ISSN: 0041-3216 (Online), 0041-3216 (Print)
Volume 77 Number 1
Nitrogen and carbohydrate responses of dwarf napiergrass tillers to N fertilizer. (06)
Mott' dwarf napiergrass [Pennisetum purpureum (L.) Schum.] is a productive forage species, but it is difficult to propagate. This study was conducted to investigate the influence of autumn N application on nitrogen and total nonstructural carbohydrates (TNC) in tiller components. Zero and 100 kg N ha-1 were applied on four dates (4 Oct., 21 Oct., 11 Nov., and 2 Dec. 1988) at Beeville, TX, U.S.A. Similar rates were applied on 3 Oct. and 24 Oct. 1988 at College Station, TX, U.S.A. Tillers were harvested twice weekly and separated into leaf blade, sheath, stem base (lower 30 cm), stem top (above 30 cm), and dead tissue. Near infrared reflectance spectroscopy estimated both nitrogen and TNC concentrations. Tissue from unfertilized plots decreased in nitrogen and TNC concentration from October through the end of the study except stem base which increased at Beeville and did not change at College Station. Nitrogen concentration of most samples increased (P < 0.05) within 3 to 11 days following N application, while TNC concentration decreased in the majority of components. Application of N increased the tiller nitrogen pool at both locations. Tiller TNC pool was not influenced by N (P > 0.05) at either location. Approximately 30-80% nitrogen and TNC content in napiergrass tillers was found in leaf blades, suggesting that use of intact tillers as seed pieces might improve establishment of dwarf napiergrass.
Keywords: Dwarf napiergrass; Forage species; Nitrogen; Total nonstructural carbohydrates; Tillers