Expected results: Through the production, testing and application of soil additives, composed of ash from residual forest biomass combustion, biological sludge and/or organic compost, to regenerate degraded soils in mining areas in Portugal, the following specific results are expected:
• The neutralisation of soil acidity (increased pH from 2.5-3.5 to 5.5-6.5);
• A 300-400% increase in soil organic carbon stock;
• A 100-300% increase in the available pool of plant nutrients (Ca, Ma, Na and K); A 90-100% decrease in available pools of potentially toxic elements;
• Up to 100% reduction of soil erosion rates;
• A 40-70% increase in soil water-retaining capacity;
• Up to 80% increase in plant biomass production;
• Up to 100% increase in microbial biomass;
• Up to 100% increase in enzymatic activity; and
• Up to one tonne of CO2 sequestered per 40 tonnes of ash applied to soil.
Additional expected achievements of the project include:
• Up to 100% reduction in the consumption of other expensive soil ameliorants (e.g. fertilisers, lime);
• Up to 100% reduction in diffuse pollution from the mining areas (e.g. Cd, Zn, Cu and Pb);
• Supporting the circular economy and accomplishing ‘end-of-waste’ criteria for biomass ash; and
• Contributing to the sustainability of important economic sectors in Portugal (i.e. pulp and paper industry, energy production, waste management and mining).