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

ABSTRACT

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.

Acknowledgments

Contribution No. 13-241-J of the Kansas Agricultural Experiment Station, Manhattan, KS. The laboratory assistance of T. S. Erikson is gratefully acknowledged. The technical assistance of C.M. Cramer, K. R. McNickle, P. Markley, and D. Kerley is also appreciated.