A biorefinery generates wood-based ash in bio-oil production. It is possible to productize this ash for use as a soil amendment and forest fertilizer, for example. In granulated form, ash provides a steady release of nutrients.

Bioash as a forest fertilizer

Ash generated in wood combustion contains an abundance of nutrients (including phosphorus and potassium) as well as micronutrients, which the tree has absorbed from the soil during growth. Utilizing ash as a forest fertilizer helps to restore nutrients back into the forest and to reduce the use of non-renewable mineral-based fertilizers.

The nitrogen content of wood ash is very low, so it is best suited for use in forest drainage areas that are rich in nitrogen and have a thick layer of peat. Additionally, the alkalinity of ash helps to increase the pH level of peat and stimulate micro-organism activity and thus accelerate the decomposition of organic matter in the soil.

In 2003, only 10% of the wood ash generated was utilized as forest fertilizer. Unfortunately, most of the ash suitable for fertilizing often ends up in landfills. The co-firing of wood and peat impedes the use of ash as fertilizer, because it is difficult to separate the usable ash from the other types of ash that are generated.

Share Print