Agricultural pursuits in post‐mining environments are becoming increasingly important globally as many regions are challenged with food insecurity and post‐mining land‐use legacies. Although there are many advantages for agricultural production at post‐mining sites, these substrates have abiotic and biotic challenges for plant growth, including poor fertility, heavy metals, and lack of beneficial soil microbes. We investigated whether increased potassium (K) levels in a post‐phosphate mining substrate on Christmas Island, Australia, could improve plant productivity and reduce heavy metal concentrations. Addition of K (80 and 160 kg ha−1) significantly increased plant biomass and enhanced root growth and mycorrhizal fungal colonisation rates. Potassium amendment was also strongly correlated with lower heavy metal concentrations in leaf material. Clearly, K is the critical limiting nutrient for legumes in post‐phosphate mining sites on Christmas Island for enhancing biomass and health. We hypothesise that heavy metals were either being diluted in a larger biomass and/or healthy plants could also select against heavy metal uptake; however, this requires further investigation of the mechanisms involved. These results have significant global ramifications for sites transitioning from mining to agriculture.

中文翻译：

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钾修正增加了生物量并降低了磷酸盐开采后 Lablab Purpureus 中的重金属浓度

随着许多地区面临粮食不安全和采矿后土地利用遗留问题的挑战，采矿后环境中的农业追求在全球变得越来越重要。尽管采矿后地点的农业生产有许多优势，但这些基质对植物生长存在非生物和生物挑战，包括肥力差、重金属和缺乏有益的土壤微生物。我们调查了澳大利亚圣诞岛磷矿开采后基质中钾 (K) 水平的增加是否可以提高植物生产力并降低重金属浓度。添加 K（80 和 160 kg ha-1）显着增加植物生物量并增强根生长和菌根真菌定植率。钾修正剂也与叶片材料中较低的重金属浓度密切相关。显然，钾是圣诞岛磷矿后开采地点豆类的关键限制性营养素，可提高生物量和健康。我们假设重金属在更大的生物量中被稀释和/或健康的植物也可以选择对抗重金属吸收；然而，这需要进一步调查所涉及的机制。这些结果对从采矿业向农业转变的地点具有重大的全球影响。