Concomitantly pursuing superior maize (Zeamays L.) productivity with grain quality is essential for food security. Therefore, this study provides a meta-analysis of 21 studies assembled from the scientific literature to tackle the effect of the two most limiting factors for maize production, water and nitrogen (N), and their impacts on grain quality composition, herein focused on protein, oil, and starch concentrations. Water stress levels resulted in erratic responses both in direction and magnitude on all the grain quality components, plausibly linked to a different duration, timing, and intensity of water stress treatments. Nitrogen fertilization more consistently affected the grain protein concentration, with a larger effect size for protein as fertilizer N levels increased (protein change of +14% for low, ≤70 kg N ha⁻¹; +21% for medium, >70–150 kg N ha⁻¹; and +24% for high, >150 kg N ha⁻¹). Both starch and oil grain concentrations presented less variation to fertilizer N levels. The positive protein–oil correlation (r = 0.49) permitted to infer that although the oil concentration may reach a plateau (8%), further increases in protein are still possible. Augmented research on grain quality is warranted to sustain food production but with both high nutritional and energetic value for the global demand.

中文翻译：

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水和氮管理实践会影响玉米的谷物质量吗？

同时追求优质玉米（Zea maysL.) 粮食质量的生产力对于粮食安全至关重要。因此，本研究对从科学文献中收集的 21 项研究进行了荟萃分析，以解决玉米生产的两个最限制因素，水和氮 (N) 的影响及其对谷物质量组成的影响，本文重点关注蛋白质、油和淀粉浓度。水分胁迫水平导致所有谷物质量成分在方向和幅度上的反应不稳定，这可能与水分胁迫处理的不同持续时间、时间和强度有关。施氮更一致地影响谷物蛋白质浓度，随着肥料 N 水平的增加，蛋白质的影响更大（蛋白质变化 +14% 低，≤70 kg N ha ^-1; +21% 中等，>70–150 kg N ha ^-1；+24% 高，>150 kg N ha ^-1 )。淀粉和油粒浓度对肥料 N 水平的变化较小。蛋白质-油的正相关性 ( r = 0.49) 允许推断，尽管油浓度可能达到平台 (8%)，但蛋白质的进一步增加仍有可能。加强对谷物质量的研究有必要维持粮食生产，但对全球需求具有高营养和能量价值。