民勤绿洲边缘植被恢复与重建初探

干旱缺水是导致民勤绿洲边缘植被退化的根本原因,也是民勤绿洲边缘退化植被恢复与重建的关键限制因子。恢复存在着一个过去时间的参照系,要恢复民勤绿洲边缘植被到过去某一时期的状态是不可能的;提取地下水灌溉恢复退化植被只能加速植被的进一步退化;采用滴灌灌溉目前还不具备条件;集流降水也于事无补;而目前尚无抗逆性更强的植物种用以取代退化植被。目前只能做到:⑴实施封育保护,使其进入退化→自然稀疏→沙丘活化→储存降水→自然演替的过程,使其形成在现有水资源条件下的植物群落或植被;⑵破坏土壤表面结皮,储存有限降水提高沙丘水分;⑶充分利用农田边缘和渠道渗漏剩余水;⑷农业节水是根本。

A Study on the Rehabilitation of Vegetation Around Minqin Oasis

Water shortage,a fundamental cause leading to the degradation of vegetation around the Minqin oasis,is a pivotal factor to the rehabilitation of vegetation aroundthe Minqin oasis.There is a frame of reference on time background to the rehabilitation,it is almost impossible to restore the vegetation to a state of certain times in the past.Pumping groundwater to restore the vegetation will contribute to further worsening of vegetation.The application of drip irrigation is beyondthe reach of farmers in this area.It can hardly expect to raincollect.Moreover there is no more adversity-resistant plant species to replace the current ones.At present what can be done includes⑴ closing off to form a vegetation or flora under the existing moisture condition through the process of degradation-natural thinning-dune activation-storing rainfall-natural evolvement;⑵ break the crust of soil to improve the moisture in dunes;⑶ making use of percolating water from canals and the fringe of farmland;⑷ water saving in agriculture being an essential way.