Vegetation restoration is a common and effective method to combat desertification and to prevent sand encroachment into adjacent areas in many arid regions of the world. To date, ecological engineering projects have successfully reduced hazards of sandstorms and desertification in northern China. 

Scientists from Cold and Arid Regions Environmental and Engineering Research Institute (CAREERI) explored how soil CO₂ efflux and its components change after moving sand dunes are stabilized with shrubs, and how abiotic factors affect those components at different scales. 

Soil CO₂ efflux from a sand-stabilized area was compared to that from moving sand dunes in the Tengger Desert. To partition rhizosphere respiration (R_R) from soil basal respiration (R_B), a root-isolation plot was established. 

The result shows that, compared to moving sand dunes, total soil respiration (R_T) in the sand-stabilized area increased 3.2 fold to 0.28±0.08 μmol CO₂ m^-2s^-1, two thirds of which was from R_B. Shrub patchiness produced spatial variation in soil respiration, whereas temporal dynamics of soil respiration were affected mainly by soil water content. Shallow soil water content (0-20 cm) influenced R_T and R_B, whereas deep soil water content (30-201 cm) influenced R_R and the ratio R_R/R_T. During most of the year when soil water content was below field capacity, diumal changes in soil respiration were partially decoupled from soil temperature but could be modeled using soil temperature and photosynthetic active radiation. 

The conclusions show that the sand-dune stabilization increased soil respiration, and increased R_B from biological soil crust and altered soil properties such as increased soil organic matter contributed more than increased R_R from increased shrubs. 

This paper has been published on the Journal of Plant and Soil.