|Dewald, Chester - RETIRED USDA/ARS|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 3, 2003
Publication Date: November 14, 2003
Citation: SPRINGER, T.L., DEWALD, C.L., SIMS, P.L., GILLEN, R.L. 2003. HOW DOES PLANT POPULATION DENSITY AFFECT THE FORAGE YIELD OF EASTERN GAMAGRASS. CROP SCIENCE 43:2206-2211. Interpretive Summary: Much is known about the effects of fertilization and harvest frequency on the yield of eastern gamagrass [Tripsacum dactyloides (L.) L.], however, information on the effects of plant density is lacking. We studied the affects of plant population density on the dry matter yield, vegetative shoot density, and basal area of plant crowns of irrigated eastern gamagrass. In young stands, higher plant densities generally produce higher dry matter yields compared to 3 year old or older stands. At Woodward, OK, the highest sustained forage yields were obtained with a density of 4.8 plant per meter squared. Planting recommendations for eastern gamagrass were developed primarily for seed production stands, where wide row spacings were recommended to accommodate seed production equipment. Narrower row spacings for pasture plantings may facilitate establishment while increasing forage production early in the life of the stand.
Technical Abstract: Eastern gamagrass [Tripsacum dactyloides (L.) L.] is a highly productive and palatable forage grass that can be grown throughout the Southern Plains and the eastern United States. Although much is known about the effects of fertilization and harvest frequency on the yield of eastern gamagrass, information on the effects of plant density on yield is lacking. Our objectives were to investigate the effects of plant population density on annual dry matter yield, vegetative shoot density, and basal area of plant crowns of irrigated eastern gamagrass. Cumulative forage dry matter yield varied significantly with Year x Density interactions (P < 0.01). Higher plant densities produced greater dry matter yields with the highest sustained forage yields obtained at a density of 4.8 plant per meter squared. Variation in number of vegetative shoots per meter squared was attributed to Year (P < 0.05) and Density (P < 0.01). Higher plant densities also had a greater number of vegetative shoots; however, plots with higher initial stand densities reached equilibrium much faster than plots with lower stand densities. Variation in crown area was associated to Year x Density interactions (P < 0.01). Mature shoots near the edge of the crown probably produce a greater number of tillers until an equilibrium is reached. This is suggested by our data where the number of vegetative shoots per plant increased with decreasing plant density. Most planting recommendations for eastern gamagrass call for seeding into wide rows. These recommendations were developed for seed production stands where wider rows allow for equipment passage through the field. Narrower row spacings, however, may facilitate stand establishment while increasing forage production early in the life of the stand.