THE SHORT-TERM EFFECTS OF WOOD-ASH AMENDMENT ON FOREST SOILS

In the heavily forested regions of the northeastern U.S. the potential for producing electricity from wood-fired boilers is also creating a growing supply of wood-ash requiring disposal. Landfill space is expensive and limited, which has resulted in an interest in spreading wood-ash on forest sites. This greenhouse study was designed to provide information on soil and seedling response to wood-ash applications. Red maple (Acer rubrum) seedlings were grown in either O or B horizon forest soil material and amended with six levels of ash (0, 4, 8, 12, 16, and 20 Mg ha-1) and two levels of N fertilizer (0 and 224 kg ha-1). Ash amendments increased pH and exchangeable base cations, and decreased extractable Al and Fe concentrations, in both soil materials. Ash treatments increased seedling foliar K and Na concentrations in O horizon soils, but had little effect on growth. No significant effects on seedling properties from ash in B horizon soils were found. Fertilizer N treatments did not improve seedling growth in either soil material. Soil and seedling response to N were notably different for the different soils used. Based on this short-term study it appears that (a) land applications of wood-ash at the rates used may be a viable approach to recycling this solid waste, and (b) long-term studies are required to evaluate this practice under field conditions. © 1990 Kluwer Academic Publishers.