Fiber composition of eastern gamagrass forage grown on a degraded, acid soil.

摘要

With increasing emphasis on sustainable agriculture, there is renewed interest in the use of native plants as alternative sources for food, fibre, and soil improvement. Eastern gamagrass [Tripsacum dactyloides (L.) L.] is a native, warm-season, perennial grass found in the eastern United States that has been used for forage and soil improvement. The objective of this research was to investigate the forage composition and digestibility of eastern gamagrass grown on a degraded, acid soil at the Beltsville Agricultural Research Centre, Beltsville, MD. Eastern gamagrass forage samples were harvested at time of heading in July of 1997, 1998, and 1999 from plants grown on a degraded hillside with increasing soil acidity and decreasing surface soil depth from the bottom to top of the hillslope and analysed for fibre, crude protein, and in situ digestibility. Year of harvest had the greatest effect on forage composition. Fibre composition was related to slope position and soil acidity. Plants were generally high in fibre as reflected by high neutral detergent fibre (NDF) and acid detergent fibre (ADF) contents, but were not particularly high in lignin. Crude protein (6-11%) and digestibility were good. In general, forage quality, as indicated by lower fibre (NDF, ADF, lignin) and higher digestibility and crude protein, increased as soil condition degraded and environmental stress (deficit rainfall) increased. Thus, eastern gamagrass is comparable in forage composition and digestibility to many forages currently used even when grown on poor soil and under environmental stress..