Abstract:

Based on the rice field experiment data from the Jiangjin National Agricultural Meteorological Experimental Station in Chongqing in 2020, authors constructed and utilized a locally calibrated DSSAT−CERES− Rice model to simulate the impact of different high temperature on the growth and development of rice during its key growth stages, as well as yield. In addition, the appropriate sowing date for 'Yixiangyou 2115' rice based on the Twenty−four solar terms scale was explored, providing a reference for achieving high and stable yield in the Sichuan basin. The results showed that: (1) the simulated values of the DSSAT−CERES−Rice model, calibrated with local parameters, exhibit a significant correlation with the observed values. The coefficients of determination for the model's simulated rice flowering date, maturity date and final yield, compared to the actual observed values, were 0.97, 0.94 and 0.70, respectively, while the root mean square errors were 0.95d, 1.35d and 248.06kg·ha⁻¹, respectively. (2) When rice was only subjected to high temperature stress (daily maximum temperature ≥35℃ for 3d or more consecutive days) during the heading−flowering stage, the yield reduction rate ranged from 4.3% to 6.8%, which was significantly higher than the yield reduction rate (<2.2%), when rice was subjected to high temperature stress during the grain filling−milky stage. This indicated that rice during the heading−flowering stage was more sensitive to high temperatures, and the higher temperature and the longer duration, the higher yield reduction rate of rice. When both the heading−flowering and grain filling−milky stages were subjected to compound high-temperature stress with a daily maximum temperature of 39℃ lasting 7d at each stage, the yield reduction reached 8.2%, increasing by 1.7 and 7.5 percentage points compared with single−stage stress during the heading−flowering and grain filling−milky stages, respectively. (3) The simulation results of the locally parameterized DSSAT−CERES−Rice model for rice yields at different sowing dates showed that the optimal sowing date for 'Yixiangyou 2115' in Jiangjin of Chongqing, was on the day of the Hibernator Awakening.

Key words: Twenty?four solar terms, Rice yield, High?temperature stress, DSSAT?CERES?Rice model