Soil basal respiration response to grass vegetation restoration and its’affecting factors in the Loess Hilly-Gully Region

Soil respiration response to different stages of vegetation restoration was determined via closed system measurements of carbon dioxide and selected factors affecting the correctitude and sensitivity of soil respiration. Eight different soil samples under different vegetation restoration stages were separately collected at 0~20 cm and 20~40 cm soil depth in spring and summer and both fresh and air-dried samples analyzed. The results show that the period of vegetation restoration significantly influences soil basal respiration (SBR), which logarithmically increases with vegetation recovery time. Measurements of equivalent daily respiration (EDR) and cumulative respiration (CR) show that respirations in 73- and 78-year recovery sites are highest, while those in farmland and 3-year recovery sites are lowest. SBR is distinctly different for the spring and summer samples. SBR of spring samples better reflect soil basal microbial activity. Air-dried soils can be used for measuring SBR after pre-incubation, more stably reflecting difference among soils. 1 or 3-day EDR mean data can better reflect soil quality. CR more directly and clearly reflects microbial activities of different soil types than EDR. There is a positive correlation between SBR and soil organic carbon and nitrogen content.