
61.9 (52.04)
61.6 (51.76)
46.7 (43.07)
96.3
97.9
96.4
88.6 (70.49)
93.1 (74.84)
91.0 (72.59)
77.0
82.2 (65.12)
77.1 (61.58)
71.8 (58.02)
52.1
68.3
--
( 7.64)
( 4.85)
(10.30)
(
6.49)
57
ROOT GROWTH INHIBITION BY HOE 23408
HOE 23408 has been found to cause root inhibition on many
species (American Hoechst Technical Information Bulletin).
The ob-
ject of this study was to determine if this root inhibition could be
caused by either placement of HOE 23408:
tions.
foliar or root applica-
A sensitive species, Italian ryegrass, and a tolerant
species, 'Hyslop' wheat, were selected to determine if differences
in root inhibition were related to differences in inherent sensitivity to the chemical.
Materials and Methods
A nutrient culture experiment was devised so root growth could
be monitored on a daily basis.
Standard-size (qt) glass Mason jars were
prepared by applying a coat of black paint followed by a coat of
silver paint on the outside.
A balanced nutrient solution (Hewitt,
1952) was placed in the jars and was replenished as necessary to
keep the solution level within 2 cm of the top of the jar.
All
solutions were aerated throughout the experiment.
Seeds were planted in silica sand and grown in plastic pots for
a period of 6 weeks in the case of ryegrass and 3 weeks in the case
of wheat.
At that time, cotton was placed around the base of the
plant and the plant was then suspended in a nutrient solution jar as
shown in Figure 12.
herbicide treatment.
Plants grew for 3 days in the solution prior to
On the day of treatment, HOE 23408 was applied
at the prescribed rate (Table 19) either to the nutrient solution or
58
Figure 12.
An illustration of materials used for the root inhiRyegrass foliage is shown 10 days
bition studies.
after HOE 23408 application. A. Control; B. foliage
only, low rate; C. foliage only, high rate; D. solution only, low rate; E. solution only, high rate.
Figure 13.
Root and shoot appearance of wheat plants 10 days
A. Control;
after treatment with HOE 23408.
B. foliage only, low rate; C. foliage only, high
rate; D. solution only, low rate; E. solution only,
high rate
60
within the first 24 hours after treatment.
Symptoms included
browning of root tips and reduction in vigor, followed by overall
browning, necrosis, and death.
Both species had similar responses.
An illustration of root and shoot appearance for the various treatments on wheat plants is given in Figure 13.
In the solution-
treated plants, foliage was also greatly reduced.
However, the
reduction came later than it did in the foliage-treated plants.
Also, the foliage did not develop chlorosis.
Instead it turned a
darker green and appeared to die because of wilting.
Data from measurements of the longest root (Figure 14) and
root dry weights (Table 20) were in good agreement.
In both species,
a low rate of application to the foliage caused essentially no root
growth reduction, and in some cases appeared to stimulate growth.
A high rate applied to the foliage caused a slight reduction in
root weight.
Both solution treatments drastically reduced root
growth in both species.
In conclusion, HOE 23408 appears to be relatively non-mobile
in the plant.
In this study, contact action was observed and visual
injury symptoms developed on the plant parts which were exposed to
the herbicide.
Both ryegrass and wheat developed injury from either
site of application.
Therefore, site of uptake does not seem to be
involved as a mechanism of selectivity for HOE 23408 on the two
species.
However, wheat did require higher rates of foliar appli-
cation to obtain injury.
61
200
180
7
160
140
120
100
80
4-
0
60
_c
4-,
40
20
/
0.
A
1
1
C
D
Ryegrass
Vi Wheat
D.
Foliage application - low rate
Root application - low rate
Foliage application - high rate
Root application - high rate
E.
Control
A.
B.
C.
Figure 14.
Influence of root or foliar applications of HOE 23408
on the root growth of wheat or ryegrass.
62
Table 19.
Rates in ppm (w/vol) of HOE 23408 applied to either the
wheat and ryegrass.
root or the foliage of two species:
Experiment 3
Wheat
Experiment 1
Ryegrass
Experiment 2
Ryegrass
Foliage only low rate
50
30
500
Root only low rate
50
50
50
Foliage only high rate
500
300
5000
Root only high rate
500
500
500
Table 20.
Dry weights (g) of wheat and ryegrass root growth from
foliar or nutrient solution applications of HOE 23408.
Treatment
HOE 23408
Dry wt. (g)
Wheat
Ryegrass
Dry wt. - % of Control
Wheat
Ryegrass
Foliage only low rates
.0763
.0306
115
93
Solution only low rate
.0300
.0116
45
35
Foliage only
high rate
.0620
.0186
93
57
Solution only high rate
.0260
.0168
39
51
Control
.0664
.0329
100
100
LSD
.0217
.0067
a
.05
Rates given in Table 19.
63
CONCLUSION
HOE 23408 was found to be active from both foliar and soil
applications.
Maximum herbicide efficacy may be obtained when con-
ditions are favorable to both sites of uptake.
Root uptake of the herbicide from the soil solution was found
to vary greatly.
Conditions such as ample soil moisture and low
organic matter soils favor root uptake.
Adsorption to organic
matter and clay particles appear to be reasons for inactivation in
the soil.
Adsorption to organic matter was the predominant factor
in these studies.
Some of the experiments raised the question of
why soil only applications could be more effective than combination
applications.
Further research is needed to obtain an answer to
this question.
HOE 23408 is known to affect the meristematic regions of the
plant.
American Hoechst has determined that the growing point,
followed by the coleoptile, were the most sensitive plant parts in
wild oats.
Visual observations of treated corn foliage revealed
that the newly emerging leaf was the first to develop symptoms.
Root tips of ryegrass and wheat turned brown when exposed to the
herbicide.
studies:
Different species susceptibilities were noted in these
ryegrass, highly sensitive; wild oats, moderately sensi-
tive; and wheat, tolerant.
This knowledge, coupled with the fact
that the actively growing plants were injured to the greatest extent, could lead to an elucidation of the mechanism of action for
the herbicide.
64
Severe root-pruning is one type of injury which contributes to
the death of HOE 23408-treated plants in the field.
These studies
indicated that this root-pruning effect is the result of soilapplied HOE 23408.
Plants treated with only a foliar application
could not be easily pulled from the soil.
Plants grown in nutrient
solution did not exhibit decreased root growth when HOE 23408 was
applied to the foliage.
These observations pointed to a contact
action by the herbicide.
The research completed here has some important implications
for use of the chemical in the field.
Willamette Valley winters
are characterized by intermittant rain, high soil moisture, overcast skies, and high relative humidity.
HOE 23408 would be expected
to perform well under these conditions, which would favor both
foliar and root uptake.
Conversely, hot, sunny weather and dry
soils would be expected to diminish HOE 23408 effectiveness.
Field
research is in agreement here, as spring treatments of HOE 23408
have been less reliable than winter treatments.
The use of surfactants with a herbicide is an important economic consideration.
The high degree of HOE 23408 activity when en-
vironmental conditions are favorable to both sites of uptake, would
make a surfactant an unnecessary expense.
However, if the herbi-
cide was applied during hot, sunny weather, or to a dry soil, or to
a soil high in organic matter, a surfactant may be necessary to increase the effectiveness of foliar applications of the material.
These studies assessed the relative importance of foliar or
root uptake of HOE 23408 in two species.
The results should
65
contribute to a more efficient utilization of this material in
the field.
Further research on the site of uptake would be greatly
facilitated by the use of radioactively-labeled materials.
66
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68
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APPENDIX
70
Appendix Table 1.
Source of Var.
Reps
Analysis of variance for Appendix Table 3 data.
Arcsin of percent fresh weight reduction.
df
4
8
Treatments
Place
Rate
P x R
Error
31
Total
43
2
2
4
-
SS
252.51
4081.96
2225.87
1056.56
799.53
2857.47
7191.94
MS
63.13
510.25
1112.94
528.28
399.77
92.18
F
21.00
5.54**
12 07**
5.73*
4.34*
LSD005 = 12.4
LSD
01
= 16.7
C.V. = 14.0%
Appendix Table 2.
Source of Var.
Reps
Analysis of variance for Appendix Table 4 data.
Arcsin of percent fresh weight reduction.
df
4
8
Treatments
Place
Rate
P x R
Error
31
Total
43
- 11.08
LSD
LSD
.01
= 14.92
C.V. = 15.10%
2
2
4
SS
859.52
11062.47
6996.92
2988.20
1077.35
2280.49
14202.48
MS
207.38
1382.81
3498.46
1494.10
269.34
73.56
F
2.82*
18.8**
47.6**
20.3**
3.66*
Appendix Table 3.
Placement
Fresh weight, percent fresh weight reduction (including Arcsin transformation) and
visual rating for ryegrass treated with HOE 23408 at three rates and three sites of
application.
Fresh Wei'hts
k
Rate
2.24
1,12
1.68.
Wt. Reduction
Rate (kg/ha)
1.68
2.24
1.12
Fres
Arcsin Transformation
Rate (kg/ha)
2.24
1.68
1.12
Visual Rating
Rate (kg/ha)
1.68
2.24
1.12
Foliage only
R1
R2
R3
R4
R5
70.00
39.87
66.74
28.86
19.91
71.50
67.70
58.76
65.12
43.80
69.38
64.75
55
73.21
82.3
47.9
87.6
81.8
92.6
89.5
93.5
71.09
75.22
49.7
75.8
89.0
45.08
61.38
88.8
85 5
88.9
86.3
91.4
87.0
91.4
.1208
53.0
86.4
88.7
91.3
87.2
91.5
94.4
46.72
68.36
70.36
72.85
69.04
2.618
.1962
81.3
88.2
91.5
.1222
.1433
.1438
.1719
.1520
.1374
.1908
.1052
.1889
.0807
.1069
.0904
.1525
.1012
.1113
94.6
93.0
94.8
91.0
93.0
94.0
95.6
96.2
.1466
.206
.1125
75
45
0
70
60
25
80
25
65
50
80
90
95
70.93
36
52
76
70.45
67.62
70.54
68.28
72.95
68.87
72.95
74.77
70.97
30
76.31
100
80
55
90
80
80
65.47
69.97
72.77
76.56
74.66
76.82
72.54
74.66
75.82
77.89
78.76
71.66
96.3
95.3
95.6
94.5
94.7
94.8
93.3
94.4
95.0
75.05
1.9149
2.1574
89.9
85.6
,2299
.2927
.7496
.3393
1.9068 1.1231
.2820
.3704
.2076
.2007
.1407
88.3
84.4
23.3
11,6
73.1
.8501
.5469
.2403
1.0673
.2951
.2772
.3159
.1667
.2762
.2546
.2956
.3106
.2619
.1862
.4207
.2649
1,1992
.4343
.4454
41.1
5
Soil only
R1
R2
R3
R4
R5
.1762
.1926
--
93.1
55
90
100
85
85
100
60
70
85
90
80
85
100
100
90
90
100
78.91
77.48
77.89
76.44
76.69
76.82
100
100
95
100
100
100
100
76.61
77.06
91
96
99
80
55
Foliage + soil
R1
R2
R3
R4
R5
90.1
Control
R1
2.2706
R4
R2
2.0361
R5
R3
2.7888
2.2336
Appendix Table 4,
Placement
Fresh weight, percent fresh weight reduction (including Arcsin transformation) and
visual rating for wild oats treated with HOE 23408 at three rates and three sites
of application.
Fresh Weights (g)
Rate (kg/ha)
1.12
1.68
2.24
Fresh Wt. Reduction
Rate (kg/ha)
1.12
1.68
2.24
Arcsin Transformation
Rate (kg/ha)
1.12
1.68
2.24
1.12
1.68
2.24
0.635
5.076
5.817
6.460
5.747
2.874
2.499
5.090
2.472
1.434
2.875
25.0
7.4
25.3
55.00
49.49
50.77
45.36
57.80
10
20
60
60
30
45
90
65
80
50
80
90
5.930
2.874
2.420
2.328
1.469
2.586
1.089
Visual Rating
Rate (kg/ha)
Foliage
R1
R2
R3
R4
R5
67.1
57.8
60.0
53.2
71.6
30.00
15.79
30.20
10.9
54.4
34.7
43.9
77.8
19.28
55.00
47.52
36.09
41.50
61.89
2.824
13.7
55.6
53.2
19.05
48.40
51.68
10
57
73
1.213
2.205
3.934
0.756
0.478
0.985
1.207
1.262
0.474
0.472
72.3
57.5
86.1
68.40
50.65
64.23
39.99
65.73
44.71
70.36
62.03
66.27
65.50
70.81
70
70
75
65
83.1
88.7
78.0
83.8
89.2
92.7
58.24
59.8
49.5
82.8
90.6
73.21
73.32
90
90
65
40
80
100
85
85
90
95
95
1.978
1.717
0.880
67.1
74.2
86.5
55.50
60.64
68.76
74
75
90
0.678
1.318
0.369
2.099
0.832
76.1
89.3
93.4
97.3
93.0
93.8
73.78
60.60
77.48
46.38
56.04
71.19
67.29
75.94
70.18
60.73
70-:91
0.501
92.2
75.9
95.3
52.4
68.8
89.6
2.011
0.908
0.818
0.462
0.508
1.543
80.54
74.66
75.58
95
80
100
85
75
95
90
98
98
85
95
99
100
100
100
1.295
0.848
0.463
76.9
86.7
93.4
62.86
69.07
75.36
87
93
99
R4
R5
4.406
2.311
3.119
2.824
1.830
0
67.1
0
0
20
0
Soil only
R1
R2
R3
R4
R5
81.1
41.3
49.31
Foliage + soil
R1
R2
R3
R4
R5
0.361
0.212
0.308
85.1
94.1
88.5
Control
R1
R2
R3
8.732
5.480
7.792
"X
6.451
6.592
75.11
73
Appendix Table 5.
Dry weights for ryegrass and wild oats treated
with HOE 23408 at three rates and three sites
of application,
Rye grass
Placement
1.12
Rate (kg/ha)
2. 24
1.68
Wild Oats
Rate (kg/ha)
1.68
1.12
2.24
Foliar only
.802
.2941
.0792
.0982
.0939
.0899
.1012
1.626
1.407
1.678
1.596
1.425
.820
.782
1.319
.722
.618
.1784
.1499
.0925
1.546
.852
.827
.2151
.1301
.1091
--
.734
.785
.554
.886
.489
.776
.1190
.1062
.1240
.0964
.1415
.1485
.1397
.0980
.0852
.451
.492
.322
.400
.435
.483
.287
2.960
.1389
.1248
.1026
.682
.662
.380
.0630
.0607
.0658
.1065
.0622
.0772
.0600
.0890
.0755
.0734
.351
.351
R2
R3
R4
R5
.0667
.0870
.0860
.1128
.0780
.534
.280
.682
.630
.370
.307
.294
.530
.382
.220
.173
.237
.356
R
.0704
.0716
.0750
.495
.370
.274
R2
R3
R4
R5
.0760
.1892
.1008
.1317
.3944
.0710
.0992
.1387
.1467
X
R1
.711
.897
1.048
.675
Soil only
R1
R2
R3
R4
R5
R
.0997
.1163
1.232
Foliar + soil
R1
Control
R1
.2642
R2
R3
R4
R5
.2321
R
.3251
.3156
.4064
.4070
2.170
1.553
2.038
.985
1.509
1.651
74
Appendix Table 6.
Source of Var.
Treatments
Place
Rate
P x R
Error
Total
Analysis of variance for dry weights in
Appendix Table 9.
df
8
2
2
4
36
44
SS
800658.31
706139.54
41124.34
53394.43
180468.66
981126.97
MS
353069.77
20562.17
13348.61
5013.02
F
70.43**
4.10*
2.66 NS
C.V. = 58.44%
Appendix Table 7.
Source of Var.
Treatments
Place
Rate
P x R
Error
Total
Analysis of variance for data in Appendix Table 10.
df
8
2
2
4
36
44
LSD.05 = 16.76
Appendix Table 8.
Source of Var.
Treatments
Place
Rate
P x R
Error
Total
LSD
27304.93
26481.72
450.28
372.93
6191.62
33496.55
MS
3413.12
13240.86
225.14
93.23
171.99
F
76.99**
1.31 NS
<1.00 NS
C.V. = 21.38%
= 22.43
LSD
LSD
SS
05
.01
= 9.26
= 12.39
Analysis of variance for Arcsin transformation
of visual ratings from Appendix Table 11.
df
8
2
2
4
36
44
SS
16057.73
15731.48
204.24
122.01
1889.81
17947.54
C.V. = 12.47%
MS
7865.74
102.12
30.50
52.49
F
149.84**
1.95 NS
<1.00 NS
75
Appendix Table 9.
Placement
Dry weights and visual rating for ryegrass
treated in New Zealand with HOE 23408 at
three rates and three sites of application.
Dry Weights
Rate (kg/ha)
1.68
.56
1.12
Visual Rating
(% injury basis)
Rate (kg/ha)
.56
1.12
1.68
foliage only
.296
.337
.315
.183
.448
100
75
95
100
55
.542
.584
.586
.377
.944
.260
.424
.234
75
75
75
100
75
85
75
95
85
85
.536
.146
.255
80
82
88
4.238
5.690
4.028
3.747
2.133
3.829
R2
R3
R4
R5
2,637
3.073°
10
75
25
0
35
10
10
60
35
75
R
R1
.336
R2
R3
R4
R5
.631
R
Soil only
2.796
.838
10
10
10
10
20
3.967
2.926
2.048
12
29
38
R4
R5
.273
.213
.196
.334
.128
.257
.149
.142
.634
.252
.343
.115
.157
.254
.173
100
100
100
95
100
95
100
100
95
100
95
100
100
100
100
R
.229
.287
.208
99
98
99
R1
.789
3.076
1.101
4.141
2,589
Roliage + soil
R1
R2
R3
Control
R2
R3
R4
R5
.169
.115
.108
.069
.160
0
0
0
0
0
R
.124
0
R1
76
Appendix Table 10.
Arcsin transformation of visual rating
data from
Table 9.
Rate (kg/ha)
Placement
.56
1.12
1.68
Foliage only
R2
R3
R4
R5
90
60
60
60
60
77.08
47,87
90
60
67.21
90
60
77.08
67.21
67.21
X
66.0
68.43
72.30
18.43
60.00
30.00
R4
R5
18.43
18.43
18.43
18.43
26.57
36.27
18.43
18.43
50.77
36.27
60.00
X
20.06
28.94
36.78
77.08
90
90
77.08
90
77.08
R4
R5
90
90
90
77.08
90
X
87.42
84.83
87.42
R1
Soil only
R1
R2
R3
0
Foliage + soil
RI
R2
R3
90
90
90
90
Appendix Table 11.
Dry weights, percent dry weight reduction, visual ratings of wild oats
treated in New Zealand with HOE 23408 at three rates of herbicide and
three sites of application.
Dry Weights
1.12
1.68
2.24
% Dry Wt. Reduct.
Rate (kg/ha)
1.12 1.68
2.24
.8040
.8000
.4240
.5070
.4580
.9640
.7610
.6740
.5750
.6490
.7060
.6990
.5550
.5760
.8280
71.2
71.3
84.8
81.8
83.6
65.4
72.7
75.8
79.4
76.7
80.1
.5990
.7350
.6730
78.5
74.0
3.1770
3.9170
3.6290
3.0890
2.8470
3.0130
3.3500
3.4960
2.6100
2.9220
2.7110
2.1820
2.4720
3.2030
3.2220
0
0
0
0
0
0
0
0
3.3320
3.0780
2.7580
0
.5630
.5210
.3670
.6770
.8300
.7390
.4510
.7170
.7970
.6640
.8520
.4280
.5160
.4860
.4330
.5920
.6740
.5430
Rate (kg /ha,)
Placement
Arcsin of
Visual Rating
Rate (kg/ha)
1.12
1.68
2.24
Visual Rating
Rate (kg/ha)
1.12
1.68 2.24
Foliage only
R1
R2
R3
R4
R5
53.73
60.00
56.79
63.43
60.00
60.00
63.43
71.57
71.57
53.73
65
55
75
70
75
65
75
70
79.4
70.3
53.73
47.87
60.00
56.79
60.00
75
80
90
90
65
75.9
55.68
58.79
64.06
68
73
80
2.8
21.8
11.4
26.57
33.21
39.23
39.23
36.27
33.21
39.23
36.27
39.23
6.5
0
-0
33.21
30.00
39.23
26.57
33.21
33.21
20
30
35
30
25
40
40
30
40
20
40
35
40
30
30
1.3
7.2
31.85
35.49
36.23
28
34
35
79.8
81.3
86.8
75.7
70.3
73.5
83.8
74.3
71.4
76.2
69.5
84.7
81.5
82.6
84.5
71.57
71.57
90.00
77.08
90.00
67.21
90.00
77.08
71.57
71.57
90.00
90.00
90.00
90
90
100
95
100
85
100
85
100
95
90
90
100
100
100
78.8
75.8
80.6
80.04
78.30
82.63
95
93
96
R4
R5
.2460
.3380
74.7
74.9
80
75
Soil only
R1
R2
R3
R4
R5
Foliage + soil
R1
R2
R3
R4
R5
Control
R1
R2
R3
90.00
67.21
Base weight
2.4960
2.8700
2,4260
R4
R5
2.5530
3,6070
2.7900
R1
R2
R3
.3300
.3250
.2350
2950
78
Appendix Table 12.
Analysis of variance for data in Appendix
Table 13.
Source' of Var.
df
8
Treatments
Place
Rate
P x R
Error
2
2
4
36
44
Total
For P x R Means:
= 3.95
LSD
.05
LSD
.01
= 5.28
SS
452.00
150.00
106.00
196.00
343.56
MS
56.50
75.32
53.35
48.96
9.54
5.92**
7.89**
5.59**
5.13**
79
Appendix Table 13.
Placement
Dry weights of ryegrass grown in silica
SAM AM treated i n New Zealand.
.56
Rate (kg/ha)
1.12
1.68
Foliage only
.055
.132
.082
.109
.056
.155
.032
.146
.087
.053
R4
R5
.113
.119
.114
.126
.106
.176
.092
.125
.150
.094
.086
.089
.027
.107
.073
X
.116
.127
.076
R3
R4
R5
.046
.076
.063
.032
.055
.036
.108
.020
.068
.072
R
.054
.061
R1
R2
R3
R4
R5
R
.207
.153
.125
.101
.051
.053
.052
.054
Soil only
R1
R2
R3
Foliage + soil
R1
R2
Control
R3
R4
R5
1.703
1.546
1.649
1.542
1.625
R
1.613
R1
R2
Base weight
R1
.036
R2
R3
R4
R5
,041
X
.033
.029
.031
.029
.049
.121
.061
.094
.048
.075
80
Appendix Table 14.
Analysis of variance for Arcsin transformations
of visual ratings from Appendix Table 15.
Source of Var.
df
Reps
Treatments
Stage
Place
P x S
Error
4
5
1
SS
911.97
11498.35
227.99
2299.67
833.61
833.61
5308.60
23.77
10617.20
47.54
2
1426.16
20
13836.48
29
Total
C.V. = 19.96%
LSD.05 = 7.88 for placement means
2
LSD.01 = 10.74
LSD.05 = 6.43 for stage of growth means
LSD.01 = 8,77
LSD.05 = 11.14 for P x S means
LSD
.01
= 15.19
MS
71.31
F
3.2*
32.25
11.69**
74.45**
<1.00 NS
81
Appendix Table 15,
Placement
Dry weights, visual rating, and Arcsin transformation of visual rating for ryegrass treated
with HOE 23408 at two growth stages.
Dry Weight (y)
Stage 2
Stage 1
Visual Rating
Stage 2
Stage 1
Arcsin
Stage 2
Stage 1
Foliage only
R1
R2
R3
R4
.083
.046
.131
50
60
80
63.43
56.79
56.79
56.79
63.43
45.00
46.43
45.00
50.77
63.43
58.5
59.45
50.13
80
70
50
.101
70
70
80
,212
.462
.357
.313
52.5
R5
.113
.093
R
.093
.201
74
.671
.751
0
5
20
26.57
.780
.663
.355
0
0
0
40
30
10
20
39.23
R5
.265
.332
.606
.148
.167
33.21
18.43
26.57
R
.304
.644
18
7
19.84
11.58
.249
.286
.496
.468
.087
80
80
80
80
80
50
50
R4
R5
.065
.067
.088
.278
.078
55
70
63.43
63.43
63.43
63.43
63.43
45.00
45.00
52.24
47.87
56.79
X
.115
.317
80
75.5
63.43
49.38
.259
.265
.225
.591
.177
.752
1.111
.620
.395
0
0
0
0
0
0
0
0
0
0
.241
.694
0
0
R2
R3
R4
R5
.035
.042
.063
.047
.044
.128
.213
.325
.134
.115
R
.046
.183
Soil only
R1
R2
R3
R4
0
0
12.92
0
0
Foliage + soil
R1
R2
R3
62.5
Control
R1
R2
R3
R4
R5
R
.281
Base weight
R1
Appendix Table 16.
Placement
Fresh weights and visual ratings for ryegrass grown in three soil types and
treated with HOE 23408 at three placement sites (subirrigation study).
Fresh Wt. (g)
Silt
Sandy
Loam
Loam
Sand
% Fresh Wt. Reduc,
Sandy Silt
Loam
L.:6am
Sand
Arcsin
% Fresh Wt. Reduc,
Silt
Sandy
Loam
Loam
Sand
Foliage only
83
90
90
90
90
90
73.88
75.6
89.6
90.0
58.44
54.76
69.64
54.94
69.56
56.54
63.43
68.03
53.79
68.87
75
70
95
75
88
72
55
75
65
75
55
75
75
65
75
69.16
61.47
62.13
30.6
68.4
69.0
72.95
71.76
72.85
66.82
73.15
79.53
78.17
80
80
85
75.46
72.34
87
85
95
90
98
75
93.7
90.8
68.53
69.30
73.89
66.97
74.32
94.6
70.60
71.51
76.82
91
83.8
R4
R5
1.6541
74.77
76.82
68.61
76.56
72.64
75
75
70
75
91.1
73.46
65.80
75.94
68.28
74.00
89.6
92.1
65.32
71.5
84.0
78.8
92.4
87.3
72.6
66.7
87.9
67.0
69.6
80.0
86.0
.4711
92.1
87.8
87.0
66.42
62.58
74.00
69.12
73.68
.8758
.8985
86.7
76.4
77.5
.2888
.2455
.1755
.2534
.1810
.3716
.4186
.3410
.3898
.1928
.1253
.2479
.1197
.2256
,3340
86.6
87.5
92.3
84.7
96.7
95.8
92.7-
91.4
90.2
91.3
84.5
91.6
.2288
.3428
.2105
88.8
89.8
4.2964
4.2667
2.2755 3.9108
3.7711
.7149
.2294
.3444
.2998
82.0
74.8
88.3
78.6
87.6
91.9
83.2
.3620
.3873
.3001
82.3
R1
.3441
R2
.4143
.1722
.2104
.1955
1.1754
1.4199
.4717
.8324
.4795
1.1449
1.1863
.4332
1.2572
.2673
R2
R3
R4
R5
95
75
95
93
90
64.90
59.87
70.00
62.44
69.38
.2592
.3102
.4127
.1946
.3239
R1
.3882
.4933
.2664
.3535
.3088
.3481
94.1
86.3
92.4
83.1
94.8
86.7
94.6
Soil only
R3
R4
R5
65.1
Foliage + soil
R1
R2
R3
R4
R5
96.1
Control
R1
R2
R3
Visual Rating
Silt
Sandy
Loam
Loam
Sand
2.1541
1.9571
5.9315
3.0932
5-c
78.61
2.4870
2.5196
3.9315
3.6012
3.6256
2.1056
3.7850
4.0045
82
85
82
95
90
90
85.0
Appendix Table 17.
Placement
Fresh weights and visual ratings for ryegrass grown in three soil types and
treated with HOE 23408 at three placement sites (overhead irrigation study).
Fresh Wt, (g)
Sandy
Silt
Sand
Loam
Loam
% Fresh Wt. Reduc.
Sandy Silt
Sand
Loam
Loam
Arcsin
% Fresh Wt. Reduc.
Sandy
Silt
Sand
Loam
Loam
82.3
69.64
67.70
73.89
70.54
65.57
57.8
72.15
76.06
71.19
69.04
71.28
69.82
66.89
64.23
65.12
92
70
95
92
85
80
90
80
88
75
78
85
75
75
Visual Rating
Sandy
Silt
Sand
Loam
Loam
Foliage only
R1
R2
R3
R4
R5
.2436
.4696
.1713
.1888
.2733
.7651
.2555
.2655
.2451
.2214
.3407
.4229
.2912
.4168
.4055
87.9
85,6
92.3
88.9
82.9
71.6
90.6
94,2
89.6
87.2
.2693
.3505
.3754
87.5
86.6
85.2
69.47
69.25
67.47
86.8
82.6
77.6
.9414
40.2
67.2
68.6
65.8
48.9
71.4
63.7
70.6
51.8
65.2
63.87
75.46
70.00
39.35
55.06
55.92
1.0644
.7979
80.6
93.7
88.3
79.4
87.3
98
90
95
92
94
50
45
60
50
51
65
50
65
50
60
.2819 1.1257
.9312
85.9
58.1
89.7
88.1
84,6
81.1
75
Soil only
R1
R2
R3
R4
R5
.3912 1.6132
.2051
.8864
.2600 1.4380
.3503
.8054
.2027
.8854
1.2947
.5574
63.01
54.21
69.12
44.37
57.67
52.95
57.17
46.03
53.85
64.5
68.29
49.78
53.53
94
51
60
66.66
80
98
98
73
98
80
93
90
75
85
83
75.94
66.97
64.16
73.46
70.63
72.64
70.54
71.28
70.01
71.71
89.4
84.6
80.2
Foliage + soil
R1
.3271
R2
.3778
.1560
.3460
.1472
.4238
.1518
.2703
.3607
.3282
.2659
.3899
.1695
.2459
.2367
83.8
88.4
92.3
79.6
90.8
84.3
94.4
91.9
89.0
94.1
91.1
84.7
81.0
88.9
89.7
66.27
70.09
73.89
63.15
72.34
.3112
.3070
.2616
87.0
87.7
90.1
69.15
2.6965
2.7066
4.5877
3.2948
3.5623
R4
R5
1.7023
1.5978
2.3544
1.7339
2.2083
2.2946
2.1580
2.8157
2.6514
R3
R4
R5
76.31
Control
R1
R2
R3
2.0159
3.2519
2.2221
1.8971
75
90
78
75
Appendix Table 18.
Placement
Fresh weights and visual ratings for wild oats grown in three soil types and
treated with HOE 23408 at three placement sites (subirrigation study).
Fresh Wt. (g)
Sandy
Silt
Sand
Loam
Loam
% Fresh Wt. Reduc.
Sandy Silt
Sand
Loam
Loam
Arcsin
% Fresh Wt. Reduc.
Sandy
Silt
Sand
Loam
Loam
Visual Rating
Sandy
Silt
Sand
Loam
Loam
Foliage only
R1
R2
R3
R4
R5
2.6550 1.8195
1.4918 1.9245
1.1383 1.5567
.9993 1.4049
.7397 1.1459
2.5353
2.8847
.9065
2.2937
1.8205
39.9
25.8
38.2
62.2
59.7
64.1
57,3
59.0
66.3
65.6
56.0
42,0
76.2
54.6
50.6
39.17
30.53
38.17
52.06
50.59
53.19
49.20
50.18
1.4048 1.5703
2.0881
45.16
62.5
55.88
2.8065
1.9873
1.8434
85.0
79.9
57.8
70.5
81.5
44.6
56.0
2.3461
.3401 1,8810
4.3771
2.5722
2.7889
3.6257
2,7420
.5930 2.1729
3.2212
.7494 1.4972
1.5138 1.4158
.6686 2.0892
1.2483 1.8349
30
40
57.5
52.5
65
75
54.09
48.45
40.40
60.80
47.64
45.34
68
87.5
70
55
82
65
80
42.10
52.23
48.53
49
74.1
70.4
24.1
67.21
29.40
44.03
31.24
32.08
30.46
62.5
90
85
70
95
37
70
25
80
12.5
60
47.5
43.5
63.36
49.49
57.10
64.53
41.9
48.45
45.86
41.32
41.27
32.5
48.3
26.9
28.2
25.7
74.94
47.84
30.64
60.34
43.76
33.44
80.5
48.9
43
60.4
24.7
63.7
52.8
71.5
70.4
68.6
45.0
55.9
57.54
55.37
48.50
60.67
50
50
70
58
90
85
46.61
57.04
55.92
42.13
48.39
57.5
86.1
71.2
67.7
74.9
76.0
78.4
51.00
29.80
52.95
.4614
1.6582
1.6045
.9569
1.2132
.7979
57.73
68.11
62.31
85
72.5
92.5
70
90
87.5
77.5
84
1.3407 1.4597
1.2461
54.62
65.2
73.64
47.62
54.32
56.88
62.5
79.6
81.8
R4
R5
2.6421
1.8341
4.1630
3.3290
5.0507
3 6884
2.5493
4.1727
4.6578
54.51
55
85
Soil only
R1
R2
R3
R4
R5
.6620
.4046
.7778
.7807
51.543.6.
25
70
Foliage + soil
R1
R2
R3
R4
R5
.5233
Control
R1
R2
R3
4.4177
2.0107
1.8420
5.0616
4.5122
3.7977
5.7636
4.9721
3.8140
co
Appendix Table 19.
Placement-.
Fresh weights and visual ratings for wild oats grown in three soil types and
treated with HOE 23408 at three placement sites (overhead irrigation study).
1Tresh Wt. Reduc.
Freshikt.
Sandy
Silt
Sand,..Wam_
Load,
Salur.
Sandy
Loam
Silt
Loam
Arcsin
% Fresh Wt. Reduction
Sandy
Silt
Sand
Loam
Loam
Visual Rating
Sandy
Silt
Sand
Loam
Loam
Foliage only
R1
R2
R3
R4
R5
2.4672
2.2081
1.7176
2.3599
1.6546
2,9059
2.9119
2.9160
2.0515
1.6984
21.5
35.3
34.9
50;0
42:6
53.4
51.7
47.8
50.0
44;3
55.9
48.9
41.5
63.6
1.1041 2.0815
2.4967
36;86
49.44
1.8103
.9914
.9372
.7952
.9863
48:39
44.37
64;8-
54.00
40.74
46.95
45.97
43.74
45.00
41.73
54.94
37.20
44.68
27.62
36.45
36.21
62
70
70
53
85
55
75
53.61
40
50
53.5
55
60
47.87
51.7
68
67.5
25
48
10
37.5
45
22.5
70
40.11
52.89
72.5
62.5
72.5
Soil only
R1
R2
R3
R4
R5
.6422-5.3089. 4.5256
.8680 2.4615 2.5603
.4284 2.6210 2,6770
.2832 3.5124 3.7749
.4741 2.1317 1.5093
72.2
43.4
70:2
82.2
72.4
0
31.4
58.18
46.1
55.1
46.3
68.7
42.76
26.78
30.33
32.14
34.08
47.93
42.88
35.12
55.98
70
80
20.3
25.5
28.3
41.21
56.91
65.0558.31
33.1
0
94.5
90
92.5
40
60
20
.5392 3.2071
3.0094
68.08
24.04
46.92
55.93
26.4
44.2
85.4
38.6
37
.3786 1.9944
.6280 1.9424
2.4516
2.4761
1.1706
1.8363
1.2108
83:6
59.0
88;5
70;6
64;7
62.4-
62.8
56.676:5-
80.7-
67.4
74.9
66:1150;1870.18.
57.17
53.55
52.18
57.5
70.2
52.42
48.79
61.00
55.18
59.93
93
90
95
92.5
95
55
65
82
82
65
65
70
75
85
R4
R5
1.5896
1.7173
4.7153
2.9732
5.6388
4.8265
1.5893
4.1694
5.5488
Foliage + soil
R1
R2
R3
R4
R5
.1657
.9789
.4667
.9123
.6065 1.5011
49.5
49.31
56.91
63.94
44.71
78.5
x
Control
R1
R2
R3
2.3075
1.5330
1.4390
5.2181
4.5701
6.5929
3.2904
4.9828
5.7031
co
cn
86
Appendix Table 20.
Analysis of variance for Arcsin transformation
of percent fresh weight reduction data from
Appendix Table 16.
Source of Var.
df
4
8
2
Reps
Treatments
Place
Soil type
P x S
Error
4
32
Total
44
LSD
LSD
.05
.01
2
SS
30353.00
1086.72
596.85
72.47
417.40
504.78
1895.03
MS
75.88
135.84
298.42
36.24
104.35
15.77
F
4.81**
8.61**
18.92**
2.30 NS
6.62**
C.V. = 5.7%
= 8.11 for P x S means
= 10.92
Appendix Table 21.
Analysis of variance for Arcsin transformation
of percent fresh weight reduction data from
Appendix Table 17.
Source of Var.
df
Reps
Treatments
Place
Soil type
P x S
Error
Total
4
8
2
2
4
32
44
SS
MS
295.37
2955.18
1865.50
296.87
73.84
369.40
932.75
148.43
198.20
792.81
160.46
3411.01
C.V. = 3.4%
LSD
LSD
.05
.01
= 2.89
= 3 89
5.01
F
14.73**
73.73**
186.18**
29.63**
39.53**
87
Appendix Table 22.
Analysis of variance for Arcsin transformation
of percent fresh weight reduction data from
Appendix Table 18.
Source of Var.
df
Reps
4
8
Treatments
Place
Soil type
P x S
Error
4
32
Total
44
2
2
SS
240.05
2741.24
408.77
142.94
2189.53
1688.91
4670.20
MS
60.01
342.66
204.38
71.47.
547.38
52.78
F
1.14
6.49**
3.87*
1.35 NS
10.37**
C.V. = 14.9%
L$D.05 = 9.38
LSD.01 = 12.64
Appendix Table 23.
Analysis of variance for Arcsin transformation
of percent fresh weight reduction data from
Appendix Table 19.
Source of Var.
df
SS
MS
4
8
310.20
4405.87
1801.40
747.34
1857.13
2286.70
7002.77
77.55
550.73
900.70
373.67
464.28
71.46
Reps
Treatments
Place
Soil type
P x S
Error
Total
2
2
4
32
44
C.V. = 17.9%
LSD
LSD
.05
= 10.92
= 14.7
.01
F
1.09 NS
7.71**
12.60**
5.23*
6.50**
Appendix Table 24.
Placement
Fresh weight, percent fresh weight reduction (including Arcsin transformation),
and visual rating for ryegrass grown in three soil types and treated with a
soil application of HOE 23408 (subirrigation).
Fresh Wt. (g)
Silt
Sandy
Loam
Sand
Loam
% Fresh Wt. Reduc.
Sandy Silt
Loam
Sand
Loam
Arcsin
% Fresh Wt. Reduc.
Sandy
Silt
Sand
Loam
Loam
Visual Rating
Sandy
Silt
Loam
Loam
Sand
1.12 kg/ha HOE 23408
Soil only
R1
R2
R3
R4
R5
.2718 1.7744
.3380 2.0115
.7095
.3213
.5566
.2657
.5045
.2600
1.6464
2.6642
1.2049
.2914 1.1113
1.2852
4.2847
4.5086
3.4806
3.4240
2.9975
3.5098
3.2270
3.2018
2.3698
2.5809
1.9424 3.7391
2.9779
.5250
.3856
Control
R1
R2
R3
R4
R5
2.0315
2.2557
2.1647
1.6209
1.6392
Base Wt.
R1
R2
R3
R4
R5
.3573
.3497
.3032
.2803
.2805
.5282
.6052
.5275
.5563
.5137
.6712
.8280
.7398
.6554
.5846
.3142
.5462
.6958
99
45
30
75
75
78
35
10
45
65
80
94.2
60.6
47.0
46.78
24.65
52.18
61.89
67.29
92
90
95
85.1
67.37
66.11
66.50
49.95
48.10
63.15
66.19
67.62
59.16
67.14
59.0
50.56
53.1
68.53
17.4
62.4
77.8
67.21
84.1
58.6
55.4
79.6
83.7
85.5
84.9
72.56
86.6
85.0
85.2
83.6
95
89
Appendix Table 25.
Analysis of variance for data from
Appendix Table 24.
A) Arcsin transformation for visual rating data.
Source of Var.
Reps
Treatments
Error
df
4
2
8
14
Total
SS
1535.03
3103.98
418.27
5057.28
MS
383.76
1551.99
52.28
F
7.34**
29.68**
C.V. = 12.7%
LSD
.05
= 10.55
= 15.34
LSD
B) Arcsin transformation for percent fresh weight reduction data.
Source of Var.
Reps
Treatments
Error
Total
SS
MS
4
811.06
202.77
2
687.81
8
14
632.84
2131.71
343.91
79.11
df
= significant at the 10% level of probability.
C.V. = 15.1%
LSD
LSD
.05
.01
= 10.46
= 12.97
F
2.56 NS
4.35 +
90
Appendix Table 26.
A) Analysis of variance for soil only treatments from Appendix
Table 16.
Source of Var.
df
Reps
4
Treatments
Error
2
Total
8
14
SS
MS
409.04
181.67
97.39
688.10
102.26
90.84
12.17
F
8.40*
7.46*
C.V. = 5.4%
LSD
LSD
.05
= 5.09
= 7.40
.01
B) Analysis of variance for soil only treatments from Appendix
Table 17.
Source of Var.
Reps
Treatments
Error
df
4
2
8
14
Total
SS
MS
158.50
957.49
254.27
1370.26
39.62
478.75
31.78
C.V. = 9.9%
LSD
LSD
.05
= 8.22
= 11.96
F
1.25 NS
15.06**
91
Appendix Table 27.
Analysis of variance for three experiments
comparing ryegrass injury in overhead or
subirrigation.
A) Percent fresh weight reduction data with silica sand as soil type.
_
Source of Var.
df
SS
199.59
81.08
5
Treatments
30.86
2
Place
2.78
1
Irr.
47.62
2
P x I
234.76
20
Error
515.43
29
Total
= 3.20 for placement means
LSD
05
= 4.36
LSD*
01
= 2.61 for irrigation means
LSD°
05
= 3.56
LSD'
4
Reps
MS
49.90
16.22
15.43
2.78
F
4.25*
1.38 NS
23.81
11.74
01
B) Percent fresh weight reduction data with sandy loam as soil type.
Source of Var.
df
Reps
4
Treatments
Place
5
Irr.
1
P x I
Error
Total
LSD
LSD
LSD
LSD
.05
.01
.05
.01
2
2
20
29
SS
MS
466.578
2386.919
1818.36
287.93
280.63
927.64
3781.135
116.64
477.38
909.18
287.93
140.32
46.38
= 6.35 for placement means
= 8.66
= 5.19
= 7.08
for irrigation means
F
2.52
10.29
19.60**
6.21*
3.02 NS
92
C) Percent fresh weight reduction data with silt loam as soil type.
Source of Var.
4
5
Reps
Treatment
Place
2
Irr.
1
2
P x I
Error
Total
LSO
LSD
LSD
LSD
.05
.01
.05
.01
df
20
29
SS
MS
83.40
1845.72
1492,79
20.85
369.14
746.40
337.41
337.41
15.52
309.67
2238.79
7.76
75.48
= 3.67 for placement means
=
5.01
= 3.00 for irrigation means
= 4.09
F
1.35
23.85**
48.22**
21.80**
<1.00 NS
93
Appendix Table 28.
Analysis of variance for three experiments
comparing wild oats injury in overhead or
subirrigation.
A) Percent fresh weight reduction data with silica sand as soil type.
Source of Var.
Reps
Treatments
Placement
Irrigation
P x I
Error
Total
SS
df
4
5
2
1
2
20
29
568.75
2308.70
1850.87
5.27
452.56
1186.80
4064.25
MS
F
149.69
461.74
925.43
5.27
226.28
59.34
2.52
15.60**
<1.00 NS
3.81*
C.V. = 15.3%
LSD.05 = 10.16 for P x I means
LSD
.01
= 13.86
B) Percent fresh weight reduction data with sandy loam as soil type.
Source of Var.
df
Reps
4
Treatments
Placement
Irrigation
P x I
Error
5
Total
2
1
2
20
29
SS
174.90
2767.84
1869.79
555.65
342.40
1520.76
4463.50
C.V. - 19.0%
LSD
LSD
LSD
.05
.01
.05
= 8.13 for placement means
= 11.09
= 6.64 for irrigation means
LSD 01 = 9.06
MS
43.73
553.57
934.90
555.65
171.20
76.04
F
<1.00 NS
12.30**
7.31*
2.25 NS
94
C) Percent fresh weight reduction for data with silt loam as soil
type.
Source of Var.
df
Reps
4
Treatments
Placement
Irrigation
P x I
Error
5
Total
2
1
2
20
29
SS
MS
124.53
1843.37
1599.36
49.28
194.73
933.56
2901.46
31.13
368.67
799.68
49.28
97.37
46.68
C.V. = 14.4%
LSD005 - 6.37 for placement means
LSD
= 8.69
.01
F
<1.00 NS
17.13**
1.06 NS
2.09 NS
Appendix Table 29.
Fresh weight, percent fresh weight reduction, and visual ratings for overhead
versus subirrigation study for ryegrass grown in silica sand.
Arcsin
% Fresh Wt. Reduc.
Over
Sub
Visual Rating
Over
Sub
Over
% Fresh Wt. Reduc.
Sub
Over
R2
R3
R4
R5
.3882
.4933
.2664
.3535
.3088
.2436
.4696
.1713
.1888
.2733
82.0
74.8
88.3
78.6
87.6
87.9
85.6
92.3
88.9
82.9
64.90
59.87
70.00
62.44
69.38
69.64
67.70
73.89
70.54
65.57
75
75
70
75
83
92
70
95
92
85
R
.3620
.2693
82.3
87.5
65.32
69.47
75.6
86.8
R1
.3441
.3912
R2
R3
R4
R5
.4143
.1722
.2104
.1955
.2051
84.0
78.8
92.4
87.3
66.42
62.58
74.00
69.12
73.68
63.87
75.46
70.00
92.1
80.6
93.7
88.3
79.4
87.3
69.12
75
70
95
75
88
98
90
95
92
95
R
.2673
.2819
86.9
85.9
69.16
68.29
80.6
94
.3271
R3
R4
R5
.2888
.2455
.1755
.2534
.1810
.3778
.560
.3480
.1472
86.6
87.5
92;3
84.7
92.7
83.8
88.4
92.3
79.6
90.8
68.53
69.30
73.89
66.97
74.32
66.27
70.09
73.89
63.15
72.34
87
85
95
90
98
80
98
98
73
98
R
.2288
.3112
88:8
87.0
70.60
60.15
91
89.4
2.1541
1.9571
2.2755
2.0159
3.2519
2.2210
R4
R5
1.6541
2.4870
1.7023
1.5978
R
2.1056
2.1580
Fresh Wt.
Placement
.(g)
Sub
Foliage only
R1
Soil only
.2600
.3503
.2027
63.01
Foliage + soil
R1
R2
Control
R1
R2
R3
ko
Appendix Table 30.
Fresh weights, percent fresh-weight reduction and visual ratings for overhead
versus subirrigation study for ryegrass grown in a sandy loam soil.
Arcs in
Fresh Wt.
(g)
% Fresh Wt. Reduce
Over
Sub
Sub
Over
R1
.3481
.7651
R2
R3
R4
R5
.7149
.2294
.3444
.2998
.2555
.2655
.2214
86.3
92.4
71.6
90.6
94.2
89.6
87.2
R
.3873
.3505
89.6
86.6
1.1754
1.4199
.4717
.8324
.4795
1.6132
.8854
72.6
66.7
87.9
67.0
87.8
40.2
67.2
68.6
65.8
48.9
.8758
1.1257
76.4
58.1
R2
R3
R4
R5
.3716
.4186
.3410
.3898
.1928
.4238
.1518
.2703
.3607
.3282
91.4
90.2
91.3
84.5
91.6
84.3
94.4
R
.3428
.3070
89.8
37.7
4.2964
4.2667
3.9108
2.6965
2.7066
4.5871
Placement
Visual Rating
Over
% Fresh Wt. Reduc.
Over
Sub
Sub
57.80
72.15
76.06
71.19
69.04
95
75
95
93
90
75
80
90
80
89.6
82.6
72
55
75
65
75
50
45
60
50
50
68.4
51
75
82
85
82
95
80
93
90
75
85
83.8
84.6
Foliage only
.2451
91.9
83.2
94.1
73.46
65.80
75.94
68;28
74,00
88
Soil only
R1
R2
R3
R4
R5
R
.8864
1.4380
.8054
58.44
54.76
69.64
54.94
69.56
23.70
55.06
55.92
54.11
44.37
Foliage + soil
R1
94.1
84.7
81.0
72.95
71.76
72.84
66.82
73.15
66.66
76.31
75.94
66.97
64.12
Control
R1
R2
R3
R4
R5
2.5196
3.9315
2.3544
1.7339
R
3.7850
2.8157
Appendix Table 31,
Fresh weights, percent fresh weight reductions, and visual ratings for
overhead versus subirrigation study for ryegrass grown in a silt loam soil.
Arcs in
Placement
Fresh Wt. (g)
Over
Sub
% Fresh Wt. Reduc,
Over
Sub
Visual Rating
Over
% Fresh Wt. Reduc.
Over
Sub
Sub
90
90
90
90
90
75
78
85
75
75
Foliage only
.3407
.4229
.2912
.4168
.4055
93.1
89.7
R2
R3
R4
R5
.2592
.3102
.4127
.1946
.3239
94.8
86.7
94.6
88.1
74.77
76.82
84.6
68-;61
81.1
91.1
82.3
76.56
72.64
71.28
69.82
66.89
64.23
65.12
X
.3001
.3754
92.1
85.2
73.88
67.47
90
77.6
56.54
63.43
68.03
53.79
68.87
57.67
52.95
57.17
46.03
53.85
55
75
75
65
75
65
50
65
50
70
R1
Soil only
1.1449
1.1863
.4332
1.2572
.9414
1.2947
.5574
69.6
80.0
86.0
1.0644
65.1
.4711
.7979
87.0
71.4
63.7
70.6
51.8
65.2
.8985
.9312
77.5
64.5
62.13
53.53
69
60
.2659
.3899
.1695
.2459
.2367
96.7
95.8
91.9
89.0
79.53
78:17
R3
R4
R5
.1253
.2479
.1197
.2256
.3340
96.1
91.1
78.61
88.9
89.7
75.46
72.34
80
80
85
90
90
83
75
90
93.7
90.8
73.46
70.63
72.64
70.54
71.28
R
.2105
.2616
94.6
90.1
76.82
71.71
85
80.2
R1
3.7711
R2
R3
5.9315
3.0932
3.2948
3.5623
R4
R5
3.6012
3.6256
2.2083
2.2946
R
4.0045
2.6514
R1
R2
R3
R4
R5
R
Foliage + soil
R1
R2
Control
1.8971
78
75
Appendix Table 32.
Placement
Fresh weights and visual rating of overhead versus subirrigation study
using wild oats in silica sand.
Fresh Wt. (g)
Over
Sub
% Fresh Wt. Reduc.
Over
Sub
Arcsin
% Fresh Wt. Reduc.
Sub
Over
Sub
Visual Rating
Over
Foliage only
R1
2.6550
1.4918
1.1383
.9993
1.8103
39.9
25.8
38;2
62.2
59.7
21.5
35.3
34.9
50.0
42.6
39;17
30.53
38;17
52.06
50.59
27.62
36.45
30
40
36.21
57.5
52.5
45.16
36.86
42.10
72.2
43.4
70.2
82.2
72.4
67.21
65
40
50
53.5
55
60
37.20
49
51.7
58,18
41.21
62.5
90
85
70
80
58.31
70
95
90
92.5
60.34
55.93
80.5
85.4
83.6
59.0
88.5
70.6
64.7
51.00
29.80
52.95
66.11
50
50
70
57.73
50.18
70.18
57.17
53.55
85
93
90
95
92.5
95
73.28
47.62
59.44
62.5
93.1
R4
R5
2.6421
1.8341
1.5896
1.7173
R
2.5493
1.5893
.7397
.9914
.9372
.7952
.9863
1,4048
1.1041
.6620
.4046
.7778
.7807
.6422
.8680
.4284
.2832
.3401
.4741
85.0
79.9
57.8
70.5
81.5
.5930
.5392
74.94
68.08
R1
.7494
R2
R3
R4
R5
1.5138
.6686
1.2483
.5233
.3786
.6280
.1657
.4667
.6065
60.4
24.7
63.7
52.8
71.5
R
1.3407
.4491
54.62
4.4177
2.0107
1.8420
2.3075
1.5330
1.4390
R2
R3
R4
R5
R
45.00
40.74
Soil only
R1
R2
R3
R4
R5
R
63.36
49.49
57.10
64.53
56.91
65.05
94.5
Foliage + soil
46.61
Control
R1
R2
R3
57.5
Appendix Table 33.
Placement
Fresh weights and visual rating of overhead versus subirrigation study using
wild oats in sandy loam.
Fresh Wt. (g)
Over
Sub.
% Fresh Wt. Reduc.
Sub
Over
Arcsin
% Fresh Wt, Reduc.
Over
Sub
Sub
Visual Rating
Over
Foliage only
2.4672
64.1
R2
R3
R4
R5
1.8195
1.9245
1.5567
1.4049
1.1459
2.2081
1.7176
2.3599
1.6546
57.3
59.0
66.3
65.6
53.4
51.7
47.8
50.0
44.3
53.19
49.20
50.18
46.95
45.97
43.74
54.51
45
75
68
54.09
41 73
87.5
62
70
70
53
85
X
1.5703
2.0815
62.5
49.44
52.23
44.68
74.1
68
2.8015
1.9873
44.6
56.0
51.5
43.6
43.5
0
46.1
32.5
20.3
25.5
28.3
41.90
48.45
45.86
41.32
41.27
42.76
26.78
30.33
32.14
37
70
25
80
25
40
60
20
48
R1
55
85
Soil only
R3
R4
R5
1.8431
2.3461
1.8810
5.3089
2.4615
2.6210
3.5124
2.1317
R
2.1729
3.2071
47.8
24.04
43.76
26.90
48.9
38.6
1.9944
1.9424
70.4
68.6
45.0
55.9
57.04
55.92
42.13
48.39
49.31
56.91
86.1
62.4
57.5
70.2
80.7
49.5
52.18
R2
R3
R4
R5
1.4972
1.4158
2.0892
1.8349
.4614
68.11
44.71
58
90
85
70.5
92.5
55
65
82
82
78.5
R
1.4597
1.4658
65.2
64.06
54.32
53.41
79.6
72.5
5.0616
4.5122
3.7977
5.2981
4.5701
R4
R5
4.1630
3.3290
4.7153
2.9732
R
4.1727
4.1694
R1
R2
0
Foliage + soil
R1
.9789
.9123
1.5011
63.94
Control
R1
R2
R3
3.2904
Appendix Table 34.
Placement
Fresh weights and visual rating_of overhead versus subirrigation study using
wild oats in silt loam.
Fresh Wt. (9)
Sub
Over
% Fresh. Wt. Reduc.
Sub
Over
Arcsin
% Fresh Wt. Reduc.
Over
Sub
Sub
Visual Rating
Over
Foliage only
56.0
42.0
76.2
54.6
50.6
55.9
48.9
41.5
63.6
64.8
48.45
40.40
60.80
47.64
45.34
48.39
44.37
1.8205
2.9059
2.9119
2.9160
2.0515
1.6984
2.0881
2.4967
55.88
54.94
48.53
4.5256
2.5603
2.6770
3.7749
1.5093
24.1
31.4
48.3
26.9
28.2
25.7
55.1
R3
R4
R5
4.3771
2,5722
2.7889
3.6257
2.7420
R
3.2212
3.0094
1.6582
1.6045
2.4516
.9569
1.2132
.7979
R1
R2
R3
2.5353
2.8847
70
55
82
65
55
75
80
72.5
62.5
72.5
47.87
70.4
67.5
34.08
47.93
42.88
35.12
55.98
12.5
60
47.5
68.7
29.40
44.03
36.24
32.08
30.46
25
70
10
37.5
45
22.5
70
30.64
46.92
33.49
44.20
43
37
62.8
56.6
76.5
67.4
74.9
57.54
55.37
48.50
60.67
65
65
62.31
52.42
48.79
61.00
55.18
59.93
70
1.1706
1.8363
1.2108
71.2
67.7
74.9
76.0
78.4
1.2461
1.8291
73.64
67.94
56.88
55.46
81.8
R1
5.7636
R2
R3
4.972]
6.5929
5.7031
4.9829
R4
R5
5.0507
3.6884
5.6388
4.8365
R
4.6578
5.5488
R4
R5
R
.9065
2.2937
40.11
52.89
53.61
Soil only
R1
R2
46.3
33.1
Foliage + soil
R1
R2
R3
R4
R5
R
2.4761
Control
3.8140
90
87.5
77.5
84
70
75
85
72
101
Appendix Table 35.
Dry weights.(g) of ryegrass plants
subjected to two levels of water stress.
Level of Herbicide
Concentration (ppm w/v basis)
Stress
Level
No
Reps
(bars)
1.048
.452
.687
R
.936
.578
.547
.324
3
.741
4
.575
.575
.575
.562
.469
.361
2
.483
.540
.499
.456
.439
.404
.393
R
.585
.545
.520
.423
MS
.125
24
.874
.604
.048
.222
.652
31
1.526
Total
319
.461
SS
(7)
= .235
.760
Analysis of variance for data in
Table 35.
Treatments
(4) Herbicide
(2) Water stress
Herbicide x water stress
Error
.01
.100
.470
.334
.392
4
df
LSD
.490
.681
Source of Var.
.05
1000 ppm
3
2
Appendix Table 36.
LSD
100 ppm
.547
.677
.515
.449
1
- 2.5 bars
10 ppm
.666
.648
1.382
1
- 0.3 bars
Herbicide
3
1
3
.201
.048
.074
.026
.049
4.80**
7.73**
1.85 NS
2.85 NS
102
Appendix Table 37.
Analysis of variance for soil moisture study I.
Arcsin for visual ratings were analyzed.
Source of Var.
df
Reps
Treatments
Place
Moisture
P x M
Error
4
8
2
2
4
32
Total
44
SS
408.33
14699.39
13025,86
673.04
1000.49
1121,20
16228,92
MS
100.08
1837.42
6512.93
336.52
250.12
35.04
F
2.91*
185.87**
9.60**
7.14**
C.V. = 8.8%
LSD.05 = 7.64
LSD
- 10 03
.01
Appendix Table 38.
Analysis of variance for soil moisture study II.
Arcsin for percent fresh weight reduction were
used.
Source of Var.
df
4
113.26
5576.23
5055.76
249.99
270.48
40
53
638040
Reps
5
Treatments
Place
Moisture
P x M
Error
8
Total
SS
2
2
690.91
C.V. = 8.1%
LSD
LSD
.05
01
= 4 85
= 6.49
MS
22.65
697.03
2527.88
124.99
67.62
17.27
F
1.31 NS
40.35
146.35**
7.24**
3.91**
103
Visual rating for soil moisture study I.
Appendix Table 39.
Arcsin for Rating
Soil Moisture
Placement
96% F.C.
Visual Rating
Soil Moisture
96% F.C.
60% F.C.
32% F.C.
60% F.C.
32% F.C.
53.73
45.00
42.13
49.60
36.27
47.87
35.72
49.60
56.79
63
60
55
60
58
59.2
Foliage only
45
58
35
55
53
58
70
56.6
54.2
.65
65
50
R2
R3
R4
R5
52054
50.77
47.87
50.77
49.60
x
50.31
48.84
47.45
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
90
90
90
100
100
100
Foliage + soil
R1
77.08
90.00
R2
67.21
67.21
67.21
67.21
42.13
47.87
90.00
67.21
51.94
50.77
51.94
56.79
60.00
95
100
85
85
100
85
85
45
55
85
62
60
62
70
75
78,3
58.33
54.29
94
71
65.8
R1
53.77
Soil only
R1
R2
R3
R4
R5
R3
R4
R5
T(
Control
R2
R3
R4
R5
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
;(
0
0
0
R1
Dry weights anthvisual .rating for soil moisture study II.
Appendix Table 400
Placemeflt
Dry Weights
Soil Moisture
60% FC
96% FG
120% FC
Visual Ratin - Arcsin
Soil Moisture
Soil Moisture
60% FC
96% FC
120% FC
60% FC
96% FC
120% FC
Foliage only
.2869
.3195
.2863
.3196
.2314
.2128
40
35
40
35
50
62.5
R2
R3
R4
R5
R6
.2701
.2660
.2547
.2582
.3603
.2865
.3544
.2728
.3138
.2162
.2550
X
.2708
.2831
.2411
43.8
.1174
.1640
.1815
.1814
.1552
.1498
.1817
.1578
.1530
99
.2090
.1196
.2473
.1827
.1808
.1886
.1460
.1577
.1669
.1838
.1632
96.3
.1929
.2203
.2174
.2608
.1637
.2511
.2208
.1908
.2080
77.5
70
74
75
79
.2011
.1967
.2445
.2037
.2202
.2142
.3395
.2351
86.5
.2094
.2365
.2186
77.0
R1
.2156
39.23
36.27
39.23
36.27
45.00
52.24
35
25
32.5
32.5
40
42.5
36.27
30.00
34.76
34.76
39.23
40.69
47.5
25
30
25
52.5
57.5
43.57
30.00
33.21
30.00
46.43
49.31
39.6
34.6
Soil only
R1
R2
R3
R4
R5
R6
R
.2101
91.5
95
94
99
99.5
84.26
73.05
77.08
75.82
84.26
85.95
98
96.5
98
97
99
99
81.87
79.22
81.87
80.03
84.26
84.26
97.5
92.5
97.5
93
99
99
80.9
74,11
80.9
74.66
84.26
84.26
96.4
97.9
Foliage + soil
R1
R2
R3
R4
R5
R6
R
.2057
61.68
56.79
59.34
60
62.73
68.44
55
42.5
42.5
42.5
55
75
52.1
47.87
40.69
40.69
40.69
47.87
60.00
70
65
67.5
67.5
70
70
68.3
56.79
53.73
55.24
55.24
56.79
56.79
,
Appendix Table 40 (continued)
Placement
Dry Weights
Soil Moisture
120% FC
96% FC
60% FC
Visual Ratin.
Arcsin
Soil Moisture
Soil Moisture
120% FC
9.6% FC
60% FC
120% FC
96% FC
60% FC
Control
R1
.4710
R2
06331
R3
06231
R4
R5
R6
.5720
06053
.2834
2809
.5121
.3254
.4858
.4440
04486
3829
.3829
x
.4943
05733
04116
.5158
.6800
.6125
4963
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Fresh weights and percent fresh weight reduction for soil moisture study II.
Appendix Table 41.
Placement
Fresh Weight
Soil Moisture
60% FC
96%-FC
120% FC
% Fresh Weight Reduction
Soil Moisture
60% FC
96% FC
120% FC
Arcsin
Soil Moisture
60% FC
96% FC
120% FC
Foliage only
48.1
40.11
45.8
55.43
51.35
56.35
53.49
40.05
41.09
38.29
49.08
49.78
73.26
71.66
75.7
70.54
73.46
74
75.11
74.11
70.54
63.58
71.57
74.88
76.44
64.23
71.95
73.05
72.44
62.44
68.36
68.87
65.57
63.72
61.75
63.29
61.75
64.67
64.9
61.48
53.37
57.42
61.14
59.08
62.94
54.88
52.65
41.5
41.4
43.2
38.4
56.6
55.98
57.04
57.10
57.1
39.2
55.4
51.4
67.8
61.0
69.3
64.6
46.78
38.76
1.3845
61.9
61.6
46.7
.2594
.2492
.2027
.2044
.1890
88.3
91.7
92.4
88.9
80.2
90.0
90.1
.3060
.3527
.3618
.1819
.3688
.2707
.2708
.2876
.1966
.1982
93.9
93.4
93.2
94.5
93.5
88.9
91.9
92.5
90.4
91.5
90.9
.3329
.2655
.2281
88.6
93.1
91.0
R2
R3
R4
R5
R6
.5979
.5915
.5186
.7166
.3577
.4062
.7555
.9979
.7558
.7587
.8168
1.0881
.6754
.7199
.7146
.5710
.7979
.7608
78.6
86.4
87.0
82.9
80.4
77.6
79.8
77.6
81.7
82.0
77.2
64.4
71.0
76.7
73.6
79.3
66.9
63.2
x
.5314
.8621
.7066
82.2
77.1
71.8
69.7
68.7
70.4
70.5
R6
1.1008
2.1616
1.3297
1.6418
1.0976
1.0822
1.3626
1.8127
1.5362
1.6997
1.0339
.8617
R
1.0964
1.4962
R1
.3258
R2
.3591
R3
R4
R5
R6
R
R1
.8455
R2
R3
R4
R5
1.3580
1.1854
1.2321
.8568
1.6641
35.1
58.3
Soil only
.2641
70
Foliage + soil
R1
Appendix Table 41 (continued)
Placement
Fresh Weight
Soil Moisture
96% FC
60% FC
120% FC
% Fresh Weight Reduction
Soil Moisture
60% FC
120% FC
96% FC
Arcsin
Soil Moisture
120% FC
96% FC
60% FC
Control
R2
R3
R4
R5
R6
2.7918
4,3386
4.0000
4.1824
1.8278
1.8112
R
3.1586
R1
3 7331
2.3301
3.5781
3.0556
3.0938
2.7046
2.7607
2.4126
2.0673
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
4.4475
4.1298
4.2118
3.8593
2.5616
0
0
0
0
0
0
0
0
0
0
0
108
Appendix Table 42,
Analysis of variance for ryegrass root growth
(Appendix Table 45) in nutrient culture
experiment I.
Source of Var.
df
SS
MS
Treatments
Error
4
20
24
2584.64
3996.40
6581.04
646.16
199.82
Total
F
3.23*
C.V. = 71.7%
LSD
LSD
.05
= 18.6
25.4
.01
Appendix Table 43.
Analysis of variance for ryegrass root growth
(Appendix Table 46) in nutrient culture
experiment II.
Source of Var.
df
Treatments
Error
4
20
24
Total
SS
28178.00
13112.00
41370.00
C.V. = 50.7%
= 33 9
LSD
LSD
46.2
.01
MS
7044.5
659.6
F
12.6
109
Appendix Table 44.
Analysis of variance for wheat root growth
(Appendix Table 47) in nutrient culture
experiment.
Source of Var.
df
Treatments
Error
Total
4
20
24
SS
2372.24
2484.80
4857.04
C.V. = 81.2%
LSD
LSD
.05
.01
= 14.71
= 20 06
MS
593.06
124.24
F
4.77**
Appendix Table 45.
Placement
Change in root growth_of ryegrass following. HOE 23408:treatment (Experiment 1).
Day 1
Day,a#!
140
134
156
162
122
140
148
160
179
146
Length of Longest Root (mm)
A 4-2 (9 units added to each)
Day.3
Day-.4
50 ppm, HOE 23408
Foliage only
R1
R2
R3
R4
R5
138
166
140
180
161
_164
195
168
204
191
9
41
13
34
54
30.2
R
50 ppm, HOE 23408
Solution only
R1
R2
R3
R4
R5
165
123
118
130
132
163
142
125
145
127
160
150
134
141
144
162
147
132
149
136
8
14
16
13
18
13.8
R
500 ppm, HOE 23408
Foliage only
R1
141
R2
133
142
R3
R4
R5
R
151
132
155
142
154
155
130
155
144
141
168
124
165
147
146
188
126
19
14
1
42
5
16.2
Appendix Table 45 (continued)
Length of Longest Root (mm)
A 4-2
Da
3
Da 4
Placement
5000 ppm, HOE 23408
Solution only
R1
R2
R3
R4
R5
128
106
120
146
181
121
125
116
140
175
117
108
116
140
174
115
116
112
142
176
3
0
5
11
10
5.8
X
Control
R1
156
R2
R3
R4
R5
101
132
128
152
155
106
155
130
155
X
*Day of treatment, measurement prior to treatment.
173
115
202
171
131
190
140
156
156
131
56
34
44
19
10
32.6
9 units added to each
Appendix Table 46.
Placement
Change in root growth of ryegrass following HOE 23408 treatment (Experiment 2).
Day
1
Day 2*
Day 4
109
123
118
119
135
107
149
119
135
144
Length of Longest Root (mm)
A x4-2
Day 5
Day 6
Day 7
Day 8
Day 9
124
177
126
211
171
230
180
174
A x9-2
30 ppm, HOE 23408
Foliage only
R1
R2
R3
R4
R5
107
114
112
111
127
-2
26
1
16
9
109
164
135
145
147
113
181
159
152
153
122
169
190
163
158
142
191
51
71.4
10.0
R
29
80
124
73
50 ppm, HOE 23408
Solution only
R3
138
139
88
R4
R5
82
95
R1
R2
154
140
90
156
142
2
2
91
1
91
93
2
112
111
-1
155
142
92
95
112
108
140
88
96
112
155
139
93
96
112
153
138
89
96
108
152
138
88
96
106
10.6
1.2
R
10
10
10
17
6
300 ppm, HOE 23408
Foliage only
R1
R2
R3
R4
R5
R
25
30
94
147
127
145
95
101
121
20
138
100
100
145
92
86
102
115
2
1
148
133
155
122
137
151
151
123
156
124
147
125
158
112
163
149
123
157
110
174
151
124
171
110
187
18
34
68
28
98
49.2
Appendix Table 46 (continued)
Len th of Lon est Root
A X-
x-
A
Placement
Day 1
Day 2*
Day:4
4-2
Day 5
Day 6
Day 7
Day 8
Day 9
9-2
162
85
92
177
-1
176
89
95
113
127
174
89
88
108
122
173
88
88
106
127
8
10
118
126
180
90
100
113
127
182
101
176
90
93
115
130
500 ppm, HOE 23408
Solution only
R1
R2
R3
R4
R5
102
90
91
0
2
-3
4
91
94
115
129
9
0
13
0.4
R
Control
R1
121
R2
R3
R4
R5
137
104
X
111
90
122
147
117
122
109
135
160
137
141
139
13
13
20
19
30
19.0
*Day of treatment, measurement prior to treatment
(x-12 units added to each)
139
178
146
146
150
146
198
157
162
169
154
220
175
178
187
158
238
181
191
202
162
257
185
202
220
52
122
80
92
123
93.8
Appendix Table 47.
Change in root growth of wheat following HOE 23408 treatment.
Length of Longest Root (mm)
A
Placement
Day 1
Day 2*
Day 3
Day 4
99
159
122
166
115
99
159
119
174
118
95
160
101
158
120
175
117
4-2
A
Day 5
Day 6
2
101
101
103
3
160
161
4
2
1
121
160
122
178
122
123
180
122
4
6
4
Day 9
9-2
50 ppm, HOE 23408
Solution only
R1
R2
R3
R4
R5
121
175
116
R
1
-1
179
117
1.2
4.0
500 ppm, HOE 23408
Solution only
R1
R2
R3
R4
R5
220
136
134
120
116
236
138
134
118
123
236
135
135
115
122
235
137
137
119
126
-1
-1
3
1
3
237
138
136
118
127
237
138
138
123
126
240
140
140
124
130
1.0
R
4
2
6
6
7
5.0
500 ppm, HOE 23408
Foliage only
R1
R2
R3
R4
R5
R
117
176
153
180
109
112
184
162
191
112
114
192
175
199
115
115
202
179
204
121
3
18
17
13
9
12.0
118
208
195
213
123
118
212
194
214
124
120
241
194
229
128
8
57
32
38
16
30.2
Appendix Table 47 (continued)
A
A
Placement
Day 5
Day 6
Day 9
9-2
138
142
6
161
162
132
139
131
147
145
174
133
142
21
-2
138
139
4-2
Day 1
Dater
Day 3
Day 4
123
138
144
135
128
126
145
133
151
155
130
132
143
157
131
-2
136
4
5000 ppm, HOE 23408
Foliage only
R1
R2
R3
R4
R5
133
132
141
131
6
143
10.8
2.4
R
0
23
0
10
Control
R1
R2
R3
R4
R5
205
103
136
117
131
221
107
145
120
139
232
110
146
120
142
R
*Day of treatment, measurement prior to treatment.
246
110
150
124
150
25
3
5
4
11
9.6
251
251
113
153
126
156
119
153
124
158
256
114
163
130
162
35
7
18
10
23
18.6
116
Appendix Table 48.
Analysis of variance for dry weights from
Appendix Table 50.
Source of Var.
df
Treatments
Error
Total
LSD
LSD
05
.01
4
20
24
SS
1028313.4
538922.4
1567235.8
MS
F
9.54**
257078.3
26946.1
= 216.6
= 295.4
Appendix Table 49.
Analysis of variance for dry weights from
Appendix Table 51.
Source of Var.
df
Treatments
Error
Total
LSD
LSD
.05
.01
= 66.8
= 91.0
4
20
24
SS
169740.00
51211.84
220951.84
MS
42435.0
2560.6
F
16.57**
117
Appendix Table 50.
Dry weights (g) of root growth of ryegrass
in nutrient solution experiments.
Treatment
Dry Wt. (g)
30 ppm HOE 23408
Foliage only
R4
R5
.0458
.1114
.0760
.0886
.0596
x
.0763
R1
R2
R3
50 ppm HOE 23408
Solution only
R1
R2
R3
R4
R5
.0397
.0337
.0238
.0248
.0279
.0300
300 ppm HOE 23408
Foliage only
R1
R2
R3
R4
R5
.0534
.0498
.0470
.0631
.0967
.0620
500 ppm HOE 23408
Solution only
R1
.0251
R2
R3
R4
R5
.0204
.0289
.0188
.1369
X
.0260
Control
R1
.0782
R2
R3
R4
R5
.0541
x
.0664
.0838
.0549
.0610
118
Appendix Table 51.
Dry weights (g) of wheat root growth in
nutrient solution experiments.
Treatment
Dr
Wt.
50 ppm HOE 23408
Solution only
R2
R3
R4
R5
.0114
.0148
.0105
.0128
.0083
X
.0116
R1
500 ppm HOE 23408
Solution only
R1
.0171
R2
R3
R4
R5
.0112
.0188
.0126
.0245
X
.0168
500 ppm HOE 23408
Foliage only
R1
.0302
R2
R3
R4
R5
.0251
X
.0306
.0380
.0375
.0221
5000 ppm HOE 23408
Foliage only
R4
R5
.0225
.0136
.0195
.0187
.0185
x
.0186
R1
R2
R3
Control
R4
R5
.0324
.0419
.0325
.0314
.0264
X
.0329
R1
R2
R3