Effects on soil nutrient and yield of winter wheat of planting different green manures during summer fallow

In order to measure the effects of green manure cropping on soil fertilization and crop field in Guanzhong area, a field experiment, with bare fallow and no-tillage as control (CK), was conducted to study the effects of planting different green manures on the soil available nutrients and crop yield during summer fallow in Yangling of Shaanxi. Smooth vetch (Vicia villosa Rothvar), hairy vetch (Vicia villosa Roth), milk vetch (Astragalus sinicus) and sweet clover (Melilotus suaveolens Ledeb) were chosen as the green manure treatments. The results showed that the contents of soil Available P, Available K and Hydro-N were increased by planting green manures. The degree of increase was closely correlated with the nutrient content and biomass of the green manure crop. Compared with CK, the green manure treatments significantly affactedincrease ear number, kernel and 1000-kernl weight of per unit area of winter wheat, with the yield increased by 21.1%, 24.3%, 6.0%, and 11.6% for the four treatments of green manure crops, respectively.