Keywords: by-products, organic fertilisers, wastes, legislation.
Organic industrial by-products can supply significant amounts of plant nutrient to farmers. Nitrogen in organic form, not subject to leaching, and phosphorus are the elements present in highest concentrations.
By-products need to be safe for man, animals and the environment and be easy to handle, to transport and to be treated. Last but not least, the fertilisers based on by-product raw materials have to be competitive against traditional mineral formulations.
The most interesting materials are coming from the industries processing meat, fish, hide and leather, sugar-rich materials (molasses, fruits, wine, etc.), antibiotics and oil seeds.
BSE crisis played an important role in the availability of meat and bone meals and on by-product offer/demand ratio on the market of materials suitable both as feedstuff and fertilisers.
The treatments involved in the transformation of all these by-products are described, as well as the value as fertiliser of the final products.
These types of fertilisers are not ruled by common regulations across European Union. This involves big problems in trading of by-products and derived fertilisers.
Dr P L Graziano, Dr R Calzavara, Dr M Perelli, Arvan srl, Mira, Italy.
Dr G Roccuzzo, CRA, Acireale, Italy.
28 pages, 6 figures, 16 tables, 13 references.