Effects of four typical plant community litter input on soil physical and chemical properties under the fenced condition in desert steppe

Litter not only can avoid plants being suffered from splash erosion, wind erosion and other physical protection of rain, but also can accelerate the accumulation of soil moisture, nutrients, and improve soil fertility. In the last decade, The National Projects of Ecological Engineering such as Returning Cropland to Grass and Enclosure Steppe, have been performed, but effects of litter input on soil physical and chemical properties under the fenced condition in desert steppe remain poorly understood.We created field decomposition experiment and laboratory experiment based on four typical plant communities under a fenced condition, which were Agropyron crisatum community, Glycyrrhiza uralensis community, Leymus secalinus community and Artemisia desertorum community, and analyzed the basic characteristics of four typical plant communities, litter accumulation and decomposition, and soil moisture and nutrients, respectively.The results showed that the litter accumulation under the fenced condition was significantly higher than that of the no fenced condition, and the litter accumulation increased soil water holding capacity, while the litter decomposition had weak effect on soil bulk density, total porosity and water holding capacity in the short term. Although soil pH value decreased with the litter accumulation, but the variation was small. Litter input had positive effect on the soil total nitrogen in the short-term, but the effect was weak, and the soil total nitrogen and organic carbon increased with increasing litter accumulation. These results supported that the litter accumulation and decomposition in the desert steppe could effectively improve the soil water movement and spatial distribution, and transport more organic and nutrient elements into the soil, thus change the physical and chemical properties of soil.The finding suggests that litter has positive effect on vegetation and soil restoration of the desert steppe, which plays more important role in maintaining ecosystem stability in the arid sand areas.