Remediation of Ni toxicity by liming - field validation

被金属污染的土壤的修复可以通过施用农用石灰来实现，这有望通过增加土壤pH值来减少植物可利用的金属。然而，提高pH值可能会降低必需元素的生物利用度，这可能会对作物产量产生负面影响。本研究将重新审视一组农业领域在科尔伯恩港（ON）升高的镍，铜，钴，砷，这是修订与石灰石在10或50吨/公顷的十年前，燕麦和大豆的产量在随后的三年中确定。这些田地将重新种植大豆，以评估石灰作为补救策略的长期效果（目标1）。这些数据将与最近用88吨/公顷石灰（目标2）改良的农田中大豆的农艺产量进行比较。将在两组田地中比较方解石石灰与方解石石灰对大豆农艺产量的影响。对于这两个领域，农艺响应和组织积累的镍将与土壤总镍，土壤化学参数已知修改生物利用度，土壤溶液镍和植物有效镍（目标3）。作为一种补救策略，石灰的替代方法是通过植物修复降低表层土壤中的镍浓度。使用Ni超富集植物（Alyssum murale），盆栽和原位田间研究将提供土壤到植物转移的数据，这些数据将用于填充STELLA®模型，该模型允许随着时间的推移模拟系统。其结果将是在若干不同的情况下对镍在表层土壤中的半衰期的估计（目标4）。最后，将评估通过“深耕”稀释表面污染的潜力与将较不肥沃的B层土壤带入根区预期的作物生产力损失（目标5）。这些研究的整合将使决策支持系统的土壤修复战略，这也可以适用于其他金属污染地区在加拿大（如棕地）。新知识将支持加拿大采矿业在世界范围内的竞争力，开发和展示适合大规模使用的实用农艺干预措施，而不是技术密集型工艺。

Remediation of soils contaminated with metals may be achieved through application of agricultural lime, which is expected to reduce plant-available metal by increasing soil pH. However, raising the pH can potentially reduce the bioavailability of essential elements, which may negatively impact crop yields. The present study will revisit a set of agricultural fields in Port Colborne (ON) elevated in Ni, Cu, Co, and As, which were amended with dolomitic lime at either 10 or 50 t/ha a decade ago and yields of oat and soybean were determined in three subsequent years. These fields will be replanted with soybean to evaluate the long-term efficacy of liming as a remediation strategy (Objective 1). These data will be compared to agronomic yield of soybean in fields more recently amended with 88 t/ha of lime (Objective 2). The effect of calcitic versus dolomitic lime on agronomic yield of soybean will be compared in two sets of fields. For both fields, agronomic response and tissue accumulation of Ni will be related to total soil Ni, soil chemistry parameters known to modify bioavailability, soil solution Ni and plant available Ni (Objective 3). An alternate to liming as a remediation strategy is reducing the Ni concentration in surface soils through phytoremediation. Using a Ni hyperaccumulator (Alyssum murale), pot and in situ field studies will provide data of soil to plant transfer which will be used to populate STELLA® models, which allow simulation of a system over time. The outcome will be estimates of the half-life of Ni in surface soils under a number of different scenarios (Objective 4). Finally, the potential for dilution of surface contamination by 'deep tilling' versus the expected loss in crop productivity by bringing less fertile B horizon soils into the root zone, will be evaluated (Objective 5). Integration of these studies will enable a decision support system for soil remediation strategies for this site, which can also be applied to other metal-contaminated areas in Canada (e.g. brownfields). The new knowledge will support the Canadian mining industry in being competitive worldwide by developing and demonstrating practical agronomic interventions suitable for large-scale use, rather than technology-intensive processes.