Bermudagrass is the backbone perennial grass forage for
Southern United States. Nitrogen, phosphorus and potassium fertilization are essential for forage yield and quality. Limited studies have been conducted on how varying rates of fertilizer affect the quality of bermudagrass. Six rates of nitrogen (200, 300, 400, 500, 600, 700 lbs/acre) were applied in a randomized complete block design with four replications on previously established Tifton 85 bermudagrass at two locations in
Tifton, GA. Each plot was split with three rates of phosphorus and potassium fertilizer (50%, 100% and 150% of plant tissue uptake). Plots were harvested at 5 week intervals over three years. Dry weight yields were determined and dried samples were ground and prepared for chemical composition and quality evaluation.
In vitro dry matter digestibility (IVDMD), neutral detergent fiber (NDF) and acid detergent fiber (ADF) were estimated by near infrared spectroscopy (NIRS). An improvement of digestibility occurred up to 500 lbs N/acre. A linear increase in IVDMD occurred with increased yield and with increased forage nitrogen. No significant differences were found among the three P and K fertilizer rates.