喀斯特山区土地利用方式对土壤质量演变的影响

通过调查喀斯特山区典型土地利用方式对土壤养分和土壤容重的影响 ,结果表明 ,森林的破坏以及随后的耕种显著增加了土壤容重 ,并降低了大部分土壤养分。和林地相比 ,灌木林、灌丛、草地和退耕 3年的蒿草地容重分别增加了 32 % ,2 0 .3% ,4 6 .9% ,5 2 .3%。除全钾外 ,草地和退耕蒿草地土壤养分显著下降 ,和林地相比 ,草地有机质减少了 2 9.3% ,全氮减少了 4 8.2 % ,全磷减少了 6 6 .3% ,碱解氮减少了 4 5 .8% ,有效磷减少了 5 6 .3% ,有效钾减少了 6 0 % ;退耕 3年的蒿草地土壤有机质、全氮、全磷、碱解氮、有效磷和有效钾分别减少了 85 .6 % ,84 .7% ,81.4 % ,74 .9% ,87.5 %和 90 .6 %。土壤退化指数的计算结果表明 ,草地和退耕蒿草地发生了非常严重的退化

Effects of Land Use on Soil Quality in Karst Hilly Area

The effects of land use on soil nutrients and soil bulk density in Karst hilly area was studied.The results indicated that deforestation and cultivation led to increase in soil bulk density and decrease mostly in soil nutrients.Compared to forest,the bulk density value of bush forest,low growing bushes,grassland and 3 years decultivated land increased by 32%,20.3%,46.9% and 52.3% respectively.Most soil nutrients except total K in grassland and 3 years decultivated land decreased significantly in comparison with forest.Grassland wintnessed a decrease in soil organic matter by 29.3%,total N by 48.2%,total P by 66.3%,alkalysis N by 45.8%,available P by 56.3% and available K by 60%;While 3 years decultivated land saw a decrease in soil organic matter by 85.6%,total N by 84.7%,total P by 81.4%,alkalysis N by 74.9%,available P by 87.5% and available K by 90.6%.The results of soil degradation index showed a severe degradation occurred to grassland and 3 years cultivated land.