Nutrient mining in different agro-climatic zones of bihar

摘要

Intensive production system causing heavy nutrient mining followed by inadequate replenishment through fetilizers has ultimately led to emergence of multiple nutrient deficiencies in soils of different agro-climtic zones of bihar. For whole state, the ratio of annual removal of NPK is 1:0.213:1.020 whereas addition as fertilizers in terms of NPK ratio is 1:0.242:0.10. The soils of zone III indicate the most serious situation where the net annual removal of 33.9%N, 41.3% P and 97.3% K is recorded. The situation becomes more alarming when net balances sheet of mining of NPK is computed on the basis of nutrient use efficiency. Zonewise systematic research works on assessment of all macro-, secondary and micronutrient inputs through different surces are inadequate. Addition of nutrients through fertilizers is erratic and far below the national average consumption whereas addition through FYM, crop residues, irrigation water, compost, biofertilizers and vermiculture is neither appropriately documented nor in practice by farming mass. The occurrence of annual flood and upwelling of wate rin some zones complicates the computation procedures for nutrient's addition and removal to soils. THe state has immense potneital of orgnaic manures, crop residues and similar recyclable wastes which may be scientifically processed for beneficiation and applied for promoting soil health and crop yields. Integrated plant nutrient supply system following balanced fertilisation needs to be developed specifically for resource poor farmers of the state and this may only sustain the potnetial productivity ofthe soils. The present report is based on review work done on the extent of nutrient mining and suggestions for minimizing the threats of unsustainability owing to exhaustive cultivation coupled with imbalanced and inadequate fertilization of soils in different agro-climatic zones of bihar.