花岗岩崩岗不同层次土壤抗冲性及其影响因素

针对湖北通城花岗岩崩岗区发育的淋溶层(A层)、淀积层(B层)、过渡层(BC层)以及母质层(C层),采用不同坡度(8.8%,17.6%,26.8%,36.4%,46.6%)和不同流量(0.2,1.0L/s)相结合的室内放水冲刷试验,分析崩岗各层次土壤的抗冲性指数,初步探讨花岗岩崩岗不同坡度及各层次土壤主要理化性质对抗冲性的影响。结果表明:(1)湖北通城县崩岗土壤A层、B层、BC层以及C层的理化性质存在较大差异。(2)当流量一定时,随着坡度的增大,土壤的抗冲性指数均表现为减小的趋势;当坡度一定时,大流量条件下土壤的抗冲性指数较小;在相同坡度和流量条件下,土壤的抗冲性指数均由A层向C层递减,说明A层抗冲性能最好,C层最差。(3)各层次的土壤抗冲性指数随坡度呈显著的线性递减关系(p0.05),土壤的抗冲性能随坡度的增加而减小,其中A层回归方程的系数项绝对值最大,常数项也最大,说明A层的抗冲性随坡度的变化最快,抗流水侵蚀能力最强,土壤流失量最少。(4)土壤抗冲性与粉粒含量、黏粒含量、水稳性指数、渗透系数呈正相关;与土壤干密度、砂粒含量呈负相关,其中和干密度以及水稳性指数的相关性较高,表现为极显著相关;土壤抗冲性与有机质含量、CEC、游离氧化铁呈正相关,与土壤pH呈负相关,其中与有机质含量的相关性系数大于0.9,相关性极显著。

Anti-scourability on Different Soil Horizons of Granite Collapsing Gully and Its Driving Forces

For developed eluvial horizon (A),illuvial horizon (B),transition horizon (BC) and the parent material horizon (C) of granite collapsing gullies region in Tongcheng,Hubei province,the impact of slope and flow on soil anti-scouribility and related soil physical properties were explored.Specifically,the slope were 8.8％,17.6％,26.8％,36.4％,and 46.6％,and the flow were 0.2 L/s,and 1.0 L/s,respectively.The results showed that physical and chemical properties were:(1) significant different among layer A,layer B,layer BC,and layer C of granite collapsing gully soil.(2) When the flow was constant,index of soil antiscourability showed a decreasing trend,with the increase of the slope;when the slope was constant,the index under high flow conditions was low;at the same slope and flow conditions,the index decreased from layer A to layer C,indicating that layer A has the best anti-scourability,while layer C has the worst.(3) The soil anti-scourability index of all layer decreased linearly with the increase of the slope (p＜0.05),and the erosion resistance of soil decreased with the increase of the slope.The absolute values of the coefficients of regression equation in layer A were the largest and the constant was also the largest.This shows that theantiscourability of layer Achanges sharply with the slope,the erosion resistance of layer A is the strongest and the soil loss is the least.(4) There was a positive correlation between soil anti-scourability index and the content of silt,clay content,water stability index and permeability coefficient,and negative correlation with soil dry density and sand content.The correlation between dry density and water stability index was very high,which showed extremely significant correlation.The soil anti-scourability was positively correlated with organic matter content,CEC and free iron Oxide,while negatively correlated with soil pH,specifically,the correlation coefficient with the organic matter content was greater than 0.9,which was extremely significant.