The availability of water and nitrogen (N) to maize during its flowering stage affects the growth of individual kernels. The present study reports the variability of maize kernel dry weight under different levels of water and N applications. Two consecutive-year experiments were conducted during 2009 and during 2010 to study the interaction between three irrigation regimes and five N application rates on weekly maize kernel growth. Logistic and regression equations were fitted to kernel moisture content and kernel dry weight as a function of thermal time (TT) during critical crop stages. Kernel moisture content and growth rate increased non-linearly from 1 week after silking to physiological maturity. By applying logistic function we were able to improve simulation of kernel moisture content and daily increases in kernel dry weight. The logistic curve showed kernel moisture contents linearly correlated with kernel dry weight. Similarly, regression analyses of kernel dry weight showed a significant positive correlation with kernel moisture content for the 2009 (R2 = 0.86 NRMSE = 23%) and 2010 growing seasons (R2 = 0.92; NRMSE = 19%). Therefore, the logistics curves derived from the observed data may be helpful for predicting daily kernel growth for the semi-arid conditions. The results showed that the optimal N rate for maximum kernel dry weight was 250 kg ha−1 under 525 mm delta of water application ha−1. This rate might be considered in formulating good agricultural practices for optimum maize kernel growth in the semi-arid regions. Thus, our results contribute to better understanding of best management practices of N fertilizer and irrigation water for optimum maize productivity under semiarid region.

中文翻译：

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在控制水和氮的应用下预测玉米的籽粒生长

玉米开花期水和氮 (N) 的可用性会影响单个籽粒的生长。本研究报告了不同水平的水和氮应用下玉米籽粒干重的变异性。在 2009 年和 2010 年期间进行了连续两年的试验，以研究三种灌溉方式和五种施氮量之间的相互作用对每周玉米籽粒生长的影响。Logistic 和回归方程拟合谷粒水分含量和谷粒干重作为关键作物阶段的热时间 (TT) 的函数。从脱丝后 1 周到生理成熟，籽粒水分含量和生长速率呈非线性增加。通过应用逻辑函数，我们能够改进对籽粒水分含量和籽粒干重每日增加的模拟。Logistic 曲线显示籽粒水分含量与籽粒干重呈线性相关。同样，对 2009 年（R2 = 0.86 NRMSE = 23%）和 2010 年（R2 = 0.92；NRMSE = 19%）的籽粒干重的回归分析显示，其与籽粒水分含量呈显着正相关。因此，从观测数据导出的物流曲线可能有助于预测半干旱条件下的每日籽粒生长。结果表明，在 525 毫米增量水应用 ha-1 下，最大籽粒干重的最佳施氮量为 250 kg ha-1。在为半干旱地区最佳玉米籽粒生长制定良好农业规范时可能会考虑该比率。因此，