Abstract:

To study the impact of climate change on dry farming grain in eastern Gansu tableland, the climate factor data of 60 years from 1961 to 2020 were used, the linear regression, polynomial function and climate tendency rate methods were used to analyze the characteristics of agroclimatic resource change and the effect on winter wheat and maize under 80% guarantee rate. The results showed that the first day of average daily temperature stabilized at 0℃ and 10℃ showed an earlier trend, while the last day showed a later trend, and the duration increased significantly. Under the guarantee rate of 80%, during the period that the average daily temperature was stable through 0℃ and 10℃, the precipitation showed a decreasing trend with the advancing of years, accumulated temperature ≥0℃ and ≥10℃ showed an increasing trend with the advancing of years, and sunshine duration showed a decreasing trend. The change of agroclimatic resources caused wheat sowing delay and ripening advance, the shortening of the growth period was mainly reflected in the shortening of overwintering period, and the effective growth period was guaranteed. The increase of heat resources in summer ensured the growth of maize, and the earlier maturity period gained time for the autumn sowing after the harvest of early autumn crops, which effectively expanded the planting area of crops. In eastern Gansu tableland, there was a significantly positive correlation between the climatic yield of wheat and maize and the precipitation during the growing period. Water affected the whole process of grain yield, and water shortage was the limiting factor of crop growth. Average temperature had non significantly negative effect on wheat and maize, and temperature was an important factor. The effects of effective accumulated temperature and sunshine hours on wheat and maize were different, and maize was more affected by climate uncertainty than wheat.

Key words: agroclimatic resources, eastern Gansu tableland, dry farming grain, impact analysis