Soil Testing
SOIL TESTING
As we all know, agriculture today became a science which requires certain parameters to know before you saw. In this consent the farmers need to know the fertility and availability /Unavailability of nutrients in it so that they can choose the right crops for the right agri-lands also to take decision for the choice of right fertilizers. In Oshnic group we are providing the consultancy for the testing it. All these consultancies are being provided through our group’s company Meenesh Irrigation India Private Limited.
WHAT IS SOIL TESTING?
The testing is a Chemical process by vertue of which requirement of neutrients for plant can be analysed so as to maintain the soil fertility. The test may refer to one or more of a wide variety of analyses conducted for one of several possible reasons. Possibly the most widely conducted tests are those done to estimate the plant-available concentrations of plant nutrients, in order to determine fertilizer recommendations in agriculture. Other tests may be done for engineering (geotechnical), geochemical or ecological investigations.
OBJECTIVE OF TESTING:
- To promote organic fertilizer & insecticides on the basis of balanced use of fertilizer.
- To prepare fertility map of specific area such as Block or Microwatershedetc based on the testing report. This will help in advocating appropriate cropping system in the said area.
- To make certain specific cropping system more economically viable with respect to crop production.
- To stop indiscriminate use of fertilizer.
- Appropriate fertilizer dozes can be recommended on the basis of testing such as – In Normal (Ph- 6 to 6.5) all Nitrogeneous fertilizer, Super phasphate, Amoniumphasphate etc. can be used. Similarly in it 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, Amoniumcloride, Super phasphate , Amoniumphasphate, Murate of potash etc are recommended. The water logges can be applied Urea, Amoniniumsulphate, Super phasphate ,Amoniumphasphate , Amonium chloride etc.
- To identify the quantity of organic carbon in it, is one of the major objective of 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.
- Soil testing recommends the ingradiant required to reclame the acidic or saline etc.
- The deffeciancy of micro element like Znic, Copper, Boron, Molebdinum, Iron, Cobalt, Silicon, Mangnese & Clorineetc also advarsely affect the crop condition & ultimately the production.
WHY TESTING IS NECESSARY?
- Soil fertility is assessed by its testing.
- High dose of Chemical fertilizers are being used by the farmers to increase production of various hybrid verities of crops.
- If farmers can use the balanced doze of fertilizer for crop production then unnecessary financial loss can be avoided.
- The testing can be useful to maintain its health. To know the fertility, periodically the testing is necessary.
- Ph status (Acidic or base) of the Ag. field can be known by testing. Appropriate use of fertilizer for crop production can be recommended on the basis of Ph value of it.
- The testing categorizes the soil in to various categories such as Saline, Alkaline or Mineral. The farmers can be advised to convert such soils in to normal.
SOIL SAMPLE PROCESS
The testing in the laboratory requiresonly a few grams of the 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.
- The sample collected from the selected sites should be composite and mixed thoroughly in a container.
- From this lot a representative sample, about 500 gm should be taken out and air-dried under shade.
- 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 it and/or the crops grown therein.
- Then the sample should be taken to the laboratory where facilities for testing for micronutrients are available.
PRESCRIBED AREA FOR TAKING SAMPLES:
| LAND USE | AREA |
|---|---|
| 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 it is too wet to plow, it is too wet to sample'.Try collecting samples at the same time every year
FREQUENTY OF SOIL SAMPLING?
Soils from coastal plains, sandy, light textured - sample once after every 2-3 crops Silty, clay loams and mountain - sample once every four cropping years.
SOIL SAMPLING TOOLS
- Easy to clean, rust resistant, strong and easy to use
- Take small, equal volume of it from each sub-sampling site to obtain composite size.
- Adaptable to dry sandy soils as well as moist sticky soil
- 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 it 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.
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 |
DIRECTION WHILE SAMPLING AND PREPARATION
- Soil samples should not be collected from recently fertilized areas, bunds, low lying corners, spots near trees, fences, channels, compost pits, etc.
- Samples should be drawn between rows in line sown cropping areas.
- Sampling should be done separately for areas represented by different crops, problem spots, etc.
- Once it is collected, the bulk soil is mixed thoroughly and desired quantity of the sample is obtained by 'quartering method'.
- Soil samples should not be placed in fertilizer bags, and in porous cloth.
- Wet samples should be dried in shade before sending them to the laboratory.
SOIL TEST INTERPRETATION FOR FERTILIZER RECOMMENDATIONS
After collection and analysis of the samples, it is the responsibility of the analyst/scientist to interpret the results and properly give the fertilizer 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 fertilizer form so that harvests are assured. Nevertheless, the testing is much more than determining nutrient availability.
VARIOUS APPROACHES USED FOR FERTILISER RECOMMENDATIONS
- Generalized fertilizer recommendations (or) Agronomic fertilizer recommendations.
- Fertilizer recommendations based on soil critical levels
- Fertilizer recommendations adjusted based on its fertility categories
- Fertilizer recommendations for maximum yield
- Fertilizer recommendations for certain percentage of maximum yield
- Fertilizer recommendations for specific yield targets
SOIL TEST CALLIBERATION
Incorporation of generated data through intensive research and establishing a significant relationship between.
- Soil test values and the uptake of applied plant nutrients by a particular crop
- Calibration between the tests values and crop yield responses to rates of plant nutrients applied through fertilizers in the field
- Changes in soil test values that occur when known quantities of fertilizers are applied to the soil
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 different-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 testing program needs to be augmented almost 15-20 times.
Madhya Pradesh is having presently 22 Testing Labs and Surveyors. The main objective of Health Centres is to maintain the soil health by analysing nutrient status of the and to give suggestions on the quantities of major nutrients like nitrogen, phosphorus, potassium to be applied to them. Micro Nutrient analysis is also important to know the status of Manganese, Boron, Zinc, Iron etc., present in it and accordingly suggest supplimental application for better plant growth.
Steps required to strengthen the survey are improve the capacity utilization of existing 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 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
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 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 testing for assessing the micronutrient status of soils and determining 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 the testing laboratories for nutrient. Farmers are advised to make the best use of this service rendered by these laboratories. The test can be performed for the soil of farmer by just paying Rs 50. Farmer near Bhopal makes quite often use of it.
Madhya Pradesh is having presently 22 Testing Labs and Surveyors. The main objective of Health Centres is to maintain the soil health by analysing nutrient status of the and to give suggestions on the quantities of major nutrients like nitrogen, phosphorus, potassium to be applied to them. Micro Nutrient analysis is also important to know the status of Manganese, Boron, Zinc, Iron etc., present in it and accordingly suggest supplimental application for better plant growth.
Steps required to strengthen the survey are improve the capacity utilization of existing 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 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
| AVAILABLE 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 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 testing for assessing the micronutrient status of soils and determining 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 the testing laboratories for nutrient. Farmers are advised to make the best use of this service rendered by these laboratories. The test can be performed for the soil of farmer by just paying Rs 50. Farmer near Bhopal makes quite often use of it.
- Classification of soils.
- Evaluate and monitor soil fertility.
- Identify salinity, alkalinity, acidity, etc., problems.
- Assess the relative nutrient supplying power of it.
- Predict profitable responsiveness of soil to added fertilisers, lime, gypsum and other amendments for optimum and economical crop production.