Author
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Belesky, David |
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Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 9/14/2005 Publication Date: 2/7/2006 Citation: Belesky, D.P. 2006. Regrowth Interval Influences Productivity, Botanical Composition, and Nutritive Value of Old World Bluestem and Perennial Ryegrass Swards. Agronomy Journal. 98:270-279. Interpretive Summary: A consistent and dependable supply of forage is a prerequisite for successful forage-based livestock systems. Maintaining sown forages in pasture in much of the Appalachian Region is difficult because stands often are invaded by common species naturalized or native to the site. This occurs because weather patterns interacting with management practices create conditions that allow this to occur. Cool- and warm-season grasses dominate pasture in the region, often with complementary growth patterns during the growing season. A cool-season (perennial ryegrass) and a warm-season (old-world bluestem) grass were subjected to various clipping treatments to determine the distribution of herbage mass and nutritive value within and among growing seasons as a product of the longer-term change in botanical composition of the stand. Seeded species, defoliation practices and variation in growing conditions within and among years influenced production and persistence of components with varying sward botanical composition, productivity and nutritive value. The potential exists to create co-seeded swards of cool- and warm-season grasses that have similar management requirements but complementary patterns of growth to improve distribution of herbage mass and nutritive value within and among seasons. Technical Abstract: Maintaining abundance of sown forages in pasture in much of the Appalachian Region is difficult because stands often are invaded by various plant species common to the site. This occurs because weather patterns interacting with management create conditions that allow a range of native and naturalized forbs, grasses and legumes to occupy temporal and spatial gaps in the stand. The extent and duration of changes in botanical composition of the sward depend on the growth habits and competitive attributes of species comprising the sward, which ultimately influence sward persistence and productivity. Perennial grasses representing warm- [old world bluestem Bothriochloa caucasia (Trin.) C.E. Hubb.], and cool-season [perennial ryegrass (Lolium perenne L.)] species were subjected to defoliation frequencies based on canopy development to determine botanical composition and distribution of herbage mass and nutritive value of swards across and among growing seasons. Naturalized white clover (Trifolium repens L.) and cool- and warm-season weedy grasses common in pasture in the region volunteered in all stands. The proportion of forbs increased substantially by the third growing season, reflecting combined effects of repeated defoliation and weather conditions. The potential exists to create co-seeded swards of cool- and warm-season grasses with similar canopy defoliation requirements and complementary growth patterns to improve distribution of herbage mass and nutritive value within and among seasons. Seeded species, defoliation practices and variation in growing conditions within and among years influenced production and persistence of components with varying sward botanical composition, productivity and nutritive value. |
