By far the largest part of field cultivation is carried on with the use of artificial fertilizers. The main nutrients considered in fertilizers are nitrogen (N), phosphorus (P), potassium (K), calcium (Ca) and sulfur (S) along with numerous trace elements. Organic waste contains these same nutrients but is not the best fertilizer available in terms of nutrient concentration or cost of application. In view of the fact that the price of synthetic fertilizers has doubled between years, that it is a matter of limited resources and its unfriendly production, organic waste and by-products of processing have become even more important resources that are worth using more and more.
The research and innovation project Sustainable fertilizer production - a comprehensive approach to the circular economy was funded by Ranni's Target Program at the beginning of 2021, where the collaborative group explores ways to use local organic resources, by-products from various types of production and processes to produce sustainable fertilizers for Icelandic agriculture and land reclamation . This report is one part of the project where an assessment was made of the organic waste generated in Iceland, both in terms of quantity and nutrient composition.
The objectives of this report were as follows:
– To identify and calculate the amount of organic waste that is generated in Iceland and could be used in the production of fertiliser. calculate the amount of organic waste that is generated in Iceland and could be used in the production of fertilizer.
- To calculate the amount of nutrients (NPK) in organic waste according to the measurements carried out in the project together with national and foreign sources where information was missing.
- To make proposals and identify where the main opportunities lie in the increased use of organic waste for fertilizer production in Iceland.
The amount of organic waste from animals was calculated based on the number of animals, their feed needs and feed utilization. When calculating the amount of other organic substances, the accounts of the Environment Agency were used. The nutritional content of organic raw materials was found out either through chemical measurements, literature searches, or both.
The results of this project shed light on opportunities for increased utilization of organic waste for fertilizer and the existing facilities. Results indicate that the total amount of NPK nutrients in organic waste generated in Iceland is similar to that in imported synthetic fertilizers, but the amount of nitrogen is considerably lower. In terms of opportunities for increased utilization, fish farm sludge, slaughterhouse waste and poultry droppings should be mentioned most prominently. Organic waste is usually rich in water and the concentration of nutrients is low. Therefore, a larger amount of waste with associated transport costs or further processing is needed to obtain a similar effect as with imported synthetic fertilizers.