The extend of biogeochemical cycling of nickel (Ni) by tropical hyperaccumulator plants in their native habitat is largely unknown, although these unusual plants are suspected to play a major role in the recycling of this element in ultramafic ecosystems. In this study, we have assessed the biogeochemical cycling of Ni (and other elements, including mineral nutrients) by a tropical Ni hyperaccumulator plant, i.e., Phyllanthus rufuschaneyi, which is one of the most promising species for tropical Ni agromining. The study site was a young secondary forest in Sabah (Malaysia) where Phyllanthus rufuschaneyi occurs as the dominant species on an ultramafic Cambisol. For 2 years, we monitored a 100-m² plot and collected information on weather, biomass increase, soil fertility, water fluxes to the soil and litter fluxes for a wide range of elements, including Ni. The Ni cycle is mainly driven by internal fluxes, notably the degradation and recycling of Ni-rich litter. Over the period of investigation, the Ni litter flux corresponded to the total Ni stock of the litter (5.2 g m⁻² year⁻¹). The results further show that Ni turnover varies significantly with the accumulation properties of the plant cover. This points to the major influence of Ni hyperaccumulator plants in building up Ni available stocks in the topsoils, as has also been shown in temperate ultramafic systems. Litterfall and throughfall contribute substantially to the cycling of phosphorus, sulphur and potassium in this ecosystem, with throughfall contributing 2-, 220- and 20-fold higher to the respective nutrient fluxes relative to litterfall. The magnesium:calcium ratio far exceeded 1 in the soil, but was < 1 in the leaves of Phyllanthus rufuschaneyi. The insights from this study should be taken into account when designing tropical agromining operations; as Ni stocks could be more labile than initially thought. The removal of Ni- and nutrients-rich biomass will likely affect available Ni (and major nutrients) for the next cropping seasons, and requires sustainable fertilisation, to be utilized to replenish depleted major nutrients. These findings also have major ecological implications.

尽管这些不寻常的植物被怀疑在超镁铁质生态系统中镍元素的循环中发挥了重要作用，但热带超富集植物在其原生栖息地对镍（Ni）的生物地球化学循环的范围在很大程度上尚不清楚。在这项研究中，我们评估了热带镍超富集植物（即叶下珠）的镍（和其他元素，包括矿质营养素）的生物地球化学循环，它是热带镍农矿开采最有前途的物种之一。研究地点是沙巴州（马来西亚）的一片年轻的次生林，其中， 叶下珠是超镁铁质甘比土上的优势物种。两年来，我们监测了一块 100 米^{2 的}地块，收集了有关天气、生物量增加、土壤肥力、土壤水通量和包括镍在内的多种元素的凋落物通量的信息。镍循环主要由内部通量驱动，特别是富镍垃圾的降解和回收。在调查期间，镍凋落物通量相当于凋落物的总镍储量（5.2 g m ^-2 年^-1）。结果进一步表明，镍周转率随植物覆盖物的积累特性变化显着。这表明镍超富集植物对表土中镍可用储量的主要影响，正如温带超镁铁质系统中所显示的那样。凋落物和径流对该生态系统中磷、硫和钾的循环做出了重大贡献，相对于凋落物，径流对各自养分通量的贡献分别高出 2 倍、220 倍和 20 倍。土壤中镁钙比远超过1，但叶下珠叶片中镁钙比< 1。在设计热带农业采矿作业时应考虑这项研究的见解；因为镍库存可能比最初想象的更加不稳定。富含镍和营养物质的生物量的去除可能会影响下一个种植季节的可用镍（和主要营养物质），并且需要可持续的施肥，以补充耗尽的主要营养物质。这些发现也具有重大的生态意义。