内蒙古土默特左旗典型草甸土中硒赋存形态特征

Speciation of selenium in typical meadow soils in Tumed Left Banner,Inner Mongolia,China

以内蒙古土默特左旗塔布赛乡表层土壤、土柱剖面等样品为研究对象,测定了土壤硒形态、有效态、理化性质等指标,据此研究了土壤硒形态、有效态组成特征及其影响因素。结果表明,表层土壤硒形态主要以腐殖酸结合态、强有机结合态和残渣态为主;阳离子交换量(CEC)、有机质、磷、钾含量与腐殖酸结合态硒含量呈正相关,全量硒含量与腐殖酸结合态硒、铁锰氧化物结合态硒、强有机结合态硒、残渣态硒含量呈正相关,均表现为促进作用;硫含量与水溶态硒含量呈负相关,表现为抑制作用;由表层至深层,各形态硒含量具有由高趋低特征;有效硒含量与全量硒、有机结合态硒、水溶态硒含量呈正相关,与硫含量呈负相关性。研究区土壤中水溶态硒含量处于高硒等级状态,生物有效性处于较高水平,适合种植、开发富硒农产品。

This study determined the speciation,available content,and physicochemical properties of selenium in soils using samples of topsoil and soil column profiles from Tabusai Township,Tumed Left Banner,Inner Mongolia,China.Accordingly,this study inves-tigated the compositions of the speciation and available content of soil selenium,as well as their influencing factors.The results indi-cate that:(1)the major forms of selenium in topsoil include humic acid bound,strong organic bound,and residue forms;(2)the concentration of in the humic acid bound selenium correlates positively with the cation exchange capacity(CEC)and the concentrations of organic matter,phosphorus,and potassium;the total selenium concentration correlates positively with the concentrations of humic acid bound selenium,Fe-Mn oxide bound selenium,strong organic bound selenium,and residue selenium,all of which exhibit promo-tion effects;(3)the sulfur concentration correlates negatively with the concentration of water-soluble selenium,demonstrating an inhib-itory effect;(4)the concentrations of selenium in various forms tend to decrease from the surface layer to the deep layer;(5)the con-centration of bioavailable selenium correlates positively with the total selenium concentration,organic-bound selenium,and water-solu-ble selenium and correlates negatively with the sulfur concentration.The soils in the study area,featuring a high concentration of water-soluble selenium and fairly high bioavailability,are suitable for planting selenium-rich agricultural products.