Partial Factor Productivity of Nitrogen and its Use Efficiency in Rifficiency in Rice and Wheat

摘要

Data from 21 studies in rice and 14 in wheat were examined to study the range of partial factor productivity (PFP),a gronomic efficiency (AE),apparent recovery (AR) and physiological efficiency (PE)of nitrogen in rice and wheat. On an average 20 kg N is removed with each tonne of rice grain harvested while wheat removed 24.4 kg N t~(-1) grain. PFP was same in rice and wheat, but AE and AR were higher in wheat. AE declined in both rice and wheat with an increase in level of N applied. This was also true for AR and PE,more so in wheat. The overall mean (over N levels)for AE was 17 kg grain kg~(-1) N in rice and 21.6 kg grain kg~(-1) N in wheat.