Plant population and maize grain yield: a global systematic review of rainfed trials

Maize (Zea mays L.) productivity has increased globally as a result of improved genetics and agronomic practices. Plant population and row spacing are two key agronomic factors known to have a strong influence on maize grain yield. A systematic review was conducted to investigate the effects of plant population on maize grain yield, differentiating between rainfall regions, N input, and soil tillage system (conventional tillage [CT] and no-tillage [NT]). Data were extracted from 64 peer-reviewed articles reporting on rainfed field trials, representing 13 countries and 127 trial locations. In arid environments, maize grain yield was low (mean maize grain yield = 2448 kg ha−1) across all plant populations with no clear response to plant population. Variation in maize grain yield was high in semiarid environments where the polynomial regression (p &lt; 0.001, n = 951) had a maximum point at ∼140,000 plants ha−1, which reflected a maize grain yield of 9000 kg ha−1. In subhumid environments,...玉米（Zea mays L.）的全球产量随遗传改良与农艺技术进步而持续提升。种植密度与行距是公认对玉米籽粒产量具有显著影响的两大核心农艺因子。本研究通过系统综述分析了种植密度对玉米籽粒产量的影响，并按降雨分区、氮肥施用量以及土壤耕作制度（常规耕作[CT]与免耕[NT]）进行分组区分。研究数据源自64篇经同行评议的雨养田间试验论文，覆盖13个国家的127个试验点位。在干旱环境中，所有种植密度下的玉米籽粒产量均处于较低水平（平均产量为2448 kg·ha⁻¹），且未随种植密度变化呈现明确响应规律。半干旱环境下玉米籽粒产量的变异程度较高，多项式回归分析（p < 0.001, n = 951）显示产量峰值出现在约140000株·ha⁻¹的种植密度下，对应玉米籽粒产量为9000 kg·ha⁻¹。在亚湿润环境中，……