ABSTRACT
Geology exerts a fundamental control on concentrations of soil selenium (Se), which influenced the human dietary Se intake. Researchers have tried to solve the uncertainty about nutrient content in soil and its connection to bacterial strains, competitive ions, organic matter, pH, and redox status, as well as dry and harsh climate, evapotranspiration, precipitation, temperature, land use type, and topography. There are four types of landform classes: Desert, Yellow River alluvial plains, platform mountain, and large basin geomorphic unit, as well as seven types of soil: Sierozem, loessal, aeolian sandy, anthropogenic-alluvial, alluvial, saline, and red clay. Concentrations of Se in soil samples were measured after acid digestion. The average total Se content and the bioavailable Se content of top soils in Zhongwei are 0.2 mg/kg and 0.03 mg/kg, respectively. The variable Se distribution in Zhongwei arable land is controlled and influenced by different geochemical factors like high pH and low organic matter.
