Ecological benefit of different revegetated covers in the middle of Hexi corridor, northwestern China

Desertification is one of the major obstacles to the development and utilization of oases in arid and semi-arid regions of China. Revegetation of oases is an effective means of protecting oases from sand invasion (the main cause of desertification) and enhancing the ecological stability of oasis. In order to assess the effects of revegetated plant communities, 21-year-old Haloxylon ammodendron shrubland (Shrubland), 28-year-old Populus simonii Carr. land (Poplar land) and 33-year-old Pinus sylvestris var. mongolica Litv land (Pine land) were selected as study objects. The topsoil properties and material changes were monitored, taking the native desert shrubland (Desert land) as a basis. The results show that different revegetated covers can lead to significant changes in soil organic carbon (SOC), as well as soil inorganic carbon (SIC) and total nitrogen (TN). SOC, SIC and TN content can be significantly increased from 0.56, 0.06, and 4.93 g kg(-1) in Desert land to 5.85, 0.47, and 7.26 g kg(-1) in revegetated covers, respectively. Different revegetated covers can also change plant species richness, productivity, and plant C and N content. It is also found that Poplar land and Pine land were more effective than Shrubland in improving soil fertility and plant productivity. In addition, this study confirmed that the establishment of revegetated covers can reduce the rates of wind erosion on soil surface up to 74.83-94.15 % compared to natural desert shrubland. The atmospheric dust fall was also affected significantly by the different covers. The results show that there are significant advantageous changes in soil characteristics and vegetation parameters, as well as the reduction of soil erosion and retention of atmospheric dust fall in the revegetated covers and habitat conditions. The results suggested the appreciable ecological effects of the different revegetation covers on soil development and restoration process of plant communities. Additionally, some rational management practices could also cause positive influence on the quality of soil, e.g. irrigation. Understanding these ecological effects may be helpful for designing and establishing protective forest systems in desert-oasis areas.