喀斯特山区不同土地利用方式下土壤质量变化及其对水环境的影响

Effects of Land-Use Patterns on Soil and Environmental Water Quality in Karst Hilly Areas

对贵州中部喀斯特山区不同土地利用方式(阔叶林地、灌木林地、灌丛草地、耕地)对土壤、地表径流和浅层地下水进行采样与分析。结果表明,在喀斯特山区土地利用模式从阔叶林地—灌木林地—灌丛草地方向的演变过程中,土壤有机质、速效氮磷钾、交换性钙镁含量出现明显的下降,粘粒含量增加,土壤质量出现退化,耕地有机质含量明显低于林地和草地;耕地地表径流中SO42-,NH4+,PO43-,COD均显著高于林地和草地;浅层地下水的SO42-,NH4+,NO3-,PO43-,COD也显著增加;土地利用由林地变为耕地后,地下水质量出现一定程度的下降。

The samples collected from a karst hilly area in central Guizhou were analyzed to effect of different land-use patterns （forest land, shrub land, shrub-grass mixed land and cultivated land） on environment of soil, runoff water and shallow ground water. The results showed that with the evolvement of land-use patterns from forest land, shrub land, shrub-grass mixed land to cultivated land, content of the organic matter, the available nitrogen, the available phosphorus, the available potassium, the exchangeable calcium and the exchangeable magnesium were obviously decreased, in contrast, content of the lay particles increased, and the quality of soil began to decrease. Content of the organic matter of the cultivated land was lower compared with forest land and grass land. The concentration of SO4^2-, NH4^＋, PO4^3- and COD was obviously higher in the runoff water from the cultivated area than the forest land and grass land, and the concentration of SO4^2-, NH4^＋, NO3^-, PO4^3- and COD in shallow groundwater was also obviously increased. These results demonstrated that the quality of groundwater was some extent decreased with evolvement of land-use patters from the forest land to the cultivated land.