Effects of different grassland restoration approaches on soil properties in the southeastern Horqin sandy land, northern China

Abstract

In the semi-arid Horqin sandy grassland, continuous grazing has led to decreased ground cover. The bare land surface is then directly exposed to strong wind erosion, leading to desertification. Different restoration approaches have been used to recover these desertified sandy grasslands. This study compared soil properties subjected to different grassland restoration approaches, i.e., three restoration treatments and an unrestored control: FG, grassland enclosed by sheltering forest (Populus×beijingensis); MG, artificially sparse Pinus sylvestris var. mongolica grassland; UG, artificially sparse Ulmus pumila grassland; CK, desertified grassland. Soil samples were taken from depths of 0–20cm, and physical (i.e., bulk density, particle size distribution, waterholding capacity, total porosity), chemical (i.e., pH, soil organic matter, total N, total P, total K, available N, available P, available K, cation exchange capacity, exchangeable Ca2+, exchangeable Mg2+, exchangeable Na+, exchangeable K+), and biological (i.e., microbial biomass carbon, substrate richness index, Shannon's diversity index) properties were selected as soil indicators. The three different approaches to grassland restoration were confirmed to alleviate wind erosion and enhance sand surface stabilization, as well as improve soil physicochemical and biological properties, in comparison with unrestored control. Soil physical, chemical, and biological properties in two types of artificial sparsely forested grassland were significantly better than those in grassland enclosed by shelter forest; however, there was no significant difference between the two types of artificial sparsely forested grassland. These results suggest that an artificial sparsely forested grassland restoration approach may be more effective at restoring the poor and arid soils of desertified sandy grasslands, such as the Horqin sandy land.