Productivity and botanical composition of orchardgrass - white clover swards in a cool-temperate hill land region of the eastern United States

Authors: MALINOWSKI, DARIUSZ - Texas Agrilife Research; BELESKY, DAVID - Former ARS Employee; RUCKLE, JOYCE - Former ARS Employee; FEDDERS, JAMES - Former ARS Employee

Submitted to: Grassland Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/18/2012
Publication Date: 12/1/2012
Citation: Malinowski, D.P., Belesky, D.P., Ruckle, J.M., Fedders, J.M. 2012. Productivity and botanical composition of orchardgrass - white clover swards in a cool-temperate hill land region of the eastern United States. Grassland Science. 58:188-200.

Interpretive Summary: Forage-based livestock production requires a reliable supply of herbage to meet production goals. 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. Our objective was to determine botanical composition and herbage productivity of orchardgrass and white clover, which dominate pastures in the Appalachian Region, when managed as a function of canopy development and regrowth interval. Productivity was influenced by defoliation regimen when mixtures were managed according to canopy development. Instances of orchardgrass and white clover mixtures exceeding the productivity of either species growing alone were rare. The sown species tended to decline in the sward regardless of management practice, but seemed to differ with the type of orchardgrass grown. The amount of orchardgrass and white clover tended to differ depending on the type of orchardgrass and clover grown. Plant species other than those sown appeared in each plot regardless of the grass-clover mixtures sown or defoliation management. Managing grass-clover mixtures might depend more on weather conditions within and among growing seasons interacting with plant growth patterns during the growing season than how the mixtures are used. This allows producers a array of management options when using grass-clover mixtures in the Appalachian region.

Technical Abstract: Understanding the growth dynamics of grass-legume swards is critical as pastoral management practices are adapted to economic constraints and environmental considerations. Efficient management must synchronize use of accumulated herbage with the needs of grazing livestock. This must be accomplished against the dynamic background of within and among year weather patterns interacting with herbage growth and grazing animal behavior. Pastures often are dominated by orchardgrass (Dactylis glomerata L.) and white clover (Trifolium repens L.) in the Appalachian region of the eastern United States. Our objective was to determine botanical composition and herbage productivity of orchardgrass and white clover swards managed as a function of canopy development and regrowth interval. Productivity was influenced by defoliation regimen when mixtures were managed according to canopy development. White clover declined and orchardgrass increased in the sward irrespective of treatment. Productivity was greatest when swards were managed as hay or when clipped to a 5-cm residue each time mean canopy height reached 20cm. Botanical composition of mixtures with the erect growing orchardgrass tended to be more stable, whereas swards including the decumbent orchardgrass tended to be invaded by weeds. Some facilitation in productivity occurred during the first growing season when mixtures were clipped at either 2-wk or 4-wk intervals. Regardless of defoliation strategy, white clover, and in some instances orchardgrass, presence declined during two consecutive growing seasons. Productivity and sward composition appear to respond to weather conditions within and among growing seasons and are a product of interactions of morphological and physiological plasticity of sward components.