河北坝上农牧交错带草地不同方式持续利用对土壤颗粒空间分布的影响

为探究河北坝上农牧交错带典型草原不同方式持续利用对土壤颗粒空间分布状况的影响，本研究通过对河北坝上封育10年，中度放牧，重度放牧草地以及不同开垦年限的垦殖草地（持续利用5年，10年，15年）土壤进行分层（0～10 cm，10～20 cm，20～40 cm，40～60 cm）研究其土壤颗粒分布及变化。结果表明：随放牧强度的增加，土壤中2000～250 μm，250～150 μm，150～53 μm颗粒含量均显著减少，而53～20 μm，20～2 μm，<2 μm颗粒含量均显著增加，即增加了重度放牧草地土壤风蚀退化的潜在危险性；对于垦殖草地，随着持续利用年限的增加，土壤中2000～250 μm，250～150 μm，150～53 μm颗粒含量均显著增加，而53～20 μm，20～2 μm，<2 μm颗粒含量均显著减少，这表明随着垦殖年限的增加，土壤逐渐趋向沙化。因此，为保证草地的可持续性，放牧草地需要避免重度放牧而垦殖草地需要改变现有的耕作方式。

The Effect of Different Uses of Grassland on Spatial Distribution of Soil Particle Size in Hebei Ectone

In order to investigate the effect of different uses of grassland on spatial distribution of soil particle size at the agro-pastoral ectone of Bashang region, Hebei Province, three different grazing grassland (enclosed 10-year grassland, moderate grazing grassland, and heavy grazing grassland) and three different reclamation ages of converted grassland (5year, 10years and 15years) were selected to study the dynamics of soil particle size distribution in different soil layers (0~10 cm,10~20 cm,20~40 cm,40~60 cm). The results showed:the contents of 2000~250 μm, 250~150 μm and 150~53 μm soil particle significantly decreased with increasing grazing intensities, however, the contents of 53~20 μm, 20~2 μm, and <2 μm soil particle significantly increased. This change increases the potential risk of soil erosion under heavy grazing intensity; As for reclamation grassland, the content of 2000~250 μm, 250~150 μm, and 150~53 μm soil particle significantly increased as the reclamation ages increased, but the content of 53~20 μm, 20~2 μm, and <2 μm soil particle significantly decreased. It indicates that reclamation grassland is gradual desertification with increasing cultivated years. Therefore, to keep the sustainability of different uses of grassland,grazing grassland need to avoid heavy grazing and reclamation grassland need to change current cultivated method.