The Amazon is an important reservoir of biodiversity and carbon but it is under pressure by multiple threats such as artisanal and small-scale gold mining (ASGM). In Peru ASGM has degraded 90,000 ha of old-growth forest since the eighties, leaving vast areas as wastelands. As most ASGM in the region is illegal, efforts to recover degraded areas have been scant. Here we assessed the potential of Stylosanthes guianensis to recover soil health as a first step in the restoration of gold mine spoils in a Native community and a mining concession in Madre de Dios, Peru. We evaluated plant growth and analyzed changes in physical, chemical, and biological soil parameters. After 470 days from sowing, the average plant height was 46.7 cm with a survival rate >50% and yields of 23.9 t ha⁻¹ and 450 kg ha⁻¹ of dry biomass and nitrogen, respectively. Multiple soil parameters increased significantly, including cationic exchange capacity (3.3 to 4.0 cmol [+] kg⁻¹), soil organic matter (0.03% to 0.39%), soil respiration (0.02 to 0.06 mg CO₂ g⁻¹ d⁻¹) and biomass (0.03 to 0.15 mg C g⁻¹). Soil macrofauna increased from 2 to 11 taxonomic groups, including ants, considered as soil engineers. Furthermore, S. guianensis increased soil carbon sequestration of impacted areas from 0.004 t C ha⁻¹ by more than 1650%, up to 0.07 t C ha⁻¹. These promising findings clearly illustrate S. guianensis potential to kick-start natural succession of Amazonian forests after degradation by ASGM and hence help to achieve the Sustainable Development Goals.

中文翻译：

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使用柱花草（一种很有前途的覆盖作物）恢复秘鲁亚马逊河冲积金矿的土壤

亚马逊是生物多样性和碳的重要储存库，但它受到多种威胁的压力，例如手工和小规模采金业 (ASGM)。在秘鲁，自 80 年代以来，手工和小规模采金已经退化了 90,000 公顷的原始森林，大片地区变成了荒地。由于该地区的大多数手工和小规模采金都是非法的，恢复退化地区的努力很少。在这里，我们评估了柱花草恢复土壤健康的潜力，这是恢复秘鲁马德雷迪奥斯的一个土著社区金矿弃土和采矿特许权的第一步。我们评估了植物生长并分析了土壤物理、化学和生物参数的变化。播种 470 天后，平均株高为 46.7 cm，成活率 >50%，产量为 23.9 t ha ^-1和 450 kg ha ^-1的干生物量和氮，分别。多种土壤参数显着增加，包括阳离子交换容量（3.3 至 4.0 cmol [+] kg ^-1）、土壤有机质（0.03% 至 0.39%）、土壤呼吸（0.02 至 0.06 mg CO ₂  g ^-1  d ^-1）和生物量（0.03 至 0.15 mg C g ^-1）。土壤大型动物群从 2 个增加到 11 个分类群，包括被视为土壤工程师的蚂蚁。此外，S. guianensis将受影响地区的土壤碳固存量从 0.004 t C ha ^-1增加了 1650% 以上，增加到 0.07 t C ha ^-1。这些有希望的发现清楚地说明了S. guianensis 在手工和小规模采金退化后启动亚马逊森林自然演替的潜力，从而有助于实现可持续发展目标。