Lyu Chenhao, Qin Yongjie, Zhao Zhuqing, Liu Xinwei
College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China; Microelement Research Center, Huazhong Agricultural University, Wuhan, 430070, China; Hubei Provincial Engineering Laboratory for New-Type Fertilizer, Wuhan, 430070, China.
College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China; Microelement Research Center, Huazhong Agricultural University, Wuhan, 430070, China; Hubei Provincial Engineering Laboratory for New-Type Fertilizer, Wuhan, 430070, China.
Environ Pollut. 2021 Jan 15;273:116507. doi: 10.1016/j.envpol.2021.116507.
Agricultural products from seleniferous areas commonly face problems associated with substantial variation in selenium (Se) concentration, which is mainly caused by the heterogeneity of Se bioavailability in soil. Many studies have assessed the bioavailability of Se and its influencing factors using soil samples treated with exogenous Se. Given the distinctly different characteristics of Se-spiked soils and naturally seleniferous soils, exploring Se bioavailability in naturally seleniferous soils is crucial to the stable production of Se-enriched agricultural products. In this study, we used the classical sequential extraction method to determine the Se fractionation and then applied the diffusive gradients in thin-films (DGT) technique to assess the Se bioavailability in naturally seleniferous soils. The results indicated that soluble and exchangeable Se fractions with high bioavailability accounted for only 0.7% and 5.1% of total Se, respectively. Both soluble and exchangeable Se concentrations were significantly positively correlated with soil pH (r = 0.329 and 0.262, respectively; P < 0.01). Se mainly exists in Fe-Mn oxide-bound, organic matter-bound, and residual Se fractions with low mobility (94.2% of total Se), among which organic matter-bound Se was the predominant fraction (49.5% of total Se). A significant positive correlation was found between total Se and soil organic matter (r = 0.539; P < 0.01). Multiple regression analysis revealed that the DGT-determined Se was mostly derived from soluble and exchangeable Se. The high correlation between the DGT-determined Se fraction and Se uptake by rice (r = 0.91; P < 0.01) confirmed that DGT can accurately assess Se bioavailability in naturally seleniferous soils in Enshi and other similar environmental settings.
来自富硒地区的农产品通常面临硒（Se）浓度大幅波动的问题，这主要是由土壤中硒生物有效性的异质性引起的。许多研究使用外源硒处理的土壤样品评估了硒的生物有效性及其影响因素。鉴于添加硒的土壤和天然富硒土壤具有明显不同的特征，探索天然富硒土壤中硒的生物有效性对于富硒农产品的稳定生产至关重要。在本研究中，我们使用经典的连续提取法确定硒的形态，然后应用薄膜扩散梯度（DGT）技术评估天然富硒土壤中硒的生物有效性。结果表明，生物有效性高的可溶性和可交换性硒组分分别仅占总硒的0.7%和5.1%。可溶性和可交换性硒浓度均与土壤pH呈显著正相关（r分别为0.329和0.262；P<0.01）。硒主要存在于迁移性较低的铁锰氧化物结合态、有机质结合态和残留态硒组分中（占总硒的94.2%），其中有机质结合态硒是主要组分（占总硒的49.5%）。总硒与土壤有机质之间存在显著正相关（r=0.539；P<0.01）。多元回归分析表明，DGT测定的硒主要来源于可溶性和可交换性硒。DGT测定的硒组分与水稻对硒的吸收之间的高度相关性（r=0.91；P<0.01）证实，DGT可以准确评估恩施及其他类似环境中天然富硒土壤中硒的生物有效性。
