Characteristics and Influencing Factors of Soil Selenium in Shimen County, Hunan Province

  Objective  The aims were to clarify the characteristics and spatial distribution of selenium (Se) content in cultivated soil in Shimen County, and to provide basis for the development of Se-rich agricultural products in shimen County.

  Methods  By field investigation and sampling, indoor analysis, mathematical analysis and model simulation, the total Se contents in soil of 2647 cultivated land samples in Shimen County were determined, and the characteristics and spatial distribution of total Se content in cultivated land soil were analyzed, and the influencing factors were explored.

  Result  ① The average Se content of cultivated soil in Shimen County was 1.02 mg kg⁻¹, 3.52 times higher than the national average. ② The Se-rich cultivated land area in Shimen County was large, showing the characteristics of high in the middle and low in the north and south, and there was a Se-rich zone in the middle. ③ The Se content of soils developed by limestone weathering materials was significantly higher than that of other soil parent materials, and the Se content of limestone soil was significantly higher than that of Alluvial soil and purple soil. ④ There was a positive correlation between soil Se and organic matter. When pH<5.5, soil Se contents decreased with the increase of pH; when pH > 5.5, soil Se contents enhanced with the increase of pH.

  Conclusion  The overall Se content of cultivated soil in Shimen County was relatively higher, and gradually decreased from central to north and south. Soil Se inherits its parent material and is affected by factors such as leaching, deposition, organic matter and pH. There are Se-rich zones suitable for the development of Se-rich agricultural products.