Stabilization of copper mine wastes in a semi-arid environment with perennial grasses

Abstract

Experiments were conducted in Arizona to study the effects of four soil materials (desert soil, copper overburden, overburden plus copper mine tailings, and tailings) on germination, seedling establishment and growth of six perennial grass species. Perennial ryegrass ( Lolium perenne L.), crested wheatgrass ( Agropyron cristatum (L.) Gaertn.), Lehmann lovegrass ( Eragrostis lehmanniana Nees.), weeping lovegrass ( Eragrostis curvula (Schrad.) Nees.), Welman lovegrass ( Eragrostis superba Peyr.) and blue panicgrass ( Panicum antidotale Retz.) were broadcast planted on each substrate. Plant growth indicated that desert soil had the highest productivity, followed by overburden, overburden plus tailings and tailings, in decreasing order. All species produced taller plants, more vegetation and more ground cover during their second year of growth than they did during the first year. Planting a variety of grasses on copper mine wastes increases the chances of obtaining successful revegetation and helps blend the disturbed areas into the surrounding environment.