赤泥掺拌马尾松叶对芦竹与翠芦莉生长的影响

赤泥是铝土矿提炼氧化铝后排放的强碱性废渣,数量巨大且环境风险大,如何改良及筛选适生植物是其生态修复的关键。该研究通过掺拌不同比例的马尾松叶2%,4%,6%(w/w),分析其对赤泥pH与有机质含量及芦竹与翠芦莉生长的影响。结果表明:掺拌马尾松叶35 d后,赤泥pH由11.08显著下降至9.70,但随后趋于平稳;随着掺拌比例的增加,赤泥pH呈下降趋势,有机质含量由6.13 g·kg~(-1)显著增至17.52 g·kg~(-1)。芦竹与翠芦莉在纯赤泥上生长2个多月后死亡,但在掺拌4%马尾松叶的赤泥上均能较好地生长。其中,芦竹的生物量及相对生长速率(RGR)与栽培土相比不受影响,但地下/地上生物量比(B/A)显著增加;相反,翠芦莉的生物量和相对生长速率与栽培土相比显著降低,但B/A不受影响。

Effects of red mud mixed with pine needles on growth of Arundo donax and Ruellia brittoniana

Red mud is a waste residue with strong alkalinity after extracting alumina from bauxite. Due to its huge production and high environmental risks, how to remedy it and how to choose suitable plant species are key for ecological restoration. In this study, we mixed different proportions of pine needles 2%, 4% and 6%(w/w), with the objective to study the changes of pH and organic matter content of red mud, and their effects on growth of Arundo donax and Ruellia brittoniana, two alkali-tolerant species. The results indicated pH of red mud reduced significantly from 11.08 to 9.70 after 35 d mixture with pine needles, and then leveled off. When the proportions of pine needles increased, pH of red mud decreased and organic matter content significantly increased from 6.13 to 17.52 g·kg^-1. When grown in pure red mud, Arundo donax and Ruellia brittoniana died after more than two months. However, they could grow well at amended red mud(mixed with about 4% pine needles). Compared with limestone soil, Arundo donax had similar biomass and relative growth rate(RGR)but significantly higher below-/above-ground biomass(B/A)in amended red mud, while Ruellia brittoniana showed significantly lower biomass and RGR but similar B/A.