Abstract: Persisting in an organic way, starting with afforestation and growing legume green manure crops, along with reforming cropping system and agricultural structure, Chagan village transformed from a typical backward, povertystricken village into one of advanced villages in northwest Liaoning province in the last two decades. Soil degradation has been controlled, vicious circle of agroecosystetn has changed into a virtuous one, and the trend of soil-Ndepletion has been reversed. In this paper, the main experiences were analysed from an ecological point of view and dynamic models for simulating N-cycling of three different stages were presented and discussed.

Key words: Anammox, Nitrogen removal, Autotrophs