Inventory of waste fertilizers – the situation in Switzerland

For the first time a comprehensive inventory of wastes that could be recycled in the Swiss agriculture as fertilizer was established. It includes about 60 different types of wastes, which amount to a total quantity of 4.7 million tons of dry matter, of which 0.7 tons are at present used in crop production. They thus cover 8 % of the nitrogen, 15 % of the phosphorus and 3 % of the potassium requirement of the agricultural crop production. In comparison with manure and mineral fertilizers, the heavy metal load of waste fertilizers (relatively to the load of N+P+K) is high. Therefore a guideline for the quality control and registration of waste fertilizers will be introcuced in Switzerland to minimize the environmental risk in connection with the use of waste fertilizers.