Browsing by discipline "Agroekologi"

A considerable part of nutrients in the food chain ends up being slaughter by-products. By-products amount to one third of materials processed in slaughterhouses and they are the raw material for meat and bone meal (MBM). For many decades meat and bone meal was fed to domestic animals. Meat and bone meal has also been used as raw material for various processes in technical, chemical and food industry. It is still used in making soap and oleo chemicals. The BSE-crises has been the most severe risk for the safety in the European food system since the Second World War. Subsequent to BSE-crises the usage of MBM as animal feed, as well as the processing in many industrial branches, was legally prohibited in EU area in the end of 2001. MBM contains appreciable amounts of nutrients and it had been used as fertilizer hundreds of years. Therefore, and due to the fact that EU had in 2002 permitted use of MBM as fertilizer, the interest of farmers and researchers did already exist. In year 2002 the working group of the Finnish Ministry of agriculture and forestry issued a report, where the use of MBM as fertilizer was emphasized. The Finnish MBM contains 8-9% nitrogen, 5-6% phosphorus and 12-13% calcium as well as about 50% organic substances. MBM contains also microelements and its C/N ratio is rather low, about 3, 5. The low C/N ratio indicates that nutrients of MBM are quite quickly useable for plants. MBM as a fertilizer can also mineralize nutrients from storages in the soil. MBM contains relatively much of phosphorus. The P is bounded with calcium. Therefore only a part of it is immediately usable. Approximately 26% of phosphorus is extractable by the acetic acid. Because the entire phosphorus quantity is bounded with calcium, it has been shown that the fertilizing effect of MBM phosphorus lasts for 3-5 years. For that reason MBM could be a high-quality fertilizer for organic farming. Circulation of nutrients and organic materials are the basic of agroecology systems. The field experiments have given evidence of the fertility effect of MBM. In favourable conditions MBM has given a nitrogen effect, which is about 70-80% of the comparable chemical fertilizers. In Swedish tests MBM showed good N efficiency and has been used as fertilizer for many years in organic farming. In Germany MBM is used as phosphorus fertilizer for conventional sugar beet farming. The Agrifood Research Center's Kannus station in Finland conducted a field experiment in 2000 to 2003. MBM and conventional industrial fertilizer (Kemira's Y3® 20N-3P-9K) were compared. Both fertilizers were used at levels of 60, 90 and 120 kg total nitrogen per hectare. Oats was sown in the third week of April every year. Herbicides were applied as conventionally. The soil was silty loam and had a quite low fertility, pH being 5,4. After 3 years of fertilizing, there was a year without fertilization: in this fourth year it was shown, how large after-effect the three years of fertilization would bring. Fertilization effect of MBM was 96 % of the chemical fertilizers under three years in this field experiment. Fertilization effect in year when there was no fertilization, was 24 % higher after MBM than after chemical fertilizers. This experiment showed that MBM is good fertilizer at least for organic farming, where that high amount of phosphorus is not a big problem. It is concluded that fertilizer use of MBM should be developed further and encouraged in Finnish farming.