PRAIRIEGRASS-BRASSICA HYBRID SWARDS FOR AUTUMN DRY MATTER PRODUCTION IN THE APPALACHIAN HIGHLANDS

Authors: Belesky, David; Neel, James; Ruckle, Joyce

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/17/2006
Publication Date: 7/20/2006
Citation: Belesky, D.P., Neel, J.P., Ruckle, J.M. 2006. Prairiegrass-Brassica Hybrid Swards for Autumn Dry Matter Production in the Appalachian Highlands. Agronomy Journal. 98:1227-1235.

Interpretive Summary: Forage-based livestock production enterprises require a reliable supply of herbage of appropriate nutritive value to meet specific system goals. Herbage productivity varies with weather conditions and growth habit of plants, influencing the amount and seasonal distribution of herbage. Autumn herbage productivity often is limited by cool temperatures in the Appalachian region. Stockpiling herbage, or deferring use, can help redistribute herbage availability and supplement quantity to sustain or finish livestock, depending on production objectives. Some species such as the forage brassicas, grow well in cool conditions. While brassica production is good, the nutritive value may not result in optimal nutrient utilization by the grazer. Planting a companion grass would help balance the nutritive value of brassica-rich diets and supplement dry matter production. A mixture including prairiegrass and a brassica hybrid were sown in a field experiment to determine production duration and quantity of the stockpiled mixture in autumn. Prairiegrass sown alone produced the greatest and brassica hybrid sown alone the least dry matter. Praireigrass appears to retain nutritive value during autumn making it a good option for stockpiling. Herbage growth continued for about 80 d after the first harvest was made in early September, demonstrating the suitability of prairiegrass – hybrid brassica mixtures for autumn stockpiling. Prairiegrass appears to be a good option for stockpiling in systems where the traditionally stockpiled grass, tall fescue, is not suitable.

Technical Abstract: Autumn herbage productivity and supply often is inadequate for certain livestock production operations in the Appalachian region. Stockpiling herbage can help redistribute nutrient availability and supplement quantity to sustain or finish livestock, depending on production objectives. Brassica species are adapted to cool conditions occurring in autumn, and can provide herbage mass and nutritive value; however, the highly digestible brassica herbage has minimal fiber, which requires supplementation, possibly with a fibrous companion species to optimize rumen function and nutrient use. A prairiegrass (Bromus catharticus Vahl.) – brassica hybrid [Brassica rapa L. x B. rapa subsp. pekinensis (Lour.) Hanelt.] mixture, and pure stands of each were established to determine production duration and quantity, and nutritive value of stockpiled stands in autumn. Field plots were established in late June of 2003 and 2004, and clipping began 65 and 72 days after planting, respectively. Sown species and weather conditions interacted to influence stand composition, dry matter productivity, and nutritive value. Dry conditions occurring shortly after planting in 2003 slowed brassica hybrid establishment and affected productivity. Total DM productivity was similar for monospecific and prairiegrass and brassica hybrid mixed stands, but distribution of productivity differed. Nutritive value varied with years and met or exceeded values suggested for efficient rumen function. Herbage growth continued for about 80 d after the first clip in early September for all sward types demonstrating the compatibility of co-seeded prairiegrass and brassica hybrid, and suitability of the mixture for autumn stockpiled production.