Effect of Amendments on Chemical Properties of Bentonite Mine

Revegetation efforts generally have failed to establish substantial cover on bentonite mine spoil, but certain amendments have shown promise for improving spoil as a plant growth medium. These growthpromoting improvements were at least partially the result of effects of these amendments on spoil chemistry. We undertook this study to determine the effects of selected amendments (gypsum, fertilizer, and wood residue with N) and combinations thereof on several chemical properties of spoil. Amendment with wood residue with N increased the effects of either fertilizer (N, P, and K) or gypsum. Amendment with gypsum increased the level of soluble salts. Each amendment had chemical effects that would improve spoil as a plant growth substrate with the possible exception of increased salinity associated with gypsum.