Responses of eastern gamagrass [Tripsacum dactyloides(L.) L.] forage quality to nitrogen application and harvest system

Eastern gamagrass is a warm-season perennial with good forage yield and quality, but both may be increased with nitrogen (N) fertilization. The effects of N and harvest management on neutral- and acid-detergent fibers (NDF and ADF), lignin, in vitro dry matter digestibility (IVDMD), and crude protein (CP) were studied. Nitrogen (0, 50, or 100 kg ha−1) was applied by broadcasting or knife placement, and forage was harvested from 1- or 2-cut systems. Data were obtained during four years of N treatment, and three intervening years with no N treatment. Neutral- and acid-detergent fibers and lignin were usually lower, and IVDMD and CP were generally higher in the 2-cut than in the 1-cut system. Increasing N affected forage quality in minor ways, except for CP. When 100 kg ha−1 was applied, CP was increased over no N by 0.14 in the 1-cut system and by 0.25 in cut 1 of the 2-cut system.