| An experiment was carried out in Gansu Hexi oasis irrigation area to investigate，under the condition of
total amount of N application remaining unchanged, the effect of green manure replacing chemical fertilizer with the same content of N on wheat yield and chief characteristics，soil fertility and soil microbial quantity . The results showed that，in the first year, the wheat yield decreased with the increase of green manure, but the content of soil available N, P, K and organic matter increased after green manure harvest; In the second year， the increase of green manure increased wheat yield, and 70% green manure N+30% chemical fertilizer N achieved the highest yield of 8 562 kq/ hm2，24.7% more than that by FFP. Green manure replacing N fertilizer by 30%~45% improved soil fertility and wheat yield，and had good economic and ecological benefits. |