Cattle Manure Application Strategies Effects on Bahiagrass Yield, Nutritive Value, and Phosphorus Recovery

Animal manure application based on crop N requirements often leaves excess P in the soil because of the differences in the N/P ratio in manures and that required by the plants. This experiment was designed to evaluate the effects of cattle ( Bos taurus ) manure applied alone or in combination with ammonium nitrate (AN) on bahiagrass ( Paspalum notatum Flügge) dry matter (DM) yield, nutritive value, tissue P concentration and recovery, and soil P concentrations. Treatments consisted of a control, two N rates (200 and 400 kg ha −1 ), two N sources [manure alone or manure plus AN (50/50% combination)], and two application frequencies (single vs. split). Bahiagrass was harvested at 28‐d intervals and evaluated for DM yield, crude protein concentration (CP), in vitro digestible organic matter (IVDOM), and tissue P concentration. Soil samples were analyzed for Mehlich‐1 extractable P. Bahiagrass DM yield, nutritive value, and P recovery were greater for the manure plus AN treatments when compared to the control and manure alone. Although greater N rates increased DM yield and CP, bahiagrass P recovery was reduced as the N rate increased. Approximately 20 and 53% of the applied P was recovered by bahiagrass when manure was applied alone and in combination with AN, respectively. Soil‐test P (0–15 cm depth) was greater for the treatments receiving manure alone compared to manure plus AN treatments. Our results demonstrated that applying manure in combination with an inorganic N source can increase forage yield and nutritive value while reducing the risks of soil P accumulation.