Responses of rice grain yield and nitrogen use efficiency to nitrogen fertilizer reduction in a rice-wheat cropping system(Nitrogen fertilizer reduction for high yield and high nutrient efficiency in a wheat-rice cropping system;Enhancing rice crop product
作者单位：Anhui Academy of Agricultural Sciences Rice Research InstituteInnovation Center of Rice Cultivation Technology in the Yangtze ValleyMinistry of Agriculture
会议名称：《全国第十七届水稻优质高产理论与技术研讨会》
会议日期：2017年
关 键 词：paddy rice nitrogen fertilizer nitrogen accumulation nitrogen use efficiency grain yield
摘 要：As the largest contributor to crop yield increase,continuously increased nitrogen(N) fertilizer application is mainly responsible for the lower N use efficiency in *** improve N use efficiency while concurrently maintaining high yield,a two-year field experiments used Yongyou2640 and zhendao18 as materials in 2014 and 2015,respectively,were conducted during 2014-2015 to explore the appropriate N application rate through reducing or increasing N fertilizer application in rice production *** experiment were laid out in a randomized complete block design in three replicates with six treatments including CK(270 kg·ha N as local farmers’ N application rate during rice growing season),CK-30%(189.0 kg·ha N as reducing by30%of CK),CK-15%(229.5 kg·ha N as reducing by 15%of CK),CK+15%(310.5 kg·ha N as increasing by 15%of CK applied),CK+30%(351.0 kg·ha N as increasing by 30%of CK applied)and N0(no N fertilizer applied during rice growing season).The N uptake and use efficiency(NUE) of rice were quantified under different N application *** results showed that rice grain yield significantly decreased at N fertilizer application reduced by 30%of the conventional rate in both years,but no significant difference in grain yield was observed at N fertilizer application reduced by 15%of the conventional rate.N accumulation in the straw and grain increased with the increased application of N fertilizer in both *** N accumulation in rice plant at maturity varied from 99.03 to255.63 kg ha in 2014 and from 173.47 to 349.87 kg ha in 2015,with the average of 208.32 kg ha and 294.15 kg ha,respectively,across all six treatments *** 2014,N accumulation ratio in the straw continued to increase as N application rates increased,but decreased in the grain.A similar trend was observed for grain/straw N accumulation ratio,ranging from 2.65 to 1.17 for different N *** finding revealed that application of excessive N fertilizer will resulted in a much higher N