Mixed papermill residues affect yield, nutritive value and nutrient use of a grass-alfalfa sward
Mixed papermill residues (MPR) can improve soil quality, but their impact on forage yield and quality is not well documented. Three MPRwere applied to mixed grass-alfalfa (Medicago sativa L.) sward in 1997 and 1998 at near 100, 200 and 400 kg N ha-1 and were compared to calcic ammonium nitrate (CAN) at 0, 50, 100 and 200 kg N ha-1 on a Bedford clay loam (Humic Gleysol). The MPR and CAN induced a significant linear increase in forage DM yield and relative yield (RY). The sward response to MPR addition in 1997 was related to the MPR C:NH4+ ratio. MPR and CAN increased the forage NDF concentration in 1998, but there was no effect in 1997. Nitrogen concentration in forage tissues was increased by MPR and CANinputs in 1997, but was decreased in 1998. In all treatments, NO3− tended to accumulate in forage tissues when the N nutrition index (INN) exceeded the optimum level. Forage nutritive value from the MPR was comparable to CAN.The results of this study suggest that MPR can be an efficient N source for grass-alfalfa swards on fine-textured soils. Key words: Acid detergent fiber, forage, grass, Medicago sativa L., mineral fertilizer, neutral detergent fiber, papermill residues