Bio-slurry as fertilizer. Is bio-slurry from household digesters a better fertilizer than manure? A literature review.

Abstract

In many developing countries manure is anaerobically digested to produce biogas. The residue of manure digestion, bio-slurry, can be used as fertilizer for crop production and aquaculture. This study compared bio-slurry and manure as fertilizers. Nutrients in bio-slurry, especially nitrogen, are more readily available then in manure, leading to a larger short term fertilisation effect. However, risks for N losses through volatilisation and leaching are large for bio-slurry than for manure during storage, handling and application. Unfortunately, most studies that compared bio-slurry and manure exhibited methodological shortcomings that hamper an adequate comparison.