Nutrient Mining in Different Agro-climatic Zones of the North-Eastern Hills Region

摘要

Based on climate, soils topography and agricultural practices, North-Eastern Hills Region has six agro-climatic zones, viz., sub-alpine or temperate, sub-tropical hills, sub-tropical plains, mild-tropical hills and mild-tropical plains. The annual removal of N, P_2O_5, K_2O, S,Zn, Mn, Fe, B,Cu and Mo by different crops, vegetables and fruittrees at the present production levels is about 96300, 17360, 84200, 6328, 63.7, 76.3, 492.1, 48.4, 16.7 and 1.5 tonnes, respectively, The annual replenishment on N, P_2O_5 and K_20 through fertilisers and organic sources is only 26.4, 41.5 and 9.4%, respectively. Replenishment of micronutrients is met through the use of orgnaic manures in the region and that appears to be adequate at the present rate of productivity. However, with increase in the area and productivity, the deficiency of zinc is likely to aggravate in some pockets if corrective measures are not undertaken. Application of sulphur is desirable in oilseed crops. The average productivity of foodgrains in different agro-climatic zones of the region is only 82% of the national average and needs to be augmented with the use of mineral fertilisers. At present, the combined use of N,P_2O_5 and K_2O per unit area in the region is only 24.3% of the national average and a crash programme is required to improve the situation. The soils in the region are depleted of N,P_2O_5 and K_2O at the rate of 70670, 10130 and 76260 tonnes, respectively annually and this trends needs to be arrested, not only to sustain but increase the productivity.