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Know Your Soil: Hows and Whys of Soil Testing

Know Your Soil: Hows and Whys of Soil Testing

Before the start of any crop cycle it is important for any farmer to know his soil quality well. Knowing the nutrient content of farm soil is the first step towards a proper farm management cycle. Every crop has a specific nutrient requirement, which is fulfilled through the soil. It is important for the soil to be rightly fertilized before the start of the crop cycle, as under or over fertilized soil will have a direct effect on the crop yield. Nutrient imbalances in the soil will also have an affect on the water quality and soil ecology of the farm.

Considering the degrading soil and water quality and increasing agricultural costs , farmers are largely relying on precision farming to move towards profitable farming. Soil Testing and Analysis are proving to be important tools for the farmer to implement precision farming

Timely done soil analysis proves to be very fruitful for the farmer. It not only minimizes the fertilizer expenditure but also limits over fertilization. Over fertilization apart from leading to over expenditure also degrades soil and affects subsequent crop yield.

Soil Analysis normally comprises of Soil pH, EC, quantitative analysis of macro (N,P,K), Secondary & micro nutrients (Ca, Mg, S, Mn, Fe, Bo etc.)

Every soil sample collected must be a true representative of the area being sampled. Lab analysis largely depends on the sampling precision. Soil sampling for soil analysis should be done at the rate of at least one sample for 2 hectares.
Soil collection for analysis is normally recommended between two crop cycles.

Soil Sampling Methodology

Steps to be followed to collect Soil sample :

Step 1: Collect the soil sample during the fallow period, when the farm is idle. If soil analysis is to be done during standing crop, collect samples between rows.

Step 2: Avoid sampling in dead furrows, wet spots, areas near main bunds, trees, manure heaps and irrigation channels.

Step 3: Divide the field into different similar units.

Step 4: Remove the surface debris/waste material at the sampling spot.

Step 5: Make a ‘V’ shaped cut up to a depth of 15-90 cm depending on crops in the sampling spot using spade.

Step 6: Collect at least 10 to 15 samples from each sampling unit and place in a bucket or tray.

Step 7: Mix the samples thoroughly and remove foreign materials like roots, stones, pebbles and gravels.

Step 8: Reduce the bulk to about half to one kilogram by quartering. [Quartering is done by dividing the thoroughly mixed sample into four equal parts. The two opposite quarters are discarded and the remaining two quarters are remixed and the process repeated until the desired sample size is obtained.]

Step 9: Collect the sample in a clean cloth or polythene bag.

Step 10: Label the bag with information like Farmer Name, location of the farm, survey number, previous crop grown, present crop, crop to be grown in the next season, date of collection, name of the sampler etc.


Guidelines for sampling depth:

Sr.No.CropSoil sampling depth in (cm)
1Rice, millet, groundnut,etc.(shallow rooted crops)15
2Cotton, sugarcane, banana, vegetables etc. (deep rooted crops)22
3Perennial crops, plantations and orchard cropsThree soil samples at 30, 60 and 90 cm

Regular and timely soil analysis will always continue to be an important tool for farmers striving to optimize nutrients, yields and profitability.

Hope this was helpful. You can get your soil tested by putting in a request through our Kheti Buddy Farm application which is available on Google play store and App store.  To download our farm app click here