Tis study was conducted at the experimental area of the Field Crops Department of Çukurova University (37°01 ′N, 35°18 ′E) in the 2010 and 2011 growing seasons to determine the efects of sole or combined applications of 3 organic materials (poultry litter, cattle manure, and leonardite) with supplemental inorganic fertilizer on the forage yield and quality of silage maize. Te feld trial was arranged in a complete randomized block design with 3 replications. Poultry litter (PL) and cattle manure (CM) were applied based on P or N requirements (PL-P, PL-N, CM-P, and CM-N) of the crop, whereas leonardite was applied in only 1 dose (500 kg ha –1 ) and was also combined with 3 inorganic fertilizer doses (100%, 75%, and 50% of the recommended inorganic fertilizer dose, called LEO-100, LEO- 75, and LEO-50, respectively). Te results show that the highest values of dry matter (DM) and crude protein (CP) yields (18.3 t ha–1 and 1652 kg ha–1, respectively) were observed in LEO-100, whereas the lowest (11.2 t ha–1 and 758 kg ha–1, respectively) were observed in PL-N. In terms of forage quality parameters (CP, acid detergent fber, neutral detergent fber, and relative feed value), the P-based poultry litter and cattle manure treatments (PL-P and CM-P) gave similar results to conventional fertilization treatment, whereas the N-based treatments (PL-N and CM-N) signifcantly decreased forage quality. Te combined use of organic materials with inorganic fertilizers instead of a conventional fertilization regime may be efective in maintaining forage supply but N-based treatments have the risk of restricting forage production from silage maize.Tis study was conducted at the experimental area of the Field Crops Department of Çukurova University (37°01 ′N, 35°18 ′E) in the 2010 and 2011 growing seasons to determine the efects of sole or combined applications of 3 organic materials (poultry litter, cattle manure, and leonardite) with supplemental inorganic fertilizer on the forage yield and quality of silage maize. Te feld trial was arranged in a complete randomized block design with 3 replications. Poultry litter (PL) and cattle manure (CM) were applied based on P or N requirements (PL-P, PL-N, CM-P, and CM-N) of the crop, whereas leonardite was applied in only 1 dose (500 kg ha –1 ) and was also combined with 3 inorganic fertilizer doses (100%, 75%, and 50% of the recommended inorganic fertilizer dose, called LEO-100, LEO- 75, and LEO-50, respectively). Te results show that the highest values of dry matter (DM) and crude protein (CP) yields (18.3 t ha–1 and 1652 kg ha–1, respectively) were observed in LEO-100, whereas the lowest (11.2 t ha–1 and 758 kg ha–1, respectively) were observed in PL-N. In terms of forage quality parameters (CP, acid detergent fber, neutral detergent fber, and relative feed value), the P-based poultry litter and cattle manure treatments (PL-P and CM-P) gave similar results to conventional fertilization treatment, whereas the N-based treatments (PL-N and CM-N) signifcantly decreased forage quality. Te combined use of organic materials with inorganic fertilizers instead of a conventional fertilization regime may be efective in maintaining forage supply but N-based treatments have the risk of restricting forage production from silage maize
