黄土高原陡坡耕地土壤侵蚀对土壤性质的影响

Effect of Soil Erosion on Soil Proper ties in Deep Cultivated Hill Slope in Loess Plateau

以137Cs示踪技术和室内分析的方法研究了黄土高原北部陡坡耕地土壤侵蚀对土壤养分流失的数量、变化规律及影响因素。结果表明,黄土高原陡坡耕地的土壤侵蚀对土壤中有机质、有效P的含量变化有很大影响,即随着土壤侵蚀速率的增大,土壤中有机质、有效P的含量也明显降低,对有效N的影响无明显规律,土壤侵蚀对土壤养分含量变化的影响规律是:有机质>有效P>有效N。土壤中较大颗粒(1—0.25mm)及细颗粒(<0.001mm)的含量随着土壤侵蚀的增加而呈下降趋势。坡度变化是影响该地区土壤养分流失变化的主导因子,在整个山坡的坡度范围内,随着坡度的增加,土壤的侵蚀速率也增大,土壤中有机质及有效P的含量也逐渐降低。

The effect of soil erosion on the loss of soil nutrients was studied by using 137 Cs technique and the effect factors quantitative evaluated over the cultivated hill s lope in north Loess Plateau.The resu lt showed that the content of soil org anic matter(OM%)and the available phosphorus(available P)were strongly affected by soil erosion,it decreased evidently with the i ncrease of soil erosion rate.There was no correlation ship b etween the change of available nitro gen(available N)and the soil erosion in this study.The effect of soil erosion on the soil nut rient is in the order of:OM%>availab le P >available N.The soil particle c ontent (1-0.25mm and <0.001mm)decreased with the increase of soil erosion rate.The slope was one of the m ost important factors affecting the spatial patterns of the loss amount of soil nutrients,the loss amount of O M%and available P increased with the slope over the whole cultivated hill slope.