克拉玛依人工碳汇林区景观地球化学特征与规律

Characteristics of landscape geochemistry in Karamay artificial carbon-sink forests

  • 摘要: 以克拉玛依人工碳汇林区的土壤可溶性盐分离子、地下水矿化度和植被为研究对象, 综合运用描述性统计和相关性分析等方法, 研究其景观地球化学特征, 旨在通过对克拉玛依人工碳汇林区的景观地球化学特征的研究, 为这一地区盐渍化土壤改良和沙漠化防治提供理论依据。结果表明: 克拉玛依人工碳汇林区土壤Cl-、SO42-、Ca2+在0~80 cm范围内变异系数较大, 80~100 cm范围内, 土壤总盐和各离子变异系数相对较小; 盐分表聚现象严重; 该地区盐土类型主要是硫酸盐型, 其中SO42-和Na++K+为土壤可溶性盐的主要成分。研究区地下水呈弱碱性, 除HCO3-外, 其他离子和矿化度表现出较强的变异性; 地下水的化学类型主要为Cl·SO4-Na, 矿化度和Cl-、SO42-、Na++K+相关系数较为显著。种植人工碳汇林后, 除土壤HCO3-含量有轻微上升外, 其他离子均有所下降, 其中SO42-含量的降低趋势最为明显。俄罗斯杨林分土壤含盐量随种植年限的增长明显降低, 种植后的土壤盐渍化状况有明显改善。

     

    Abstract: Karamay artificial carbon-sink forest is located in the southern margin of Gurbantunggut Desert, where soil salinization is a severe ecological problem. With adequate knowledge on the patterns of soil soluble salts/ions distribution, mechanisms of change, chemical constituents of groundwater and varied characteristics of landscape patterns, saline soils can be rationally utilized and ecological agro-forestry efficiently developed. This paper aimed to lay the theoretical basis for ameliorating soil salinity and controlling desertification via analyzing the characteristics of Karamay landscape geochemistry. Using monitoring field data for soil soluble salt, groundwater salinity and vegetation cover in Karamay artificial carbon-sink forest, the characteristics of landscape geochemistry were analyzed via descriptive statistics and correlation analysis. The results showed great variation in contents of Cl-, SO42-, Ca2+ in 0~80 cm soil, while less variation in salinity and salt ions contents in 80~100 cm soil layer was found. Soil salinity increased with increasing soil evaporation resulting in severe salt accumulation in surface soils of Karamay carbon-sink forest. Sulfate was the dominant salt in study area, which consisted mainly of soluble SO42- and Na+ and K+ salts. With the exception of HCO3-, variations in groundwater salinity and the related compounds exhibited strong variation. Cl-, SO42-, Na+ and K+ were the main elements of groundwater mineralization, and significant linear correlations were noted among salinity and these ions. The groundwater chemical type was Cl·SO4-Na. Forest protection ameliorated soil salinity. Although the dynamics of soil salinity varied from forest to forest, salinity (more for SO42- salts) dropped after planting forests. Furthermore, soluble total salts significantly dropped with increasing age of the Russia poplar forest.

     

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