Australian Contribution to A National
Agricultural Research System in PNG
(ACNARS)
SOIL AND PLANT SAMPLE COLLECTION, PREPARATION AND
INTERPRETATION OF CHEMICAL ANALYSIS
A TRAINING MANUAL AND GUIDE
Prepared by Dr K. Thiagalingam
November 2000
for AusAID
Prepared by
AACM International
Project Managers and Consultants
Adelaide Australia
TABLE OF CONTENTS
1.0 Introduction
1
2.0 Soil Analysis : Guidelines for Interpretation
2.1 Soil pH
2.2 Electrical Conductivity
2.3 Soil Organic Carbon and Nitrogen
2.4 Available phosphorous
2.5 Cation Exchange Capacity and Exchangeable Cations
2.6 Sulphur
2.7 Micronutrients
2.8 Conclusion
1
2
3
4
5
5
7
8
9
3.0 Plant Analysis: Guidelines for Interpretation
9
3.1 Introduction
3.2 Functions of nutrients in crops and pastures
3.3 Key to deficiency symptoms
4.0 Critical Levels to Interpret Plant Analysis
for Some Important Crops of Papua New Guinea.
4.1 Banana
4.2 Broccoli
4.3 Cabbage
4.4 Cashew
4.5 Cassava
4.6 Coconut
4.7 Cocoa
4.8 Coffee
4.9 Guava
4.10 Maize
4.11 Mango
4.12 Oil Palm
4.13 Peanuts
4.14 Potato
4.15 Rubber
4.16 Sweet Potato
4.17 Tea
4.18 Winged Bean
i
9
11
13
15
17
17
18
18
19
19
20
20
21
21
22
22
23
23
24
24
25
25
5.0 Foliar Analysis Results from the National Agricultural Chemistry Laboratory
26
NARI, for Selected Crops in Papua New Guinea
5.1 Aibika
26
5.2 Cassava
27
5.3 Cardamom
27
5.4 Cocoa
28
5.5 Coffee
28
5.6 Guava
29
5.7 Mango
29
5.8 Pepper
30
5.9 Peanuts
30
5.10 Sweet potato
31
5.11 Tea
31
5.12 Taro
32
5.13 Yam
32
6.0 References
33
7.0 Acknowledgements
33
8.0 Appendix
34
8.1 Guide for soil sample collection and preparation
34
8.2 Soil sample collection information form
39
8.3 Guide for plant sample collection and preparation
40
8.4 Plant sample collection information form
45
ii
1.0
INTRODUCTION
This handbook is prepared to assist soil chemists, agronomists, plantation managers,
extension officers, soil scientists, NARI cadets and other clients to collect and prepare
soil and plant samples and to interpret the soil and plant analyses produced by the
National Agricultural Chemistry Laboratory (NARI). It is a guide to interpreting soil and
plant analyses for some of the important crops in PNG, for fertilizer formulation and
other remedial action. It is essential to take into account other information such as
climate, crop species, soil condition, and soil type, past fertilizer history or previous crop
grown before suggesting any recommendations.
Crop production is a function of genetic, environmental and management factors.
Researchers have identified that 16 nutrient elements are necessary for plants to grow and
produce to full potential. These elements are derived from air and water (carbon,
hydrogen and oxygen) and soil or fertilizers (nitrogen, phosphorous, potassium, calcium,
magnesium, sulphur, manganese, iron, boron, zinc, copper, molybdenum and chlorine).
Some of these elements are needed in large quantities and are called macronutrients,
while others are needed in very small quantities and are called micronutrients.
In crop nutrition it is important that we understand the inter-relationships of the different
nutrients. The following inter-relationships or balances are possible:
 A high quantity of phosphorous in the soil or plant may result in a deficiency of
zinc.
 A high amount of potassium may result in a deficiency of magnesium or high
amount of magnesium may result in a deficiency of potassium.
 When we add more nitrogen we create the need for more potassium because the
yield is greater and the plants will need more potassium.
Plants, like animals and humans, need all the essential nutrients, water, light and energy
to synthesize food. If any of the 16 essential nutrients are not available or low in the soil,
the plant functions will be upset and characteristic symptoms will develop.
An experienced farmer or researcher will use certain rules to identify symptoms and
diagnose and correct the deficiency. However, it is important to be careful with visual
symptoms because a number of other factors like moisture stress, high salinity, herbicide
damage, pests and diseases can cause symptoms similar to actual deficiency symptoms.
Sometimes plants deficient in a particular nutrient may not exhibit any deficiency
symptoms but will not produce to maximum capacity. Therefore, it is essential to analyse
soil and plant samples to confirm symptoms identified visually.
2.0. SOIL ANALYSIS: Guidelines for interpretation
Soils provide thirteen of the sixteen essential elements necessary for crop production.
Soil testing will provide information on the level of total or available nutrients and it is
1
possible to formulate suitable fertilizer recommendations to correct any nutrient
deficiencies or amendments to rectify any toxicity problems.
Soil tests are very useful for determining whether soils are acidic or alkaline and should
reveal any toxicities such as excessive iron, manganese and aluminium that are harmful
to many crops and pastures. Such tests will also reveal excessive salinity due to high
sodium in low rainfall areas or irrigated soils with imperfect drainage. It is important to
analyse the soils annually to determine the nutrient supplying power of the soil in order to
improve the soil under a consistent management system.
The most important aspects of soil analysis are the sample collection and
preparation. A detailed method for collection and preparation is presented in
Appendix 8. 1.
2.1
Soil pH
Soil pH or soil reaction is a very important measurement which provides an estimate of
acidity or alkalinity. The National Soil Chemistry Laboratory (NARI), for routine
determination of soil pH, uses air dry soil in a 1:5 soil: distilled water suspension. When
the pH is measured in an electrolyte solution (Calcium chloride) using similar ratios the
pH will be higher than when measured in distilled water.
The pH of most soils fall within the range of 4.5 to 8.5 with values of 5.5 to 7.0 preferred
by most crops and pastures. Below pH 5.5, acid tolerant plants (coffee, tea and sweet
potato) will grow but as the pH decreases from 5.5 to 4.5 excessive aluminium, iron and
manganese will usually be present and will be toxic to legumes, cereals and other crops.
If the pH values are in excess of 8.5 to 9.0, this will indicate high levels of exchangeble
sodium and poor soil physical conditions. The ratings of pH are presented in Table 1.
Table 1: Ratings of soil pH (in distilled water)
Description
pH
Extremely acid
Strongly acid
Moderately acid
Slightly acid
Neutral
Slightly alkaline
Moderately alkaline
Strongly alkaline
Very strongly alkaline
< 4.5
4.6-5.5
5.6-6.0
6.1-6.5
6.6-7.2
7.3-7.8
7.9-8.4
8.5-9.0
> 9.0
Rating
Very Low
Low
Medium
Medium
High
High
Very high
Very high
Very high
The pH of the soil can change under different climatic and soil management practices
over a period of 10 to 20 years. A good example is that when single super-phosphate is
2
applied continuously to legume pastures it will result in a lowering of the soil pH. The
following factors will decrease soil pH:
1.
2.
3.
4.
5.
Continuous leaching of soils in high rainfall areas.
Addition of sulphur containing nitrogen fertilizers (e.g. ammonium sulphate).
Minimum tillage and the practice of green manuring
Drainage of acid sulphate soils.
Removal of calcium by plant growth.
Soil pH significantly influences the availability of plant nutrients. At pH below 5.5, the
solubility of aluminium, manganese, iron, zinc, copper and boron will increase causing
toxicity to plants and micro-organisms. If the soil pH is high (> than 8.5) trace elements
zinc, boron manganese and iron will be low. Some soil types can affect the pH
measurements e.g. in calcareous soils, as the time of contact between the soil and extracting
solution increases, the pH can increase due to dissolution of calcium carbonate.
2.2
Electrical Conductivity
Soil salinity is the measure of the concentration of soluble salts present in the soil. The
electrical conductivity that is obtained when a soil is suspended in water (soil: water ratio
of 1: 5) results from the dissolution of soluble salts. Sodium and chloride anions usually
cause most of the salinity problems, but sometimes soluble anions like sulphate, nitrate,
bicarbonate and borate will contribute to salinity. In coastal areas salinity is associated with
presence of magnesium. In semi-arid and arid areas, gypsum (calcium sulphate) may be the
major contributor to soil soluble salts.
Saline soils contain high accumulations of soluble salts that will adversely affect plant
growth. However, these soils contain low amounts of exchangeable sodium and the soil
remains flocculated. As the level of exchangeable sodium increases, the soils tend to
become dispersed and the pH will be greater than 8.5. The following ratings are used for
assessing soil conductivity (soil: water ratio of 1:5).
Table 2: Electrical conductivity ratings (mS*/cm)
Rating
1:5 soil : water ratio
Very low
Low
Medium
High
Very high
< 0.15
0.15-0.4
0.4- 0.8
0.8-2.0
>2.0
* mS=millisiemens
3
2.3
Soil organic matter (Carbon and Nitrogen)
Organic matter is the key to sustainable agricultural production and it contributes
significantly to the Cation Exchange Capacity of soils. It is also a storehouse for carbon,
nitrogen, phosphorous and sulphur which are released by mineralisation. It plays a key
role in aggregating soil particles and builds up soil structure. This assists in soil aeration,
water movement and the water holding capacity of the soil.
The ratings of carbon and nitrogen provide an indication of the total organic matter in the
soil and the ratio between carbon and nitrogen indicates the state of decomposition. When
the organic matter is well decomposed and stable it has a C/N ratio of about 10-12. When
the C/N ratios are more than 20 this is an indication of freshly added organic matter or
that decomposition may have been retarded by water logging or low available nitrogen.
The organic matter of mineral soils usually varies between 1 and 10% depending on
climate and drainage conditions. Average organic matter contains 58 % C, 5 % N, 0.5 %
P and 0.5 % S. Organic carbon is the main component of organic matter and is reported
as % C. Soil organic carbon values of less than 1.0 % will indicate problems of low
nutrient holding capacity. The carbon, nitrogen and sulphur ratio of the organic fraction
of the soil is 125: 10: 1.2
Soil organic matter is indirectly measured by determining soil organic carbon. A
conversion factor of 1.72 is used.
Soil organic matter % = Soil organic carbon x 1.72.
The National Agricultural Chemistry Laboratory (NARI) measures nitrogen as total
nitrogen and this is expressed as % N. Most of the total nitrogen within the organic matter
fraction is not immediately available to plants. The conversion of organic nitrogen into
available nitrogen (ammonium and nitrate nitrogen) depends on the rate of mineralisation
and is highly correlated with soil pH, moisture, temperature and the presence of nitrifying
organisms. A guide to the ratings for carbon and nitrogen is presented in Table 3.
Table 3: Ratings for Carbon and Nitrogen
Rating
Carbon %
Total nitrogen %
Nitrate-N (ppm)
Very High
High
Medium
Low
Very Low
> 50
25-50
15-25
5-15
<5
> 20
10-20
4-10
2-4
< 2
>1.0
0.6-1.0
0.3-0.6
0.1-0.3
< 0.1
4
2.4
Available phosphorous
The National Agricultural Chemistry Laboratory (NARI) analyses several forms of
phosphorous: Total P measured in profile samples; acid extractable and bicarbonate
(Olsen’s P) extractable P. The Olsen’s-P has given good correlation with plant uptake and
is widely used in many countries. A small proportion of the total P in soil is immediately
available to plants.
The main part of the phosphorous is present in permanently unavailable form or
potentially available form (Organic P; Primary P minerals like rock phosphate).
Phosphorous is made unavailable through fixation by clay mineral allophane, which is
found in volcanic ash soils in wetter climates. The fixation of added phosphorous is pH
dependent, as acid soils with high iron and aluminium will complex the P and make it
unavailable. Acid soils will have the largest fixation and the lowest availability of added
phosphorous.
Table 4: Ratings for available phosphorous
Rating
Olsen-P (mg/kg)
Very high
High
Medium
Low
Very low
> 50
30-50
20-30
10-20
< 10
N.B. mg/kg = ppm
For most crops the adequacy level for phosphorous is in the 20-30 ppm range (Olsen-P).
Soils with low levels are likely to give response to P application and this will depend on
the soil type, organic matter content, type of crop and method of application. One
example is that legumes need more phosphorous than grasses. Soils with high levels of
available phosphorous are not likely to show plant growth responses to added
phosphorous. Soils with low to very low levels are likely to give responses.
2.5
Cation Exchange Capacity and Exchangeable Cations
Cation Exchange capacity (CEC) is a measure of the total number of sites available in a
soil for the exchange of cations. The majority of soil nutrients (cations Ca, Mg, K and
Na) are held on negatively charged surfaces of the clay and organic particles. It is a
measure of the general fertility of the soil and is widely used for agricultural assessment.
The actual values obtained for CEC have a limited use in interpreting soil properties.
However, CEC can be used to cross check other properties in which high CEC is
associated with high pH, at least up to 8.5, and low CEC is associated with low levels of
total P and K.
5
Calcium is usually the most abundant and dominant cation, followed by magnesium, and
largely controls the base saturation and pH. Deficiency of Ca as a nutrient is very rare and
occurs only in the very low range. An excess of one cation may inhibit the uptake of
another, for example when calcium is dominant in calcareous soils, this may cause
magnesium deficiency or vice versa. The desired ratings for CEC and the cations are
presented in Table 5.
Table 5: Ratings for Cation Exchange Capacity and Exchangeable Cations
Rating
CEC (me/100g)
Very high
High
Medium
Low
Very low
> 40
25-40
15-25
10-15
<10
Base Saturation
%
80-100
60-80
30-60
20-30
< 20
Ca
Exchangeable
Mg
K
Na
me/ 100g
>20
10-20
2-10
1-2
<1
>7
>1.2
3-7
0.6-1.2
1-3
0.3-0.6
0.5-1 0.1-0.3
< 0.5 < 0.1
>2
0.7-2
0.3-0.7
0.1-0.3
< 0.1
Plants usually contain more potassium than any other nutrient except N. Crops utilise
from 50 to over 200kg of potassium per hectare, depending on the crop type and yield.
In general field crops, will respond to K application (Walsh and Beaton, 1973) if the
exchangeable K is:
 Less than 85 ppm or 0.20 m.e. / 100g for sands and loamy sands.
 Less than 100ppm or 0.20-0.30 m.e / 100g for sandy loams or loams
 Less than 125 ppm or 0.30-0.40 m.e / 100g for silt loams or clays
Exchangeable calcium in the soil can range from 250- 5000ppm. Calcium deficiency has
been produced in a number of crops where excessive levels of K or Na salts have been
applied. Ideal soil CEC is generally saturated with 65 % Ca, 10% Mg and 5% K (13: 2:1)
If the exchangeable magnesium constitutes less than 6% of the CEC, crops are likely to
respond to magnesium application. If the magnesium exceeds 50% saturation, plant
growth will be reduced. When the exchangeable magnesium levels are:
 0-25 ppm Mg: Deficiency symptoms are generally present in most of field
crops, vegetables and fruit crops. Application of magnesium is advised.

25- 50 ppm Mg: Application of magnesium is advised for fruit crops. Cereal
crops will not respond to magnesium application
 50-100ppm Mg: Absolute deficiency is not likely in field and vegetable crops.
If symptoms occur they are likely to be induced by other factors such as a wide
6
K: Mg ratio. The K: Mg ratio on an equivalent basis should be less than 1.5 for
field crops, 1.0 for vegetables and 0.6 for fruits.
Exchangeable Na levels are useful for indicating possible salt effects in soil in coastal
areas or those with salinity problem. If the percentage of sodium in the CEC exceeds 1215%, dispersion of clay and breakdown of soil structure will occur.
2.6
Sulphur
Most of the sulphur in soils is present as part of the soil organic matter. It is not available
to plants in the organic form but will be converted into available sulphate ions through
bacterial action. When the soil is moist, warm and well aerated the release of sulphur is
increased resulting in variation during the growing season.
In general, crops require the same amount of S as P. Cereals generally remove 15kg S /
ha, forage crops 15-35 kg S /ha and crops belonging to the crucifer family, especially the
brassicas (cabbage, broccoli), require high S, 22-45 kg S /ha. Legumes generally require a
high level of available sulphur. Ratings for phosphate extractable sulphur are presented in
Table 6.
Table 6: Ratings for phosphate extractable sulphur
Rating
Sulphate (mg/kg)
Very high
High
Medium
Low
Very low
> 150
50-150
15- 50
5-15
< 5
It is important to consider the following when interpreting data for sulphur. When the pH
is low microbial activity will be low and will slow down the release of sulphur. Soils with
high P fixation capacity and low pH will have increased sulphate adsorption. Soils high in
surface organic matter will have high total sulphur. When the soil is waterlogged,
sulphate may be reduced to sulphide or transformed into hydrogen sulphide gas.
Application of elemental S or gypsum will reduce soil pH and will possibly induce Mo
deficiency. Crops generally have an N: S ratio of 17:1. If the ratio exceeds 17:1 it will
result in the depletion of available S and possible S deficiency. Typically soils will have a
N: S ratio of 8:1.
7
2.7
Micronutrients
Micronutrients are found in low concentrations in the soil. The National Agricultural
Chemistry Laboratory (NARI) uses the DTPA method to determine Zinc, Copper,
Manganese and Iron and the hot water extraction method for Boron. A general guide to
critical levels is presented in Table 7.
Table: 7 A general guide to micronutrient critical levels
Rating
B
Zn
Fe
Cu
Mn
High
Medium
Low
V. low
2-5
1-2
0.5-1
<0.5
5-15
0.8-5
0.3-0.8
<0.3
> 4.5
2.5-4.5
<2.5
5-15
0.3-5
0.1-0.3
<0.1
50-500
2-50
1-2
<1.0
Boron availability decreases with increase in pH and high Ca levels. Low Ca, high pH
and high K levels accentuate toxicity. Boron leaches very rapidly through acid sandy
loams. Boron deficiency is likely to occur in highly leached soils, calcareous soils and
organic soils. In PNG, B is generally deficient in volcanic ash derived soils of low pH in
the highlands.
Zinc deficiency is common in high pH soils and high levels P application will induce Zn
deficiency. Zinc deficiencies in crops are not common in acid soils. Increase in humus
content increases Zn availability.
Iron interacts with excesses of other micronutrients (Zn, Cu, Mo and Mn) and iron
chlorosis may develop in plants. Iron deficiency is also common in calcareous and high
pH soils and foliar application will reduce the deficiency.
Increasing humus and pH can decrease copper availability. Toxicity is less likely to occur
in soils with high buffering capacity.
Soils with low pH may contain high levels of manganese and this can be aggravated by
poor aeration and water logging and in compacted and hot dry soils (Bruce, 1988).
Increasing pH reduces Mn availability. Deficiencies of Mn are very rare at pH < 5.5, but
if these soils have high natural manganese, manganese toxicity may develop. Sometimes
overliming can create Mn and other micronutrient deficiencies. Manganese toxicity may
be induced by the application of acidifying nitrogen fertilizers (ammonium sulphate).
Molybdenum availability is pH dependent. Deficiency occurs in acid soils, soils high in
free iron, acidic organic soils and soils derived from sandstone. Molybdenum is important
for nitrogen fixation and nodules from Mo deficient legumes are white or green in colour
8
compared with the red or pink colour in non-deficient plants. Vegetable crops belonging
to the cucurbit and brassica groups are sensitive to Mo deficiency.
2.8
Conclusion
Interpretation of a soil test is not simple because many factors other than the available
nutrient in the sample at the sampling date affect the availability of the soil and fertilizer
nutrients to plants. Some of the factors that affect soil test interpretation are:
 Soil sample collection and preparation techniques.
 Climate, disease, weeds, and management that determine plant yield and nutrient
demand.
 Soil chemical properties that change with time and depth of soil (mineralisation,
fixation, leaching).
The simplest method to interpret your soil sample is to use the accepted critical values
and take into account other factors affecting growth.
3.0
PLANT ANALYSIS: Guidelines for interpretation
3.1
Introduction
Crop and pasture production are functions of environmental, genetic and management
factors. Quality and yield determine the economic value of the crop. These are in turn
controlled by the genetic potential of the crop, environmental factors and management.
The mineral nutrition of the plant plays a major role in determining the yield and quality
of the crop. Plant nutrients other than C, H and O are described as mineral nutrients. The
elemental composition of plant dry matter is:
Carbon- 40-50%
Oxygen- 42-44%
Hydrogen-6-7%
Mineral elements - < 10%
The chemical substances required by crops are known as nutrients and their supply and
absorption for growth and metabolism is defined as nutrition. Researchers have identified
that 16 elements are essential for plant growth and development. Three of the elements
(carbon, hydrogen and oxygen) are derived from air and water and thirteen of them
(nitrogen, phosphorous, potassium, calcium, magnesium, sulphur, iron, manganese,
boron, zinc, copper, molybdenum and chlorine) are derived from soils and fertilizers.
The mineral nutrition of the plant plays a major role in determining the yield and quality
of crops. If any of the 16 essential elements are not available or are low in the soil the
plant function will be upset and characteristic symptoms will develop. Farmers and
9
scientists for generations have used visual deficiency symptoms to identify nutrient
deficiencies. We have to be careful with visual deficiency symptoms because a number of
factors other than low nutrients can cause similar symptoms to nutrients. e. g. moisture
stress, high salinity, herbicide damage or disease caused by bacteria, fungus or viruses
Plant analysis, along with soil analysis and other supporting data is used as a valuable
tool for managing the nutrition of crops and pastures. The main purpose of plant analysis
is to:
 Provide information on the nutrient status of plants as a guide to nutrient






management for optimal plant production.
Diagnose existing nutrient problems and problems likely to affect crop or pasture
production.
Monitor crop nutrient status for optimal crop production.
Identify and monitor environmental problems associated with over fertilization of
crops and pastures.
Assess the quality of plant products.
Estimate overall nutrient status of regions, districts or soil types.
Assess nutrient levels in stock feed and food for human consumption.
Researchers, extension officers and others use the relationship between nutrient
concentration and yield of plants or plant parts to assess plant nutrient status. The
standard concentrations used for diagnosing nutrient deficiency or toxicity are based upon
the concept of “ Critical nutrient concentration” that forms the basis of most methods
of plant analysis to assess plant nutrient status. In real situations it is not a single value
but it is a narrow range of concentrations above which the plant is adequately supplied
with nutrients or below which it is deficient.
These values are generally obtained from properly designed sand culture, water culture,
green-house or field experiments using increasing levels of nutrients in a deficient
growing medium. An appropriate yield (generally 90% of maximum yield) is selected
and the nutrient concentration in the selected plant part at this yield is accepted as the
critical nutrient concentration (For details refer: Reuter and Robinson, 1997). Critical
concentrations for specific nutrient deficiencies or toxicities are derived through
experiments as constant values. However, in practice, they vary widely due to a number
of environmental and other factors. All these factors should be taken into consideration
when interpreting any plant analysis data. Some of the factors are:
 Plant age and part of plant sampled: As the plant grows changes in nutrient
concentration take place in the plant tissues. In perennials, the concentration of
nutrients in leaves and other organs fluctuates with seasonal flushes of shoot
growth and fruit development. It also varies between leaves of vegetative and
fruiting shoots. Therefore it is necessary to define growth stages at sampling to
assist interpretation. As critical concentrations vary with age of plant parts it is
10
essential that parts of the same physiological age are used, irrespective of degree
of deficiency. Generally the youngest fully expanded leaf is used.
 Critical nutrient concentrations are found to be diverse among different
genotypes. However, when values are derived from similar tissues and plants of
similar physiological age this diversity is reduced. (e. g. sulphur requirements of
graminaceous crops are less than those for leguminous crops).
 Critical nutrient concentrations for diagnosis of nutrient deficiencies vary as a
result of interactions with light, temperature, carbon dioxide concentration,
diseases, soil and other nutrients. Critical concentrations for toxicities also vary
with environmental factors. In a number of species sodium can substitute for
potassium. Therefore the level of sodium in the soil can affect the critical
concentration of potassium.
Detailed information on plant sample collection and preparation is presented in
Appendix 8.3.
3.2
Functions of nutrients in crops and pastures:
All the essential nutrients are directly involved in the nutrition of the plant. Some are
required in larger quantities and are known as macronutrients whereas others are required
in small quantities and are called micronutrients or trace elements. The functions of the
nutrient elements are listed below:
Nitrogen:
The nitrogen content of plant dry matter generally ranges from 1 to 5 %. However
occasionally it may be either lower or higher than this range. Plants need a wide range of
proteins to grow, develop and mature. The main body of protein is amino acids and
nitrogen is the major component of amino acids. Nitrogen is also present in chlorophyll
(the green pigment which traps sunlight). Soil micro-organisms feed on soil nitrogen
during break down of organic materials. Nitrogen improves quality of leafy vegetables. It
promotes rapid growth and if the supply is out of balance with other nutrients flowering
and fruiting may be delayed.
Phosphorous:
The phosphorous content in plants is usually between 0.1 and 0.5 % of the dry matter.
Phosphorous simulates early root formation and growth, gives a rapid and vigorous start
to plants and stimulates flower and seed production. Phosphorous is needed in the genetic
coding material which controls cell division.
11
Potassium:
The potassium content in plants is usually between 1-5 % of the dry matter. Potassium is
essential for efficient water relationships in the plant, both for controlling water content
in cells and movement of water through tissues, and in the control of the stomatal cells.
Potassium aids in providing mechanical strength to plants and assists in the resistance to
diseases. Potassium is also associated with the formation and translocation of
carbohydrates. It improves the quality of fruits and helps in the development of tubers.
Calcium:
The calcium content of plants is less than 1%. It promotes early root hair formation and
growth. Calcium helps to maintain strong cell walls in plants. It also neutralises poisons
produced in the plant. It encourages grain and seed production. Plants which contain high
potassium, especially grasses, will contain less calcium
Magnesium:
The magnesium content in plant dry matter is similar to that of P (0.1-0.5%). It is the
essential component of chlorophyll and acts as a carrier of P in plants. It is necessary for
the formation of sugars and promotes the formation of oils and fats.
Sulphur:
Sulphur is an essential component of many proteins. It promotes nodule formation in
legumes and stimulates seed formation. Sulphur plays a key role in chlorophyll
formation.
Boron:
The content of boron in plant dry matter ranges between 10 and 100-200 ppm. Boron
helps in the manufacture of sugars and carbohydrates in crops. Boron is essential for fruit
development, translocation of sugars and the development of seed and seed quality in
some crops like mungbeans. Boron aids in the utilisation of calcium, nitrogen and
phosphorous. Boron is also important in the development of young roots and shoots.
Zinc:
Plants contain 20- 100 ppm of Zinc in the dry matter. Zinc is an essential component of
many enzymes, including some plant growth hormones. Zinc is also essential for
chlorophyll formation. It plays a role in protein synthesis, seed maturity and plant height
development.
12
Copper:
The copper content in plants ranges from 1 to 20 ppm of the dry matter. Copper is
essential for normal seed setting in legumes and cereals. It is associated with enzymes
that convert nitrogen to protein. Copper is a constituent of the chloroplast and aids in the
stability of chlorophyll.
Manganese:
Plants contain about 20-250 ppm Mn on a dry weight basis. If the levels exceed 500 ppm
toxicity symptoms will appear. Plants with a manganese level of 15-25 ppm will exhibit
deficiency symptoms. It plays a specific role in the formation of chlorophyll. Manganese
accelerates germination and maturity.
Iron:
The iron content of healthy plant tissue ranges from 50-200 ppm of dry matter. Iron is
essential for proper functioning of chlorophyll.
Molybdenum:
The molybdenum content of plant material is usually less than 1 ppm in the dry matter.
Molybdenum is important in the process of nitrogen fixation by legumes and also in the
process where the plants use nitrogen.
Chlorine:
The chlorine content of plants ranges from 0.2 –2.0 %. It is essential for photosynthesis.
It is also involved in the uptake, movement and efficient use of water in plants.
3.3
Key to deficiency symptoms:
Nitrogen:
Plants are generally light green and growth is stunted. The symptoms will start from the
lower leaves, which will turn yellow, followed by a drying up of the leaves.
Phosphorous:
The plants will be small and stunted. In many crops the leaves will be darker green than
normal. During the early stages of the growth leaves, or stems may develop a reddishpurplish colour. Maturity is delayed and the root system restricted. Petioles, leaf margins
and leaves may take an upward direction.
13
Potassium:
Symptoms appear in the lower leaves as scorching or burning along the leaf margins.
Poorly developed root systems and weak stalks with lodging are common. Plants possess
a low resistance to diseases. In legumes, symptoms initially appear as white spots or
yellowish dots along the leaf margins while later the edges turn yellow and the leaves die.
Calcium:
The leaves may be crinkled or cup shaped, the terminal buds deteriorate and the petioles
break down. In some horticultural crops (Tomato), the blossom end will rot and the fruit
may break down.
Magnesium:
Symptoms will appear on older leaves with light yellow colour between the veins while
veins will remain green (inter-veinal chlorosis). In some crops, reddish purple colour
develops with green veins.
Sulphur:
Plants are pale green and look very much like nitrogen deficient plants. The symptoms
first appear on the upper leaves whereas nitrogen deficiency will show up on the lower
leaves. Sometimes the entire plant can take on a light yellow colour. Leaves shrivel as the
deficiency progresses and stems thin. Sulphur deficiency occurs mostly in sandy soils low
in organic matter and in areas with moderate to heavy rainfall. Generally the symptoms
appear early in the season and disappear when the plant roots penetrate the subsoil.
Zinc:
Symptoms appear on the youngest leaves and other plant parts. In maize, young buds
may turn white or yellow while the leaves show bleached bands. In legumes, brown spots
appear and there is yellowing of leaves. Fruit trees will show symptoms of little leaf.
Manganese:
Symptoms first appear in younger leaves, with yellowing between the veins and
sometimes black specks. The deficiency is sometimes confused with magnesium
deficiency. However, the symptoms for magnesium will appear in the lower and older
leaves. If the pH is above 7 it is likely to be manganese deficiency.
Iron:
Iron deficiency symptoms usually appear on younger leaves in which the vein remains
green and the deficiency appears in between the veins. In case of severe deficiency, the
entire plant will turn yellow.
14
Copper:
In cereals, deficiency symptoms start as yellowing of tips of the youngest leaves to
spiralling leaves, giving a stunted, bushy appearance to plants. Ears will have difficulty in
emerging, have white tips and be devoid of grain. Dieback in citrus can occur.
Boron:
Boron deficiency is characterised by the death of the apical growing point of the main
stem and failure of lateral buds to develop shoots. Leaves may become thickened and
sometimes they curl. See hollow hearts in peanuts.
Molybdenum: Molybdenum is important in nitrogen fixation in legumes and a
deficiency of molybdenum will show symptoms similar to nitrogen deficiency. The
internal colour of the nodules will be pale. General yellowing and stunting of plants may
occur. Molybdenum deficiency is common in acid soils where molybdenum precipitates
with iron.
Chlorine:
Chlorine deficiency symptoms are rarely observed in crops, apart from coconuts.
However, under severe conditions, the following symptoms are observed:
1. Wilting of the entire plant.
2. Chlorosis (yellowing), bronzing and eventual necrosis (death of tissue) of leaf tips
and margins.
4.0
Critical Levels to Interpret Plant Analysis for Some Important Crops of
Papua New Guinea.
There is very little information available in Papua New Guinea on critical levels for
various crops grown. Therefore most of the information compiled is from overseas work
presented in Reuter and Robinson (1997) and other stated sources. This information is
used only as a guide to establish levels which are deficient, adequate or toxic to crops.
The nutrients are classified with the following definitions by Reuter and Robinson, 1997.
Deficient: This is the range of concentrations in the specified plant part which is
associated with visible deficiency symptoms on the plant and severely reduces plant
growth and production. When values are found within or below the deficient range it is
expected the plants will respond to fertilizer application.
Critical value for deficiency: Critical values for deficiency are defined experimentally
and plant nutrient status should be kept above the critical value. The critical concentration
for a specified plant part is that concentration of the single nutrient at which growth or
production is found experimentally to be affected. Generally the nutrient concentration at
90 or 95 % maximum yield is chosen.
15
Adequate: The concentrations within this range in the specified plant part will not result
in any increase or decrease in growth or production. This classification is also known as
normal or sufficient. This is generally defined experimentally or derived from field
observations.
Critical level for toxicity: The critical values for toxicity are defined experimentally.
The plant nutrient status should be kept below the critical value.
16
4.1: Banana (Musa spp)
Plant part: 3rd youngest leaf: 15-20 cm wide leaf blade strips from each side of the
midrib.
Growth stage: Medium size suckers with broad leaves during periods of active growth
Nutrient
Unit
Nitrogen
Phosphorous
Potassium
Calcium
Magnesium
Sulphur
Chloride
Zinc
Boron
Iron
Copper
Manganese
Molybdenum
%
%
%
%
%
%
%
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
Deficient
<2.6
<0.13
<2.5
<0.5
<0.20
<0.1
< 14
< 10
Critical
Value
2.6
0.2
3.0
0.5
0.3
0.23
0. 6
18
11
80
9
<10
1.5-3.2
Adequate
Range
2.8-4.0
0.2-0.25
3.1-4.0
0.8-1.2
0.3-0.46
0.23-0.27
0.8-0.9
21-35
20-80
70-200
7-20
1000-2200
> 3.2
Toxic
> 300
Source: Reuter and Robinson, 1997
Incitec, 1989
4. 2: Broccoli (Brassica oleracea var.italica)
Plant part: Wrapper leaf (WL)
Growth stage: Head
Nutrient
Unit
Deficient
Critical
Value
Nitrogen
%
Phosphorous %
Potassium
%
Calcium
%
Magnesium %
Zinc
mg/kg
Boron
mg/kg
< 20
Manganese mg/kg
Copper
mg/kg
Molybdenum mg/kg
< 0.1
Source: Reuter and Robinson, 1997
17
Adequate
Range
3.2-5.5
0.3-0.7
2.0-4.0
1.2-2.5
0.23-0.4
45-95
30-200
25-150
1.0-5.0
0.3-0.5
Toxic
4.3: Cabbage (Brassica oleracea L. var. capitata)
Plant part: Wrapper leaf (WL)
Growth stage: Head
Nutrient
Unit
Deficient
Critical
Value
Nitrogen
%
2.5
Phosphorous
%
0.2
Potassium
%
2.0
Calcium
%
1.0
Magnesium
%
0.15
Zinc
mg/kg
15
Boron
mg/kg
20
Iron
mg/kg
50
Copper
mg/kg
5
Molybdenum
mg/kg
0.2
Source: Reuter and Robinson, 1997
Adequate
Range
3.0-4.6
0.25-0.50
3.0-4.0
1.5-3.0
0.20-0.60
20-200
20-60
60-200
5.2
0.3-0.5
Toxic
4. 4: Cashew (Anacardium occidentale L.)
Plant part: Most recently matured hardened leaf on an actively growing shoot.
Growth stage: During the non-flowering vegetative flush
Nutrient
Unit
Deficient
Critical
Adequate
Toxic
Value
Range
Nitrogen
%
<1.38
2.40-2.58
Phosphorous
%
< 0.14
0.16-0.20
Potassium
%
< 0.26
1.10-1.29
Calcium
%
< 0.11
0.24-0.75
Magnesium
%
< 0.11
0.22-0.31
Sulphur
%
< 0.08
0.11-0.14
Zinc
mg/kg
< 12
> 20
Boron
mg/kg
< 39
56-67
Iron
mg/kg
< 92
148-165
Manganese
mg/kg
< 26
91-204
Copper
mg/kg
< 7
>7
Source: Reuter and Robinson, 1997
18
4. 5: Cassava (Manihot esculenta)
Plant part: Youngest mature leaf blade
Stage of growth: 3-4 months
Nutrient
Unit
Nitrogen
%
Phosphorous
%
Potassium
%
Calcium
%
Magnesium
%
Sulphur
%
Zinc
mg/kg
Boron
mg/kg
Iron
mg/kg
Manganese
mg/kg
Copper
mg/kg
Deficient
< 4.7
< 0.30
< 1.0
< 0.65
< 0.27
< 0.24
< 25
< 20
< 100
< 45
<5
Critical
Value
5.1
0.36
1.3
0.75
0.29
0.26
30
30
120
50
6
Adequate
Range
5.1-5.8
0.36-0.50
1.3-2.0
0.75-0.85
0.29-0.31
0.26-0.30
30-60
30-60
120-140
50-120
6-10
Toxic
>120
>100
>200
>250
> 15
Source: Reuter and Robinson, 1997
4. 6: Coconut (Cocos nucifera)
Plant part: Leaflets from the mid-region of the 14th leaf below the first fully opened leaf
Growth stage: Northern hemisphere-May, Southern hemisphere-November
Nutrient
Unit
Deficient
Nitrogen
%
1.4
Phosphorous %
0.1
Potassium
%
0.6
Calcium
%
0.2
Magnesium
%
< 0.17
Chloride
%
Zinc
mg/kg
Boron
mg/kg
Iron
mg/kg
20
Manganese
mg/kg
20
Copper
mg/kg
Source: Reuter and Robinson, 1997
Incitec, 1989
Critical
Value
1.4-1.7
0.1-0.12
0.6-0.9
0.2-0.4
0.24
<10
<10
20-40
20-30
2.5
19
Adequate
Range
1.8-2.0
>0.13
1.2-1.5
>0.4
0.25-0.30
0.30-0.40
>10
> 10
>40
>30
> 2.5
Toxic
4.7: Cocoa (Theobroma cacao)
Plant part: 3rd leaf from recent hardened flush
Growth stage: leaf
Nutrient
Unit
Deficient
Nitrogen
Phosphorous
Potassium
Calcium
Magnesium
Sulphur
Zinc
Boron
Iron
Manganese
Copper
%
%
%
%
%
%
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
< 2.0
<0.12
<1.1
<0.5
<0.3
<0.02
<20
<15
<30
<15
<4
Critical
Value
2.0 - 2.3
0.12 - 0.16
1.1 - 1.6
0.5 - 0.8
0.3 - 0.4
0.02 - 0.03
20 - 30
15-25
30-50
15-30
4-6
Adequate
Toxic
2.3-3.0
0.16-0.30
1.6-2.6
0.8-2.0
0.4-1.0
0.03-0.1
> 30
> 25
> 50
> 30
> 6
Source: Fahmy F.N., Department of Primary Industry, Papua New Guinea
International soil Conference, Kuala Lumpur, Malaysia, 1977.
4.8: Coffee (Coffea arabica)
Plant part: 3rd or 4th pair of leaves from the tip of actively growing and bearing branches
(Do not count the terminal pair of leaves less than 50mm long)
Growth stage: In PNG sampling is recommended in February-April or SeptemberOctober: Collect sample before 11am.
Nutrient
Unit
Nitrogen
%
Phosphorous
%
Potassium
%
Calcium
%
Magnesium
%
Sulphur
%
Zinc
mg/kg
Boron
mg/kg
Iron
mg/kg
Manganese
mg/kg
Copper
mg/kg
Aluminium
mg/kg
Molybdenum
mg/kg
Source: Willson, 1985
Deficient
Subnormal
Normal
Excess
< 2.00
< 0.10
<1.50
< 0.40
< 0.10
< 0.10
< 10
< 25
<40
<25
<3
2.00-2.60
0.10-0.15
1.50-2.10
0.40-0.75
0.10-0.25
0.10-0.15
10-15
25-40
40-70
25-50
3-7
2.61-3.50
0.16-0.20
2.11-2.60
0.76-1.50
0.26-0.40
0.16-0.25
16-30
41-90
71-200
51-100
8-20
>3.50
>0.20
>2.60
>1.50
>0.40
>0.25
> 30
> 90
> 200
>100
> 20
> 60
<0.5
0.5-0.8
20
4.9: Guava (Psidium guajava)
Plant part: 3rd pair of fully developed leaves from tip of fruiting terminal shoot
(essentially mid shoot leaves). Wash the leaves twice in distilled water
Growth stage: Nov-Dec
Nutrient
Unit
Deficient
Critical
Value
Nitrogen
%
Phosphorous %
Potassium
%
Calcium
%
Magnesium
%
Zinc
mg/kg
Iron
mg/kg
Manganese mg/kg
Copper
mg./kg
Source: Reuter and Robinson, 1997
Adequate
1.4-1.6
0.14-0.16
1.3-1.8
0.9-1.5
0.25-0.40
28-32
144-162
202-398
10-16
4.10: Maize (Zea mays)
Plant part: Ear leaf
Growth stage: Early silking
Nutrient
Nitrogen
Phosphorous
Potassium
Calcium
Magnesium
Sulphur
Zinc
Boron
Iron
Copper
Manganese
Unit
%
%
%
%
%
%
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
Deficient
Optimum
< 2.00
< 0.15
< 1.25
< 0.10
< 0.10
< 0.10
< 10
<2
< 10
<2
< 15
2.25-3.30
0.18-0.32
1.71-2.25
0.21-0.50
0.13-0.24
0.13-0.25
21-70
6-20
20-250
6-20
20-150
Source: Daly and Wainiqolo, 1993
21
Toxic
4. 11: Mango (Mangifera indica)
Plant part: There is no one accepted sampling procedure. Leaves from non-bearing
branches.
Growth stage: Sampling immediately after flowering
Other conditions: A dilute acetic acid wash and distilled water rinse suggested
Nutrient
Unit
Nitrogen
%
Phosphorous %
Potassium
%
Calcium
%
Deficient
Low
Optimum
High
1.0-1.5
0.08-0.18
0.3-1.2
2.0-3.5 (acid soil)
3.0-5.0 (alkaline soil)
0.2-0.4
20-150
50-100
70-200
60-500
10-20
< 0.25
Magnesium %
Zinc
mg/kg
Boron
mg/kg
Iron
mg/kg
Manganese mg/kg
Copper
mg/kg
Source: Daly and Wainiqolo.1993
4. 12: Oil Palm (Elaeis guineensis)
Plant part: Frond 17, about 6 leaflets (equal number from upper and lower rank). The
central 15cm of each leaflet sub-sampled.
Growth stage: Mature
Nutrient
Unit
Nitrogen
Phosphorous
Potassium
Calcium
Magnesium
Zinc
Boron
Copper
Manganese
Molybdenum
%
%
%
%
%
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
Deficient
Critical
Value
Source : Reuter and Robinson, 1997
22
Adequate
Range
2.7-2.8
0.18-0.19
1.3
0.6
0.3-0.35
15-20
10-20
5-8
150-200
0.5-1.0
Toxic
4.13: Peanut (Arachis hypogaea)
Plant part: Youngest Mature Leaf (YML)
Growth stage: Pre-flowering to Flowering
Nutrient
Units
Nitrogen
%
Phosphorous %
Potassium
%
Calcium
%
Magnesium
%
Sulphur
%
Zinc
mg/kg
Boron
mg/kg
Iron
mg/kg
Manganese
mg/kg
Copper
mg/kg
Deficient
Critical
Value
1.3-2.5
0.13-0.15
Adequate
3.5-5.0
0.25-0.55
1.6-3.0
1.2-2.4
0.3-0.8
0.2-0.35
25-80
25-60
50-300
50-300
6-30
Toxic
>700
Source: Reuter and Robinson, 1997
4.14: Potato (Solanum tuberosum)
Plant part: Youngest mature leaf
Growth stage: Early flowering
Nutrient
Unit
Deficient
Nitrogen
Phosphorous
Potassium
Calcium
Magnesium
Sulphur
Zinc
Boron
Iron
Manganese
Copper
%
%
%
%
%
%
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
< 4.2
< 0.23
< 3.3
< 0.6
<0.22
< 0.20
< 15
< 15
Critical
Value
4.2-4.9
0.30
3.3-3.9
0.22-0.24
< 20
<3
Source: Reuter and Robinson, 1997.
23
Adequate
5.0-6.5
0.30-0.55
4.0-6.5
0.8-2.0
0.25-0.50
0.3-0.5
20-50
30-60
50-150
50-300
5-20
Toxic
>800
4.15: Species: Rubber (Hevea brasiliensis)
Plant part: Mature leaves- (low shade leaves)
Growth stage: Mature trees
Nutrient
Nitrogen
Phosphorous
Potassium
Calcium
Magnesium
Sulphur
Manganese
Boron
Zinc
Iron
Manganese
unit
%
%
%
%
%
%
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
Deficient
<3.00
< 0.17
<1.20
<0.18
0.015
<50
<20
15
60
<50
Marginal
3.00-3.30
0.17-0.19
1.21-1.36
0.6-1.00
0.18-0.20
Adequate
Toxic
3.31-3.90
0.20-0.27
1.37-1.85
0.21-0.27
51-100
101-200
51-100
101-200
>500
Source: Reuter and Robinson, 1997
National Agricultural Chemistry Laboratory, NARI, PNG
4.16 Species: Sweet potato (Ipomoea batatas)
Plant part: Youngest mature blade
Growth stage: 28 days after transplanting (DAT)
Nutrient
Unit
Nitrogen
Phosphorous
Potassium
Calcium
Magnesium
Sulphur
Zinc
Boron
Iron
Manganese
Copper
Molybdenum
%
%
%
%
%
%
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
Deficient
Critical
Deficiency
4.2
0.22
4.0
0.76
0.12
0.34
11
40
33
19
4-5
0.2
Source: Reuter and Robinson, 1997
O’Sullivan et al., 1997
24
Adequate
4.3-4.5
0.26-0.45
4.7-6.0
0.90-1.20
0.15-0.35
0.35-0.45
12-40
50-200
45-80
26-500
5-14
0.5-7
Toxic
85
220-350
1600
4.17: Species: Tea (Camellia sinensis)
Plant part: Mature leaves
Growth stage: At plucking
Nutrient
Unit
Deficient
Nitrogen
Phosphorous
Potassium
Calcium
Magnesium
Sulphur
Zinc
Boron
Iron
Manganese
Copper
%
%
%
%
%
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
< 2.6
< 0.1
< 0.8
< 0.6
< 0.2
< 200
< 3
< 8
< 60
< 50
<9
Critical
Value
3.0
0.16
1.0
0.9
0.24
300
5
12
120
100
12
Adequate
Source: Reuter and Robinson, 1997
4.18 Species: Winged Bean (Psophocarpus tetragonolobus)
Plant part: Whole shoot
Growth stage: 42 days after sowing
Nutrition
Nitrogen
Phosphorous
Potassium
Calcium
Magnesium
Zinc
Iron
Manganese
Copper
Molybdenum
Unit
%
%
%
%
%
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
Deficient
1.72-1.92
Source: Reuter and Robinson, 1997
25
Adequate
2.55-4.02
0.27-0.36
3.33-3.68
0.37-0.56
0.15-0.18
76-113
60-76
29-49
12-15
5-10
Toxic
5.0: Compilation of Foliar Analysis Results from the National Agricultural
Chemistry Laboratory, NARI, for selected crops in Papua New Guinea.
This section is included to provide some idea of the levels of nutrients present in crops
that are important to PNG. The major difficulty in compiling this information is that a
number of samples sent to the Chemistry Laboratory did not provide adequate
information such as the exact stage of growth or plant part. The reason for including this
information in this section is to provide some training material to point out the
importance of providing the correct information to the chemist when sending samples for
analysis.
5.1: Aibika (Abelmoschus manihot)
Plant part: Youngest mature blade
Growth Stage: Mature plants (1st crop 3-4 months)
Nutrient
Unit
Nitrogen
Phosphorous
Potassium
Calcium
Magnesium
Sulphur
Zinc
Boron
Iron
Copper
%
%
%
%
%
%
mg/kg
mg/kg
mg/kg
mg/kg
Range
3.82-4.95
0.25-0.40
1.47-3.19
1.74-4.23
0.86-1.21
0.12-0.40
23-75
26-35
223-417
9-150
Source: National Agricultural Chemistry Laboratory, NARI
John Sowei, National Research Institute, PNG
26
Mean
4.27
0.35
2.49
2.58
0.99
0.25
40
29
291
17
5.2: Cassava (Manihot esculanta)
Plant part: leaves
Growth stage: Not known
Nutrition
Unit
Nitrogen
Phosphorous
Potassium
Calcium
Magnesium
Zinc
Iron
Manganese
Copper
%
%
%
%
%
mg/kg
mg/kg
mg/kg
mg/kg
Concentration
Range
2.13-2.25
0.16-0.24
1.18-1.52
0.34-2.61
0.28-0.42
19-42
20-74
14-97
6-7
Mean
2.21
0.19
1.41
1.63
0.34
28
55
68
6
Source: National Agricultural Chemistry Laboratory, NARI
5.3: Cardamom (Elettaria cardamom)
Plant Part: Leaf, Stem and Rhizome
Growth stage: 3rd leaf or the index leaf
Nutrient
Nitrogen
Phosphorous
Potassium
Calcium
Magnesium
Zinc
Iron
Manganese
Copper
Unit
Leaf
2.13
0.15
1.35
1.60
0.34
37
39
350
15
%
%
%
%
%
mg/kg
mg/kg
mg/kg
mg/kg
Concentration
Stem
0.86
0. 10
2.00
0.40
0.38
70
30
59
13
Source: National Agricultural Chemistry Laboratory, NARI
27
Rhizome
1.26
0.10
2.50
0.40
0.60
110
41
81
14
5.4: Cocoa (Theobroma cacao)
Plant part: leaves
Growth stage: Unknown
Nutrient
Unit
Nitrogen
Phosphorous
Potassium
Calcium
Magnesium
Sulphur
Zinc
Boron
Iron
Manganese
Copper
%
%
%
%
%
%
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
Concentration
Keravat
Popondetta
1.92
1.90
0.19
0.19
1.79
1.46
1.16
1.43
0.37
0.45
0.16
45
82
25
47
60
34
89
9
5
Source: National Agricultural Chemistry Laboratory, NARI
5.5: Coffee (Coffee arabica)
Plant part: 3rd pair of leaves from the tip of actively growing and bearing branches
Stage of sample: March
Nutrient
Nitrogen
Phosphorous
Potassium
Calcium
Magnesium
Zinc
Boron
Iron
Manganese
Copper
Unit
%
%
%
%
%
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
Range
1.18-3.0
0.11-0.45
0.74-2.35
0.51-1.26
0.16-0.71
1.6-17
17-37
78-217
30-442
17-41
Source: National Agricultural Chemistry Laboratory, NARI
28
Mean
2.32
0.21
1.45
0.83
0.35
8.5
25
130
201
24
5.6: Guava (Psidium guajava)
Plant part: Leaves
Growth stage: Unknown
Nutrient
Nitrogen
Phosphorous
Potassium
Calcium
Magnesium
Sulphur
Zinc
Iron
Manganese
Copper
Unit
%
%
%
%
%
%
mg/kg
mg/kg
mg/kg
mg/kg
Concentration
1.89
0.26
1.54
1.77
0.20
0.24
22
53
27
11
Source: National Agricultural Chemistry Laboratory, NARI
5.7: Mango (Mangifera indica)
Plant part: leaves
Growth stage: unknown
Nutrition
Nitrogen
Phosphorous
Potassium
Calcium
Magnesium
Zinc
Iron
Manganese
Copper
Unit
Concentration
Range
Mean
%
%
%
%
%
mg/kg
mg/kg
mg/kg
mg/kg
1.35-1.86
0.14-0.33
0.89-1.42
0.22-1.08
0.22-0.34
22-35
42-113
51-113
8-9
1.62
0.27
1.27
1.11
0.27
26
89
74
9
Source: Samples collected from Laloki in 1994 and used as reference material by Brian
Dally. National Agricultural Chemistry Laboratory, NARI
29
5.8: Pepper (Piper nigrum)
Plant part: Leaves- 3rd and 4th leaves from top of the branches
Growth stage: Not specified
Nutrient
Healthy
N%
P%
K%
Ca %
Mg %
S %
Mn ppm
Fe ppm
Zn ppm
Cu ppm
B ppm
2.6
0.21
1.73
2.00
0.19
0.07
51
65
21
11
19
Young leaves
with Mn
symptoms
Old leaves
with severe
Mn symptoms
3.16
0.23
2.42
1.34
0.20
0.04
43
61
22
15
18
2.32
0.15
2.20
2.00
0.19
0.08
19
123
22
9
20
Young leaves
with mild Mg
symptoms
2.00
0.13
1.98
2.00
0.10
0.08
49
103
20
8
20
Source: National Agricultural Chemistry Laboratory, NARI
5.9: Peanuts (Arachis hypogaea)
Plant part: leaf
Growth Stage: Not known
Nutrition
Nitrogen
Phosphorous
Potassium
Calcium
Magnesium
Zinc
Iron
Manganese
Copper
Unit
%
%
%
%
%
mg/kg
mg/kg
mg/kg
mg/kg
Concentration
4.59
0.33
2.18
1.31
0.62
59
119
98
11
Source: National Agricultural Chemistry Laboratory, NARI
30
Old leaves
with severe
Mg symptoms
1.76
0.15
2.15
2.0
0.06
0.08
80
>200
19
8
21
5.10: Sweet potato (Ipomea batatas)
Plant part: 4th leaf from terminal leaf and vines
Growth stage: Harvest
Nutrient
Nitrogen
Phosphorous
Potassium
Calcium
Magnesium
Zinc
Iron
Manganese
Copper
Unit
%
%
%
%
%
mg/kg
mg/kg
mg/kg
mg/kg
Leaves
Range
2.58-3.51
0.13- 0.36
0.98-5.1
0.92-1.92
0.5-1.3
16-38
192-2364
94-468
8-17
mean
3.10
0.21
2.31
1.38
0.71
24
780
236
12
Vine
range
0.93-2.11
0.10-0.36
0.81-3.66
0.63-1.07
0.28-0.57
4-50
102-470
40-300
10-22
Source: National Agricultural Chemistry Laboratory, NARI
5.11 Tea (Camellia sinensis)
Plant part: 4th leaves
Growth stage: Plucking
Nutrition
Nitrogen
Phosphorous
Potassium
Calcium
Magnesium
Sulphur
Zinc
Iron
Manganese
Copper
Unit
%
%
%
%
%
%
mg/kg
mg/kg
mg/kg
mg/kg
Concentration
Range
2.23-3.72
0.13-0.33
0.40-1.50
0.72-2.95
0.21-0.46
0.20-0.45
10-120
73-516
1030-4580
1-18
Source: National Agricultural Chemistry Laboratory, NARI
31
Mean
3.08
0.23
0.95
0.95
0.33
0.31
20
156
2598
7
mean
1.45
0.14
1.53
0.86
0.46
20
289
110
14
5.12: Taro (Colocasia esculanta)
Plant Part: Tubers
Growth stage: Harvest
Nutrient
Unit
Nitrogen
%
Phosphorous
%
Potassium
%
Calcium
%
Magnesium
%
Sulphur
%
Zinc
mg/kg
Boron
mg/kg
Iron
mg/kg
Manganese
mg/kg
Copper
mg/kg
Concentration
0.58
0.24
1.33
0.20
0.09
0.03
45
6
83
8
7
Source: National Agricultural Chemistry Laboratory, NARI
5.13 Yam (Diascoria spp)
Plant part: Leaves (Three fully opened leaves)
Growth Stage: 3-5 months (Chlorosis)
Nutrient
Nitrogen
Phosphorous
Potassium
Calcium
Magnesium
Sulphur
Zinc
Boron
Iron
Manganese
Copper
Unit
%
%
%
%
%
%
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
Concentration
2.09
0.35
3.42
0.79
0.25
0.17
58
23
69
18
9
Source: National Agricultural Chemistry Laboratory, NARI
Sample submitted by David Mitchell
32
Protein
3.6
6.0 References:
1. Bruce, R.C. (1988 b). Soil acidity and liming. In I.F. Fergus (Ed), Understanding soils
and soils data: Australian Society of Soil Science Incorporated, Queensland Branch:
Brisbane, Australia.
2. Daly, B.K and Wainiqolo, J.L. (1993). Guide to Interpretation of Agricultural Sample
Analysis Results; Soil, Plant, Animal Feed, Irrigation water and Others. Fiji
Agricultural Chemistry Laboratory Technical Report 04.
3. Incitec, Ltd, (1989). P.O.Box 142, Morningside, Queensland.
4. Mengel, K and Kirkby, E.A. (1987). Principles of Plant Nutrition. International
Potash Institute, PO Box, CH-3048 Worblaufen-Bern/ Switzerland.
5. National Agricultural Chemistry Laboratory, NARI, PO Box 8277, Boroko, National
Capital District, Papua New Guinea.
6. O’Sullivan, J.N, Asher, C.J and F.P.C Blamey (1997). Nutrient disorders of Sweet
Potato. ACIAR Monograph No 48.
7. Peveril, K.I., Sparrow, L.A and Reuter,D.J.(1999).Soil Analysis: An Interpretation
manual. CSIRO , P.O.Box 1139, Colingwood, Victoria, Australia.
8. Reuter, D.J and Robinson, J. B.(1997). Plant Analysis: an Interpretation Manual,
CSIRO, Australia.
9. Walsh, L.M and Beaton, J.D. 1973. Soil Testing and Plant Analysis. Soil Science
Society of America
10. Willson, K.C (1985). Mineral nutrition and fertiliser needs. In: Coffee- botany,
biochemistry and production of beans and beverage: 135-156. Eds.Clifford M.N and
Willson K.C. Croom Helm, London.
7.0
Acknowledgements:
We wish to acknowledge the support and encouragement given by Mr. Valentine
Kambori, Director General and Mr. P. Corbett, Chief Chemist, National Agricultural
Chemistry Laboratory, NARI. Dr. A. Quartermain for reviewing the manuscript and the
valuable comments.
33
8.0
APPENDIX
8.1.GUIDELINES FOR SOIL SAMPLE COLLECTION AND PREPARATION
FOR CHEMICAL ANALYSIS.
Introduction
Soil is one of the major components of the natural resource base for agricultural
production and it is essential to carefully manage it to maintain sustainable production.
Soil not only supports crop growth but also acts as a filter, cleaning air and water. Soil
nutrient levels change with crop and soil management practices and, therefore, it is
essential to have the soil tested periodically for efficient economic and environmental
management.
If the soil becomes degraded, more resources are necessary in terms of agricultural inputs
to maintain stability and sustainability. As we know the soil plays a major role in
providing a physical, chemical and biological environment for fertility maintenance and
crop production. Therefore it is essential to monitor the changes that take place with
agricultural practices through careful sampling and study of the physical, chemical and
biological properties of the soil in order to achieve efficient, economic and sustainable
management.
Taking inappropriate samples will result in making inaccurate fertilizer or other
recommendations for land and crop management. Appropriate sampling techniques will
enable reliable analysis and correct recommendations.
What is the purpose of soil sampling?
 To determine the physical, chemical and biological properties of soil, e.g.: soil
texture, organic matter, nutrient elements.
 To diagnose of soil nutrient problems and assess the quality of soil for supporting
growth in plants
 To determine the level of available nutrients essential for plant growth and to
formulate efficient and economic fertilizer recommendations.
 To determine any chemical nutrient deficiencies or toxicities, e.g. low or high
level iron, boron, manganese and zinc.
 To monitor of soil nutrient or other related problems caused by other activities.
34
 To support decisions relating to land utilisation, environmental protection and
human health.
 To measure variability among farms and monitor long term fertility trends.
 To identify and describe the main problem of soil degradation (e.g. soil
acidification) and suggest solutions.
 To assess the present state of soil quality and predict future trends.
 To identify soil type and determine its inherent soil properties.
 To select suitable crops for specific environment.
 To assist in developing management strategies for future improvement, where
areas of low productivity are identified.
When to collect soil samples for crop production:
 Soil samples may be collected at the following stages of crop production.
1. Before sowing a crop
2. During the early development of the crop
3. During the period of maximum nutrient consumption, e.g. at flowering
4. At harvest
 When diagnosing a soil nutrient problem.
What should we do before taking a soil sample.
Survey the area visually and decide on the boundaries of the sampling area as illustrated
in Figure 1. The land area tested must be divided according to uniformity.
Prepare a soil sampling plan as illustrated in Figure 1, based on the differences in the
farm or farm block. . Samples from each area should be kept separate for sample
preparation and analysis
Figure 1. Divide the farm block into several sampling areas
35
The size of the sampling area depends on the intensity of cropping and should not be
larger than 15-20 hectares.
If the sampling area is uniform in relation to soil texture, colour, organic matter, slope,
past management and crop to be grown, one or two samples may be collected in a 15-20
hectare area. However, if the variations are greater with respect to these characteristics,
the area should be divided accordingly and multiple samples collected.
Road sites, burnt areas, wet spots, areas where animals have been penned or patches of
good growth should be avoided or sampled separately.
Soil sampling tools and other materials:
Select proper and good sampling tools which should have the following properties:
1. Easy to clean
2. Adaptable to dry and moist soil conditions
3. Provide uniform cores or slices of equal volume at all spots within the
composite area.
4. Durable and rust resistant. Tools are generally made out of stainless steel,
otherwise they may cause contamination.
The following sampling tools can be used:
1. Soil sampling tubes: Open sided, plain cylinder, constricted tip and uniform
bore. This type of sampling tool is most accurate.
2. Soil augers. This type of tool is also accurate.
3. Spades, shovels. These may not result in accurate samples.
The following are also necessary for soil sampling:
1. Bucket to mix the soil
2. Plastic bags
3. Labelling materials, i.e. marker pens, labels
4. Recording sheet to record information on the site.
What depth do we need to sample:
This will depend on the crop or pasture species and the purpose (monitoring the leaching
of nutrients means deeper profiles). Normally take soil samples to the depth of the root
zone of the crop, pasture or plant to be grown.
36
1. Pasture grasses and legumes: A sampling depth of 0-7.5 cm or 0-10cm is used.
2. Crops: A sampling depth of 0-10 cm, 0-15cm or 0-20cm is used. To determine
movements of nutrients (nitrate nitrogen, potassium) it is better to take samples at 030cm, 0-60cm, 0-100 cm and in the tropics 0-150cm. For most of the crops sub-soil
sampling is done only when required.
3. Orchards: A sampling depth of 0-15 cm and 15-30 cm or 0-10 cm, 10-20 cm and
20-30cm is used. For orchards or plantation crops, the patterns of sampling will vary
according to planting design, under canopy and between row soil management, fertilizer
placement, tree age and plant root distribution. The general principles for sampling
design and the patterns described for pastures and crops can be used for plantations
Procedures for collecting soil samples:
 Locate the sample site
 Scrape away surface litter
 Take sample to the desired depth (e.g. 0-10cm for pastures) using preferably a
soil tube or an auger. Small size cores will require larger numbers of samples. For
a pasture and cropping situation, take a surface sample from 0-10cm or 0-15cm
from at least 30 different spots at regular intervals over the block or farm
according to the pattern shown below in figures 2a, 2b, 2c and 2d.
2a. Zig Zag pattern
2c. Transect pattern
2b. Orchards
2d. Systematic strips
Source: Peverill et al, 1999
Thoroughly mix the soil to form one sample. Take a sub-sample from the bucket and
place it in a labelled plastic bag. Do not place a paper label inside the bag with the soil. If
37
you do not have a processing facility you should send the samples as soon as possible to
the NARI Agricultural Chemistry Laboratory. Do not keep them too long.
 Clean soil sampling tools and bucket separately before taking another sample
from a different site, block or farm.
Procedures for processing soil samples:
 Before sending a sample to the chemistry laboratory, air dry it in a dust free
environment or dry it in a dehydrator or oven at a temperature of 40 degrees
centigrade. Do not dry above this temperature. If analysis is required for
ammonia, the sample should be analysed immediately or frozen. Manganese and
Iron increase when drying temperature is increased.
 After drying, sieve the sample to pass through a 2mm sieve. All soil clods should
be crushed by using a motar and pestle or a rolling pin and sieved. Gravel and
concretions should be excluded.
 Place the sample in a labelled plastic bag or bottle and submit the sample to the
Chief Chemist, National Agricultural Chemistry Laboratory, NARI, PO Box
8277, Boroko, National Capital District. Telephone: 3212690, 3213099.
Fascimile: 3202411
Please provide the following information on a separate sheet of paper or fill the form
provided by the National Agricultural Chemistry Laboratory.
1.
2.
3.
4.
5.
6.
7.
8.
Name and address of the sample owner.
Location of the sample collected.
Date of collection
Depth of sample
Previous site history i.e. crop, pasture, rotation, fertilizer.
Purpose of sampling: Diagnostic, fertilizer management or other
Proposed crop or pasture
Any other relevant information, ie. Altitude, soil type, climate, slope
38
8.2
SOIL SAMPLE COLLECTION INFORMATION FORM
1. Name of person/ organisation who took the sample-----------------------------------2. Address:-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------3. Telephone:----------------
Fascimile:-----------------------E-mail---------------------
4. Has this area been sampled previously?
Yes: ( )
No: ( )
5. Name of the farm / block/ experiment-----------------------------------------------------.
6. Nearest town/ District/ Province or locality of the farm:-------------------------------7. Depth soil sample was taken from: -------------,---------------,----------------------8. Number of spots sampled: -----------------------------------------------------------------9. Date of sampling:---------------------------------------------------------------------------FARM /BLOCK DETAILS.
10. Block/ Farm size(ha)
Under one hectare ( )
1-5 hectares
6-20 hectares
over 20 hectares
Drainage
Topography
Poor ( )
Average ( )
Good
()
Annual Rainfall(mm)
Flat ( )
Slope ( )
Hilly ( )
under 1500
1500-2500
2500-4000
2000-3000
()
()
()
()
11. Fertiliser, lime, manure history ( Include rate of application)
12. Cropping history; include fallow period, rotations if any, previous crop including any
legumes.
13. Analysis Required : N, P, K, Ca, Mg, S, Zn, B, Mn, Cu, Fe, Mo
Soil pH, Organic Carbon, Electrical Conductivity, CEC
Particle size analysis.
Other / Special methods (e.g. other P measurements; P fixation)
39
8.3
GUIDELINES
FOR
PLANT
SAMPLE
PREPARATION FOR NUTRIENT ANALYSIS
COLLECTION
AND
INTRODUCTION
Soil fertility decline and nutrient stress are one of the major natural constraints to food
and commodity crop production in Papua New Guinea. In order to practice efficient and
economical crop production, information is needed about the nutrient status of your crops
The economic return from a crop is largely determined by its yield (production), quality
and growing costs, all of which are directly related to its nutrient status.
Plant analysis will provide information about possible deficiencies or toxic levels of
essential nutrients. It measures the concentration of essential nutrient elements in plant
tissues and provides a simple, fast and relatively inexpensive means of evaluating the
nutrient status of crops. Plant analysis is based on the concept that the concentration of a
nutrient element in a plant or part of a plant is an indication of the supply of the element
from the soil to the plant. By reference to established standards it is possible to judge
whether the nutrient in the crop falls into the normal, toxic or deficient range or if there is
an imbalance between nutrients.
Plant tissue analysis is only one of the diagnostic tools used in nutritional problem
solving or advising. Generally it should be used in conjunction with soil analysis, careful
monitoring of the crop, assessment of environmental conditions and information about
the previous crop, site or farm history. The National Agricultural Chemistry Laboratory
at Kila Kila provides a plant analysis service but scientists, extension offices, farmers and
others must understand and follow certain procedures when collecting and preparing
samples to enable achievement of accurate results.
The Purposes of Plant Analysis:
1. To diagnose or confirm visual deficiency symptoms or toxicity problems.
2. To identify deficiencies where nutrient levels are low enough to reduce potential yield
but not low enough to produce deficiency symptoms.
3. To maintain or improve the balance of different nutrients.
4. To provide a basis for the compilation of fertilizer recommendations.
5. To monitor the outcome of fertilizer applications and the appropriateness of fertilizer
recommendations.
6. To predict whether nutrient deficiencies are likely to occur in the current or
succeeding crops.
7. To estimate the removal of key nutrients by a crop with a view to replacing them and
maintaining fertility.
8. To estimate the nutritional value of a crop to an animal or human consumer.
40
How you should sample:
Plant tissue analysis is done on whole plant samples or from plant parts (petiole, stem,
leaf). If the analysis is done at an early stage of growth it will be useful to correct any
current deficiency. However, if done at flowering and harvest the information will be
useful for the next seasons crop. The sample collected should represent the crop
treatment area or farm block. The person sampling should collect adequate number or
quantities of plants or plant parts to represent the total plant population (20 – 100 leaves
or plants).
For diagnostic samples if a deficiency is suspected, separate samples should be collected
from the “deficient” and “normal” or “non-deficient” areas. Where a crop is uniformly
affected, one sample representing the affected area is sufficient. It is important to collect
the samples when the deficiency symptoms are first observed. For crop nutrient
monitoring on the farm, the area should be roughly divided into sections and each section
should be sampled systematically as illustrated in diagrams a and b, c and d.
Sample area
Field
Sample
area
(a)
(c)
(b)
(d)
Source: Reuter and Robinson,1999
41
The quality of the sample collected and submitted to the Chemistry Laboratory will
directly affect the quality of the analysis and the advice you receive for interpretation to
the farmers. Therefore samples must be representative of the field conditions, unaffected
by things that may produce spurious results and supplemented with information that
facilitates interpretation of results. It is important to consider and record the following
factors before sampling:
1. Describe the crop species and variety, soil type, sampling site location, observed
symptoms, previous crop and fertilizer history.
2. Do not collect plant or plant parts that are dry or dead, mechanically damaged or
affected by insects and diseases.
3. Do not sample when the plants are under stress, e.g.: when plants are exposed to dry
spells or when day temperatures are high.
4. Collect samples between 8 and 11 o’clock in the morning.
5. Use gloves or clean hands to avoid contamination of samples until placed in a clean
bag or other container, e.g.: esky.
6. Avoid collecting samples near roads, cattle pads or camps, trees, water logged areas
or other abnormal sites.
7. Avoid collecting samples from plant that have been recently sprayed with fungicides
etc. If this cannot be avoided then note if sprays have been recently applied.
When and what you should sample
As the crop develops, changes occur in the concentration of nutrients in the whole plant
and its parts. Therefore, in order to accurately interpret the results of the plant analysis, it
is essential to record the stage of crop growth when the sample was collected. Samples
are generally collected at standard, defined stages of crop growth or physiological age.
Plant samples from most of the field crops for monitoring should be collected at the
active vegetative stage (generally 4 weeks after sowing for field crops like sorghum,
maize, peanut) or at flowering. Stages of growth and plant parts for sample collection for
some field and commodity crops are as shown in the Table 1.
42
Table 1: Stage of Growth and Plant Parts for sample Collection for selected crops
grown in Papua New Guinea.
Crop
1. Avocado
Growth Stage
April-May
2. Banana
Medium sized suckers
3. Broccoli
4. Cashew
Head
Non flowering vegetative
flush
3-4 months
5. Cassava
6. Coconut
7. Cocoa
8. Coffee
May (Northern hemisphere)
November (Southern
hemisphere)
Mature plants
February-April or
September-October
9. Guava
November-December
10. Maize
Vegetative
Tasselling
Silking
11. Mango
Sampling from the latest
mature flush
Mature
42 days after sowing
Pre-flowering
Late flowering
25-35 days after planting
Early flowering
Mature trees
12. Oil Palm
13. Peanut
14. Potato
15. Rubber
16. Sweet potato
17. Tea
28 days after transplanting
Harvest
At plucking
N.B. for crops not listed please enquire
43
Plant part to sample
Recently matured fully expanded
leaf from non-fruiting terminals
3rd youngest leaf, cut strips of leaf
blade 15-20 cm wide from each side
of midrib
WL=Wrapper leaf
Most recently matured hardened leaf
on an actively growing shoot.
Youngest mature leaf blade (YMB)
i.e. leaf 4 and 5
Leaflets from the mid-region of the
14th frond
3rd leaf from recent hardened flush
3rd or 4th pair of leaves from the
actively growing and bearing
branches
3rd pair of fully developed leaves
from tip of fruiting terminal shoot
Whole plant
Ear leaf or BOBC
Ear leaf or BOBC (blade opposite
and below cob)
Leaves from non-bearing branches
17th Frond-about 6 leaflets
Youngest mature leaf
Youngest mature leaf
Youngest mature leaf
Whole plant
Youngest mature leaf
Mature leaves-low shade leaves
Youngest mature blade
Whole plant or 4th leaf from
terminal, 1st leaf + bud, 3rd leaf or
mature leaves
How to prepare your plant sample
The plant sample will need to be properly processed before it is submitted for chemical
analysis. Remember it is still alive and can be easily contaminated or the chemical
composition of some elements changed. The following steps are required:
1.
Place the collected sample in a labelled, open paper bag and place it in an esky or
cool container, car fridge or water tight bag. Do not leave samples in open bags
or in the car for longer periods than absolutely necessary and get them to the
closest laboratory or area for processing within 24 hours. Be careful that the
correct sample is placed in the correct bag. Double check this as mistaken identity
will invalidate the test and waste your time and the chemists effort.
2.
If possible, wash the sample with distilled, deionised or rain water and remove
excess water with a paper towel. Special washing techniques are necessary for
certain nutrients, especially micronutrients, and for dusty and dirty samples.
Contact your chemist or crop nutrition agronomist for details. If the plant samples
are clean and without any contamination there is no need for washing the samples
with water.
3.
Place the washed sample in a labelled bag and dry the sample at 65 degrees in a
forced draught oven for 24 to 48 hours. Prolonged drying at temperatures more
than 80 degrees centigrade will result in breakdown of tissues and loss of some
volatile nutrients.
4.
Drying fresh samples at ambient temperature or at temperatures below 40 degrees
centigrade or above 80 degrees centigrade is not recommended. Any large sample
should be chopped or ground in a hammer mill to small pieces and sub samples
collected to grind in a stainless steel mill.
5.
Grind the sample in a stainless steel mill fitted with a screen less than 1mm in
diameter. Generally a 0.5mm sieve is used. Collect the sample in a plastic
container or bag. Sesame and Peanut seed samples may be ground in a coffee
grinder so that the final ground product is free flowing and not clumpy.
6.
Submit the sample to the Chemistry Laboratory for chemical analysis. Specify
the analysis to be conducted and any other relevant information to the laboratory
( see attached information form)
44
8.4: PLANT SAMPLE COLLECTION INFORMATION FORM
A. Personal details:
1. Name: ---------------------------
Telephone:------------------------------
1. Address: -----------------------------------------------------------------------------------------Facsimile:--------------------------- E-mail address ------------------------------------------3. Name of the person /organization who took the sample ------------------------------------4. Has this area been sampled previously?
Yes :-------------
No :-------------
5. Name of the farm/ block/ experiment----------------------------------------------------------6. Nearest Town or Locality of the farm (District, Village, Census Division) -------------------------------------------------------------------------------------------------------------------------7. Date of sampling -------------------B. Site Details
8. Block/Farm size (hectares)
Under one hectare ( )
1-5 hectares
()
6-20 hectares
()
over 20 hectares ( )
Drainage
Poor
()
Average ( )
Good
()
Topography
Flat ( )
Slope ( )
Hilly ( )
Rainfall (mm)
Under 1500
1500-2500
2500-4000
above 4000
()
()
()
()
C. Sample Description:
Crop-------------------------- Species---------------------
Variety--------------------------
Age/ Date sown-------------
Previous crop-----------------
Stage of Growth: Seedling ( )
Vegetative ( )
Flowering ( )
Harvest/Fruiting ( )
Other
Plant part submitted : Whole plant ( ) Leaf Blade ( ) Stems ( ) Petiole ( ) Grain/ Fruit ( )
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Description of crop symptoms if any :
Are the symptoms on: Old leaves ( ) Young leaves ( )
Terminal new leaves ( )
Has the crop been subjected to: Waterlogging ( ) Drought ( )
Pests ( )
If yes describe the situation or symptoms:
How do you rate the crop vigour ? Good ( ) Average ( ) Poor ( )
D. Crop rotation and block history for the last five years :
Year:
Rotation:
Crop Yield:
Fertiliser/Manure used:
Fallow history:
Any other information you think may be useful:
E. Analysis required:
1. Total N, P, K, Ca, Mg, S, Zn, B, Fe, Mn, Cu, Mo, Cl
2. Any other elements or compounds
3. Fibre
4. Ether extract
5. Other analysis required
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Diseases ( )