Can graminoids used for mine tailings revegetation improve substrate structure?

Abstract

Seeding of agronomic graminoid species that are tolerant to the compacted and low aeration conditions associated with mine tailings allow for rapid cover of mine waste, which, in turn, controls erosion. These graminoids have the potential to be used as primer-species on mine tailings to improve the rooting of other plant species compared to other plants types which may not tolerate soil compaction and low aeration. Yet tailings colonization by graminoid roots could alleviate ecological filters such as low air-filled porosity and elevated bulk density. The effect of above-and below-ground development of hay graminoid species on macroporosity and density of gold mine tailings was studied under controlled conditions as well as in situ. All graminoids improved tailings macroporosity after only two months of growth under greenhouse conditions, but had no effect on tailings density. Perennial B. inermis was most efficient in improving tailings macroporosity with greater root diameter, biomass, and volume. Annual A. sativa also produced high root biomass and length which improved tailings' macroporosity. However, under field conditions, graminoids had a low cover and no effect on macroporosity, which highlights that their growth should be improved to use them as primer-plants.

Influence of vegetation and additional surface layers on the water balance of a reclamation cover with elevated water table

“…This impact constitute a significant share of the water loss from the cover in humid climates (Waugh 2001). The second is the formation of bio-pores by root penetration (Guittonny-Larchevêque et al 2016c;Beck-Broichsitter et al 2018b;Zhang et al 2021) and introducing organic matter (OM) into the cover materials which can alter their porosity infiltration capacity, and moisture retaining properties (Guittonny-Larchevêque et al 2013, 2016aBeck-Broichsitter et al 2018a;Villagra-Mendoza et al 2020;Iskandar et al 2022). In an oxygen-barrier cover, formation of such porosity can change water flow in cover materials (Angers and Caron 1998;Nespoulous et al 2019;Proteau et al 2021), and affect infiltration, water storage and percolation.…”