Abstract:Soil organic carbon is an important component of the soil carbon pool,and plays a key role in ecosystem productivity and the global carbon cycle. In this research,litter removal and detritus input treatment (DIRT) methods were used to study the litter productivity,litter amount,and effects of different litter treatments on the soil organic carbon in two Reaumuria soongarica communities in the Sangong River Basin. The results showed that the litter productivities of two communities had almost identical seasonal changes;they reached their second-maximum and maximum values in July (August) and October,and both showed "N" distributions. The litter amount also presented similar seasonal change trends;both showed "W" distributions,and reached their maximum values of 30.65 g/m2 and 57.87 g/m2 in October,respectively. The soil organic carbon content gradually reduced with soil depth;Community 1 and Community 2 decreased by 61.73%-62.39% and 18.24%-25.84%,respectively. The average soil organic carbon content of Community 1 and Community 2 was reduced by 6.97% and 18.38% by the litter removal treatment (no litter,NL),and increased by 19.64% and 13.66% by the litter treatment (double litter,DL),respectively. The soil organic carbon storage values of Community 1 and Community 2 were 1007.36 kg/hm2 and 709.30 kg/hm2 after NL treatment,and 1197.88 kg/hm2 and 1010.78 kg/hm2 after DL treatment,respectively. Two-way analysis of variance showed that the interaction of soil organic carbon between the soil depths and three litter treatments was significant in Community 2,but not Community 1. Regression analysis showed that soil properties were determinants of the differences in soil organic carbon between the two communities. The relatively high litter amount and low soil organic carbon content were attributed to the high soil pH and salt content, which inhibited litter decomposition. Otherwise,the relatively high soil water content and low soil bulk density promoted both soil organism activity and soil organic carbon mineralization,which led to the decrease in soil organic carbon content.