毛乌素沙地西北缘不同类型沙丘土壤水分分布特征

1.长安大学 西部矿产资源与地质工程教育部重点实验室,陕西 西安 710054; 2.陕西师范大学 旅游与环境学院,陕西 西安 710062; 3.中国科学院地球环境研究所 黄土与第四纪地质国家重点实验室,陕西 西安 710061

土壤含水量; 沙丘微地貌; 沙丘植被; 土壤粒度; 毛乌素沙地; 鄂托克旗

Distribution characteristics of soil moisture content in different types of sand dunes in the northwestern margin of the Mu Us sandy land
FU Chao-feng1,2,3,ZHAO Jing-bo2,BIAN Zi-hao1,ZUO Jun1

(1.Key Laboratory of Western Mineral Resources and Geological Engineering of Ministry of Education,Chang'an University,Xi'an 710054,China; 2.College of Tourism and Environment Science,Shaanxi Normal University,Xi' an 710062,China; 3.State Key Laboratory of Loess and Quaternary Geology,Institute of Earth and Environment,CAS,Xi'an 710061,China)

soil moisture content; microtopography; vegetation of dunes; soil particle constituent; Mu Us sandy land; Etuoke Qi

DOI: 10.13800/j.cnki.xakjdxxb.2015.0406

备注

干旱区的土壤水分分布特征受气候、区域地形、植被、土壤质地等因素的影响,其本身也是整个区域环境的重要影响因子。文中通过对位于毛乌素沙地西北缘鄂托克旗境内的裸露流动沙丘、灌木覆盖沙丘、乔木覆盖沙丘3种类型沙丘不同地貌部位0~4 m深度范围内的土壤含水量研究,采用钻孔取样、烘干称重和粒度测试等方法,分析不同植被、地形和土壤质地等因素对研究区土壤含水量分布特征的影响。结果 表明:对于垂直方向0~4 m 深度范围内的裸露流动沙丘、灌木和乔木覆盖沙丘平均含水量变化均表现为迎风坡高于背风坡,且在灌木覆盖沙丘和乔木覆盖沙丘的丘间洼地的土壤含水量多高于迎风坡和背风坡,不同类型沙丘在各地貌样点不同层段含水量变化差异明显,变化趋势不统一。相同的沙丘微地貌,不同类型植被覆盖对于沙丘土壤含水量在垂向上的变化有较大影响,且灌木植被的影响大于乔木植被。除了植被以外,浅层基岩的隔水作用对土壤含水量同样有重要影响。土壤水分分布特征与土壤中不同粒级的颗粒含量有关,而植被通过拦截空气中的粉尘,提高了土壤中粘土与粉砂等持水能力强的颗粒组分,进而提高了土壤平均含水量。

The distribution characteristics of soil moisture in arid areas are affected by climate,regional topography,vegetation,soil texture,etc.,and soil moisture is also an important factor of regional environment change.In the study area,the sand dunes are divided into bare migratory dunes,shrubs-covered dunes and trees-covered dunes according to the vegetation forms and vegetation coverage on the surface of sand dunes,and the samples of drilling holes in the depth of 4 m at different topography sites of the dunes were taken for analyzing the change of soil moisture content and soil granularity characteristic of the sand dunes.The results are as follows:The average soil moisture varies in different types of dunes,with the following sequences ordered from highest to lowest:in three types of dunes the sequence is from windward slope to leeward slope,and in the shrub-covered dunes and the tree-covered dunes the sequence is from inter-dunes lowland to windward slope and leeward slope in most situations,the variation of soil moisture content at different depth of each type dune was different.Vegetation form and surface coverage affect the range of soil moisture of different types of dunes in the same topographic position.The coefficient of variation of the soil moisture of shrub-covered dunes is higher than that of other types of dune.Furthermore,the shallow bedrock aquifuge affects sharply the variation of soil moisture content near the bedrock of different topographic position.The average moisture of vegetation-covered dunes existed in obvious correlation with clay and silt constituent of sandy soil,which can be explained in terms of the greater ability of vegetation special shrubs to trap fine-grained atmospheric dust and hold moisture.