藏南扎西康矿集区土壤盐渍化空间分布及成因分析

Spatial distribution and genesis of the surface soil’s salinization in Zhaxikang mine area, southern Tibet

关键词:  土壤盐渍化  水溶性盐分总量  成因分析  扎西康矿集区

Key words:  salinization of soil  total amount of water-soluble salts  genesis of soil's salinization  Zhaxikang mine areas

摘要:

旱—半干旱高寒地区土壤盐渍化，对区域农牧业发展及地质环境造成较大的影响。本文在西藏扎西康矿集区环境地质调查的基础上，通过对宿麦朗沟盐渍化3处土壤剖面系统采样分析，查明土壤盐分的空间分布及盐渍化成因。结果表明：相同层位土壤电导率与水溶性盐分总量之间呈正相关关系，0~80cm之间，土壤中盐分离子含量变化较大；80cm之下，土壤盐分含量趋于稳定；因子分析进一步揭示，研究区土壤盐分主要由氯离子、钠离子组成，两者之间相关性较强（R²=0.9592）；维美组地层以高硅、高钠为特征，三角洲及河流相的沉积环境及地下水活动等共同造成该区域土壤盐渍化。在此基础上，针对性地提出了降低地下水位、定期人工喷淋洗盐及施入有机肥料等方法是干旱区土壤盐渍化防治的有利措施。

Abstract:

Soil salinization in arid, semi-arid and alpine areas has a great impact on regional agriculture, livestock farming industry and geological environment. Based on the environmental geological survey of the Zhaxikang mine areas in Tibet, the spatial distribution of soil salt and its genesis are found out through the systematic sampling analysis of three soil profiles in Sumailang gully. The results show that there is a positive correlation between the soil conductivity and the total amount of water-soluble salts in the same depths of soil layers, and the content of salt ions in the soil vary greatly from the surface to 80 centimeters underground. When the soil layers deeper than 80 centimeters underground, salt content in the soil tends to be stable. Factor analysis further reveals that the salt in soil in studied areas is mainly composed of chloride and sodium ions, and the correlation between them is strong (R²=0.9592). The soil's salinization in studied areas is caused by the high contents of silicon and sodium elements in the Weimei Formation, the delta and fluvial sedimentary environments of Weimei Formation, and the groundwater activities in the areas. The authors suggest that lowering the groundwater level, spraying water to dilute salt contents in the soil, and applying organic fertilizer to the soil, are suitable preventing methods for soil's salinization in arid areas.