Abstract:

Based on the daily meteorological data and growth period data of spring maize from seven meteorological stations in Shenyang, the spatiotemporal change characteristics of the growing degree days (GDD), heating degree days (HDD), precipitation, and climatic tendency rate of spring maize during sowing, seeding, elongation, heading, maturation, and whole growing periods were analyzed. The results indicate that the GDD of spring maize shows an upward trend during the whole growing period. The spatial distribution difference of GDD during different growth periods is not significant, which demonstrates an ascending trend from the north to the south, with the high value mainly distributed in Hunnan and Sujiatun Districts, and the low value in Kangping and Faku counties. The HDD of spring maize during the whole growing period increases progressively. Except for Kangping, which shows a decreasing trend during the mature period, the HDD in other regions shows an increasing trend during the growing period, increasing from northwest to southeast in space. In the last 40 years, the whole growing period of spring maize in the Shenyang area shows a decreasing trend, and the spatial trend is decreasing from southeast to northwest. At the seedling stage, the precipitation in all regions shows an increasing trend, and the other periods show a decreasing trend. During the whole growing period of spring maize in Shenyang, the heat resources show increasing trends, but the precipitation shows a decreasing trend, which will increase the risk of extremely high temperature and meteorological drought in the region.

Key words: Growing degree days (GDD), Heat degree days (HDD), Precipitation