毛乌素沙地人为干扰苔藓结皮的土壤水分和风蚀效应

目的]为了探讨在毛乌素沙地人为干扰生物结皮的必要性与可行性,并为该区生物结皮的高效利用提供实验依据。方法]在毛乌素沙地东南缘设置裸沙、苔藓结皮、干扰苔藓结皮、沙蒿、沙蒿+苔藓结皮以及沙蒿+干扰苔藓结皮6个处理小区,通过动态监测各小区土壤水分及风蚀变化过程,分析人为干扰苔藓结皮对土壤水分及风蚀过程的影响。结果](1)沙地苔藓结皮能够显著提高浅层土壤含水量,降低深层土壤含水量。(2)人为干扰苔藓结皮会引起浅层土壤含水量的降低和降雨入渗深度的增加。(3)与裸沙对照相比,几种处理的减蚀效率大小顺序为:沙蒿+苔藓结皮(97.01%)沙蒿+干扰苔藓结皮(90.87%)苔藓结皮(89.63%)干扰苔藓结皮(69.50%)沙蒿(64.62%)。结论]植被覆盖度较高时,对苔藓结皮进行适当破坏,能够在不加剧土壤风蚀的前提下,一定程度上改善土壤水分状况。而在无植被或低植被覆盖的地块,要禁止对苔藓结皮的干扰破坏。

Effects of Disturbed Moss Dominated Crusts on Soil Moisture and Wind Eosion in Mu Us Sandland

Objective] To discuss the necessity and feasibility of biological soil crusts(BSCs) in the Mu Us sandland and provide an experiment basis for the efficient utilization of BSCs in this region.Methods] Six treatments including bare sand, moss dominated crusts alone, disturbed moss dominated crusts alone, Arternisia ordosica alone, A. ordosica combined with moss dominated crusts and A. ordosica combined with disturbed moss dominated crusts were settled in the south edge of the Mu Us sandland, and the effects of BSCs on soil moisture and wind erosion were analyzed by dynamic monitoring the soil moisture and wind erosion of each treatment.Results] (1) Moss dominated crusts in Mu Us sandland significantly improved the soil moisture content in shallow layer and reduced the soil moisture content in deep layer. (2) Human disturbance on moss dominated crusts reduced the soil moisture in shallow layer and increase the infiltration depth of rainwater. (3) Compared with bare sand, the contribution of other five treatments to reducing wind erosion were found to decrease in the following order:A. ordosica combined with moss dominated crusts (97.01%)> A. ordosica combined with disturbed of moss dominated crusts (90.87%)> moss dominated crusts alone (89.63%)> disturbance of moss dominated crusts alone (69.50%)> A. ordosica alone (64.62%).Conclusion] Appropriate disturbances on moss dominated crusts covered by higher coverage of vegetation is beneficial to improving the soil water environment to certain degree on the premise that the wind erosion could not dramatically increase, but the disturbance in the sites without vegetation or with only little vegetation during gale seasons must be prohibited.