Short-Term Effects of Surface-Applied Gypsum on Revegetated Sodic Bentonite Spoils
- G. E. Schuman and
- J. L. Meining
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.
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