The Impact of Land Use Change on Soil Organic Carbon and Soil Inorganic Carbon Contents at Loess Plateau in Longzhong

The soil organic carbon,soil inorganic carbon contents and the δ13C values of carbonates at the arable land(AL),artificial grassland(AG),artificial woodland(AW),abandoned arable land(AAL) and desert grassland(DG) were analyzed in the Longzhong part of Loess Plateau in Northwest China.The results showed that from DG to AL or AW,the sand contents decreased and silt increased,and the variations were significant in the former conversion;soil pH decreased,being significantly different in the latter;land use conversion and electrical conductivity(EC) were both decreased significantly.From AL to AG or AAL,the sand content increased,silt decreased and pH increased.These changes were significant from AL to AG.The EC also decreased significantly from AL to AG.The conversions from DG to AL,AL to AG and AL to AAL increased soil organic carbon contents at 0-100 cm depth,and the soil organic carbon contents decreased after the conversion of DG to AW.These differences were significant between DG and AL and between AL and AG.The soil inorganic carbon contents at 0-100 cm depth decreased significantly from DG to AW and AL,while the decline was not significant from AL to AAL and AG.Profile distribution and the δ13C values of soil carbonate contents differed among different types of land use to some extent.