测墒补灌和施氮对冬小麦产量及水分、氮素利用效率的影响

【目的】测墒补灌是近年来研究的一种小麦节水灌溉新技术。论文旨在探索测墒补灌与施氮对冬小麦生长的影响，为该区节水、节氮提供依据。【方法】采用漫灌的方式设置测墒补灌和施氮两因素田间试验，补灌设置4个处理，于冬小麦拔节期、开花期依据0-40 cm土层土壤质量含水量进行测墒补灌，补灌至土壤田间持水量的50%（W₁）、60%（W₂）、70%（W₃）、80%（W₄）。施氮设置4个处理，不施氮（N₀）、施纯氮180 kg·hm^-2（N₁₈₀）、240 kg·hm^-2（N₂₄₀）和300 kg·hm^-2（N₃₀₀）。在此处理下研究了测墒补灌和施氮对冬小麦产量及水分、氮素利用效率的影响。【结果】(1)各施氮处理下，补灌量的增加可增加冬小麦籽粒产量，当补灌量至土壤田间持水量的60%-80%范围内时，冬小麦籽粒的增产效应差异不显著。各补灌处理下，当施氮量超过240 kg·hm^-2时籽粒产量无显著性变化。本试验条件下当补灌至土壤田间持水量的60%，施氮量为240 kg·hm^-2时冬小麦籽粒产量达到最高，为8 104.6 kg·hm^-2。(2)增加施氮量和补灌量均可显著增加麦田总耗水量，但当施氮量超过240 kg·hm^-2时，施氮的提高效果不显著。补灌量的增加会显著增加麦田总耗水量，但当补灌至土壤田间持水量60%（W₂）、70%（W₃）时较补灌至80%（W₄）处理显著降低耗水量，说明有利于节约灌水而获得较高产量。(3)相同施氮处理下，补灌量的增加可显著提高冬小麦水分利用效率，当补灌量增至土壤田间持水量的60%时，冬小麦水分利用效率达到最大值，为14.7 kg·hm^-2·mm^-1。相同补灌处理下，增施氮肥可显著提高冬小麦水分利用效率，但施氮量不宜超过240 kg·hm^-2，否则将导致水分利用效率降低。(4)相同施氮处理下，应控制补灌量至土壤田间持水量的60%时冬小麦氮素干物质生产效率及氮素利用效率最高，为60.1 kg·kg^-1、22.4 kg·kg^-1。相同补灌处理下，施氮量应控制在240 kg·hm^-2时可获得较高的氮素干物质利用效率及冬小麦氮素利用效率最高，为63.9 kg·kg^-1、23.5 kg·kg^-1。【结论】本试验条件下当施氮量为240 kg·hm^-2、冬小麦拔节期、开花期补灌至土壤田间持水量的60%时冬小麦籽粒产量、水分利用效率、氮素干物质利用效率、氮素利用效率均最高，为最优的节水、节氮、高产组合，推荐其作为该区域适宜水、氮用量。

Effects of Nitrogen Application on Yield,Water and Nitrogen Use Efficiency of Winter Wheat Under Supplemental Irrigation Based on Measured Soil Moisture Content

【Objective】Supplemental irrigation based on soil moisture content was a newly water-saving approach developed in wheat irrigation in recent years, so the purpose of this paper was to evaluate its application potential in Huang-Huai-Hai plain.【Method】In this study, a field experiment of supplemental irrigation based on measurement of moisture content was conducted, combining with different level of nitrogen application. The four irrigation treatments were designed in the main plots, and supplemental irrigation was based on measuring soil moisture content of 0-40 cm soil layers at jointing and anthesis stages of winter wheat. The soil moisture reached 50%FC (field capacity) (W1), 60%FC (W2), 70%FC (W3), 80%FC (W4). In the sub-plots, four nitrogen application treatments were applied at 0 (N₀), 180 (N₁₈₀), 240 (N₂₄₀), 300 (N₃₀₀) kg N·hm^-2. The effects of nitrogen application on yield, water and nitrogen use efficiency in winter wheat under supplemental irrigation based on measured soil moisture content were analyzed.【Result】(1) Under the equal nitrogen application treatments, the wheat yield increased with higher irrigation content. When the supplemental irrigation reached 60%-80%FC range, there were no significant differences in wheat yield among different treatments. For the same irrigation treatments, wheat yield was reduced when the amount of nitrogen applied exceeded 240 kg N·hm^-2. The highest yield (8 104.6 kg·hm^-2) of winter wheat was achieved under the N level of 240 kg·hm^-2 under W₂ treatment in this experimental study. (2) Increasing the amount of nitrogen, supplement irrigation could significantly increase the total water consumption of wheat. However, the effect of nitrogen application was not significant difference when the nitrogen application exceeded to 240 kg N·hm^-2. Supplement irrigation could significantly increase the total water consumption of wheat. When the irrigation reached 60%FC, 70%FC, it significantly reduced the amount of irrigation content compared to the 80%FC, which was beneficial to save irrigation and to achieve higher yields. (3) Under the same nitrogen application treatments, supplement irrigation could significantly increase the water use efficiency of wheat. When the soil moisture reached 60%FC, the highest of water use efficiency was achieved, which was 14.7 kg·hm^-2·mm^-1. For the same irrigation treatments, increasing nitrogen application could significantly improve the water use efficiency of winter wheat, but the amount of nitrogen application should not exceed 240 kg N·hm^-2, otherwise it would decrease the water use efficiency. (4) Under the same nitrogen application treatments, it should control the soil moisture reached 60%FC, and the highest of nitrogen dry matter production efficiency, nitrogen use efficiency were achieved to 60.1 kg·kg^-1, 22.4 kg·kg^-1, respectively. For the same irrigation treatments, the amount of nitrogen applied should be controlled at 240 kg N·hm^-2, and the highest of nitrogen dry matter production efficiency, nitrogen use efficiency were achieved to 63.9 kg·kg^-1, 23.5 kg·kg^-1, respectively.【Conclusion】Under the N level of 240 kg·hm^-2, when the irrigation content at jointing and anthesis stages of winter wheat reached to 60% of soil field capacity, the grain yield, water use efficiency, nitrogen dry matter production efficiency and nitrogen use efficiency were achieved highest. As a result, this mode of nitrogen and irrigation integration was recommended as the regional suitable level for water and fertilizer application.