不同农艺措施对河套灌区节水春小麦氮素利用的影响

目的]系统研究春小麦生长发育特性以及植株氮素吸收规律,阐明不同农艺措施与氮素利用的关系,深入揭示节水条件下氮肥高效利用的生理机制,明确节水灌溉春小麦实现高氮素利用效率的适宜农艺措施,以期达到减少氮肥施用量、提高氮肥利用效率、降低小麦生产成本、减少环境污染、保护生态环境的目的.方法]在前期研究确立的节水灌溉模式基础上,通过4因素5水平二次回归正交设计试验,以基本苗数、种肥磷量、施氮量和灌水定额4项主要农艺措施为决策变量,以氮素农学利用效率为目标函数,建立了内蒙古河套灌区主要农艺措施与春小麦氮素农学利用效率的二次多项式回归模型.结果]4项农艺措施对氮素农学利用效率的影响大小顺序为：基本苗数＞灌水定额＞施氮量＞种肥磷量.通过频数寻优,定量化地提出了河套灌区春小麦实现高氮素农学利用效率的农艺措施优化组合方案,即基本苗数控制在678.9万～710.9万株/hm2,种肥磷量（P2O5） 142.4 ～ 158.9 kg/hm2,拔节期追施氮量（纯N）124.5～142.0 kg/hm2,拔节期和抽穗期灌水定额均为903.5 ～951.6m3/hm2,可实现节水春小麦氮素利用率大于10 kg/kg.结论]该研究可为建立河套灌区春小麦节水省肥高产栽培技术体系提供理论依据.

Influence of Different Agronomic Measures on Nitrogen Use Efficiency of Water-saving Spring Wheat in Hetao Irrigation District

Objective] The aim was to study the wheat growth and development characteristics and its plants nitrogen use absorption law systematically to clarify the relationship between different agronomic measures and nitrogen use,reveal the physiological mechanism of high efficiency use of nitrogen under water-saving conditions deeply to confirm on the suitable agronomic measures of water-saving spring wheat to realize high efficiency use of nitrogen,then to get the goal of decreasing nitrogen application amount,improving nitrogen use efficiency,cutting down wheat production cost,reducing environment pollution to protect ecological environment.Method] On the basis of water-saving irrigation pattern of preliminary studies established,the field experiment was carried out through the four factors and five levels quadratic regression orthogonal designed test,a quadratic polynomial regression mathematical model of major agronomic measures and nitrogen use efficiency of spring wheat in Hetao Irrigation Region of the Inner Mongolia were established taking the four key agronomic measures（basic seedlings number,the amount of basic phosphorus,nitrogen application amount and irrigation water quota） as decision variables,and the nitrogen use efficiency as the objective function.Result] The effects of the four agronomic measures on nitrogen use efficiency was in the order of basic seedlings number ＞ irrigation water quota ＞ nitrogen application amount ＞ the amount of basic phosphorus.Through the frequency analysis,quantitatively proposed that optimized agronomic measures combination plan of spring wheat of the Hetao Irrigation District realizing high nitrogen use efficiency was as follows：the basic seedlings number was 6.789-7.109 million plants per hectare,the amount of basic phosphorus （P2O5） was 142.4-158.9 kg/hm2,additional nitrogen amount of jointing stage （pure N） was 124.5-142.0 kg/hm2,the irrigation quota of jointing and heading stage was 903.75-951.6 m3/hm2,which achieved that the nitrogen use efficiency of water-saving spring wheat was more than 10 kg/kg.Conclusion] The study provides a theoretical basis for establishing water-saving,fertilizer-saving and high yield production technological system of spring wheat in Hetao Irrigation Region of the Inner Mongolia.