Improving grain yield (GY) and reducing grain moisture (GM) are urgent demands for directly harvesting kernels with combine harvesters in maize production.  GY and GM are both related to leaf, stem and root characteristics, but the relationships are not fully understood.  To better understand these relationships, we conducted a field trial involving 12 maize hybrids with two sowing dates in 2017 and 10 maize hybrids with one sowing date in 2019.  GY ranged from 6.5–14.6 t ha^–1 in early-sown varieties and 9.3–12.7 t ha^–1 in late-sown varieties in 2017, and 5.9–7.4 t ha^–1 in 2019, respectively, with corresponding GM variations of 29.8–34.9%, 29.4–34.5% and 31.9–37.1% at harvest.  A large maximum leaf area contributed to a high yield, a fast leaf senescence rate accelerated grain dehydration in the late growth period, and a compact root structure resulted in both of high-yield and fast-grain dehydration.  A strong stem improved lodging resistance but maintained a high GM at harvest, and it is challenging to combine high GY and low GM in maize.  High GY co-existed with low GM in some varieties that should have a rapid grain filling, a relatively long grain-filling duration, and a rapid grain dehydration in the late growth period.  A high daily temperature in the late growth period also improved GY and reduced GM by influencing grain filling and dehydration, suggesting that adjusting the sowing date should be an alternative strategy to combine high GY and low GM in kernel harvesting. 

Leaf growth and its interaction with the growing environment critically affect leaf area, distribution, and function, and ultimately affects grain yield of maize (Zea mays L.).  To detect the effects of leaf area dynamics, growth periods, and the environment on maize grain yield, a three-year field experiment was conducted using two maize varieties, medium plant-size variety Zhengdan 958 (ZD958) and large plant-size variety Zhongnongda 4 (ZND4), and three to five sowing dates.  The sowing date significantly affected maize yield as a result of changes in leaf area, growth stage, and growing environment.  Prior to the 12th leaf stage, significant correlations between leaf area dynamics, environment, and yield were seldom detected.  The expansion of leaf area from 12th leaf stage to silking stage was significantly positively correlated with growing degree days (GDD), solar radiation, and grain yield, indicating the importance of leaf area dynamics during this period.  After silking, solar radiation played a more important role in inducing leaf senescence than GDD, particularly in the 2nd half of the grain filling stage.  Accelerated leaf senescence in late growth period can increase maize yield.  The environment affected leaf area dynamics and yield of the large plant-size variety (ZND4) more easily than the medium plant-size variety (ZD958) at the optimum plant density, reflecting the difference in varietal capacity to adapt to the growing environment.  This study indicates that optimizing the interaction among leaf area dynamics, growth periods, and environment is a sound strategy to increase maize yield.  Favorable interactions are useful to determine the optimal sowing date of a given variety.