土壤酸化增强了农业土壤在缺氧条件下磷的移动性：研究磷向水体流失的潜力及相关环境风险。
Soil acidification enhances the mobilization of phosphorus under anoxic conditions in an agricultural soil: Investigating the potential for loss of phosphorus to water and the associated environmental risk.
机构信息
Beijing Key Laboratory of Farmland Soil Pollution Prevention-control and Remediation, College of Resources and Environmental Sciences, China Agricultural University, No. 2 Yuanmingyuan Xilu, Haidian, Beijing 100193, PR China; University of Wuppertal, School of Architecture and Civil Engineering, Institute of Foundation Engineering, Water- and Waste-Management, Laboratory of Soil- and Groundwater-Management, Pauluskirchstraße 7, 42285 Wuppertal, Germany.
University of Wuppertal, School of Architecture and Civil Engineering, Institute of Foundation Engineering, Water- and Waste-Management, Laboratory of Soil- and Groundwater-Management, Pauluskirchstraße 7, 42285 Wuppertal, Germany; Biochar Engineering Technology Research Center of Guangdong Province, School of Environmental and Chemical Engineering, Foshan University, Foshan, Guangdong 528000, PR China.
出版信息
Sci Total Environ. 2021 Nov 1;793:148531. doi: 10.1016/j.scitotenv.2021.148531. Epub 2021 Jun 19.
Soil redox potential (E) and pH are key parameters regulating the solubility and fate of phosphorus (P). However, the impact of soil acidification on the redox-induced mobilization and speciation of P in soils under a wide range of E values has not been extensively studied. Here, we investigated the mobilization and speciation of P in an acidified agricultural soil at two different pH values (e.g., highly acidic soil; pH = 5.6 and slightly acidic soil; pH = 6.1) compared to the un-acidified soil (control soil; pH = 7.3) under a wide range of E condition (+459 to -281 mV). The impacts of E/pH-dependent changes of Fe-Mn oxides, and dissolved organic (DOC) and inorganic (DIC) carbon on P mobilization and speciation were also investigated using geochemical and spectroscopic (X-ray absorption near edge structure) techniques. The concentrations of dissolved P under anoxic conditions increased up to 69.3% in the highly acidic soil compared with the control soil. The decrease of the Fe-P fraction, the decrease of Ferrihydrite-P speciation, and the strong linear correlation between the dissolved P and Fe (R > 0.85) supports the finding that enhanced P mobilization under anoxic conditions may be attributed to Fe reduction in the highly acidic soil. The concentration of dissolved Fe and P remained low until pH dropped below 6.35 for P and 6.28 for Fe, while a liner increase was found in dissolved Mn accompanying a general trend of pH decrease. This result suggests that the dissolution of reducible Mn under acidic soil conditions was an important factor for enhancing mobilization of dissolved P under anoxic conditions. This trend was due to the low amount of Mn, indirectly speeding up Fe reduction. These results can help to develop management practices to effectively mitigate P export and protect water resources from diffuse P pollution.
土壤氧化还原电位 (E) 和 pH 是调节磷 (P) 溶解度和归宿的关键参数。然而，土壤酸化对 E 值范围内广泛的土壤中氧化还原诱导的 P 迁移和形态的影响尚未得到广泛研究。在这里，我们研究了在两种不同 pH 值（即高度酸化土壤；pH = 5.6 和略酸化土壤；pH = 6.1）下与未酸化土壤（对照土壤；pH = 7.3）相比，在广泛的 E 条件下（+459 至-281 mV）酸化农业土壤中 P 的迁移和形态。还使用地球化学和光谱学（X 射线吸收近边结构）技术研究了 E/pH 依赖性变化的 Fe-Mn 氧化物以及溶解有机 (DOC) 和无机 (DIC) 碳对 P 迁移和形态的影响。在缺氧条件下，高度酸化土壤中溶解 P 的浓度比对照土壤增加了 69.3%。Fe-P 分数的减少、Ferrihydrite-P 形态的减少以及溶解 P 和 Fe 之间的强线性相关性（R > 0.85）支持了在高度酸化土壤中缺氧条件下增强 P 迁移可能归因于 Fe 还原的发现。在 pH 值降至 6.35 以下之前，溶解 Fe 和 P 的浓度一直保持较低水平，而在 pH 值降至 6.28 以下时，溶解 Mn 的浓度却线性增加，同时伴随着 pH 值的普遍下降。这一结果表明，在酸性土壤条件下，可还原 Mn 的溶解是增强缺氧条件下溶解 P 迁移的重要因素。这种趋势是由于 Mn 的含量较低，间接加速了 Fe 的还原。这些结果有助于制定管理实践，以有效减轻 P 输出，保护水资源免受扩散 P 污染。
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