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Phosphorus mobilization from intact soil monoliths flooded under simulated summer versus spring snowmelt with intermittent freeze‐thaw conditions
Journal of Environmental Quality ( IF 2.4 ) Pub Date : 2021-01-01 , DOI: 10.1002/jeq2.20182
Chamara Weerasekara 1, 2 , Darshani Kumaragamage 1 , Wole Akinremi 2 , Srimathie Indraratne 1 , Doug Goltz 3
Affiliation  

Enhanced phosphorus (P) release from flooded, anaerobic soils have been extensively studied under summer temperatures, but not under cold temperatures with intermittent freeze-thaw events. We investigated the temperature and freeze/ thaw effects during flooding on the release of P to floodwater from soil monoliths (15-cm depth) collected from eight agricultural fields in Manitoba. Soil monoliths were flooded with reverse osmosis water and incubated for 56 d under simulated summer flooding (SSF, 22±1 °C), or snowmelt flooding with intermittent freeze thaw (IFT, 4±1 °C with intermittent freezing) in triplicates. Redox potential (Eh), pore water and floodwater dissolved reactive P (DRP) concentrations, pH and concentrations of Ca, Mg, Fe and Mn were determined weekly. In seven soils, Eh decreased rapidly with days after flooding (DAF) under SSF to values < 200 mV, but not under IFT. Both pore water and floodwater DRP concentrations significantly increased with DAF in all soils under SSF, and in seven soils under IFT. While DRP concentrations were consistently greater under SSF than IFT in four soils, other soils had similar concentrations at certain DAFs. Significant relationships between ion concentrations and redox status, that fitted both IFT and SSF data in most soils, suggests that similar redox-driven mechanisms are responsible for the P release; however, less P is released under IFT than SSF, since soils were not severely reduced under IFT. Substantial P release in a few soils under IFT, appeared to be unrelated to redox status, suggesting other P release mechanisms that are not redox driven. This article is protected by copyright. All rights reserved.

中文翻译:

在间歇性冻融条件下模拟夏季与春季融雪下淹没的完整土壤巨石的磷动员

已在夏季温度下广泛研究了淹水厌氧土壤中磷 (P) 释放的增强,但在具有间歇性冻融事件的寒冷温度下尚未进行过研究。我们研究了洪水期间温度和冻结/融化对从马尼托巴省八个农田收集的土壤巨石(15 厘米深)中磷释放到洪水中的影响。土壤整块被反渗透水淹没,并在模拟夏季洪水(SSF,22±1°C)或融雪洪水与间歇性冻融(IFT,4±1°C,间歇性冷冻)下孵育 56 天,一式三份。每周测定氧化还原电位 (Eh)、孔隙水和洪水溶解的活性磷 (DRP) 浓度、pH 值以及 Ca、Mg、Fe 和 Mn 的浓度。在七种土壤中,在 SSF 下,Eh 随洪水 (DAF) 几天后迅速降低至 < 200 mV,但在 IFT 下则不然。在 SSF 下的所有土壤和 IFT 下的七个土壤中,孔隙水和洪水 DRP 浓度都随着 DAF 显着增加。虽然在四种土壤中 SSF 下 DRP 浓度始终高于 IFT,但其他土壤在某些 DAF 下具有相似的浓度。离子浓度和氧化还原状态之间的显着关系,适用于大多数土壤中的 IFT 和 SSF 数据,表明类似的氧化还原驱动机制是 P 释放的原因;然而,IFT 下释放的 P 比 SSF 少,因为土壤在 IFT 下没有严重减少。在 IFT 下,一些土壤中大量 P 释放似乎与氧化还原状态无关,表明其他 P 释放机制不受氧化还原驱动。本文受版权保护。版权所有。
更新日期:2021-01-01
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