Cotton production is influenced by water and nitrogen (N). However, the magnitude and direction of seed cotton yield, water use efficiency (WUE) and N use efficiency (NUE) responses to water and N inputs varied among the available studies due to different experimental and environmental factors (such as cotton varieties, climate types and irrigation systems). To quantify the relationships between water and N inputs and seed cotton yield, WUE and NUE and estimate the potential for water and N optimization, 61 studies conducted in 9 countries were collected to establish a meta database. The relationships between water and N inputs and the interesting response variables were studied using a linear mixed-effects model in a partially restricted dataset. And the potential for water and N optimization was discussed using a meta-analysis in three classified datasets. Total water and N inputs had significant positive effects on seed cotton yield. WUE was negatively related to water input and positively related to N input, while NUE was positively related to water input and unrelated to N input. Negative interaction between water and N inputs existed in WUE and NUE, and the interaction was relatively large in NUE compared to in WUE. Reducing over-optimal water input to optimal may increase seed cotton yield by 12.3%, WUE by 25.0% and NUE by 2.2%. Similarly, reducing over-optimal N input to optimal may increase seed cotton yield and WUE by about 16.0% and NUE by 44.6%. There was great potential for optimizing water and N inputs in arid and hot desert climate (BWh) comparing with in arid and cold desert climate (BWk) and arid and cold steppe climate (BSk), and the seed cotton yield, WUE and NUE can be increased by up to around 35.0%, 16.6% and 34.5%, respectively. Surface irrigation had greater potential to optimize water and N inputs than drip irrigation, and the seed cotton yield and WUE can be increased by up to 50.7% and 43.0%, respectively. The findings provided suggestions for improving irrigation and fertilization in cotton production.

中文翻译：

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棉花生产中水和氮的利用效率：荟萃分析

棉花产量受水和氮 (N) 的影响。然而，由于实验和环境因素（如棉花品种、气候类型）的不同，现有研究中籽棉产量、水分利用效率（WUE）和氮利用效率（NUE）对水和氮输入的响应的大小和方向各不相同。和灌溉系统）。为了量化水和氮输入与籽棉产量、WUE 和 NUE 之间的关系并估计水和氮优化的潜力，收集了在 9 个国家进行的 61 项研究来建立一个元数据库。在部分受限的数据集中使用线性混合效应模型研究了水和氮输入之间的关系以及有趣的响应变量。并使用三个分类数据集的荟萃分析讨论了水和氮优化的潜力。总水和氮输入对籽棉产量有显着的正向影响。 WUE与水输入负相关，与N输入正相关，而NUE与水输入正相关，与N输入无关。 WUE和NUE中水与氮输入存在负交互作用，且NUE交互作用较WUE交互作用较大。将超优水分投入降低至最优可提高籽棉产量 12.3%、WUE 25.0%、NUE 2.2%。类似地，将过优氮输入降低至最佳值可将籽棉产量和 WUE 提高约 16.0%，NUE 提高 44.6%。与旱寒荒漠气候(BWk)和旱寒草原气候(BSk)相比，旱热荒漠气候(BWh)优化水氮投入潜力巨大，籽棉产量、WUE和NUE可提高分别增加约35.0%、16.6%和34.5%。地面灌溉比滴灌具有更大的优化水和氮输入的潜力，籽棉产量和WUE可分别提高50.7%和43.0%。研究结果为改善棉花生产灌溉和施肥提供了建议。