| It has been long-term hit by raindrops splash and runoff erosion in the soil of Stone forest Karst mountain,resulting in increased soil erosion and structural traits of soil degradation,land degradation,therefore,it has great theoretical and practical significance to strengthen the soil and water conservation in Karst mountainous area and improve soil erosion resistance great force to protect the fragile ecological environment of Karst mountain.In this paper,the main physical properties of 27 soil samples collected from three types of Stone buds slopes(A is high exposed,B is middle exposed,C is no exposed)in Stone forest Karst were measured,the evaluation indexes of soil corrosion resistance was extracted and the evaluation model was established by principal component analysis based on the characteristics of soil indicators,the results showed that the soil corrosion resistance was different,and the conclusions were as follows:(1)Mean value of the hydrocarbon disintegration index of soil in three types of stone buds Slope:slope land C(66.4%)<Stone buds slope land B(69.3%)<Stone buds slope land A(74.2%).The relationship between the hydrocarbon disintegration index of soil and soil particles soaking time was not only in a cubic function S=a0+a1t+a2t2+a3t3,but also the period characteristics was significantly with soil particles immersion time;K-means of water stable index:A(53.4%)<B(54.0%)<C(55.5%).(2)The mean of MWD of dry sieve aggregates is the highest in A sloping land(3.14mm),the B sloping land(2.91mm)with followed by,the lowest in C sloping land(2.87mm).However,bigger than 2mm of the particle size distribution of the mechanical stability of soil is better than others.The mean of MWD of wet sieve aggregates A(1.04mm)<B(1.14mm)<C(1.26mm);Greater than 0.25mm structural damage rate variation trend inversely with MWD;And bigger than 1mm of the particle size distribution of the water stability of soil by wet sieve is better than others.(3)Soil texture to the largest proportion of the type of silt soil(mean 75.11%),and with the characteristics of sanding is significantly,the proportion of soil in the clayey soil(mean 12.18%)is similar to the sandy soil(mean 12.18%).(4)The overall change of soil cohesion in the range of 25.77-54.6kpa,the mean of soil cohesion is the highest in the sloping farmland C(44.55kpa),the Stone buds sloping land B(38.12kpa)with followed by,the lowest in Stone buds sloping land A(35.43kpa).The total change of soil mocha angle in the range of 16.81-26.25°,and the mean difference is A(19.72°)<B(22.66°)<C(24°).(5)The comprehensive index model of soil anti-erodibility was Y=0.544Y1+0.228Y2+0.139Y3+0.088Y4.The highest mean and rank of soil erosion resistance is slope land(0.519),followed by B slope land(-0.122),the weakest of soil erosion resistance is A slope land(-0.397),the higher the exposed degree of stone,the weaker the soil erodibility is,while the other is stronger.At last,<0.05mm silt and clay content?>0.5mm and>0.25mm water stable aggregate content?>0.25mm rate of structural damage of aggregates?water stability index?aggregates condition?aggregates degree?dispersion rate of aggregates,eight indicators,as the best indicators of soil erosion resistance evaluation were selected by the correlation analysis and principal component analysis to Stone buds slope land of Stone forest Karst. |
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