Study On Characteristics And Influencing Factors Of Forest Soil Anti-erodibility In Headstream Area Of Oujiang Watershed In Zhejiang Province

This paper mainly focuses on forest soils, and we studied on differences on different forest soil anti-erodibilities and influencing factors of soil anti-erodibility. In order to provide basic statistics and protection methods of soil erosion within red soil area in southern China, we chose headstream area of Oujiang Watershed in Longquan City, Zhejiang Province as our study area. Through principal component analysis (PCA), entropy analysis and correlation analysis, we listed the strength of different forest soils. Furthermore, we studied on the influencing factores of soil anti-erodibility and put forward measures which could improve forest soil anti-erodibility. Water and soil conservation measures of forest soil in red soil area in southern China should be based on the research findings. The main conclusions are as follows:(1) We separately tested the strength of each forest soil and empowered the attributes by PCA and entropy method. We got the formula of comprehensive index for soil anti-erodibility and calculated the score of anti-erodibility of each forest soil. Because of the differences of two results, we modified soil dispersion rate and percentage aggregate destruction and recalculated by two methods. The same results showed that the anti-erodibilities of different forest soil ranks as pine forest> bamboo forest> shrub> economy forest> tea garden.(2) According to environmental features of the study area and the order of 11 attributes’weights, we proposed main influencing factors of forest soil anti-erodibility. They are water-stable aggregates factor, powder clay content and soil aggregation degree factor, fine grain factor. The research found that>0.5mm water-stable aggregates content,>0.25mm water-stable aggregates content and percentage aggregate destruction could be used to evaluated forest soil anti-erodibility in headstream area of Oujiang Watershed well.(3) We found that the higher soil clay content, organic matter content, total nitrogen content, water-stable aggregate content and particle diameter is, the stronger soil anti-erodibility is. Secondly, the results showed that upper soil has stronger soil anti-erodibility than deeper soil which mainly caused by the cementation between soil particle and organic matter. Furthermore, the data showed that soil with different topography condition has different anti-erodibility:most soils at the top of the slope have weaker anti-erodibilty than those at the bottom of the slope. This could probably caused by the stream carrying upper top slope soil to the bottom. On the other hand, this regularity has some correlation with forest form.