A meta-analysis was performed on 351 studies from 17 articles published between 1990 and 2016 to determine how a water use efficiency (WUE) treatment is affected by irrigation systems and management practices on clay and clay loam soils in a semi-arid environment relative to a rainfed control. Several explanatory variables (moderators) were examined to determine their impact on WUE such as crop type, irrigation capacity, rainfall, soil type, planting time, and nitrogen application. Results were sub-grouped by irrigation system. Overall, the impact of irrigation system on WUE directly correlated with the efficiency of the irrigation system. Subsurface drip and center pivot irrigation systems had the largest impacts on WUE with increases of 147 and 99%, respectively, compared to a 14% increase under furrow irrigation. Corn (Zea mays L.) had a higher response to WUE in subsurface drip irrigation (260%) compared to center pivot irrigation (46%), whereas WUE in cotton (Gossypium hirsutum L.) had a 71% change in center pivot systems compared to 63% under subsurface drip. The biggest increases in WUE relative to a rainfed control were for sorghum (Sorghum bicolor (L.) Moench), which had a 13% change under furrow irrigation, 160% change under center pivot and 341% under subsurface drip.

中文翻译：

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德克萨斯高原灌溉系统作物水分利用效率的荟萃分析

对 1990 年至 2016 年间发表的 17 篇文章中的 351 项研究进行了荟萃分析，以确定灌溉系统和灌溉系统如何影响半干旱环境中粘土和粘壤土的管理实践雨养控制。检查了几个解释变量（调节器）以确定它们对 WUE 的影响，例如作物类型、灌溉能力、降雨量、土壤类型、种植时间和施氮量。结果按灌溉系统分组。总体而言，灌溉系统对 WUE 的影响与灌溉系统的效率直接相关。地下滴灌和中心支点灌溉系统对 WUE 的影响最大，分别增加了 147% 和 99%，而沟灌下增加了 14%。玉米（Zea mays L. ) 与中心支点灌溉 (46%) 相比，地下滴灌对 WUE 的响应更高 (260%)，而棉花 (Gossypium hirsutum L.) 的 WUE 在中心支点系统中的变化为 71%，而在地下滴灌中为 63%滴。与雨养对照相比，WUE 增幅最大的是高粱（Sorghum bicolor (L.) Moench），在沟灌下变化 13%，在中心枢轴下变化 160%，在地下滴灌下变化 341%。