Wood Ash as a Soil Amendment (FS-22-08)

Forest products manufacturing facilities generate large amounts of boiler ash from burning woody biomass. Most of this ash ends up in landfills and wastewater lagoons. This situation represents a relatively untapped opportunity to recycle a mill residual into a valuable soil amendment, replace commercial fertilizers and lime, reduce landfill disposal costs and, in some cases, add a source of revenue for mills.

This fact sheet provides an overview of wood ash characteristics and the types of wood ash generated at forest products facilities, examining the benefits and challenges of application to agricultural lands and forest lands.

Keywords: wood ash, soil amendment, nutrients, beneficial use, landfill, calcium, potassium, phosphorus, land application, liming, fly ash, bottom ash, crops, plant growth, compost, topsoil