喀斯特红壤盐基离子及硅铝铁随径流流失研究

Study on the Losses of Base Cations,Silicon,Aluminum and Iron in Karst Red Soil Along With Runoff

采用模拟降雨试验,研究了黔中喀斯特红壤区坡地盐基离子、铁、铝、硅和碱度随径流淋溶流失的特征,分析了由此产生的环境效应。结果表明:红壤中7种无机成分随径流流失的总负荷呈现Ca^(2+)>Mg^(2+)>K^+>SiO_2>Na^+>Fe>Al的趋势,其中Ca^(2+),Mg^(2+),K^+和SiO_2流失较为严重,Fe和Al随径流的流失量非常小。当雨强为45 mm/h时,红壤坡地开始产生地表径流,流失在地表径流中的物质以K^+,Na^+为主,二者含量之和占地表径流中7种无机成分总流失量的90.91%。当雨强达到70mm/h时,地表径流产流量超过壤中流,流失在地表径流中的物质以Ca^(2+)和Mg^(2+)为主,占地表径流中7种无机成分总流失量的53.78%;壤中流物质组成受雨强的影响较小,K^+的浓度比率最高。Ca^(2+),Mg^(2+),K^+,SiO_2和Fe的流失以地表径流为主,不同雨强下Ca^(2+),Mg^(2+)和SiO_2的地表流失负荷可用一元线性回归方程预测。红壤碱度淋溶流失量随雨强的增加而增大,但未超过红壤的临界碱度淋溶,不会造成喀斯特红壤酸化。

The loss characteristics of base cations,silicon,aluminum,iron and alkalinity in sloping land of Karst red soil in central Guizhou along with runoff were studied by using simulated rainfall experiments,and the environmental effects were analyzed.The results showed that the total loss load of seven inorganic constituents in red soil appeared the decreasing order:Ca^2+ >Mg^2+ >K^+ >SiO2 >Na^+ >Fe >Al along with runoff.Among them,the losses of Ca^2+,Mg^2+,K^+and SiO2 were significant,whereas the loss amounts of Fe and Al were very little.When the rainfall intensity was 45 mm/h,the surface runoff began to appear on the sloping land,and the mainly lost substances to surface runoff were K^+and Na^+,which accounted for 90.91%of the total lost amount of seven inorganic constituents.When the rainfall intensity was 70 mm/h,the surface runoff flow exceeded the interflow,and the mainly lost substances to surface runoff were Ca^2+,Mg^2+,which accounted for 53.78%of the total lost amount of seven inorganic constituents.The substance composition in the interflow was little affected by rainfall intensity,and was dominated by K^+.The losses of Ca^2+,Mg^2+,K^+,SiO2 and Fe were mainly through surface runoff,and the single-variable linear regression equation can be used to predict the surface loss loads of Ca^2+,Mg^2+and SiO2 under various rainfall intensities.The leaching amount of red soil alkalinity increased with the increase of rainfall intensity,but did not exceed the critical alkalinity leaching of red soil,which may not cause soil acidification in karst red soil.