Abstract: Soil samples were collected from the plots of different vegetation configuration (Caragana korshinskii, Artemisia ordosica, and C. korshinskii-A. ordosica) in Shapotou region of Ningxia Province, Northwest China, and an incubation was conducted to study the mineralization potential of soil carbon and the litter decomposition in soil. During 103 days incubation, no significant differences were observed in the soil carbon mineralization under the same vegetation configuration and with or without litter addition, but the mineralization rate of soil carbon was higher under the vegetation configuration with high density C. korshinskii.There was a significant difference (P=0.047) in the soil CO₂-C release from the single row of A.ordosica and from the double rows of C.korshinskii under C. korshinskii-A. ordosica and without litter addition, but no significant difference under the other vegetation configurations and with or without litter addition.Overall, the soil carbon mineralization potential under C. korshinskii was higher than that under Artemisia ordosica and C. korshinskii-A. ordosica. At early phase, the decomposition rate of the litters in soil was in the order of C. korshinskii-A. ordosica > A. ordosica > C. korshinskii. After 40 days incubation, the decomposition rate of the litters tended to be the same. The higher decomposition rate of annual plant litter could be attributed to its high C and N contents and its high C/N ratio. The soil amended with A. ordosica litter under C. korshinskii had a higher potential of carbon mineralization than the soil amended with C. korshinskii litter under A. ordosica, because of the differences in the litter chemical composition and the soil nutrient availability. However, a turning point appeared during incubation, due to the higher C and N contents and the higher C/N ratio of C. korshinskii litter. Under different vegetation configuration, the soil carbon mineralization potential was higher under the canopy than outside the canopy. The existence of shrub created a ‘fertile island’ with higher organic matter and nutrient contents and higher microbial activity under canopy, and contributed more to C sequestration.

Key words: Artificial erosion, Quarry, Spatial distribution, Landscape ecological impact degree