Abstract:Heterogeneous soil landscapes are common under interaction of natural processes and human activities, and in turn, under combined impacts of land use and land cover in the hilly areas of South China. Variation of soil quality across these soil landscapes impacts development of agro-industries in rural area. In this study, 4 types of soil-landscapes including forest land under conservation on hill slope, orchard, dry crop land and paddy field in the basin, were selected in a small watershed of Zhishan Village, Jingqiao Town, Lishui District in suburb Nanjing. Topsoil samples were collected in autumn to analyze basic physico-chemical properties, soil aggregate size distribution and microbial phospholipid fatty acids as well as extracellular enzyme activities. Concerned for soil fertility, the variation of key parameters of soil organic carbon, aggregation and biological activity were explored across these soil landscapes. The relationship between soil landscape and topsoil quality was explored by soil quality evaluation method. The results showed that, compared with the conserved forestland soil-landscape, the soil organic matter (SOM) declined by 50.93% to 69.63%, the mean weight diameter of soil aggregates reduced by 41.34% to 68.71%, the total phospholipid fatty acids reduced by 19.20% to 42.04%, while normalized enzyme activity dropped by 22.48% to 63.27% in the topsoil of the agricultural soil-land scapes. Accordingly, compared with forest land, the ecosystem functions and service of topsoil under the agricultural soil-landscapes had been significantly weakened. However, paddy fields had higher SOM content and microbial activity. Regression analysis showed that, SOM content was the strongest driver for topsoil quality change within the watershed. Theevaluation of soil quality based on total data set and minimum data set and the evaluation of soil functional quality based on the concept of soil health show that, the overall topsoil quality was in an order of forest land>paddy field>upland>orchard. Further, the evaluation system based on the concept of soil health can comprehensively reflect the changes of soil quality and the significance of ecosystem function among different soil-landscapes.