title: Nutritive Value Response of Native Warm-Season Forage Grasses to Harvest Intervals and Durations in Mixed Stands.
abstract: Interest in management of native warm-season grasses for multiple uses is growing in southeastern USA. Forage quality response of early-succession mixed stands of big bluestem (BB, Andropogon gerardii), indiangrass (IG, Sorghastrum nutans), and little bluestem (SG, Schizachyrium scoparium) to harvest intervals (30-, 40-, 60-, 90 or 120-d) and durations (one or two years) were assessed in crop-field buffers. Over three years, phased harvestings were initiated in May, on sets of randomized plots, ≥90 cm apart, in five replications (blocks) to produce one-, two-, and three-year-old stands, by the third year. Whole-plot regrowths were machine-harvested after collecting species (IG and LB) sample tillers for leafiness estimates. Species-specific leaf area (SLA) and leaf-to-stem ratio (LSR) were greater for early-season harvests and shorter intervals. In a similar pattern, whole-plot crude protein concentrations were greatest for the 30-d (74 g·kg(-1) DM) and the least (40 g·kg(-1) DM) for the 120-d interval. Corresponding neutral detergent fiber (NDF) values were the lowest (620 g·kg(-1) DM) and highest (710 g·kg(-1) DM), respectively. In vitro dry matter and NDF digestibility were greater for early-season harvests at shorter intervals (63 and 720 g·kg(-1) DM). With strategic harvesting, similar stands may produce quality hay for beef cattle weight gain.
authors.affiliation: Agricultural Research Station, Virginia State University, Petersburg, VA 23806, USA. vtemu@vsu.edu.
authors.forename: Vitalis W
authors.initials: VW
authors.lastname: Temu
authors.affiliation: Animal and Dairy Science Department, Mississippi State University, Mississippi State, MS 39762, USA. BRude@ads.msstate.edu.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Rude
authors.affiliation: Plant and Soil Sciences Department, Mississippi State University, Mississippi State, MS 39762, USA. BBaldwin@pss.msstate.edu.
authors.forename: Brian S
authors.initials: BS
authors.lastname: Baldwin
keywords: bluestem; composition; crude protein; defoliation; digestibility; forage quality; harvest interval; mixed stand; native grass; warm-season