Need for Soil Testing
There are about 20 elements essential for plant growth out of which primary and secondary elements like N, P, K, Ca, Mg, S are involved in major metabolic functions of plants and their deficiency in soil affects crop yields. Soil PH is also one of the crop growth limiting factors which indicates acidic or alkaline soil condition under which growth of plants is restricted. Salt concentration is also one of the plant growth limiting factors.
Soil testing therefore involves analysis of available nutrients like N, P, K , Ca , Mg and S, micro nutrients and based on acidic and alkaline PH conditions lime and gypsum requirement of soil.
For efficient soil testing and better results, the soil testing programme can be divided into different phases viz.
1. Collection and preparation of soil sample.
2. Extraction of available nutrients and their determination.
3. Calibration and interpretation of results.
4. Recommendation of fertilizers based on soil testing results.