Effects of Land Uses on Soil Organic Carbon and Carbon Pool Management Index

Carbon management index（ICM） is used to evaluate the scientificity of soil management.Soil organic carbon（SOC） and readily oxidized carbon （ROC） contents under Leucaena leucocephala stand, Acacia glauca stand,Acacia auriculiformis stand, Azadirachta indica stand,wasteland and dry cropland were determined and their ICM were calculated.The results showed that the SOC and ROC contents under the 6 land use types were 4.22-5.92 g·kg^-1 and 1.34-2.33 g·kg^-1,respectively.No significant differences in SOC contents among these land uses were observed.The ROC contents under the 4 types of woodland,however,were significantly higher than these under dry cropland or wasteland（P<0.05）. The ROC were high significantly（P<0.001） correlated（R² is 66.3%） with SOC.Compared with wasteland,the ICM ranged from 1.77 to 2.36 under these woodlands,and 0.99 under dry cropland.It is revealed that the litter quantity and land management under these land uses may be the key factors resulting in the variation of ROC.At ecological fragile region of Dry-hot Valley,closure management is useful to sequestrate C in woodland soils.However,the management systems for soil carbon pool under dry cropland are not in a sound way.