Manures from non-organic farms and rock phosphates are considered problematic in organic plant nutrition due to the presence of contaminants (in the case of manures from non-organic farms), the usage of non-renewable sources (in the case of rock phosphates) as well as the structural dependency on conventional farms. Different farm types have different nutrient needs, and inputs of nitrogen, phosphorous and potassium are particularly important for stockless farms to avoid depletion of soils. The recycling of nutrients from human waste, mainly sewage sludge, urine and urban organic wastes, is a promising strategy to overcome the shortage and to close nutrient cycles, provided that the applied technologies fulfil stringent safety standards.
The RELACS project aims to deliver recommendations on recycling technologies suitable for organic farming to substitute the use of contentious fertilizers and manure. Therefore, RELACS will:
- Create an overview on the current use of and needs for external nutrient inputs in five European regions with contrasting agroecological and socioeconomic conditions;
- Evaluate technologies to recycle nutrients from waste streams with respect to quality and composition of the products, risk assessment, socio-economic and environmental impact, acceptability and regulations;
- Develop a planning tool to match available nutrient sources in five European regions with the need for nutrient inputs, including identification of not yet available but feasible nutrient recycling technologies and their associated economic benefits;
- Create on overview of and provide overall recommendation of recycling technologies suitable for organic agriculture.