Tap Maize Yield Productivity in China: A Meta-Analysis of Agronomic Measures and Planting Density Optimization

Maize is a staple crop in China, playing a crucial role in agriculture and food security. However, current planting densities are suboptimal, leading to lower yields and unrealized potential. This study explores the potential to maximize maize yields by optimizing planting density and implementing region-specific agronomic measures across China’s diverse agro-ecological zones. We compiled a dataset consisting of 1974 independent field trials from 720 publications across China’s main maize-growing areas, spanning the period from 2000 to 2023, to assess the impact of optimal planting density and agronomic practices on China’s maize production. Our findings reveal that increasing the planting density to optimal levels—49.34% higher than current farmer practices—can significantly boost national maize yields by 16.28%. Furthermore, adopting agronomic techniques like precision irrigation, soil tillage, and plant growth regulators enhances this effect, raising planting density by 69.91% and yield by 27.26%. Notably, the irrigated maize-growing areas in Northwest China showed the highest yield potential, whereas the southern hilly regions had the lowest. This underscores the significance of tailoring optimal density and agronomic practices to each region. Combining agronomic measures with adjusted planting densities can reduce this disparity. Precision irrigation, soil tillage, and plant growth regulators were particularly effective in optimizing planting density and maximizing yield potential, especially in Northwest China and the North China Plain. In contrast, plant growth regulators proved most effective in Southwest China and Southern China. This study underscores the potential of integrating optimized planting density with agronomic measures to significantly improve maize productivity, thereby supporting sustainable agriculture. It provides a scientific basis for regionalized agricultural management.