Characteristics of Soil Carbon Management Index of Different Farmland Types in Hilly Loess Plateau

The soil samples of different farmland types in the typical erosion environment of Zhifanggou small watershed were regarded as study objects,and organic carbon,labile organic carbon,non-labile organic carbon and carbon management index were evaluated.The results showed that fraction of soil organic carbon in the different farmland types differed significantly.Labile organic carbon was the major part of the total organic carbon,accounting for 58.0%-79.6%.Organic carbon,labile organic carbon and non-labile organic carbon behaved similarly,the highest observation was in the greenhouse vegetable land,followed by plain field,terrace,dam land and gully land,and the lowest was the slope cropland.Soil carbon pool activity,activity index,carbon pool index and carbon management index in the different farmland types differed significantly and behaved similarly.Compared with the slope cropland,all the indexes increased drastically,the increase extent was the highest in greenhouse vegetable land,followed by plain field,terrace,dam land and gully land.The results suggested that compared to the slope cropland,other farmland types were managed more scientifically.Correlation analysis showed that soil organic carbon,labile organic carbon,non-labile organic carbon,carbon pool index,and carbon management index were significantly correlated with the fertility factors,they could be considered as the indicators for monitoring the soil fertility of the local farmlands.