Abstract:Based on the daily meteorological data of 28 meteorological stations in Heilongjiang Province from 1966 to 2015 and the observation data of 20 agricultural meteorological stations during the growth period from 1991 to 2008, the effective precipitation, water requirement and water surplus deficit index and their climate trend rate in different growth stages of soybean were calculated. The drought rank and the drought frequency and intensity of each growth stage were determined according to the water surplus deficit index. Then the corresponding distribution map was drawn by using ArcMap spatial analysis, which revealed the water supply and demand and drought situation of soybean in each growth stage in Heilongjiang Province. The results showed that the annual average effective precipitation of soybean in Heilongjiang Province was 253~370mm, the average value was 321mm, in addition to the initial all the other growth stages showed the distribution trend of high in the middle part and low in the east and west, the climatic trend rate of effective rainfall during the growth period of soybean was -6.16~9.09mm/(10a), and the average value was 241mm/(10a), the effective precipitation in the initial stage was on the whole increasing, but in the late season stage was on the whole decreasing. The average annual water demand of soybean was 336~465mm, and the average value was 388mm. In each growth stage, the water demand was low in the middle and high in the east and west areas. The climate trend rate of water requirement during the growth period of soybean was -16.01~2.42mm/(10a), the average value was -5. 17mm/(10a), and the trend of water requirement in each growth stage was generally decreasing. It was increased firstly and then decreased from west to east areas when the average annual surplus deficit index was -44.5%~8.9% and the average value was -15% in the growth period of soybean, and an overall upward trend when the climate trend rate of water surplus deficit index was -1.89~4.92%/(10a). The drought frequency distribution and water requirement spatial distribution of soybean in different growth stages were roughly the same, among which the drought frequency in early growth and rapid growth stage was higher than that in middle growth and late growth stage, and the drought was easy to occur in spring and summer. The research result can provide a theoretical basis and reference for reasonable irrigation and drought prevention of soybean in Heilongjiang Province.
