Abstract:

Based on phenological data of wheat, rice, and maize from 1981 to 2022 collected at 653 agrometeorological stations across China, as well as concurrent meteorological data, trend analysis and correlation analysis methods were used to analyze the characteristics of changes in the growth periods of these three crops. The study also explored the main meteorological factors influencing these changes, aiming to provide a basis for adapting agricultural production to climate change. The results indicated that the mean temperature and growing degree days (except for late double−cropping rice) during the whole growth periods of all three crops showed significant increasing trends (P<0.05). Precipitation during the whole growth period of winter wheat significantly decreased, while it significantly increased for spring wheat and maize. The sunshine duration during the whole growth period of maize and late double−cropping rice significantly decreased. From 1981 to 2022, the whole growth periods of spring wheat, winter wheat and late double−cropping rice mainly shortened, with average decreases of 1.6d per decade, 2.5d per decade, and 2.2d per decade, respectively. In contrast, the whole growth periods of single−season rice, early double−cropping rice, and maize mainly extended, with average increases of 1.9d per decade, 0.01d per decade, and 0.6d per decade, respectively. Compared with the sowing dates in the 1980s, the sowing dates of spring wheat, winter wheat, maize, and late double−cropping rice in the 2010s were delayed by an average of 1.0d, 4.0d, 4.0d and 9.0d, respectively. In contrast, the sowing dates of single−season rice and early double−cropping rice advanced by an average of 2.0d. For spring wheat, winter wheat, and maize, more than 82%, 76% and 85% of the observation stations, respectively, showed a significant positive correlation between the length of each growth stage and sunshine duration. The mean temperature and sunshine duration were key factors influencing the phenological changes of spring wheat, with mean temperature having a particularly significant impact on the duration of the sowing−to−emergence stage of spring wheat. The active accumulated temperature ≥0℃ was the primary factor responsible for the changes in the whole growth period and the vegetative growth period of winter wheat. The mean temperature had the greatest impact on the duration of the sowing−to−tillering stage, while the overwintering period was mainly influenced by sunshine duration.The effective accumulated temperature ≥10℃ was the main factor influencing the changes in the whole growth period of rice (including single−season rice, early double−cropping rice, and late double−cropping rice). The duration from the three−leaf stage to transplanting had the highest correlation coefficient with sunshine duration, while during this stage, the correlation coefficient between precipitation and both early double−cropping rice and late double−cropping rice was the highest.The mean temperature was the primary factor determining the changes in the whole growth period of maize, and the effective accumulated temperature ≥10℃ had the highest correlation coefficient with the duration from the seven−leaf stage to the silking stage.

Key words: Main food crops, Growth period, Sowing period, Meteorological factors