Nitrogen flows in"crop -edible mushroom"production systems in Hexi Corridor Oasis Irrigation Area

With the rapid development of agricultural industrialization process,has resulted in greatly negative effects on the water resources and ecological environment in the Hexi corridor oasis irrigation area.In this study,three types of "crop-edible mushroom" production systems in the Oasis Irrigation Area of Hexi Corridor were selected.The first type was an "crop-edible mushroom intensive production mode",which included edible mushroom and crop production consisting of 100 hm-2 farmland holders;the second type was so called "crop-edible mushroom single peasant production mode;the third one was a "single cropping region which had no edible mushroom production.The characteristics of nitrogen(N) flows in these three systems were analyzed using the nutrient flows method.The results showed that it is increased by 10% of nitrogen use efficiencies through the "crop-edible mushroom" systems for crop straw returning to field.The N application rate of chemical fertilizers was 165.6 kg · hm-2 · a-1,which accounted for 37.1% of total N input.Consequently,this confirmed that the recycling of straw N is an efficient way to reduce the application rate of chemical N fertilizer.Positive cropland N balances resulted across all three types of "crop-edible mushroom"systems,the cropland nitrogen surplus reached 217.0 kg · hm-2 · a-1,indicating that the purpose of nutrient balance in circulation mode was not achieved as planned.It is concluded that a proper area of crop and edible mushroom with the optimization of N management and adjustment of the agricultural industrial structure are the keys to solve this issue.