The Comparison on the Function of Different Cotton Agroecosy-stems in Northern China Effect of no-tillage on energy flow in cotton agroecosystem Study on assessing methods for the sustainable development trend of agroecosystem‘s Advances in the study of AM fungal diversity in agroecosystems Structure and function of township agroecosystems and their correlation in northern plain areas of Zhejiang Province AN EFFECTIVE WAY TO IMPROVE SOIL FERTILITY IN TRADITIONAL AGROFORESTRY: PLANTING ALNUS NEPALENSIS