黄土峁状丘陵区坡地治理模式对土壤水分环境及植被恢复效应

在黄土峁状丘陵区研究比较了隔坡梯田、大台田、大鱼鳞坑3种坡地的治理模式,指出坡地工程治理能有效地提高坡地接纳降雨能力,提高土壤含水率,但大面积的坡地治理会破坏原有植被及土壤结构,引起40 cm以上表层土壤水分蒸发强烈;同时大台田处理侧坎水分散失严重,距田坎愈近其散失强度愈高;在坡地种植强根系、高耗水的人工林会加剧土壤干层的发育,影响林分自然更新能力。结果表明,隔坡梯田是该区坡地最佳治理模式,其土壤含水率明显高于其他处理,其顺序为：隔坡梯田〉大台田〉大鱼鳞坑〉对照。处理4年后,隔坡梯田分别与其他处理中同一种植模式比较,其牧草产量、树冠投影面积、植被覆盖度分别比大台田处理提高5.5%、29.4%、4.1%,比大鱼鳞坑处理提高22.6%、24.3%、5.4%,比对照提高出38.4%、50.5%和20.8%,经济效益及生态效益明显。

Effects of management models in sloping fields on soil moisture and vegetation restoration in the hilly and gully regions of the Loess Plateau

Effects of slope-separated terrace,large terraced field and large fish-scale pit patterns in sloping fields on soil moisture and vegetation restoration were investigated in the hilly and gully regions of the Loess Plateau using comparing method.Results indicate that the engineering treatments of sloping fields produce an efficient increase in rainwater conservation and soil water content while an obvious break in the vegetation and original soil structure.Especially,a stronger evaporation of soil moisture is occurred in 0~40 cm surface soil.Moreover,the side ridge in the large terraced field induces serious moisture losses.And the shorter distance from the side ridge is,the more losses of soil moisture would be.The plantation with stronger roots and high water consumption enhance the development of dry soil layer on the basis of the management in the sloping fields.Therefore,the renewal ability of natural forest is affected.As a result,slope-separated terrace is the best management mode,whose soil moisture is obviously higher than others in the order of slope-separated terrace > large terraced field > large fish-scale pit > the control.The herbage yield,projected area of plant canopy and vegetation coverage in slope-separated terrace were increased by 5.5%,29.4% and 4.1% more than the large terraced field,22.6%,24.3% and 5.4% more than large fish-scale pit pattern and 8.4%,50.5% and 0.8% more than the control respectively in four years after different engineering managements,resulting in marked economic and ecological benefits.