Analysis of anti-erodibility of forest soil at 4 typical forest stands in Beijing Badaling area
Zhou Wei1,2, Zha Tonggang1,2, Sun Huaining1,2, Huang Junwei1,2, Yang Han1,2
(1. School of Soil and Water Conservation,Beijing Forestry University,100083,Beijing,China; 2. Forestry Ecological Engineering Research Center,Ministry of Education,100083,Beijing,China)
[Background] In order to study the impacts of different vegetation types in Badaling area on the soil anti-erodibility and further reveal the soil anti-erodibility under different vegetation types, researches were conducted on 4 forest stands of Pinus tabuliformis, mixed conifer and broadleaf, broadleaf and shrub. [Methods] Based on the data from adequate field investigation as well as sampling and laboratory analysis, principal components analysis (PCA) along with relevant analytical methods were adopted in the study. [Results] After dry sieving, the particle size of aggregates in Badaling rea was mostly found in 5 - 2 mm and the least in 0.5 - 0.25 mm. By contrast, after wet sieving, most aggregates were in small particle size ( <0.25 mm) while large-size (10 -5 mm) aggregates accounted for he smallest proportion. The geometric mean diameter (GMD), mean weight diameter (MWD), percentage of aggregate destruction (PAD) as well as the content of soil water-stable aggregate (WSA)> 0.25 mm of P. tabuliformis forest, mixed conifer and broadleaf forest and shrub forest all showed that aggregates in 10 -20 cm layer of the forest land were the most stable, while in 0 -10 cm layer they were in the worst stability, however this was not applied to broadleaf forest. To make better comparisons about the capacity of soil anti-erodibility in the 4 types of forestland, 12 indexes were defined, including the physical and chemical features of soil and aggregate characteristics. And based on the method of PCA,the best and most suitable index system was established for evaluating the soil anti-erodibility in Badaling area. Among all the indexes, the GMD of dry-sieved soil was then selected via analysis as the best one to describe the soil anti-erodibility of the different typical forestland. Analytically, in Badaling area, the topsoil (0 -10 cm) of broadleaf forest showed the greatest resistance to soil erosion, followed by shrub forest, mixed conifer and broadleaf forest and P. tabulifomis forest. Analysis also showed the anti-erodibility of 0 - 20 cm layer, where erosion was most likely to take place, with the figures for the different types of vegetation, was shrub forest > P. tabulifomis forest > broadleaf forest > mixed conifer and broadleaf forest. Synthetically, considering the average conditions for each layer, the final result of the soil evaluation was presented in the form of comprehensive soil anti-erodibility index. And the comprehensive soil anti-erodibility of the 4 types of forestland was shrub forest > P. tabulifomis forest >mixed conifer and broadleaf forest > broadleaf forest. [ Conclusions ] The result has practical significance to the scientific evaluation of the soil and water conservation function of the different forest stand in the research area. Meanwhile, the results of the study has certain reference value for both egional soil and water conservation and the further study on the mechanism of soil erosion. Therefore,he research may contribute to the prevention and control of regional soil and water loss and the coordination of regional land use.