Evaluation of biomass power plant wood ash as a soil liming materia

Application of wood ash from biomass power plants has the potential to reduce soil acidity, improve nutrient availability and increase yields of agricultural crops. A greenhouse pot study was conducted to compare effects of wood ash and commercial agricultural limestone on selected soil properties and growth of common bermudagrass. The experiment was a randomized complete block design with three lime sources applied at six rates on two acid soils. Treatments were replicated four times. Lime sources were mixed with one thousand grams of each acid soil at six rates. Rates of lime correspond to 0, 0.5, 1, 1.5, 2, and 4 times the lime requirement of each soil expressed as effective calcium carbonate equivalent (ECCE) for each of the three lime sources. Core soil samples were collected from each pot after three weeks of incubation and final clipping. Samples were analyzed for salt pH, buffer pH, electrical conductivity, Mehlich III extractable P, K, Ca, Mg, S and KCl extractable Al and Mn. Common bermudagrass sprigs were planted in pots after incubation. Grass was clipped on day 42 and 82 from planting. Lime application significantly increased soil pH of both soils during incubation. Elevation in soil pH was not significantly different for lime sources, except at highest rates where wood ash amended soils were higher. There was no meaningful pH difference between lime sources. Data from the first clipping on both showed that common bermudagrass did not respond to liming in both soils. However, in the final clipping, grass yield increased by as much as 100 percent in amended Darco soils at half the recommended rate, however, differences were not observed beyond this rate. Grass did not respond to liming effect or lime sources in the Nacogdoches soil. Results indicate that wood ash is as effective in changing soil pH as commercially available limestone sources. However, no negative effects were observed.