Author
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Ritchey, Kenneth |
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Snuffer, Josie |
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Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 2/19/2002 Publication Date: N/A Citation: N/A Interpretive Summary: Many pastures in the Appalachian Region are abandoned, and levels of soil fertility are low. Calcium and magnesium are nutrients essential for improved pasture species growth. We examined the possibility of spreading calcium sulfate, a more soluble source than calcium carbonate (agricultural limestone), on the soil surface as a way to quickly build up adequate soil Ca levels throughout the soil profile. Calcium sulfate is available as a relatively pure by-product of coal-fired electricity-generating plants and could be inexpensively delivered near such plants. This strategy was successful in increasing soil calcium levels, and hay yields increased by 700 lb/acre. The yield increase was associated with higher phosphorus and potassium concentrations in the forage. Unfortunately, application of gypsum by itself resulted in a decrease in soil and forage levels of magnesium. It was necessary to add agricultural dolomitic limestone or another magnesium source at the same time as gypsum to avoid this problem. Technical Abstract: In restoring abandoned pastures on acidic hill land soils to productivity, it is important to bring soil Ca and Mg to adequate levels. Gypsum is a readily available Ca amendment which, in contrast to limestone, is sufficiently soluble to move rapidly into the soil when surface applied, and has been shown to reduce detrimental effects of subsurface acidity in soils of the southeastern USA. A 4-yr experiment measured forage production on a southern West Virginia Gilpin silt loam (Typic Hapludults) where abandoned hill land pasture was being restored to productivity. Treatments included 0, 1000, 8000, 16 000, and 32 000 kg/ha flue gas desulfurization coal combustion byproduct gypsum (gypsum) together with dolomitic limestone and five additional treatments designed to evaluate sources of supplemental Mg. Application of 16 000 kg/ha gypsum together with limestone increased forage yields during establishment by 42%, and increased production phase yields of orchardgrass (Dactylis glomerata)-tal fescue (Festuca arundinacea) forage by 11% compared to limestone alone. About 8% of the mean 790 kg/ha yield increase could be attributed to acidity-neutralizing effects of alkaline constituents in the gypsum byproduct. Plants in higher gypsum treatments had increased concentrations of K and P. Gypsum also increased plant Ca and S concentrations, and increased soil pHs, Ca, and S. Gypsum application decreased soil and plant Mg concentrations. Surface-applied dolomitic limestone at 4650 kg/ha effectively eliminated Mg deficiencies, but, per unit Mg applied, MgO (lightly calcined magnesite) was approximately twice as effective as dolomitic limestone at increasing soil and plant Mg. |
