Effect of Chinese Milk Vetch (Astragalus sinicus L.) as a Green Manure on Grape Productivity and Quality, Nutrient Contents, and Microbiologic Properties of Vineyard Soils

In order to explore the effect of overturning Astragalus sinicus L. on soil nutrient, microbial characteristics, grape yield and quality, a 4-year experiment of overturning different amount of milk vetch green manure in vineyards was conducted. Meanwhile, fruit quality, soil organic carbon, acid phosphatase, urease, invertase and catalase were measured. The results showed that the activities of these vineyards' acid phosphatase, urease, invertase, catalase were increased with incrasing levels of green manure under the treatments received different amount of green manure (6 000-30 000 kg·m^-2). Additionally, in comparison with NPK treatment, soil enzymatic activities under the treatments received different amount of green manure (6 000-30 000 kg·m^-2) increased by 11.7%~39.5%, the amount of microbial communities increased by 12.0%-147.8%, grape yield increased by 15.3%, soluble sugar, Vitamin C and flavonoid content in grape fruits increased by 13.5%, 8.8%, 11.9%, respectively. Moreover, the maximal tea yields of 16 530 kg·hm^-2 was obtained under the treatment at an application dose of 22 500 kg·hm^-2. Therefore, the amounts of bacteria, fungi and actinomycetes in the vineyard soils were increased, soil nutrient transformations were promoted, and grape productivity and quality were improved, especially for the treatment at an application dose of 22 500 kg·hm^-2.