Short-Term Effects of Surface-Applied Gypsum on Revegetated Sodic Bentonite Spoils
1993
Schuman, G. E. | Meining, J. L.
The high clay content and saline-sodic characteristics of bentonite mine spoils result in an environment that is not conductive to sustainable plant growth. Use of wood residue amendments have enabled revegetation of these materials; however, sodic conditions persist or worsen, threatening the long-term sustainability of these revegetated lands. Gypsum, 56 Mg/ha, was surface applied to these revegetated ecosystems to evaluate its effectiveness in ameliorating the spoil sodicity under a natural precipitation environment. The gypsum treatment significantly reduced the exchangeable Na and the exchangeable Na percentage of the 60-cm spoil profile 3 yr after treatment. The gypsum amendment also significantly increased the spoil-water storage in the 60-cm spoil profile. Gypsum treatment resulted in a significant increase in the spoil electrical conductivity; however, this increase did not detrimentally affect the vegetation. Surface-applied gypsum amendment effectively ameliorated the revegetated bentonite mine spoil sodicity under natural rainfall conditions in a semiarid environment. Contribution from the High Plains Grasslands Res. Stn., Cheyenne, WY, and the Wyoming Agric. Exp. Stn. This project was funded in part by the Wyoming Dep. of Environmental Quality, Abandoned Mine Land Program, Cheyenne, WY.
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