Beneficial effects of earthworms and arbuscular mycorrhizal fungi on establishment of leguminous trees on Pb/Zn mine tailings

• Published in: Soil biology & biochemistry 2006-06, Vol.38 (6), p.1403-1412
• Main Authors: Ma, Y., Dickinson, N.M., Wong, M.H.
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; bioavailability; Biochemistry and biology; Biological and medical sciences; Chemical, physicochemical, biochemical and biological properties; earthworms; Economic plant physiology; enzyme activity; Fundamental and applied biological sciences. Psychology; Glomus; heavy metals; lead; Leucaena leucocephala; microbial activity; mine spoil; Mycorrhizae; nitrogen fixation; nutrient uptake; Pheretima guillelmi; Physics, chemistry, biochemistry and biology of agricultural and forest soils; plant establishment; plant growth; polluted soils; Reclamation; shrubs; soil amendments; soil enzymes; soil inoculation; soil pollution; Soil science; Symbiosis (nodules, symbiotic nitrogen fixation, mycorrhiza...); topsoil; vesicular arbuscular mycorrhizae; zinc; Zoology (interactions between soil fauna and agricultural or forest soils)
• ISSN: 0038-0717; 1879-3428
• DOI: 10.1016/j.soilbio.2005.10.016

Planting trees to stabilize metalliferous mine tailings is a widely used form of land reclamation although substantial soil amendment is invariably required, both to improve the physico-chemical status of the tailings and to ameliorate toxicity prior to planting. Here, we report a glasshouse study of the combined effects of burrowing earthworms ( Pheretima guillelmi) and arbuscular mycorrhizal fungi ( Glomus spp., AMF) on establishment of a naturally invasive, woody, nitrogen-fixing legume, Leucaena leucocephala, on topsoil-amended Pb/Zn mine tailings. AMF provided the most effective preliminary inoculant, improving N, P and K uptake, but earthworms had more influence improving N nutrition. In most cases, the combined effects of AMF and earthworms were additive and proved to be beneficial to plant growth, plant nutrition and for protection against uptake of toxic metals. AMF influenced metal uptake more than earthworms, but together they reduced mobility of Pb and Zn in soil by as much as 25%. Some minor but significant negative interactions were also evident; for example, earthworms enhanced soil microbial activity but inhibited the beneficial effects of AMF on N 2-fixation. We argue that increased attention to ecological interactions in soil could reduce costs and improve the efficacy of restoring a vegetation cover to land impacted by contaminated spoils.