麦秸全量还田下水稻物质生产与分配对氮肥运筹的响应

Responses of Dry Matter Production and Distribution in Rice(Oryza sativa L.)to Nitrogen Application Regime with Total Wheat Straw Mulching

【目的】本文研究了获得麦秸全量还田下优化的水稻氮肥管理措施,以期为秸秆还田利用和减量高效施氮提供理论依据。【方法】采用土培试验,施氮量设置常量施氮(A1,270 kg/hm^2)和减量施氮(A2,240 kg/hm^2),氮运筹设置高比例基氮肥(B1,基肥∶分蘖肥∶穗肥=5∶2∶3)和高比例分蘖氮肥(B2,基肥∶分蘖肥∶穗肥=2∶5∶3),以不施氮(CK,0 kg/hm^2)为对照,对不同氮水平及氮运筹处理水稻关键生育期植株高度、干物质积累和分配特性进行了系统地比较研究。【结果】麦秸全量还田条件下,减量施氮处理水稻后期株高显著低于常量施氮处理,2种施氮量下提高分蘖氮肥比例(2∶5∶3)株高均有所升高。孕穗期至成熟期,减量施氮处理水稻地上部干物质量低于常量施氮处理。从抽穗期至成熟期,减量施氮处理水稻叶片生物量及其占总生物量的比例低于常量施氮处理,2种施氮量下高比例分蘖氮肥处理叶片所占比例均较高;减量施氮处理茎秆生物量较常量施氮有所下降,2种施氮量下提高分蘖氮肥比例茎秆生物量所占比例均降低;减量施氮处理叶鞘生物量及分配比例较常量施氮下降,其中抽穗期叶鞘生物量差异达显著水平;穗部生物量及其所占比例则为减量施氮处理高于常量施氮处理,减量施氮下提高分蘖氮肥比例穗部生物量降低。【结论】综上可知,麦秸全量还田条件下,常量施氮时水稻中后期可获得较高的株高和地上部干物质量,总体上增加叶片、茎秆和叶鞘的生物量及分配比例。常量施氮下提高分蘖氮肥比例利于水稻营养器官的物质生产和累积,而减量施氮则有利于水稻穗部的物质积累和分配。

【Objective】This paper aimed to obtain optimized management measures of rice nitrogen fertilizer with total wheat straw mulching,so as to provide the theoretical basis for straw mulching and high-efficiency nitrogen application.【Method】Constant nitrogen rate(A1,270 kg/hm^2)and reduced nitrogen rate(A2,240 kg/hm^2)were set for nitrogen levels,and high proportion of base nitrogen fertilizer(B1,base fertilizer∶tiller fertilizer∶spike fertilizer=5∶2∶3)and high proportion of tiller nitrogen fertilizer(B2,base fertilizer∶tiller fertilizer∶spike fertilizer=2∶5∶3)were set for nitrogen management,with no nitrogen(CK,0 kg/hm^2)as the control,and the soil culture experiment was conducted to study systematically the plant height,dry matter accumulation and distribution characteristics of rice at critical growth stages under different nitrogen levels and nitrogen managements.【Result】Under the condition of total wheat straw mulching,the plant height of rice in the later stage under the reduced N rate was significantly lower than that under constant N rate,and the plant height of rice with increased tillering nitrogen fertilizer ratio(2∶5∶3)increased under the both N levels.From booting stage to maturity stage,the above-ground dry matter of rice with reduced N rate was lower than that with constant N rate.From heading stage to maturity stage,the leaf biomass and its proportion in total biomass of rice with reduced nitrogen rate were lower than those with constant nitrogen rate,and the proportion of leaves with increased tillering nitrogen fertilizer ratio was higher under both N levels.The stem biomass of reduced nitrogen rate was lower than that of constant nitrogen rate,and the proportion of stem with increased tillering nitrogen fertilizer ratio decreased under both N levels.The sheath biomass and distribution ratio of reduced nitrogen rate were lower than that of constant nitrogen rate,and the difference of sheath biomass was significant at heading stage.The biomass of panicle and its proportion were higher under reduced nitrogen rate than that under constant nitrogen rate,and the biomass of panicle decreased under reduced nitrogen rate and high proportion tillering nitrogen fertilizer.【Conclusion】Under the condition of total wheat straw mulching,high plant height and above-ground dry matter could be obtained in the middle and late stages of rice under constant nitrogen rate,and the biomass and distribution ratio of leaf,stem and sheath could be increased in general.Increasing the proportion of tillering nitrogen fertilizer under constant nitrogen rate was beneficial to the material production and accumulation of the above-mentioned rice vegetative organs,while reducing nitrogen rate was beneficial to dry matter accumulation and distribution of rice panicle.