The possibilities to use ashes of biopower plants for forest fertiliser

RecAsh project (Regular recycling of wood ash to prevent waste production) is coordinated from Sweden and it belongs to EU-Life Environment program. The aim of the project is to promote ash recycling as a forest fertiliser in Sweden and Finland.This is done mainly by different demonstrations on ash classification, granulation, road haulage, forest spreading and system analysis. Wood as is a nutrient-rich and well-granulable fertiliser for peatland forests, which have a lack of mineral nutrients. Peat ash can also be suitable for forest fertilising by adding potassium into it, e.g. in the form of biotite. Some wood ash should be mixed with peat ash to ensure the granulability. For mineral soils it is necessary to add nitrogen to fertiliser if the growth is to be increased. This can be done e.g. by mixing biosludge with ash. In Finland the ash fertilisation has concentrated so far to the forests owned by forest companies. To limit the transportation distances and to have enough spreading areas in general, ash fertilisation must also be promoted to private forest owners. This requires the chemical quality control of ashes and also e.g. granulation to ensure dust-free operation and to avoid alkaline shock in the soil.