Abstract

Environmental and health concerns due to fly ash dumpsite could be prevented by phytostabilization using non-food crops that will prevent pollutants’ migration and provide additional economic returns. The growth and yield of Cymbopogon citratus in the fly ash dumpsite were evaluated in a pot experiment for a three-ratoon period. Application of compost, mycorrhiza, and NPK fertilizer, singly or the combination compost + mycorrhiza, compost + NPK fertilizer, mycorrhiza + NPK fertilizer, and compost + mycorrhiza + NPK fertilizer had increased the dry matter yield and the total essential oil content compared to the control. NPK fertilization regardless of compost and mycorrhiza resulted in more than 5-fold yield over the control. Compost lowered the available heavy metals from fly ash and supplied some essential nutrients while mycorrhiza could have improved water and nutrients acquisition and uptake. However, the nutrients supplied by the compost cannot sustain the requirements for the three-ratoon period. NPK fertilization, compost, and mycorrhiza reduced the concentrations of Cr, Cu, Ni, and Pb in shoots and in essential oil. Overall, the combined application of compost, mycorrhiza, and NPK fertilization at the rate of 120-90-90 kg NPK/ha could enhance the phytostabilization potential of C. citratus in fly ash and produce a high amount of essential oil with a low concentration of heavy metals that could be safe for human use.

Novelty Statement

Phytostabilization using aromatic plants is a potential alternative for the on-site pollution mitigation strategy of fly ash dumpsite. In this report, the appropriateness of lemongrass as a phytostabilization agent for fly ash dumpsite of the Morupule Power Plant in Botswana was evaluated for a three-ratoon period. This is the first report from Botswana that considered the effect of soil amendments, mycorrhiza inoculation, and NPK fertilization on the growth and yield of lemongrass in fly ash as well as the heavy metal availability and uptake. The results from this study are very useful for identifying site-specific cultural management strategy of using lemongrass in the phytostabilization of fly ash dumpsite in Botswana and elsewhere.

摘要

可以通过使用非粮食作物进行植物稳定来防止粉煤灰堆放场对环境和健康的影响，这将防止污染物的迁移并提供额外的经济回报。柠檬柏的生长和产量在一个盆栽实验中对粉煤灰堆放场中的烟灰进行了三响周期的评估。与堆肥相比，单独施用堆肥，菌根和NPK肥料或堆肥+菌根，堆肥+ NPK肥料，菌根+ NPK肥料和堆肥+菌根+ NPK肥料的组合提高了干物质产量和总精油含量控制。不考虑堆肥和菌根，氮磷钾肥的施肥量比对照高5倍以上。堆肥降低了粉煤灰中可利用的重金属含量并提供了一些必需养分，而菌根则可以改善水和养分的吸收和吸收。但是，堆肥提供的养分不能满足三响季的需求。NPK施肥，堆肥和菌根降低了Cr，Cu，Ni，以及芽和精油中的铅。总体而言，以120-90-90 kg NPK / ha的比例组合施用堆肥，菌根和NPK施肥可增强大豆的植物稳定潜力。粉煤灰中的柠檬衣原体，产生大量的精油和低浓度的重金属，可以安全地用于人类。

新颖性声明

使用芳香植物进行植物稳定化是粉煤灰堆放场现场减轻污染策略的潜在替代方法。在本报告中，对柠檬草作为植物稳定剂用于博茨瓦纳Morupule发电厂的粉煤灰垃圾场的适宜性进行了三段评估。这是博茨瓦纳的第一份报告，该报告考虑了土壤改良剂，菌根接种和NPK施肥对粉煤灰中柠檬草的生长和产量以及重金属的利用和吸收的影响。这项研究的结果对于确定在博茨瓦纳和其他地方粉煤灰垃圾场的植物稳定中使用柠檬草的特定地点的文化管理策略非常有用。