阿拉善荒漠区灌木群落的土壤盐分特征分析

The Characteristics of Soil Salinity in the Shrubs Community of Alxa Desert

摘要: 作为中国典型的荒漠生态系统，阿拉善荒漠区灌木群落不仅是中国北方重要的生态屏障，而且也是中国六大生物多样性中心之一。因此，阿拉善荒漠灌木群落的稳定对于我国生态安全与生物多样性保护具有重要意义，而土壤盐分是影响干旱区荒漠植物群落组成与结构、群落动态的决定因素之一。本文以2010~2011年阿拉善荒漠灌木资源野外调查为基础，分析了灌木群落下的土壤盐分含量、类型及分布格局等特征，得到如下结论：1) 就不同群落而言，柽柳灌丛的“盐岛”效应最明显，按总盐量排序依次为：柽柳>梭梭>白刺>霸王>沙冬青>绵刺>蒙古扁桃；2) 土壤中阴离子以 SO₄^2- 和C1^-为主，阳离子以Na+为主，土壤盐分类型以硫酸钠型和氯化钠型为主；3) 受黑河地表径流和下游强烈蒸发作用影响，土壤盐分分布格局整体表现为西北高东南低的特征，沿东南向西北呈逐级递增的趋势。

Abstract: As a most typical desert ecosystem in China, Alxa desert shrub is not only a significant ecological barrier of North China, but also one of the sic biodiversity centers in China. Therefore, the stabili-zation of Alxa desert shrub community, which is observably affected by soil salinity, has important effect on ecological security and biodiversity in China. Based on the field survey of Alxa desert shrub resources in 2010-2011, the content, composition and distribution of soil salinity under the shrub community were analyzed. The following conclusions were summarized: 1) There is a salt enrichment effects under the Tamarix chinensis and the content of total salt could be arranged in the following order: Tamarix chinensis > Haloxylon ammodendron > Nitraria tangutorum > Sarco-zygium xanthoxylon >Ammopiptanthus mongolicus > Potaninia mongolica > Amygdalus mongolica; 2) The soil negative and positive ion were respectively dominated by SO₄^2-, C1^- and Na+, so that the soil salinity was sodium sulfate type and sodium chloride type; 3) The characteristics of soil salinity distribution pattern was high in northwest and low in southeast, and increased from southeast to northwest, which was mainly affected by the downstream of Heihe river runoff and intense evaporation.