Abstract: Studies on biotic structure and function of farmlands in southern Jiangsu hilly region show that a compound agroecosystem can be established through afforesting bare hills and sloping lands or reclaiming them into tea garden, orchard and artificial grassland, and excavating fish ponds. An unit model of sustainable land use in this region is formulated as:hills and sloping lands-stereoscopic use for forest, tea garden, orchard and artificial grassland, erraced field-rational distribution of grain fodder, economic and green manure crops, animal husbandry-overall development of pig, poultry, dairy and fish, resource utilization-planting, animal husbandry and primary processing of farm products.On the basis of stabilized grain production. the total income from farming, forestry, animal husbandry. side-line production and fishery is increased by 2.3 times, both the income from unit land area of agricultural uses and average income per capita from agricultural industries are increased by 2.7 times.

Key words: Compound agroecosystem, Sustainable land use, Hilly area, spring maize, soil carbon storage, soil moisture., soil nitrogen storage, soil rotation tillage