不同土壤中氟赋存形态特征及其影响因素

采用连续化学提取法研究了15种土壤中氟的赋存形态特征. 土壤中氟的赋存形态按量的大小呈如下规律分布: 残余态可交换态>水溶态>有机态>无定形氧化铁态. 水溶态氟与铁锰结合态氟呈极显著正相关(r=0.7775^{* *}), 同时可交换态氟也与可交换态氟(r=0.5753^*)和有机态氟(r=0.5529^*)呈显著正相关. 对土壤中氟形态与土壤性质进行的逐步回归分析表明, 土壤pH值、有机质、粘粒、交换性钙是影响土壤氟形态分布的重要因素. 其中, pH值最为重要, 对水溶态氟和可交换态氟的影响大于其它土壤因子. 另外, 土壤母质对土壤中氟的赋存形态也有影响, 各种沉积物发育而成的土壤中水溶态氟和可交换态氟含量较比其它母质发育的土壤高.

Characteristics of Forms of Fluorine in Soils and Influential Factors

Forms of fluorine in 15 different soils were studied using sequential chemical extraction procedure. The fluoride forms in soils were separated into five fractions: water soluble fluoride (Ws-F), exchangeable fluoride (Ex-F), fluoride bound to Fe/Mn oxides (Fe/Mn-F), bound to organic matter (Or-F), and residual fluoride (Residual-F). The contents of different fluoride forms were decreased in the order: Residual-F>>Ex-F>Ws-F>Or-F>AoFe-F. Correlation analyses showed that Ws F was significantly correlated with Ex-F (r =0.7775^{* *}). Ex F was correlated with Fe/Mn-F (r =0.5753^*) and Organic-F (r=0.5529^*). Stepwise linear regression analysis was used to test the effect of various soil components on the contribution of fluoride forms, indicating that soil pH, organic matter, clay content, and exchangeable calcium content were the important influential factors and pH was the most important influential factor. In addition, soil parent materials had also influence on forms of fluorine.