Nutrient Balance in Rice

摘要

Study of nutrient balance in rice helps in optimisation of fertiliser application for achieving higher rice productivity and improving soil quality.Imbalanced use of fertilisers has deleterious effect on soil fertility and rice yield in long run.Over a period of 21-23 years,the average response to 30-60 kg K_2O/ha in laterite soil at Bhubaneswar,red loam soil at Hyderabad and Terai soil at Pantnagar varied from 0.4-0.6 t/ha.The share of N in total grain yield response to NPK+FYM decreased and that of P and K increased with years of cropping at all locations.In general,with application of N as well as P,there was positive balance of these two nutrients in rice-rice system.But even with application of K fertilisers @ 40-60 kg K2O/ha,the K balance in rice was negative suggesting the need for adequate supply of K to rice for obtaining sustainable high yield.The sustainable yield index was higher in the integrated use of N,P,K and farmyard manure than N,NP and NPK.