水稻秸秆还田配施肥料对小麦产量和氮素利用的影响

为了解高C/N比秸秆还田与肥料施用对金坛地区小麦产量和氮素利用的影响，通过设置大田试验，研究了稻秸还田与肥料施用对麦季土壤养分、微生物生物量、作物产量和氮肥利用率的影响。结果表明：稻秸还田配施肥料能够提高土壤速效养分含量。单施肥仅显著影响拔节期微生物生物量碳，单施稻秸显著影响拔节期和抽穗期微生物生物量氮，稻秸还田和肥料施用的交互作用在拔节期显著影响土壤微生物生物量和微生物熵。单施肥、稻秸配施肥料处理的氮肥表观利用率分别为31%和37%，稻秸配施肥料后的氮肥农学利用率和偏生产力表明每kg纯氮增产幅度约为6.86 kg籽粒。单施肥和稻秸配施肥料显著增加了小麦每穗粒数及千粒重，并且理论产量分别增加211%和319%，实际产量则分别增加119%和231%，而单施稻秸处理的实产却减产21%。综合分析认为，稻秸还田搭配肥料施用，能够保证当季土壤有效氮供应，促进土壤有机质转化为更易被微生物利用的形态，提高养分有效性，促进小麦对氮素的吸收利用，有利于每穗粒数和千粒重的增加，从而最终提高小麦的产量。

Effects of Rice Straw Returning Combined with Fertilizer Application on Yield and Nitrogen Utilization of Wheat

The rice-wheat rotation system in Jintan was chosen to investigate the effects of rice straw returning and fertilizer application on soil nutrients, microbial biomass, crop yield and nitrogen use efficiency in wheat season via filed experiments. Results showed that the contents of soil available nutrients could be increased by rice straw returning in combination with fertilization. The treatment of fertilization only significantly affected soil microbial biomass C at jointing stage, while rice straw incorporation notably influenced soil microbial biomass N at jointing and heading stages, and the interaction of rice straw returning and fertilization observably affected soil microbial biomass and soil microbial quotient at jointing stage. The nitrogen use efficiency of fertilization and rice straw returning in combination with fertilization treatments were 31% and 37%, respectively; while the nitrogen agronomic efficiency and partial factor productivity showed that the yield increase per kilogram pure nitrogen was about 6.86 kg grain. The spikelets per panicle and 1000-grain weight of fertilization and rice straw returning in combination with fertilization treatments were remarkably increased. The theoretical yield of these two treatments increased by 211% and 319%, respectively, while actual yield increased by 119% and 231%, respectively. However, the actual yield of rice straw returning decreased by 21%. Overall, rice straw returning to the field combined with fertilization can ensure the supply of soil available nitrogen, facilitate the transformation of soil organic matter into microbial available form, improve the nutrient availability, promote the absorption and utilization of nitrogen by wheat, and is to the benefit of spikelets per panicle and 1000-grain weight increases, thus ultimately elevate wheat yield.