滴灌背景下玛纳斯流域绿洲内外荒地土壤盐分时空变化趋势分析

干旱区内陆河流域土壤盐渍化主要集中于绿洲内灌溉农田,而对绿洲内荒地和外围荒漠（以下简称绿洲内外荒地）土壤盐分变化趋势尚不清楚。论文基于地理信息系统技术和数理统计学方法,利用玛纳斯流域绿洲膜下滴灌技术普及的初期2006年和近期2012年绿洲内外荒地0~100 cm土壤盐分数据,分析滴灌背景下干旱区绿洲南部、中部和北部内外荒地土壤盐分的0~30、30~60、60~100 cm深度时空变异的总体特征。绿洲内外荒地2012年0~100 cm深度土壤平均含盐量、阴离子含量和除Na⁺、K⁺以外的阳离子含量低于2006年的水平,土壤盐渍化类型由硫酸盐-氯化物类向氯化物-硫酸盐类转化,降低了土壤的碱性,有利于后备农业资源的开发和作物的生长;2006年玛纳斯流域绿洲内外荒地土壤盐分含量、阴离子含量和阳离子含量空间分布差异不显著,而2012年土壤盐分和除个别离子（Na⁺、K⁺、CO32-）外其他离子空间格局总体表现为绿洲中部含量最高;绿洲内外荒地土壤盐分时空变化趋势的主导因素是灌溉方式的改变和地下水的利用。玛纳斯流域绿洲内外荒地土壤盐分时空变化总体特征和可能驱动机制分析,将丰富对干旱区流域绿洲土壤盐渍化的趋势认识,并有助于干旱区后备农业土地资源的合理开发与利用。

Spatio-temporal Variation of Soil Salinity in Wastelands inside and outside of Oasis in Manas River Watershed in the Context of Dripping Irrigation

Studies on soil salinization of inland river watershed in arid area have focused on the cultivated land in oases, but the studies on the salinization of wastelands inside and outside of an oasis are poor. We employed GIS technology and mathematical statistics to investigate the general spatial and temporal variation of soil salinity at the depth of 0-30, 30-60, 60-100 cm of wastelands inside and outside of the south, middle and north parts of an oasis in the Manas River watershed under the background of dripping irrigation between 2006 and 2012. The contents of soil salinity, anions and cations except for Na⁺ and K⁺ at the soil depths of 100 cm in wastelands inside and outside of oasis in 2012 were all less than those in 2006. The dominant salt type transformed from Na₂SO₄ to NaCl during 2006-2012. The contents of soil salinity, anions and cations except Na⁺ and K⁺ did not show significant spatial differences in 2006. Whereas, the contents of soil salinity and ions except for Na⁺, K⁺ and CO32- in 2012 showed significant spatial difference, being higher in the middle part than in the south and north parts of the oasis. The utilization of groundwater and the pattern of irrigation system were the dominant factors resulting in spatial and temporal variation of soil salinity in the wastelands within and outside the oasis. The analysis of spatial and temporal variation of soil salinity in the wastelands inside and outside of oasis in the Manas River watershed would enrich the understanding of salinization and contribute to the reasonable development and utilization of land and water resources in oasis of arid watershed.