【作者】 廖晓勇；

【导师】 张杨珠； 陈新平；

【作者基本信息】 湖南农业大学 ， 土壤学， 2001， 硕士

【摘要】 本研究针对华北平原冬小麦-夏玉米轮作中农民习惯性大水高氮投入，但不见得取得增产效应，并造成资源浪费，且可能污染环境的现状，由分期优化施氮技术（即根据作物不同生育阶段氮素吸收规律确定不同阶段的所需氮素供应量，并由土壤无机氮的测试计算作物各阶段的氮肥用量以进行氮肥用量和施用时期的优化管理）结合优化灌溉和优化田间管理措施，建立资源高效的优化氮肥管理体系。通过田间小区试验，以对照和传统氮肥管理体系作对比，研究优化氮肥管理体系对作物产量、生物量、吸氮量、土壤残留无机氮及氮素的表观平衡的影响。主要结果如下： 1．冬小麦优化施氮处理和传统施氮处理的产量无显著性差异，且都达到了目标产量，施氮处理比不施氮处理的冬小麦产量要高。限量灌溉条件下的冬小麦优化施氮的氮肥用量为24kg/hm~2，传统和优化灌溉条件下的优化施氮处理冬小麦季平均施氮是78kg/hm~2，分期优化施氮技术提高施肥效益。优化施氮和传统施氮处理的生物累积动态相同且在整个生育期生物量不存在差异。秸秆不还田情况下，传统施氮处理在收获时的冬小麦地上部吸氮量显著高于优化施氮处理的吸氮量，但这高出部分是分配在秸秆中，对籽粒吸氮量无贡献。 2．优化施氮处理的夏玉米产量和传统施氮处理产量差异不显著。因为播种质量问题，间苗时，小苗太多，成穗率低，造成单位面积穗数低，致使产量没有达到目标产量。优化施氮技术必须和其它高产栽培技术相结合才能达到氮肥的高效利用。本试验条件下，土壤肥力较高，夏玉米季土壤有机氮矿化最高，优化施氮、传统施氮和当季不施氮处理作物生长和氮素吸收增长趋势相同且差异不显著。 3．优化施氮处理在冬小麦/夏玉米轮作中0-90cm土壤无机氮维持在80～185kg/hm~2内浮动，仅略高于不施氮处理土壤无机氮。而传统施氮处理0-90土壤始终残余高量无机氮（290～510kg/hm~2）。 4．优化施氮处理的氮素在冬小麦和夏玉米两季作物投入与产出基本平衡，盈亏在50kg/hm~2内。传统施氮处理在冬小麦季氮素收支大致平衡，在夏玉米季氮素亏缺严重，平均损失133kgN/hm~2。在夏玉米收获时，传统施氮处理有大量硝态氮迁移出90cm土体外，聚集在90-200cm土壤中，而优化施氮处理90-200cm土体中硝态氮与对照相差不大。更多还原

【Abstract】 At North China Plain farmers were used to mass water and N fertilization input, but the crop yield was always not I)ositivety responsible to high input of nitrogen fertilizer and water in winter wheat-summer maize rotation system while wasting resource and possible negative effect on environment. The study intended to establish an optimized nitrogen management system, in which resources could be utilized with high efficiency, and constituted by optimized N fertilization at different stages (Winter wheat N demands which were according to N uptake in different stages, coupled with soil Nmin to optimized the time and the amount of N application in different stages) , optimized irrigation and optimized farm management. A field trial was carried out to study the effect of optimized nitrogen management system on crop yield, biomass, N uptake, soil Nmin and N balance by comparing those of conventional nitrogen managerial system and no N fertilization control. The main results were summarized as follows:1 For winter wheat the yields of optimized N fertilization treatment and conventional N fertilization treatment were not significantly different and achieved target yields. The amountof N fertili~er in optimized N fertilization treatment was 24kg/hm2 under suboptimizedirrigation condition and 78kg/hin2 under conventional irrigation and optimized irrigation condition. The results showed optimized N fertilization at different stages enhanced the profit of N application. 憀抙e dynamics of accumulated biomass between optimized N fertilization treatment and conventional N fertilization treatment was similar without difference. Without straw, at harvest total N uptake in conventional N fertilization treatment was significantly higher than that of optimized N fertilization treatment, but the superfluous N distributed in straw and N uptake of grain was not different between two treatments.2~ The summer maize yield between optimized N fertilization treatment and conventional N fertilization treatment was not significantly different. Because of the quality in sowing, there were too many young plants and the rate of coming into ears was rather low, which led to lower yield than target yield. Only combining optimized N fertilization technology and other technology for high yield could best use N fertilizer. The amount of soil N mineralization was large in high fertility soil, so the trend of summer tna?ze growth and N uptake was not different among optimized N fertilization treatment, conventional N fertilizatioii treatment and no N fertilization treatment.3.in winter wheat/summer maize rotation system, 0-90cm soil Nmin of optimized N fertilization treatment fluctuated between 8OkgIhm2 and l85kglhm2, which was slightly higher32001than that of control treatment, but there was much higher soil residual Nmin(290---5lOkg/hm2) in conventional N fertilization treatment.4.The input and output of nitrogen was almost balanced on the whole rotation season in optimized N fertilization system, the gain and the loss in 5OkgIhm2. In winter wheat N income and N expenses were approximately equal in conventional N fertilization treatment, while in summer maize N was seriously lost and the mean loss was I 33kgN/hm2. At summer maize harvest lots of N03-N moved below 90cm soil layer in conventional N fertilization treatment and accumulated in 90-200cm soil layer, but soil Nmin in 90-200cm of optimized N fertilization treatment had the least discrepancy with control treatment.更多还原