Industrial wood ash as a soil amendment for crop production

Wood-ash produced as a by-product of energy generation by wood-products industries-has potential for use as a liming and nutrient source for crop production. We conducted greenhouse and field studies to evaluate the effects of landspreading industrial wood ash on the yield and elemental composition of forage crops and on soil nutrient levels. Greenhouse studies evaluated ash rates yp to the equivalent of 40 ton/acre (90 Mg ha(-1)) using alfalfa (Medicago sativa L.) and barley (Hordeum vulgare) as indicator crops. A limed and fertilized control (dosages based on soil tests) was included for comparison. In field trials, wood ash was applied to alfalfa at rates up to 20 tons/acre (45 Mg Ha(-1)) at two location in Price County, WI. Biomass yields generally increased with application up to 20 tons/acre and decreased at applications exceeding this level. Wood-ash application usually produced yields greater than those obtained with the limed and fertilized control treatment. No undesirable elements accumulated in forage tissue at ash application rates up to 20 tons/acre. These results suggest that land application of wood ash is an environmentally safe alternative to landfilling and may replace conventional limestone and fertilizer for forage crop production.