Abstract:Land management and crop rotation apparently affect upland red soil productivity. This study aimed at the effects of forest land, arable soil and different crop rotation systems on soil biochemistry properties. The results of the experiment in forest land, soybean-rape rotation and maize-fallow rotation in Taoyuan County, Hunan Province showed that: in the forest lands, soil pH, organic carbon, available nutrients, microbial biomass carbon and enzyme activity (cellulase, acid phosphatase, invertase, protease) were higher than those of the arable soils. Soil pH, nutrients contents, microbial biomass carbon and microbial quotient in soybean-rape rotation were higher than those in maize-fallow rotation, but the response of enzyme activities in different crop rotation treatments was not uniform, which may be due to the differences in the soil enzyme sensitivity induced by different land management practices and crop rotation systems. There were significant relationships between different microbial indicators and soil organic carbon or pH, which indicated that the organic carbon and pH were indicators of soil quality in upland red soils. The study manifests that increasing soil organic carbon in this area is important to maintain and improve the upland red soil biochemistry properties.