澎溪河不同高程消落带土壤磷的吸附特性

消落带土壤磷吸附特性对库区水体的营养状态有重要影响。为研究不同高程消落带土壤磷吸附特性,选取了三峡库区澎溪河流域双江140,145,155,165,180m高程土壤,进行磷等温吸附热力学试验,并探讨了不同高程消落带土壤磷吸附特性差异的原因。结果表明,随着高程的降低,消落带土壤吸附解吸平衡浓度EPC和磷最大吸附量Qmax逐渐增加,即磷吸附能力增强。结合消落带土壤颗粒表面特性分析、吸附特征参数与理化性质相关性分析的结果,认为消落带土壤具有较小的粒径分布,较高的有机质含量和Fe含量是影响不同高程消落带磷吸附能力的重要原因,且主要受到冬季淹水沉积和夏季降雨侵蚀的影响。低高程消落带土壤具有较强的磷吸附能力,对于控制库区水体富营养化具有一定的积极意义。

Phosphorus adsorption characteristics of the soils at different altitudes in water-level-fluctuating zone of Pengxi River

The phosphorus adsorption characteristics of the soils in water-level-fluctuating zone (WLFZ) have an important influence on the nutritional status of the reservoir water body. In order to study phosphorus adsorption characteristics of the soils at different altitudes in WLFZ, the 140 m, 145 m, 155 m, 165 m and 180 m altitudes soils of Shuangjiang in Pengxi River were selected for the thermodynamic experiment of phosphorus isothermal adsorption. The causes for the differences in phosphorus adsorption characteristics of soils from WLFZ were discussed. The results indicated that the adsorption-desorption equilibrium concentration (EPC) and the maximum adsorption amount (Q_max) of phosphorus gradually increased with the decrease of altitude, that is, the phosphorus adsorption capacity was enhanced. Combined with the analysis of the surface characteristics of the soil particles and that of the correlation between the adsorption characteristic parameters and the physical-chemical properties of the soil samples, it was considered that the soils from WLFZ had a smaller particle size distribution, higher organic matter content and Fe content, which were important factors affecting the phosphorus adsorption capacity, and the different characteristics of the soils were mainly affected by winter flooding sedimentation and summer rainfall erosion. Soils with low altitude has strong phosphorus adsorption capacity, which has certain positive significance for controlling eutrophication of the water bodies in Three Gorges Reservoir.