Soil testing is the method and procedure for obtaining soil samples that vary according to the purpose of testing. Analysis of soil samples may be needed for engineering and agricultural purposes. Soil sampling for agricultural purposes is described which is done for soil fertility evaluation and fertilizers recommendations for crops.
Why should we do Soil testing?
Testing your soil helps ensure you are getting the most out of your fertilizer for the healthiest and high yield. All you have to do is send a 1-Kg sample to a lab. That soil will likely represent many acres of soil, So getting a truly representative sample is important. If a good sample is collected, the results should provide a good estimate of the status of the soil.
It is the first step into soil fertility management
Gain knowledge about the soil condition and how to improve it
Minimize fertilizer expenditures
Avoid soil degradation
Soil testing provides plenty of benefits for farmers. Healthy soil improves crop growth. Farmers can begin testing their soil after harvest season to get a jump on how they can improve their soil for the next crop.
These benefits can help Farmers:
- Improving yields and profitability because you are providing necessary nutrients to your crops.
- Increasing consistency of nutrient availability across a field.
- More uniform crop growth. This also helps individual plants stronger against weeds and simplifies other processes like cultivation and spraying.
- More uniform plant maturity. This can help simplify crop harvesting and drying along with improving market quality.
- Allowing fine-tuning of which nutrients are most needed. Helping you allocate your fertilizer dollars to those nutrients will give you the greatest profit increase.
- Topsoil sample: One-acre area of land sample be collected at least from 6 - 8 spots. In the selected 6 - 8 spots, a pit of two feet depth of 1 x 1 feet area is to be dug up.
- The second sample is collected in the pits by scooping the sidewalls on all four sides at a depth of surface to one foot.
- The third sample can be collected by scooping the sidewalls on all four sides at a depth of one foot to the bottom.
- These spots are to be marked in such a way that is not in one line.
In all the selected spots dig a 2 feet depth pit of 1 feet width and 1 feet length. In each pit, three soil samples, are to be collected as detailed above. All these three collected samples which are in separate basins are powdered separately mixed uniformly.
Collection of soil sample steps are as follows
- Soil samples should not be collected from bunds, margins, marshy areas, tree shades, places where fertilizers and Farm Yard Manure (FYM) are stocked previously, irrigation channel borders, and also from non-represented areas of the plantation area.
- Soil samples should not be collected in fertilizer bags.
- If the soil is replenished recently with lime, ash, or fertilizers, in such cases the soil sample has to be collected only after the cropping period.
- Soil samples to be collected only using soil auger, crowbar, pickaxes spade, etc.
- Soil samples should not be collected in irrigated moist areas immediately after application of fertilizers and at agricultural waste burnt places.
- One acre area one handful of soil samples should be collected from 6 - 8 places into a basin and stored. Mixed thoroughly and using quadrate method retain one sample.
- Confirm that the collected and retained soil sample is sufficient for analysis.
- Provide all the related information pertaining to the soil sample without fail.
- Collected soil samples are spread on a clean dry cloth/plastic sheet.
- Dry the samples in shade, mix uniformly and remove dry matter, small pebbles, and stone pieces of plant materials.
- The powdered, fully dried samples are spread into a circular shape and split into four equal parts. From this reject the opposite sides and mix the retained two parts thoroughly.
- Repeat this process 2 - 3 times until 500g. of soil is retained for analysis.
- This dried, powdered soil sample is put into a clean dry plastic bag and labeled separately. The following information is to be provided along with the soil samples.
1. Each soil sample may be labeled separately as topsoil, one foot depth/Mid soil, and two feet depth soil/bottom soil.
The 3 samples are ready to send for analysis
Top Soil 1 Feet Depth 2 Feet Depth
- When an ongoing crop exists, soil samples in the field to be only collected in between the rows of the plantation.
- Collected soil samples dried in shade one or two days are filled in a clean polyethylene or cotton bag and sent to a soil testing laboratory.
Soil sample collection method
4. After separately testing the entire soil samples comprehensive consolidated by the testing laboratory mean results along with suitable recommendation is provided.