南疆有限灌溉小麦-玉米多熟种植体系周年水、氮利用特征及其调控机制

Wheat-maize sequential cropping is the main way of grain production in southern Xinjiang, it is of great significance to the stable and sustained development of Xinjiang. With the rapid expansion of industry and agriculture and expand of city, the contradiction between supply and demand of water resources is becoming acute increasingly in southern Xinjiang. In order to solve the problem of the shortage of water resources and low water use efficiency of grain production, and lay the foundation for food of high and stable yield, sustainable development in Southern Xinjiang, technology and methods of high use efficiency of water and nitrogen in wheat -maize sequential cropping system is explored. By setting the different water, nitrogen treatment in winter wheat season and maize season, the wheat/maize annual production is as a whole, the characteristics of water and nutrients of the system is studied quantitatively by using water balance method and the nutrient balance method. Study on the dynamic change of soil water content, nitrogen absorption and change rules of migration under limited irrigation in wheat and maize, crop water process under water deficit environment, physiological regulation and stoma response mechanism, effect of different irrigation and nitrogen on the growth of vegetative and reproductive growth and its regulation mechanism are studied. Influence of water deficit on the whole system, crop water consumption regularity, nitrogen utilization rate, yield, economic coefficient, water use efficiency and economic benefit are analyzed, in order to provide theoretical basis for the establishment of nitrogen and water efficient utilization technology system suited for wheat/maize sequential cropping in southern Xinjiang.

小麦-玉米多熟种植是南疆粮食生产的主要途径，对新疆的稳定、持续发展意义重大。随着工、农业产业规模的扩大和城市的快速扩张，南疆水资源的供需矛盾日益尖锐。为解决粮食生产中水资源紧缺、水分利用效率低下的问题，对小麦-玉米多熟种植体系水、氮高效利用的技术方法进行探索，为实现南疆粮食高产、稳产、持续发展奠定基础。本项目通过在冬麦季和玉米季设置不同的水分、氮素处理，将小麦-玉米周年生产作为一个整体，利用水分平衡法和养分平衡法定量研究该体系的水分、养分利用特征，研究有限灌溉下的小麦、玉米土壤水分动态变化，氮素吸收运移变化规律，水分亏缺环境下作物耗水过程、生理调控与气孔响应机理、不同灌水量和氮素耦合对营养生长与生殖生长的影响及其调控机制，分析亏水处理对整个体系作物耗水规律、氮素利用率、产量、经济系数、水分利用效率及经济效益的影响，为建立适合南疆小麦-玉米多熟种植水、氮高效利用技术体系提供理论依据。

小麦-玉米多熟种植是保障南疆粮食安全和社会稳定的重要途径。在当下现有资源的情况下，提高水、肥利用率，实现稳定和提高粮食产量是农业生产亟待解决的难题之一。本项目通过通过设置不同的水分、氮素处理，将小麦-玉米周年生产体系作为一个整体，研究该体系的生产特点，水分、养分利用特征，研究有限灌溉下的小麦、玉米土壤水分动态变化，氮素吸收运移变化规律，灌水量和氮素互作对营养生长与生殖生长的影响及其调控机制，探讨水氮耦合对整个体系作物耗水规律、氮素利用率、产量、经济系数、水分利用效率及经济效益的影响，以建立适合南疆小麦-玉米多熟种植水、肥高效利用技术体系。.研究结果表明，水氮耦合条件下不同施氮水平的小麦、玉米生物量、产量和植株吸氮量的年际变化都很大，气象因子、降水量、降水时期以及作物的需水特性都会对系统生物量、产量和吸氮量产生影响。灌水量和施氮不足显著降低作物产量和植株吸氮量；施尿素量超过400kg.hm-2灌水量越大作物产量和吸氮量的年际变化较小，有稳产的效果；同时冬小麦和夏玉米产量、吸氮量都达到最高水平，氮肥偏生产力、农学效率、累积表观利用率以及氮素生产效率也比较高，进一步增加施氮量，产量和吸氮量不再显著增加，反映氮肥利用效率的各项指标也都显著降低；不考虑氮肥损失及环境供氮量，冬小麦氮素携出量大于施氮量，土壤氮素表现出亏缺;夏玉米氮素携出量小于施氮量，土壤氮素表现出盈余。而冬小麦-夏玉米轮作体系中，冬小麦根系可有效利用前茬玉米季残留的氮素。因此，小麦-玉米轮作体系进行水氮配置时，应把两季作为一个整体，不仅要考虑作物产量、吸氮量和氮素利用，同时也要兼顾对土壤氮素平衡和肥力的影响。