Modeling the Effects of Sowing Dates on Maize in Different Environments in the Tropical Area of Southwest China Using DSSAT

Maize yield is affected by meteorological conditions and cultivation management. Sowing date adjustment is one of the most commonly used cultivation management methods for achieving a high maize yield in the tropical area of Southwest China. This study conducted field experiments involving five maize cultivars with different sowing dates in Yunnan Province from 2012 to 2015. The parameters of the CERES model in the decision support systems for agrotechnology transfer (DSSAT) were calibrated, and its adaptability was validated. The model was applied to simulate and analyze the maize growing period and yield with different sowing dates over 12 years (2012–2023) in the tropical area of Southwest China. The results show that the DSSAT-Maize model demonstrates good adaptability in the southwestern region of China. The model predictions for maize flowering, maturity, and yield were compared with the measured values, yielding R2 values of 0.62, 0.64, and 0.92, d-index values of 0.86, 0.87, and 0.97, and normalized root-mean-square errors (nRMSE) of 4.53%, 2.92%, and 6.37%, respectively. The verified model was used to assess the effects of different sowing dates on the maize growing period and yield. Sowing between 15 May and 29 May resulted in relatively higher yields with lower coefficients of variation. The whole growing season was shortened by 1.13 days, and the yield was decreased by 3% every 7 days ahead of the sowing date before early May. A delayed planting date after June had a positive effect on maize yields, with an average yield increase of 4% per 7 days of delay. The maize yield was significantly positively correlated with rainfall during the vegetative period and solar radiation during the reproductive period; meanwhile, it was significantly negatively correlated with solar radiation and the maximum temperature during the vegetative period and rainfall during the reproductive period. This study concluded that the sowing date significantly influenced maize’s growth period and yield in the tropical area of Southwest China. Delaying sowing after 15 May can help achieve higher yields, mainly because early sowing leads to insufficient rainfall in the vegetative period, while delayed sowing ensures adequate rainfall and higher total solar radiation.