油稻稻秸秆还田下氮肥运筹对双季稻产量及氮素吸收利用的影响

为明确油稻稻三熟制秸秆还田条件下双季水稻适宜的氮肥运筹方式,2018年在长江中游三熟制区(江西进贤)开展5个处理(秸秆不还田+氮肥3次施用、秸秆还田+氮肥3次施用、秸秆不还田+氮肥2次施用、秸秆还田+氮肥2次施用、秸秆还田+高量氮肥3次施用)的田间试验,探究该模式下氮肥运筹对双季稻产量与氮素吸收利用的影响。结果表明,在油稻稻三熟制下,秸秆还田和氮肥运筹对水稻产量的影响在早稻季和晚稻季均存在显著的互作效应,而水稻基肥中增施20%氮肥对产量的影响不明显,氮肥2次施用(后氮前移)即可实现水稻高产和稳产。秸秆还田并配合氮肥2次施用(后氮前移)可以满足水稻生育期氮素需求,从而保证水稻正常生长,氮素吸收量能够达到甚至优于3次施氮处理水平,并明显提高氮肥利用率,增加氮肥用量则不利于氮肥偏生产力的提高。

Effects of Nitrogen Application with Residues Retention on Yield and Nitrogen Use Efficiency of Double Rice under Rice-Rice-Rapeseed Cropping System

To explicit proper nitrogen application with residues retention under rice-rice-rapeseed cropping system,a field experiment with five treatments was conducted to study the effects of nitrogen application on yield and nitrogen use efficiency of double rice under this cropping system in triple-cropping areas(Jinxian of Jiangxi)in the middle reaches of the Yangtze River.Five treatments were followed as:1)N fertilization in 3 times with residues removal,2)N fertilization in3 times with residues retention,3)N fertilization in 2 times with residues removal,4)N fertilization in 2 times with residues retention,and 5)20% higher N fertilization rate in 3 times with residues retention.The results showed that nitrogen application significantly interacted with residues retention to increase rice yields in both early and late rice seasons.Rice yield was not affected by 20% higher N application rate with residues retention,while nitrogen partial factor productivity was significantly decreased with 20%higher N application rate.N fertilization in 2 times with residues retention could maintain high level yield of double rice,for meeting the nitrogen demand,ensuring the normal growth and enhancing N efficiency of rice.Therefore,N fertilization in 2 times(moving the panicle fertilizer-nitrogen forward)with residues retention can be used to ensure high level of rice yield and N efficiency under rice-rice-rapeseed cropping system.