富硒土壤硒生物有效性及影响因素研究

Bioavailability of Soil Selenium and Its Influencing Factors in Selenium-Enriched Soil

湖北恩施是典型的富硒土壤分布区,在恩施市沙地乡采集了199件表层土壤样品以及60件玉米样品进行分析测试,旨在查明研究区硒元素含量特征,并分析硒生物有效性及其影响因素。结果显示:研究区表层土壤中硒含量的平均值为1.88 mg/kg,同时土壤中水溶态硒含量只占到总硒含量的0.04%~2.91%,处于相对较低水平。研究区内,有机碳含量对硒生物有效性影响很小,影响硒生物有效性的主要因素为土壤总硒含量和土壤pH值,碱性土壤中硒生物有效性更高。由于该区土壤主要呈酸性,且水溶态硒含量较少,导致玉米中硒含量整体处于相对较低水平,可以通过人为手段适当调控土壤酸碱性,提高硒生物有效性。

To investigate and understand soil selenium concentrations with its bioavailability and influencing factors in Shadi Town,Enshi City,Hubei,which is a known selenium-enriched area,199 topsoil samples and 60 corn samples were collected and analyzed. Results showed that the average concentration of total selenium in the topsoil of Shadi Town,Enshi City was 1. 88 mg/kg,whereas the concentrations of water-soluble selenium in soil reached 0. 04%-2. 91% of the total soil selenium indicating the relatively low level of selenium. In the study area,the concentrations of soil organic carbon showed minor effects on selenium bioavailability. The main influencing factors of selenium bioavailability included the soil total selenium concentrations and soil p H value owing to the high selenium bioavailability in alkaline soil. As considerable portions of topsoil samples were acidic,and the concentrations of soil water-soluble selenium were low in the study area,the low selenium concentrations were observed in the corns. Soil p H value can be adjusted to improve selenium bioavailability.