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).
