ABSTRACT
Selenium (Se) is an essential micronutrient for humans and animals, with a narrow range between its nutrient requirement and its toxicity. Selenium consumption for humans is supplied mainly by the food chain. Several field and pot experiments have been conducted to investigate soil parameters affecting Se accumulation in crops without Se fertilization. Plant Se and soil-bioavailable Se was extracted by 0.5 mol/L NaHCO3 and determined by AFS. Statistical analyses were performed with Minitab 16. Soil and crop Se concentrations were analyzed by ANOVA. Best subset regression models were derived to correlate crop Se and soil parameters. Soil organic matter played a dual role in regulating soil Se bioavailability. The immobilization of Se by Soil organic matter of both biotic and abiotic mechanisms reduced Se bioavailability, whereas the decomposition of OM-bound Se provided more bioavailable Se in soil solution. The majority of cultivated soils in Southern Jiangxi are rather low in Se, resulting in low crop Se contents.
