Study On Relationship Between Water Depletion Regulation And Yield And Quality Of Soybean

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 spring in China. And drought in summer may occur occasionally. Water resource distribution is imbalance in Heilongjiang Province. Therefore, the problem of how to develop irritation method and how to enhance water-use efficiency needs to be solved currently. This topic focuses on the study of water depletion regulation with different quantity of water during soybean growth stages, and also focuses on the study of soybeans growth and physiology index reaction. At the same time, the article discusses effect of controlling water on yield and quality in different growth stages of soybean. All these will supply scientific basis for high yield and high quality soybean in production management.There are two kinds of soybean in this experiment: Dongnongl63 with high oil and Dongnong42 with high protein. With the method of quadric orthogonal crossing and rotating designing, first we divide soybean growth stages into four stages, that is : sprout-branch, branch-bloom, bloom-seed-filling, seed-filling-maturity; and then carry out five level treatment during four stages. Thus we can monitor soybeans reaction to water during its growth stages, and conclude water depletion regulation of soybean and its relationship with yield and quality. Chief conclusions:1 Soybean organism reactions with different water in different growth stage are : plant height, plant leaf area, dry substance weight, ratio of root and crown, chlorophyll content, rate of plant photosynthesis etc have a regular pattern with water variety. All these indexes except ratio of root and crown increase correspondingly with water increasing. Ratio of root and crown becomes larger with drought degree intense. This conclusion provides one major reference for soybean drought diagnosis index.2 By analyzing the quantity of soybean through the orthogonal crossing and rotating model, we draw a conclusion that water contribution rate of yield for both kinds of soybeanin different growth stages are as following: bloom-seed-filling > seed-filling-maturity > branch-bloom-sprout-branch. This makes it clear that bloom-seed-filling period precipitation affects yield greatly, and this period is a key water period for soybean. By the analysis of model frequency we have a conclusion that the most suitable precipitation for both kinds in different period, among water suitable range, yield except value is: Dongnong42over517g/m2 (5170kg/ha) , Dongnongl63 over434 g/m2 (4340kg/ha) .3 By analyzing the quality of soybean through the orthogonal cross and rotating model, we draw a conclusion that water contribution rate of quality for both kinds of soybean in different growth stages are as following: seed-filling-maturity > bloom-seed-filling > branch-bloom > sprout-branch. Different water effects quality distinctly during different growth stage, and water in different growth stage exists mutual effect to soybean quality. The article establishes the regression equation about the soybean quality and water depletion quantity by using statistics of water depletion quantity value and main quality index of soybean in different treatment.4 By statistics comparison from water depletion quantity formula and synchronous weight measuring method, correlation coefficient of two results is 0.9997. We calculate that water depletion quantity during soybean growth stages is about 240mm-540mm, in which sprout-branch period is 12%, which is the least; and bloom-seed-filling period is 42%, which is the highest. These show that bloom-seed-filling period is the key water period for soybean, and w...