Biochar Derived from the Dry, Solid Fraction of Pig Manure as Potential Fertilizer for Poor and Contaminated Soils

Pig manure results in the release of NH3, NOx, volatile organic compounds and odour nuisance. Pyrolysis of dried pig manure can be considered as an economical viable approach converting this agricultural waste into value added products. The produced amendment biochar can be used as a slow release fertilizer with high concentration of N, K and P and has beneficial effects as carbon sequester and improver of soil quality and crop productivity. It is proved that a 2 wt.% blending of biochar with a poor soil affects positively plant growth and crops (dwarf beans), and worm (Eisenia fetida) survival and production. Additional, available heavy metals are immobilised in the biochar and not leachable. The resulting biochar therefore offers prospects as low cost, slow release soil conditioner and fertiliser for a long term effect.