Abstract:
Bioavailable selenium (Se) is an important indicator used to evaluate the supply capacity of Se in the soil to plants. There is a lack of national standard methods for testing bioavailable Se in the soil in China presently. This study used ten different chemical extractants to extract bioavailable Se from the soil. The results show that the extraction capacity of extractants was in the order of NaOH (10.57%) > SOL-Se+EX-Se (8.10%) > AB-DTPA (6.79) > NaHCO3 (4.99%) > K2SO4 (4.57%) > KH2PO4-K2HPO4 (4.33%) > KH2PO4 (3.05%) > SOL-Se (2.28%) > EDTA (1.40%) > NH4F-HCl (1.22%). Among them, the bioavailable Se extracted from the soil by KH2PO4, NaHCO3, SOL-Se, KH2PO4-K2HPO4, and AB-DTPA was significantly correlated with the Se content of crops. As revealed by the relationship between the percentage content of bioavailable Se in soil and soil properties, the percentage content of bioavailable Se in soil significantly correlated with indicators such as the chemical index of alteration (CIA), LOI, pH, Eh, P, and SiO2. Among them, pH and Eh mainly affect the existence form of Se in the soil, while indicators such as CIA, LOI, P, and SiO2 reflect the alteration degree of soil and the effect of adsorbates on bioavailable Se in soil. The results of this study can provide data support and a scientific basis for the development of Se-based ecological agriculture and the development and utilization of Se-rich land resources.