轮作体系下麦/油减量施氮与水稻氮肥运筹对作物产量和氮素吸收的影响

为了研究麦/油-稻轮作体系麦/油减量施氮与水稻氮肥运筹对作物产量、氮素吸收和氮肥偏生产力的影响,于2017—2018年开展麦-稻轮作和油-稻轮作的田间试验,在麦/油季设置常规施氮(小麦,N 150 kg·hm^-2;油菜,N 180 kg·hm^-2)、减量施氮(小麦,N 120 kg·hm^-2;油菜,N 150 kg·hm^-2)2个处理,在水稻季N 150 kg·hm^-2用量基础上设置3个运筹M1~M3,基肥、分蘖肥、穗肥的用量比分别为2∶2∶6、3∶3∶4和4∶4∶2。结果表明:在麦-稻轮作体系下,小麦季减量施氮小麦产量、地上部生物量和地上部氮素吸收量分别显著(P<0.05)降低15.36%、14.21%和17.14%,小麦氮肥偏生产力显著(P<0.05)增加5.79%。小麦季常规施肥处理下,M3运筹的水稻产量最高,而减量施氮处理下,M2运筹的水稻产量、地上部氮素吸收量和氮肥偏生产力最高。在油-稻轮作体系下,油菜季减量施氮显著(P<0.05)降低了油菜的产量和地上部氮素吸收量,降幅分别为14.28%和16.76%。无论油菜季减氮与否,M3运筹的水稻产量、地上部生物量和氮肥偏生产力均最高。

Effects of nitrogen reduction in wheat/rape season and nitrogen fertilizer management in rice season on crop yield and nitrogen uptake in crop rotation system

In order to reveal the effects of nitrogen reduction in wheat/rape season and nitrogen fertilizer management in rice season on crop yield, nitrogen uptake and partial factor productivity in crop rotation system, a field experiment of wheat-rice rotation and rape-rice rotation was conducted in 2017-2018. In this rotation system, conventional nitrogen rate (N 150 kg·hm^-2 in wheat season or 180 kg·hm^-2 in rape season) and reduced nitrogen rate (N 120 kg·hm^-2 in wheat season or 150 kg·hm^-2 in rape season) were set. Based on the application rate of 150 kg·hm^-2 N in rice season, 3 models named M1-M3 were also set, of which the application rate of base fertilizer, tiller fertilizer and panicle fertilizer was 2∶2∶6, 3∶3∶4, and 4∶4∶2, respectively. It was shown that the yield, biomass and nitrogen uptake in aboveground part of wheat was significantly (P<0.05) reduced under reduced nitrogen rate in wheat season by 15.36%, 14.21% and 17.14%, respectively, yet the partial factor productivity of wheat was significantly (P<0.05) increased by 5.79% in wheat-rice rotation system. Furthermore, under the conventional nitrogen rate in wheat season, the highest rice yield was recorded in M3 model, while the highest yield, nitrogen uptake in aboveground part and partial factor productivity were recorded in M2 model under the reduced nitrogen rate in wheat season. In rape-rice rotation system, reduced nitrogen rate in rape season significantly (P<0.05) reduced the yield and nitrogen uptake in aboveground part of rape by 14.28% and 16.76%, respectively. Under both conventional and reduced nitrogen rate in rape season, the highest yield, aboveground biomass, and partial tactor productivity of rice were recorded in M3 model.