Study On The Land Erosion Resistance For The Mixed Artificial Chinese Fir Forests Of Mountain Areas Around Sichuan Basin

Soil anti erodibility is one of the main Study on Soil Erosion. The studies on soil erosion resistance were mainly focused on the soil erosion sensitive area in Loess Plateau and crop land. And it was rarely studied on the soil erosion resistance in Southern mountain, especially the mixed artificial Chinese fir forests of mountain areas around Sichuan basin. This paper investigated the Soil anti erodibility of the mixed artificial Chinese fir forests of the Forest Farms in Luzhou city, Yibin city, Yaan city and Meishan city. The paper discussed the relation between the different tree species arrangement of the mixed artificial Chinese fir forests and the soil anti erodibility. The results were as follows:(1) By Principal Component Analysis of sexteen soil anti erodibility indexes, it was obtained the formula of the different Stands Composition of the mixed artificial Chinese fir forests, Y=0.587Y1+0.272Y2+0.141Y3. By analysis of covariance, the soil erosion resistance of the different tree species arrangement of the mixed artificial Chinese fir forests was known:Chinese fir+Mao bamboo+broadleaved tree (62.066)> Chinese fir+ broadleaved tree+Shrubs (57.846)> Chinese fir+schimacrenata+broadleaved tree (55.656)> Chinese fir+Chinese Cryptomeria+broadleaved tree (53.573)> Chinese fir pure stand (49.208).(2)Analyzing the relativity between sexteen soil anti erodibility indexes and Comprehensive index value, it was known that:<0.05mm pink clay content, agglomeration state, aggregation degree, saturated water, capillary water holding capacity and soil integrated corrosion index were showed significant positive correlation.<0.02mm physical clay content, organic matter content, soil infiltration rate and soil integrated corrosion index were significantly positively correlated. And the correlation between the <0.002mm clay content and soil anti erodibility comprehensive index was not obvious.(3)By Principal Component Analysis and the relativity Analysis of the sexteen soil anti erodibility indexes and the site situation, the paper were determined the soil anti erodibility optimum evaluation indexes of the mixed artificial Chinese fir forests of mountain areas around Sichuan basin:<0.05mm grain content,<0.02mm grain content, agglomeration state, aggregation degree, dispersion rate, organic matter content, saturated water, capillary water holding capacity and soil infiltration rate.(4)The paper analyzed the relativity between the soil anti erodibility Comprehensive index and the different index (such as Shannon index, Simpson index, Pielou index, Richness index, Dominance index and Berger index). Simpson index and the corrosion resistance of the soil were a positive correlation. And Berger index and the corrosion resistance of the soil were also a positive correlation. Ecological dominance (Berger index) showed the changes of different populations'number. Studying on the soil anti erodibility of five tree species arrangement, the size order of Berger index was as follows:Type I (Chinese fir+broadleaved tree+Shrubs)> Type V (Chinese fir+Mao bamboo+ broadleaved tree)> Typeâ…£(Chinese fir+schimacrenata+broadleaved tree)> Typeâ…¢(Chinese fir+Chinese Cryptomeria+broadleaved tree)> Typeâ…¡(Chinese fir pure stand).