Effects of Nitrogen Management on Yield and Quality of Late Rice and Nitrogen-use Efficiency

Yield and quality of late rice and nitrogen-use efficiency were investigated by applying nitrogen with different ratios of basal,tiller fertilizer and panicle fertilizer under the same soil and nitrogen application condition.Postponing nitrogen fertilization could appropriately maintain suitable NH4+-N concentration and promote the growth of late rice,resulting in good yield,dry matter and nitrogen accumulation;When nitrogen application as basal fertilizer accounted for 53.8%,the rice yield amounted to maximum.Meanwhile,the milling quality became better with the increasing panicle fertilizer ratio,while the appearance quality and cooking quality became worse.Moreover,postponing nitrogen fertilization could appropriately improve the nitrogen-use efficiency.When nitrogen application as basal fertilizer accounted for 40.3%,the N-uptake of late rice and nitrogen-use efficiency amounted to maximum.Besides the soil N dependency showed parabolic curve relationship with the basal fertilizer ratio.And the minimum soil N dependency was 54.5% when the ratio accounted for 40.0%,however,the nitrogen harvest index and the N-requirement per 100 kg grain increased with the decreasing nitrogen application as basal fertilizer.Therefore,the best nitrogen application ratios,as the basal fertilizer,tiller fertilizer and panicle fertilizer were 40%-50%,20%-30% and 20%-30% respectively.