Fine root production, turnover of Reaumuria songarica and soil carbon and nitrogen in Alxa steppe desert of NW China

摘要

Variations of fine root production and turnover of the dominant shrubs associated with soil carbon (C) and nutrients are of key importance for evaluating desert ecosystem sustainability. Here we examined fine root production and turnover rate of Reaumuria songarica in Alxa steppe desert of northwestern China through sequential coring, ingrowth cores, and mesh-bag methods, and then assessed soil C and nitrogen (N) stock and its correlation with fine root and leaf litter input. Results showed that fine root production and turnover rate were closely related to soil water content. Fine root production density and turnover rate of R. songarica were 386.8 g m(-2) and 2.4 yr(-1), respectively. Annually, fine root and leaf litter of R. songarica input 126.3 g C m(-2) and 4.7 g N m(-2) to soil. Soil organic C and N under shrub canopies increased substantially, which promoted the heterogeneity of soil properties and is considered as an important mechanism underlying the restoration of degraded sandy lands.