Soybean is a kind of crops that needs large quantity of water. Water effects not only plant shape change of soybean, but also its physiology reaction, and then it will influence yield and quality. Serious water deficit can cut production, and content of protein and oil will come down. So water is one of the most important factors for soybean production. Drought in spring has a frequency of 70% in Heilongjiang Province, which is one of the districts that have the highest frequency of drought in s...