天山荒漠景观内蒸发地球化学垒的研究

STUDY ON EVAPO-GEOCHEMICAL BARRIERS IN SOILS OF ARID-DESERT LANDSCAPES IN TIANSHAN MOUNTAINS,XINJIANG

天山荒漠景观内的蒸发地球化学垒可分为碳酸盐蒸发垒、石膏蒸发垒和易溶盐蒸发垒。这些蒸发垒沿天山山脉呈带状分布 ,自天山山脉至两侧盆地依次分布碳酸盐蒸发垒、石膏蒸发垒和易溶盐蒸发垒。土壤中碳酸盐的积聚导致Mn、Ti、Fe、V、Sc、Cu、Co和B等元素含量的降低。石膏的富集常伴随着土壤中B和Sr含量的增加。随易溶盐的大量积累 ,元素B的聚集非常明显 ,而Mn、Fe、Ti、V、K、Ba、Li、F和Zn等元素含量则明显降低。蒸发地球化学垒对元素的生物有效性也有较明显的影响。碳酸盐的积累明显减低了Fe、Cu、B等元素的生物有效性 ,F元素在碳酸盐蒸发垒内CO2 -3 和HCO-3 含量较高的土壤中生物有效性较高。

The evapo geochemical barriers (EGB) in soils of arid desert landscapes in Tianshan Mountains, Xinjiang may be divided into carbonate EGB, gypsum EGB, and soluble salt EGB, which are mainly composed of carbonatic soil, gypsic soil, and saline soil, respectively. These EGBs are distributed along Tianshan Mountains as a sequence of carbonate EGB, gypsum EGB, and soluble salt EGB from mountain to basin. In the carbonate EGB, the concentrations of Mn, Ti, Fe, V, Sc, Cu, Co, and B in soils were diluted and lowered as the result of the accumulation of dissociated CaCO 3. In the gypsum EGB, B and Sr in soils were increased with increasing gypsum. In the soluble salt EGB, the accumulation of soluble salts always accompanied with an increase of B, and a decrease of Mn, Fe, Ti, V, K, Ba, Li, F, and Zn in soils due to the dilution of soluble salts. The EGB significantly affected the bio availability of Fe, Cu, B, F, and Zn as well. The accumulation of dissociated CaCO 3 in the carbonate EGB significantly decreased the bio availability of Fe, Cu, and B, whereas the bio availability of B increased with the concentration of soluble salts in soils. Water soluble F in the carbonate EGB was high in the soils with high concentrations of CO 2- 3 and HCO - 3. In addition, the bio availability of Cu is higher in the soils with high organic matter than in the other soils. The bio available Zn has significantly positive relationship to the content of clay in soils.