SOIL TESTING

 
Soil Testing Laboratory
 

Presently soil testing facilities are available for farmers, on subsidised rate in the soil testing Labs operated by Department of Agriculture, M.P.

Soil Testing Charges

a- Macro element(Nitrogen,Sulpher,Potash, Ph & Electrical conductivity) 12 Rs.5/ sample for General farmerRs.3/ sample for SC/ST farmer
b- Micro element(Based on the capacity of cathodlamp in the lab 12 Rs.40/ sample for General farmersRs.30/ sample for SC/ST farmers


Following are the soil testing laboratries where major soil neutrients can be analysed.

1 . Pawarkheda
2 . Bhopal
3 .Sehore
4 .Ujjain + Ujjain (Mobile)
5 .Mandsaur
6 .Dhar + Dhar (Mobile)
7 .Khargone
8 .Khandwa
9 .Balaghat
10 .Chhindwara
11 .Narsingpur
12 .Sagar
13 .Nawgaon + Nawgaon (Mobile)
14 .Rewa + Rewa (Mobile)
15 .Morena
16 .Bhind

Soil Survey Laboratories which having Soil Testing Facilities :-

S.No. Soil Survey Laboratory
1 Jabalpur
2 Indore
3 Gwalior
4 Sagar
5 Nawgaon (Chatarpur)
6 Rewa
7 Khandwa

 

Soil Testing

 

Why Soil testing is necessary :-

1. Soil fertility is assessed by soil testing.
2. High dose of Chemical fertilizers are being used by the farmers to increase production of various hybrid varities of crops.
3. If farmers can use the balanced doze of fertilizer for crop production then unnecessary financial loss can be avoided.
4. Soil testing can be useful to maintain the soil health. To know the soil fertility, periodically soil testing is necessary.
5. Ph status (Acidic or base) of the Ag. field can be known by soil testing. Appropriate use of fertilizer for crop production can be recommended on the basis of Ph value of soil.
6. Soil testing categorize the soil in to various categories such as Saline, Alkaline or Mineral soils. The farmers can be advised to convert such soils in to normal soils.

 

Before describing the objectives of soil testing, it is necessary to understand what is soil testing ?

"Soil testing is a Chemical process by vertue of which requirement of neutrients for plant can be analysed so as to maintain the soil fertility.

Objective of Soil Testing :-

1. To promote organic fertilizer & insecticides on the basis of balanced use of fertilizer.
2. To prepare fertility map of specific area such as Block or Microwatershed etc based on soil testing report. This will help in advocating appropriate cropping system in the said area.
3. To make certain specific cropping system more economically viable with respect to crop production.
4. To stop indiscriminate use of fertilizer.
5. Appropriate fertilizer dozes can be recommended on the basis of soil testing such as – In Normal soil (Ph- 6 to 6.5) all Nitrogeneous fertilizer, Super phasphate, Amonium phasphate etc. can be used. Similarly in the soil having less than 6.00 Ph value, Calcium amonium nitrate, Sodium nitrate, phasphetic fertilizer. Super phasphate, Murate of potash etc can be applied. In the soils having more than 8.5 Ph value, Urea , Ammonium sulphate, Amonium cloride, Super phasphate , Amonium phasphate, Murate of potash etc are recommended. The water logges soils can be applied Urea, Amoninium sulphate, Super phasphate , Amonium phasphate , Amonium chloride etc.
6. To identify the quantity of organic carbon in the soil is one of the major objective of soil testing , because growth of crop & availability of neutrients are based on organic carbon. The ratio of organic carbon & nitrogen is 10-12:1. The propogation of useful bactiria also depends on it.
7. Soil testing recommends the ingradiant required to reclame the acidic soil or saline soils etc.
8. The deffeciancy of micro element like Znic, Copper, Boron, Molebdinum, Iron, Cobalt, Silicon, Mangnese & Clorine etc also advarsely affect the crop condition & ultimately the production.

 

 
 

Soil Sample Process:

The testing in the laboratory requiresonly a few grams of the soil sample, yet the sample sent to the laboratory must be a true representative of the field in question. In a homogenous field, soil samples from plough layer (0-15cm) should be selected randomly in a zig-zag manner. The samples should not be collected from near the bunds, water channels, field paths and heaps of crop straw, stubbles, manure, etc.

  1. The sample collected from the selected sites should be composite and mixed thoroughly in a container.

  2. From this lot a representative sample, about 500 gm should be taken out and air-dried under shade.

  3. The air-dried sample should be transferred into a clean cloth bag bearing a slip with a mention of complete address, field number, cropping sequence being followed, source of irrigation (tubewell/canal), soil type (coarse textured fine textured, alkali or waterlogged), fertilizer/manure schedule followed in the preceding crops and any other specific observation about the soil and/or the crops grown therein.

  4. Then the sample should be taken to the laboratory where facilities for testing soils for micronutrients are available.

 
 

Prescribed Area for taking Soil Samples:

Land Use Area(in Hect.)
Pastures, permanent grass 5-10
Cultivated Crops:
-level terrain
-eroded terrain
-irrigated terrain

2 - 5
1 - 2
0.5 - 1
Orchards, vineyards, forests 0.5 - 2
Vegetable gardens, irrigated 0.5 - 1
Greenhouse, nursery, lawns 0.1 - .2

When to Take Samples

At least one month before planting time.As a rule 'if soil is too wet to plow, it is too wet to sample'.Try collecting samples at the same time every year

Frequency of Soil Sampling

Soils from coastal plains, sandy, light textured soils - sample once after every 2-3 crops Silty, clay loams and mountain soils- sample once every four cropping years.

 
 
Soil Sampling Tools
 
  1. Easy to clean, rust resistant, strong and easy to use

  2. Take small, equal volume of soil from each sub-sampling site to obtain composite size.

  3. Adaptable to dry sandy soils as well as moist sticky soil

  4. Provide uniform cores or slices of equal volume at all spots within the composite area

Soil tube, screw auger, spade, shovel are some of the sampling tools most commonly-used.

If spade or shovel is used, it is advisable to make a 'V' shaped cut into soil at required depth and few cm thick vertical slice is removed to the same depth from both sides.Before sample collection, organic debris, rocks and trash must be removed from the surface of sampling area.

 
 
Depth of Sampling
 

Prescribed Depths of soil Sampling

Crop/Soil Sampling Depth (Cm)
Arable crops 15
Orchards 20-30
Lawns and Turf 10
Gardens 15
Deep rooted crops / Problem soils 30/60
Regular tillage 20
Minimum tillage 15
Zero tillage 15-20
Continuous ridge 10/15
Pastures and Forages 8-10

 
 
Directions while Soil Sampling and Preparation
 
  1. Soil samples should not be collected from recently fertilised areas, bunds, low lying corners, spots near trees, fences, channels, compost pits, etc.

  2. Samples should be drawn between rows in line sown cropping areas.

  3. Sampling should be done separately for areas represented by different crops, problem spots, etc.

  4. Once the soil is collected, the bulk soil is mixed thoroughly and desired quantity of soil sample is obtained by 'quartering method'.

  5. Soil samples should not be placed in fertiliser bags, and in porous cloth.

  6. Wet samples should be dried in shade before sending them to the laboratory.

Soil Test Interpretation for Fertilizer Recommendations

After collection and analysis of soil samples, it is the responsibility of the analyst/scientist to interpret the results and properly give the fertiliser recommendations to farmers. Many people have an impression that soil testing is a simple procedure to determine the plant nutrients that are deficient and recommend those nutrients in fertiliser form so that harvests are assured. Nevertheless, soil testing is much more than determining nutrient availability.

Various approaches used for fertiliser recommendations

  1. Generalised fertiliser recommendations (or) Agronomic fertiliser recommendations.

  2. Fertiliser recommendations based on soil critical levels

  3. Fertiliser recommendations adjusted based on soil fertility categories

  4. Fertiliser recommendations for maximum yield

  5. Fertiliser recommendations for certain percentage of maximum yield

  6. Fertiliser recommendations for specific yield targets

Soil Test Calliberation

Incorporation of generated data through intensive research and establishing a significant relationship between.

  1. Soil test values and the uptake of applied plant nutrients by a particular crop

  2. Calibration between soil tests values and crop yield responses to rates of plant nutrients applied through fertilisers in the field

  3. Changes in soil test values that occur when known quantities of fertilisers are applied to the soil

 
 
Ratings of soil test parameters
 
Nutrients High Medium Low
Organic carbon (%) as a measure of available N <0.5 0.5 - 0.75 >0.75
Available N by alkaline permanganate method (kg/ha) < 280 280-560 >560
Available P by Olsen's method (kg/ha) <10 10-24.6 >24.6
Available K by ammonium acetate method (kg/ha) <108 108-280 >280

Quadratic Response Equation

Y = A + b1SN + b2SN2 + b3 SP + b4SP2 + b5SK + B6SK2 + b7FN + b8FN2 + b9FP + b10FP2 + b11FK + b12FK2 + b13FNSN + b14FPSP + b15FKSK

Where,

Y = Crop Yield (kg/ha)
A = Intercept
bi = Regression coefficients (kg/ha)
SN, SP, SK = Soil available N, P and K (kg/ha) respectively
FN, FP, FK = Fertiliser N, P and K (kg/ha) respectively

Mitcherlich-Bray equation

Availble Nutrient High Low Medium
N(Nitrogen) 63.10% 25.57% 11.33%
P(Phosphorous) 42.33% 37.66% 20.01%
K(Potassium) 12.93% 36.65% 50.42%

Log (A-Y) = Log A - c1b - cx

Where,

A = theoretical maximum yield
b = native soil nutrient
Y = yield obtained
x = added fertiliser
c1 = efficiency factor for soil nutrient
c = efficiency factor for added nutrien

Target Yield Equation

FD = NR/CF *100*T -CS/CF*STV

Where,

FD = Fertiliser N or P2O5 or K2O (kg/ha)
NR = Nutrient requirement of N or P2O5 or K2O (kg/t)
CF = Contribution from fertiliser N or P2O5 or K2O (%)
CS = Contribution from soil N or P2O5 or K2O (%)
STV = Soil test value of N or P X 2.29 or K X 1.21 (kg/ha)

 
 
Soil Survey
 

Soil Survey is one of the important tools to assess the nutrient requirement for a crop/cropping sequence. This helps to economize on cost of fertilizers and also in increasing fertilizers use efficiency. There are 514 soil-testing aboratories in India with a capacity of about 6.5 million samples per annum.In order to provide soil-testing facilities to all 106 million farms holding in a reasonable period of time, the existing analyzing capacity of the soil testing program needs to be augmented almost 15-20 times.

Madhya Pradesh is having presently 22 Soil Testing Labs and Soil Surveyors. The main objective of Soil Health Centres is to maintain the soil health by analysing nutrient status of the soils and to give suggestions on the quantities of major nutrients like nitrogen, phosphorus, potassium to be applied to the soils. Micro Nutrient analysis is also important to know the status of Manganese, Boron, Zinc, Iron etc., present in the soil and accordingly suggest supplimental application for better plant growth.

Steps required to strengthen soil-survey are improve the capacity utilization of existing soil-testing labs, adding facilities of micro-nutrients at selected labs, introducing tissue testing particularly for sugarcane, horticulture and plantation crops and encouraging private sector participation for adding new capacity. Based on the analysis of 4.84 million soil samples, the fertility status of the soils with regard to the content of available nitrogen, available phosphorus and available potassium have been worked out which indicate the following status on all India basis:-

Available N P K Status of soils

Availble Nutrient High Low Medium
N(Nitrogen) 63.10% 25.57% 11.33%
P(Phosphorous) 42.33% 37.66% 20.01%
K(Potassium) 12.93% 36.65% 50.42%

Soil testing till today has been used mainly to formulate precise recommendations for the major nutrients i.e. nitrogen, phosphorus fertilization of crops in different soils and to recommend appropriate doses of amendments for salt-affected and acidic soils. Micronutrients, comprising zinc, copper, iron manganese, boron and chlorine, though required by plants in much smaller amounts, yet are as essential for them as the major nutrients. Despite that, little attention has been paid to employ the soil testing for assessing the micronutrient status of soils and determining soils requirement for micronutrient fertilizers for growing crops.

With an objective to extend the advisory service to the farmers of the state regarding the nutrient problems of soils and crops and suggest appropriate remedial measures for efficient correction of the same, Jawahar Lal Nehru Agriculture University and the Department of Agriculture have established soil testing laboratories for nutrient. Farmers are advised to make the best use of this service rendered by these laboratories. Soil test can be performed for the soil of farmer by just paying Rs 50.

(i) Classification of soils.
(ii) Evaluate and monitor soil fertility.
(iii) Identify salinity, alkalinity, acidity, etc., problems.
(iv) Assess the relative nutrient supplying power of soil.
(v) Predict profitable responsiveness of soil to added fertilisers, lime, gypsum and other amendments for optimum and economical crop production.

 

Success or failure of soil testing programmes largely depends on rapidity of providing correct information to farmers, ability of the programme to provide service to a large group of farmers in a particular area, proper calibration and interpretation of results and recommendations that when followed are profitable for the farmer. Then only will this service be effectively utilized to improve local agricultural production Time and quality consciousness in the service is a real challenge for the analysts in the new millennium. This compels labs to adopt rapid, reliable, time saving procedures and methods to meet future requirements. The farmer's confidence in the programme can be established only by demonstrating that it actually provides a means of improving his profit.