Field study of plant survival as affected by amendments to bentonite spoil.
Efforts to reclaim amended and raw bentonite mine spoils with 6 plant species (2 forbs, 3 shrubs and 1 tree) were evaluated over a 4-year period near Upton, Wyoming. Plant species were fourwing saltbush (Atriplex canescens), big sagebrush (Artemisia tridentata subsp. tridentata), Rocky Mountain juniper (Juniperus scopulorum), Russian olive (Elaeagnus angustifolia), common yarrow (Achillea millifolium), and scarlet globemallow (Sphaeralcea coccinea). Spoil treatments included addition of gypsum, sawdust, perlite, straw and vermiculite; the control treatment was unamended. Fourwing saltbush had 52% survival across all spoil treatments, with greatest survival occurring on perlite-treated spoil (90%), followed by gypsum (70%) and vermiculite amendments (70%). Survival of other plant species ranged from 0 to 3% averaged across all treatments after 4 years. No differences in plant survival occurred among amendments when all species were considered.