Rendered materials partly substitute inorganic nitrogen fertilizers and improve nitrogen recovery in maize production system

Supplementing inorganic nitrogen (N) fertilizers with available organic resources is a sustainable strategy for improving crop N use efficiency (NUE) and lowering N fertilizer losses. Nutrient-rich rendered animal materials such as meat and bone meal (MBM) could be an efficient resource to sustainably supplement inorganic N fertilizers. Different MBM formulations were tested in lab incubation [non-pelletized and pelletized-MBM and lipids extracted MBM (EMBM)]. In field experiment, pelletized MBM formulation treatments [MBM (25–37.5% N) + CaNO 3 (62.5–75% N), neem oil mixed MBM (25–37.5% N) + CaNO 3 (62.5–75% N) and EMBM (25% N) + CaNO 3 (75% N)] were tested for their efficiency to supplement the inorganic N fertilizers in 3 and 2 split N fertilizer scheduling. Pelletization significantly decreased the net N mineralization rate of MBM (30%) at 26 days after incubation but not in EMBM. In field experiment, the application of MBM (25% N) + CaNO 3 (75% N) in 3 split N application resulted in higher grain yield (20–26.8%) and NUE (26.6–31.7%) than that of CaNO 3 (100% N) in 2 split N application and EMBM (25% N) + CaNO 3 (75% N) in 3 split N application. A similar grain yield of maize was observed in MBM (37.5% N) + CaNO 3 (62.5% N) in 2 split N application and CaNO 3 (100% N) in 3 split N application. The combined application of MBM (25–37.5% N) and CaNO 3 (62.5–75% N) decreased the N leaching loses by 2–5 folds than CaNO 3 (100% N) alone. Collectively, this study demonstrates that MBM can be efficiently used to supplement inorganic N fertilizers with equivalent grain yield and NUE of maize while reducing the number of N fertilizer split applications and leaching losses.