Abstract Post-mining land reclamation of Athabasca Oil Sands (AB, Canada) involves the reconstruction of soil profiles able to support a mosaic of boreal forest communities. However, the use of coarse-textured reclamation materials to recreate forest ecosystems represents a challenge in terms of soil water and nutrient availability. This work aimed to quantify nutrient leaching in reclaimed coarse-textured soils constructed with two coversoils (peat mineral mix and forest floor mineral mix) underlain by mineral materials, including a blended B/C subsoil reclamation material, lean oil sand overburden substrate, and tailing sand. Water retention and conductivity curves were estimated for each material, and their retention capacity for inorganic N and P was measured in sorption isotherm experiments. The redistribution of water, inorganic N and P five days after an intense rain event was evaluated in six different reclaimed soil profiles using a laboratory-controlled leaching experiment in 1.2-m deep columns. The redistribution of fertilizer nutrients was also measured following the addition of 15N-labelled ammonium and phosphate over the top 10 cm of the columns. In addition, a 25-day incubation experiment with the two coversoils enabled us to estimate the timing of N immobilization and nitrification processes. Our results show that, depending on the combination of materials used for land reclamation, the soil profiles may provide equal or higher amounts of inorganic N and P in the rooting zone compared to natural, coarse-textured soils of the region. Following the simulated intense rainfall, the peat-mineral mix was able to retain 44% of its initial inorganic N within the top 20 cm of the reclaimed soil profiles, while 84% of the inorganic N present in the forest floor mineral mix was leached down. Compared to the movement of water, the leaching of N down the soil profiles was slower and partly restricted by the presence of lean oil sand, and to a lesser degree tailing sand. Most of the introduced fertilizer-N remained in the first 20 cm of the soil profiles under the form of nitrate, although the incubation experiment suggested that nitrification only occurred after the simulated rainfall event. Based on our experimental data and on additional simulations of water and nutrient transport, we conclude that nutrient leaching in reclaimed soils can be significant if specific materials such as forest floor mineral material and coarse-textured subsoil are combined and when an intense rainfall occurs at a period coinciding with a high concentration of nitrate-N in the topsoil.

中文翻译：

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阿萨巴斯卡油砂地区粗质地土壤剖面中的水分和养分保留

摘要 阿萨巴斯卡油砂（AB，加拿大）的采矿后土地复垦涉及能够支持北方森林群落镶嵌的土壤剖面的重建。然而，使用质地粗糙的开垦材料来重建森林生态系统对土壤水和养分的可用性提出了挑战。这项工作旨在量化再生粗质地土壤中的养分浸出，该土壤由矿物材料（包括混合 B/C 底土复垦材料、贫油砂覆盖基质和尾矿）下的两种覆盖土（泥炭矿物混合物和森林地面矿物混合物）构成。沙。估计了每种材料的保水率和电导率曲线，并在吸附等温线实验中测量了它们对无机 N 和 P 的保留能力。水的重新分配，使用实验室控制的浸出实验在 1.2 米深的柱子中，在六种不同的再生土壤剖面中评估了强降雨事件后五天的无机氮和磷。在柱的顶部 10 cm 上添加 15N 标记的铵和磷酸盐后，还测量了肥料养分的重新分布。此外，对两种覆盖土进行的 25 天孵育实验使我们能够估计 N 固定和硝化过程的时间。我们的结果表明，根据用于土地复垦的材料组合，与该地区的天然粗质地土壤相比，土壤剖面可能在生根区提供等量或更高量的无机 N 和 P。在模拟强降雨之后，泥炭矿物混合物能够在再生土壤剖面的顶部 20 厘米内保留 44% 的初始无机 N，而森林地面矿物混合物中 84% 的无机 N 被浸出。与水的运动相比，N 沿土壤剖面的淋滤速度较慢，部分受贫油砂和尾砂的限制。大多数引入的氮肥以硝酸盐的形式保留在土壤剖面的前 20 厘米，尽管孵化实验表明硝化作用仅发生在模拟降雨事件之后。根据我们的实验数据以及对水和养分传输的额外模拟，