Forage Yield and Nutritive Value of Elephantgrass as Affected by Harvest Frequency and Genotype

Abstract

Elephantgrass (Pennisetum purpureum Schum.) is known throughout much of the wet tropics for its prolific growth and usage as a forage for ruminants. In a 3‐yr study conducted on a welldrained, infertile soil (loamy, siliceous, hyperthermic, Grossarenic Paleudult) and under subtropical conditions near Gainesville, FL, the response of this forage to three harvest frequency regimes was measured. Genotypes evaluated were four tall elephantgrasses (PI 300086, ‘Merkeron’, N‐43, and N‐51), a dwarf elephantgrass (Mott), and a semi‐dwarf Pennisetum glaucum (L.) R. Br. × P. purpureum Schum. hybrid (Selection 3). Forage dry matter (DM) yields for Merkeron, N‐43, and N‐51 did not differ. For these three genotypes, 3‐yr mean DM yields (1986‐1988) were 24.3, 21.1, and 17.0 Mg ha−1 yr−1 for one, two, and three harvests per year, respectively. Two‐year mean (1986‐1987) crude protein (CP) concentrations for all four tall genotypes were 40.3, 57.5, and 75.7 g kg−1 DM while in vitro digestible organic matter (IVDOM) concentrations were 399, 492, and 555 g kg−1 organic matter (OM) for one, two, and three harvests per year, respectively. For Mott, 3‐yr mean DM yields were 11.8, 11.8, and 11.7 Mg ha−1 yr−1 for one, two, and three harvests per year, respectively. Two‐year mean CP concentrations were 52.7, 69.4, and 85.6 g kg−1 DM whereas IVDOM concentrations were 396, 549, and 580 g kg‐1 OM, respectively. Merkeron, N‐43, N‐51, and Mott persisted well. In PI 300086 plots harvested multiple times, major stand losses occurred over the 1987–1988 winter. Selection 3 did not persist. Adapted elephantgrass genotypes can persist in colder regions of the subtropics and should provide substantial quantities of forage.

Dry Matter Productivity and Overwintering Ability of the Dwarf and Normal Napiergrasses as Affected by the Planting Density and Cutting Frequency

“…Plants hardly suffered from drought stress in both summers, though there was less precipitation in 2000. In normal napiergrass, HDMY decreases with the increase in cutting frequency (Miyagi, 1985;Woodard and Prine, 1991;Sunusi et aL, 1997). Woodard and Prine (1991) reported that the dwarf variety of Mott was less sensitive to the increased cutting frequency than normal varieties, although the two dwarf varieties in the present study were sensitive to cutting frequency.…”

“…In normal napiergrass, HDMY decreases with the increase in cutting frequency (Miyagi, 1985;Woodard and Prine, 1991;Sunusi et aL, 1997). Woodard and Prine (1991) reported that the dwarf variety of Mott was less sensitive to the increased cutting frequency than normal varieties, although the two dwarf varieties in the present study were sensitive to cutting frequency. This characteristic, insensitive to the cutting frequency may be due to the earlier recovery of ground cover by the leafage after harvest (Gardner et aL, 1985) because of larger TN in dwarf varieties than in normal varieties.…”

Improvement of Perennial Forage Species as Feedstock for Bioenergy

“…Averaged across two years, yield increased from approximately 20-40 Mg ha -1 yr -1 as the harvest interval was increased from 6 to 24 weeks. The effect of the harvesting interval varies by genotype, but in general long harvest intervals increases DM production and aids persistence (Woodard and Prine 1991;Hanna et al 2004). Harvesting can be accomplished using conventional silage choppers with large heads if the plants are planted in spaced rows.…”

Genotypic differences in forage quantity and quality of canopy strata in napiergrass (Pennisetum purpureum Schumach)

“…Dry matter yield and forage quality suitable for biomass use are expected to be variable, dependent on variations in growth attributes among genotypes of napiergrass, as affected by climate and soil factors at the observed site and dependent on the growth stage of herbages (Woodard & Prine, 1991;Ishii et al, 1998). High leaf expansion, vigorous tillering, and rapid dry matter production in tall canopy are categorized as important factors to attain high production of napiergrass (Ferraris et al, 1986;Matsuda et al, 1991;Wadi et al, 2004).…”