绿洲边缘退化梭梭林地集流试验研究

集流措施有效提高降水的深层入渗,阻止土壤水分的蒸发,改善林地的水分条件,提高梭梭对降水的有效利用率。研究表明:单株集流面积越大,降水在汇集区土壤中的入渗深度越大;土壤中的粘土层和结皮层拦蓄大量降水,阻止降水的深层入渗。不同集流场地,水分在水平结构和垂直结构上的变化均有显著差异,影响强度和范围随集流面积的增加而增强。深层粘土层保持较高的含水率,变化幅度较大,与集流面积之间存在有一定的关系。退化梭梭林地单株梭梭地上生物量为增长型,地下生物量为消长型。集流面积越大,地上生物量增长差异越显著;年降雨量越大,地上生物量差异越显著;而地下生物量无明显差异,与集流面积、年降雨量之间的相关性不明显。集流面积为9m2梭梭恢复生长较为显著,其冠幅生长和高生长差异显著,生物量年度变量差异显著。

A STUDY ON PRECIPITATION COLLECTING ON THE DEGENERATED HALAXYLON AMMODENDRON WOODLAND ON OASIS BOUBDARY

The collecting measure of precipitation is able to increase depth of precipitation seeping in soil, to hold back soil-water evaporation, to improve woodland soil-water condition and to heighten available precipitation. As a result, with the increasing of precipitation collecting area, the depth of precipitation- seeping is increasingly enhanced; the hardpan and crust layer in soil could store up a great capacity of precipitation and hold back the seeping of precipitation, its soil-water is highest, it has not relationship with the area of collecting. the distribution of soil-water in level structure and plumb structure has obvious difference among the different areas, the intensity and rang of soil-water increase with the increasing of collecting area. Single Haloxylon ammodendron biomass above ground is increased, but biomass under ground is decreased; The more collecting area and precipitation is, the more obvious difference of biomass above ground is, but biomass under ground is not obvious. The difference of Haloxylon ammodendron's growth in high and breadth is marked, and the difference of biomass above ground is obvious. Adaptable area of single Haloxylon ammodendron precipitation collecting in arid area is 9m~2.