Changes of Soil Physical and Chemical Properties with the Development of Artificial Planted and Natural Invaded Vegetation in Southern Hulunbeir Sandy Land
2016, 31 (10):
To understand the improving effect of vegetation restoration on soil properties in sandy land, a study was carried out in Hulunbeir sandy land of North China in 2014. Seven plots, named 8Y (vegetation restoration of 8 years), 5Y (5 years), 3Y (3 years), 1Y (1 years), MD (Moved Dune), SD (Semi-fixed Dune) and FD (Fixed Dune), were set for analyzing the physical and chemical properties of soil, such as content of soil water, pH, soil organic carbon (SOC), total nitrogen (N), total phosphorus (P), total potassium (K), available N, available P and available K. The seven plots belong to two series of vegetation types respectively, which are temporal pattern based on artificial vegetation (for 8Y, 5Y, 3Y and 1Y) and spatial pattern based on natural vegetation (for MD, SD and FD). The results show: 1) With the increase of restoration time, the biomass and vegetation coverage increased significantly at both types of plots. The biomass is 267.6 and 79.8 g/m2 respectively on 8Y and FD, and the vegetation coverage is 75% and 50% respectively. 2) The content of SOC increased significantly with the development of the vegetation at both types of plot, and the content in upper layer of soil is significantly higher than that in middle and lower layer of soil. The SOC of upper layer soil is up to 3.85 and 3.22 g/kg respectively in 8Y and 5Y, but is up to 7.99 g/kg in FD. 3) The content of total N and total P show similar tendency as SOC, but the content of total K has no significant difference among plots or soil layers. The total N of upper layer soil ranges between 0.08 and 0.41 g/kg from 1Y to 8Y, between 0.16 and 0.61 g/kg from MD to FD, and the total P ranges between 0.21 and 0.48 g/kg from 1Y to 8Y, and between 0.29 and 0.50 g/kg from MD to FD. 4) The content of soil available nutrients also increases with the development of vegetation to a certain extent, however with an undulation. Generally, the contents of soil nutrients at the plots of 1Y and 3Y are similar with that of MD. When it is planted after more than 5 years, the artificial vegetation can have a significant effect on improving the physical and chemical properties of soil and mitigating the desertification. However, the contents of SOC and total N are significantly lower at the plot of 8Y than that at the plot of FD. Thus, when developing the human-planted vegetation, local government should pay more attention to the protection of natural vegetation.
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