Nitrogen use efficiency as affected by time variant nitrogen application to wetland rice

摘要

Application of N to wetland rice at the rate of 90 kg ha~(-1) 10, 30 and 50 days after transplanting, either in the ratio of 50:25:25 or 25:50:25, resulted in minimum N losses and maximum increase in plant growth, grain yield, N uptake and N-use efficiency. Application of N in two splits 20 (75%) and 40 (25%) days aftertransplanting or in three splits at transplanting and 20 and 40 days aftertransplanting in the ratio of 25:25:50 and 50:25:25 resulted in the highest N losses and consequently the lowest plant growth, yield, N uptake and N-use efficiency.