Abstract:

To explore the risk variation of heat damage during heading and flowering stage of mid-season rice in Hubei Province, mathematical statistics and correlation analysis methods were used to analyze the response of mid-season rice to heat damage indicators, the interannual variation and spatial distribution of mid-season rice heat damage and the risk regionalization from the perspective of yield components based on data of annual growth period of mid-season rice from 18 agrometeorological observation stations in Hubei, the meteorological data of the province from 1960 to 2019, and the data of field high temperature control experiment in Jingzhou from 2016 to 2017. The results showed that: (1) the negative correlation between ≥35℃ accumulated temperature of heat damage and key yield components (seed setting rate) was a better indicator than the high temperature days; (2) from 1960 to 2019, the intensity of heat damage during heading and flowering stage of mid-season rice in Hubei showed a chronological change of first decrease then increase, especially since the beginning of the 21st century, the heat damage had increased frequency, strengthened intensity, and wider range; spatially, the increase of intensity and frequency was the largest in eastern Hubei, followed by Jianghan Plain and southwest Hubei, and the increase was small in northwest Hubei; (3) the high-risk areas were northwest Hubei, the Three Gorges Valley of the Yangtze River, and east Hubei; the low-risk areas were the middle and high mountains in southwest Hubei and most of the Jianghan Plain; the rest were medium-risk areas. The heat damage risk from 1990 to 2019 was higher than that from 1960 to 1989, intensified significantly.

Key words: mid-season rice, heading and flowering period, accumulated temperature of heat damage, high temperature days, temporal and spatial distribution, risk regionalization