Abstract:Hedgerow has been widely used to reduce soil erosion. However, little information is available concerning the effect of hedgerow on soil organic carbon sequestration for various land utilization patterns in purple soil. Long-term field experiment was carried out to study the effects of Leucaena leucocephala hedgerows on soil organic carbon sequestration. Surface soil samples (0-20 cm) were collected from six south-facing standard runoff plots, with reddish-brown purple soil, were selected from Soil and Water Conservation Experiment Station of in Anju District, Suining City, Sichuan Province, China for experiment. Hedgerows(Leucaena leucocephala)were planted on contour in plotⅡ、Ⅳ、Ⅴ, and plotⅠ、Ⅲ、Ⅵ without hedgerows were selected as the control group. Plots Ⅰand Ⅱwere 10° cropland, plots Ⅲ and Ⅳ were 10° economic forest, and plots Ⅴand Ⅵ were 15° cropland. The crop planting model of cropland was spring-wheat and spring-corn continuous cropping, and economic forest land was nectarine colonization. Leucaena leucocephala hedgerows has been established since 2006. Soil organic carbon (SOC), respiration rate, soil microbial biomass carbon (SMBC), and soil nutrient were measured. Results showed that soil organic carbon density of 10° cropland cropland (2.85 kg/m2), 15° cropland (2.37 kg/m2) and 10° economic forest land (3.27 kg/m2) with hedgerows planting for three years were 41.5%、43.3%、32.2% higher than those of control (2.01, 1.79, 2.28 kg/m2) respectively. Meanwhile,soil organic carbon content,organic carbon density and respiration rate in 10° economic forest land were more greater than that of 10° cropland. Moreover, 10° cropland increased SOC content,respiration rate and SMBC than those of 15° cropland significantly;Results indicated that cropland was more efficient for conservation of SMBC than economic forest land. In addition,SOC and respiration rate on downhill were significantly higher than those of uphill for the same treatment. However,neither slope position nor land utilization patterns had significant effect on microbial quotient,which may imply that effects of cropland and economic forest on the soil conversation and did not differ significantly. The correlation between SOC and soil physicochemical properties varied with different treatments. Significant positive correlations were found between SOC and SMBC for 10° cropland, 15° cropland and 10° economic forest land,while SOC and SMBC were negatively correlated with pH. In addition, significant positive correlations were also observed between respiration rate and SOC for 10° cropland, 15° cropland with hedgerows, while significant correlation between the respiration intensity and soil organic carbon of 10° economic forest land with hedgerows. The variation of soil microbial parameters accorded with that of SOC, which may reflect a change of soil quality. The results indicated that Leucaena leucocephala hedgerows was beneficial to soil organic carbon sequestration,microbial activity enhancement and improving soil quality.