沙障成林的固沙工程及生态效益研究

SAND FIXATION PROJECT WITH FOREST SAND BARRIER AND ITS ECOLOGICAL BENEFIT

温带亚湿润地区的流动沙地具有特殊的水分状况。某些风口地段的流动沙丘，植树难以成活，但利用活体杨树枝条扦插沙障，可以成活为林，是一项机械固沙与生物固沙相统一的治沙工程。沙障成林后，生态效益明显：春季大风日，林内风速削减１５％～４１．５％，夏季林内温度降低１～３℃，空气湿度增加１１％～２２％；林下土壤稳定发育，表土层粘粒增加５％～１０％，土壤有机质增加１％，土壤结构形成；沙丘植被逐渐演替，由裸沙地→沙蒿（Ａｒｔｅｍｉｓｉａｄｅｓｅｒｔｏｒｕｍ）＋沙蓬（Ａｇｒｉｏ－ｐｈｙｌｕｍｅｒｅｎａｒｉｕｍ）→沙地萎陵菜（ｐｏｔｅｎｔｉｌａｆｉｌｉｐｅｎｄｕｌａ）＋燕麦芨芨草（Ａｃｈｎａｔｈｅｒｕｍａｖｉｎｏｉｄｅｓ）→贝加尔针茅（Ｓｔｉｐａｂａｉｃａｌｅｎｓｉｓ）＋沙地萎陵菜、苔藓，使整个沙丘形成稳定的林草系统，并成为风口地段的防风屏障。

The mobile dunes in the sub humid temperate zone pose the specific water regime. Some wind gaps are difficult to support planted trees, but the sand barrier consisted of alive branches of poplar can survive to become the forest. This sand controlling project has achieved the integratation of mechanical sand controlling and biological sand controlling. The obvious ecological benefit can be obtained after the sand barriers becoming forest: in the gale days during Spring, the wind speed can be reduced by 15%￣41 5%; in Summer, the air temperature droped by 1￣3℃,the air humidity increased by 11%￣22%;the soil under the forest grows steadily, the glutinous granules in the surface layer increased by 5%￣10% and the organic matter of soil increased by 1%; The plantation successes gradually from uncovered sandland to Artemisia desertorum+Agriophyllum erenarium to Potentilla filipendla+Achnatherum avinoides to Stipa baicalensis+Potentilla filipendula and moss. At last, a stable forest grass system has become and the surrounding ecological environment has been improved also.