Early forest re-establishment in landforms constructed from materials such as overburden or mine waste is partly determined by nitrogen (N) availability in reclamation covers. Here we examined whether the ecosystem model ecosys which simulates key processes governing N availability such as mineralization, plant N uptake and N return to soil through litterfall could be used to forecast potential N limitations for forest re-establishment in these constructed landforms. In this study, N cycling was simulated and tested against measured soil, foliar and surface litter N concentrations with three soil covers differing in thickness (35, 50, and 100 cm) in a 17-year-old forest reclamation site and in an analogue natural forested site in northern Alberta. Overall, results from this study demonstrated the applicability of the ecosys model in predicting nutrient cycling in reclaimed upland forestlands. Results of this study highlight the importance of optimum cover depth to ensure sufficient N is available for plant growth. Even though the modelled net N mineralization, N uptake and thereby plant productivity increased with cover depth, the foliar and surface litter N concentrations did not. A non-linear relationship between total soil nitrogen (TN) stocks and modelled net N mineralization indicated that cover depth, which determines TN stock, had little effect on net primary productivity beyond a threshold TN. This threshold was 17 Mg N ha −1 , similar to TN for the 100 cm cover, giving a net N mineralization rate of ~ 3.5 g N m −2 year −1 , and this was attributed to reduced microbial activity in deeper soil layers.

中文翻译：

---

模拟受北阿尔伯塔开垦高地林地开垦覆盖深度影响的氮矿化和植物氮吸收

在由覆盖层或矿山废料等材料建造的地形中早期森林重建部分取决于开垦覆盖物中的氮 (N) 可用性。在这里，我们研究了生态系统模型 ecosys 模拟控制氮可用性的关键过程，例如矿化、植物氮吸收和氮通过凋落物返回土壤的关键过程，是否可用于预测这些人工地貌中森林重建的潜在氮限制。在这项研究中，在一个 17 年的森林开垦场地和一个类似物的三个不同厚度（35、50 和 100 厘米）的土壤覆盖层中，对氮循环进行了模拟和测试阿尔伯塔省北部的天然林地。全面的，这项研究的结果证明了生态系统模型在预测开垦高地林地养分循环方面的适用性。这项研究的结果强调了最佳覆盖深度的重要性，以确保有足够的 N 可用于植物生长。即使模拟的净 N 矿化、N 吸收和植物生产力随着覆盖深度增加，叶面和地表凋落物 N 浓度没有增加。土壤总氮 (TN) 库与模拟的净氮矿化之间的非线性关系表明，决定 TN 库的覆盖层深度对超过阈值 TN 的净初级生产力几乎没有影响。该阈值为 17 Mg N ha -1 ，与 100 cm 覆盖层的 TN 相似，净 N 矿化率为 ~ 3.5 g N m -2 年 -1 ，