Soil Science and Soil Health Management: Sampling, Interpretation and Amendments
Soil Science and Soil Health Management tests soil sampling, laboratory report interpretation, nutrient recommendations and amendment use. Haryana soils range from sandy loam in the south-west to heavier loam; alkalinity and salinity are local problems.
Core rules
- Sample 0–15 cm for field crops in a zig-zag pattern from 10–15 spots, mix into a composite, air-dry, label and send to a laboratory. Avoid sampling immediately after fertilizer application.
- A Soil Health Card reports pH, electrical conductivity, organic carbon, available N, P, K, sulphur and micronutrients. Interpret each value against crop requirement rather than reading only one number.
- pH above 8.5 with high exchangeable sodium percentage indicates sodic soil; gypsum and leaching are used. Acidic soil needs lime. Saline soil needs drainage and salt-tolerant crops.
- Organic carbon improves with FYM, green manure and residue retention. Place fertilizer near the root zone and follow the Haryana Package of Practices.
Worked example
A recommendation is 60 kg P2O5/ha and 120 kg N/ha. DAP is 46% P2O5, so DAP = 60 ÷ 0.46 = 130.4 kg/ha. This DAP also supplies N: 130.4 × 0.18 = 23.5 kg N/ha. Balance N = 120 − 23.5 = 96.5 kg/ha. Urea = 96.5 ÷ 0.46 = 209.8 kg/ha. If potassium is also recommended, calculate MOP separately as K2O ÷ 0.60. Always state the nutrient basis before converting to bags.
Traps that cost marks
Do not apply gypsum to acidic soil or lime to sodic soil. Do not confuse EC with pH: EC indicates salinity, while pH indicates acidity or alkalinity. Do not report one spot as a field composite, sample within one to two weeks of fertilizer application, ignore free lime before gypsum, or treat a Soil Health Card as a permanent prescription.