Meat and bone meal as fertilizer-Nitrogen dynamics

The objective of this investigation was to evaluate nitrogen mineralization from meat and bone meals (MBM) subjected to different sanitization treatments (0.1M or 0.5M KOH in autoclave at 160 C for 30 min) according with UE Directives on TSE sanitization of residual animal by-products. Their overall nutritional efficiency was also tested cultivating maize (Zea mais) in pot experiments. The two treatments were compared with untreated MBM in leaching columns filled with sand or a 1:1 w/w mixture of soil and sand. Leached NH4+ from sand columns was similar (600 i'g N equivalent to 5% of total added N) for both treatments and untreated MBM, whereas it was negligible from soil during whole time course incubation. Nitrate-N leaching from sand columns was very low until day 40 and increased linearly thereafter for all treatments reaching values below 800 i'g N at day 100 (7-10% of added N). In the soil columns leached N-NO3- was already remarkably high from day 15 to 40 reaching cumulative values from 7 to 11 mg N (12, 30 and 49% of added N for untreated, 0.1M and 0.5M KOH treated MBM respectively).