关键词: “强凉夏”事件, 夏凉多雨, 低温寡照, 春玉米, 发育期, 气候产量, 土壤过湿

Abstract:

To study the climate characteristics of strong cool summer and the impacts on agriculture, the data of precipitation, temperature, sunshine, development period and yield of spring maize in the summer of 2020 (June to August) in east Gansu Province were analyzed. The results showed that the summer in 2020 was a typical regional strong cool summer. In 2020, the average temperature in summer was lower than that in the same period of previous years, except that the temperature of the first ten days of June was slightly higher than that in the same period of previous years, and the temperature of the first ten days of July and the first ten days of August were slightly high. The average temperature in summer was generally lower than that of the previous years in all counties, except Huanxian and Xifeng, whose temperature was slightly lower than the normal values in the same period over the years. Zhenyuan and Huachi recorded the second lowest average temperature of summer in historical records. The precipitation in summer was more than that in the same period over the years, and there were more rainy days; the precipitation amount of Zhengning and the rainy days of Huanxian were the second in history. The sunshine in summer was less than that in the same period of previous years, and Xifeng and Ningxian had the least summer sunshine in history. Strong cool summer caused the extension of the growth period of crops in autumn, which was about 12 days longer than that in previous years on average. 2020 was not a high yield year, although climate yield was a positive effect. The main reasons for the decrease of yield were the low temperature and less sunlight in the later stage of reproductive growth and high soil moisture. However, the sufficient precipitation, especially soil moisture at the key maize development stage, and the particularity and adaptive adjustment of spring maize growth, were still the main factors for the climate yield to be positive effect.

Key words: strong cool summer, rainy and cool summer, low temperature and less sunlight, spring maize, development stage, climate yield, overwet soil