流动沙丘上生态垫防风固沙效果初步评价

A preliminary evaluation of Ecomat function on windbreak and sand-fixation in mobile sand dune

北京及其周边地区分布的大量裸露沙荒地是北京近年来沙尘暴频发的主要沙源之一,而增加其地表覆盖状况则是遏止就地扬沙起尘的有效措施之一。以北京西北部河北宣化黄羊滩为例,对流动沙丘上铺设生态垫并栽植灌木的防风固沙效果进行了初步研究。研究结果表明,与沙柳沙障相比,生态垫确实可以降低近地表的输沙率,提高生态垫下土壤的养分含量,一定程度上提高柠条的地径和高度,可见生态垫是一种很好的促进流沙固定和植被恢复的地表覆盖材料;与其它两种生态垫铺设方式(品字状和带状)相比,全铺可以显著降低近地表的输沙率,提高其下土壤的养分含量,但柠条的生长状况却略差,这可能与全铺降低了小雨入渗的可能性有关;就两种部分铺设的方式而言,无论从降低近地表的输沙率还是促进柠条的生长上来看,品字状都明显优于带状。从生态和经济的角度综合考虑,品字状铺设显然是该区域流沙防治措施中较好的选择。

A large area of bare sandland distributed in Beijing and its surrounding areas is one of sand source areas which contributes to high-frequent sand storms in Beijing in recent years, whereas increasing of surface coverage condition is one of effective measures to lessen local blown-sand activities. This study, conducted in Huangyangtan, Xuanhua County, Hebei Province, was aimed at the roles of ecomat and shrub-planting in windbreak and sand-fixation in mobile sand dunes. The results show that compared to Salix psammophila barrier, ecomat cover does decrease surface sand transportation rate （SSTR）, increase surface soil nutrient, and enhance growth of Platycladus orientalia to the extent, undoubtedly ecomat is one of surface cover materials for sand-fixation and revegetation; compared to two other ecomat part-cover types （banded and chessboard）, the all-cover type can also decrease SSTR, increase surface soil nutrient significantly, growth condition ofPlatycladus orientalia, however, is not good as expected, which may attributes to lower infiltration rate of slight rainfall; as for two part-cover types, chessboard type is better than banded type in increasing of SSTR and enhancement of Platycladus orientalia growth. In conclusion, ecomat chessboard type is the best measure for sand control ecologically and economically in this region.