Overview of biomass ash usage for soil quality improvement: potential benefits and applications

The degradation of urban soil is caused by pollution, poor land management practices, and soil sealing, all of which lead to lower infiltration, aeration, and permeability. At the same time, there is a substantial increase in biomass power generation, which increases ash generation, posing concerns for waste management and environmental impact. Biomass ash presents an opportunity for an environmentally friendly amendment of soil, as it provides nutrients, stabilises pH, and improves soil structure. The ash is rich in vital nutrients such as calcium, potassium, and phosphorus, which can restore nutrient-stripped soil and counteract soil acidification. The porous nature of ash improves aeration, retention of water, and root growth, especially in sandy and degenerated soil. Pelletisation makes it easier for biomass ash utilisation by reducing airborne dissemination and ensuring nutrient release occurs in a controlled, graduated process. Empirical evidence shows that granulated biomass ash can release its contents of nutrients in a gradual process, hence avoiding surpassing the safety levels of maximum allowable concentrations of heavy metals. With appropriate practices, biomass ash is a valid alternative to fertilisers, improving agricultural output and environmental sustainability and reducing the by-product troubles of biomass power generation.