Effects of Annual Cool-Season Forage on Bahiagrass Production in Silvopastures

Abstract

Interest in silvopastoral systems revolves around developing sustainable agriculture that increase food, forage, and fiber production without causing environmental degradation. Limited resource farmers are looking for alternative agricultural systems with possibilities for diversifying their farm products. We evaluated the effects of tree configurations and annual cool-season forage species combinations on the yield and nutritive value of ‘Argentine’ bahiagrass (Paspalum notatum Flügge.) forage in three tree configurations: double-row sets of trees with 15 m wide forage alleys (double-row), fourth row conventionally thinned stand (random-thinned), and open pasture, which acted as a control. A mid-rotation loblolly pine (Pinus taeda L.) was thinned in the summer of 2002 and a stand of Argentine bahiagrass was established in 2003. Cool-season forage varieties that were overseeded into bahiagrass in late fall grew in the winter-spring period. Cool-season forages included ‘Jumbo’ ryegrass (Lolium multiflorum Lam.), ‘Dixie’ crimson clover (Trifolium incarnatum L.), and ‘Cherokee’ red clover (Trifolium pretense L.). The tree configurations reduced dry matter (DM) yield of bahiagrass by 29% and 22% in the randomly-thinned and double-row (silvopastures) treatments, respectively when compared with open pasture. Generally, no differences were found between the two silvopastures. Although effects of cool-season forage production caused reductions in bahiagrass yields in the first summer harvest month (July), no subsequent yield differences were recorded in the following months. While the bahiagrass in open pasture occasionally had greater in vitro organic matter digestibility (IVOMD) than the silvopastures, the double-row tree spacing resulted in greater crude protein (CP) concentrations in the bahiagrass than that grown in open pasture. Bahiagrass digestibility and CP concentration from ryegrass–crimson–red clovers treatment plots were greater than other cool-season forage combinations (ryegrass and ryegrass–crimson clover). Bahiagrass intercropped with annual cool-season forage treatment plots had greater P concentrations compared with bahiagrass alone. This study revealed the feasibility of converting a mid-rotation loblolly pine stand into productive silvopastoral systems that generally support bahiagrass production after cool-season forage production in the winter-spring period. An improved understanding of the tradeoffs between improved silvopastures and depressed intercrop growth, as well as management options to forage production, will aid farmers design systems to improve yield and nutritive value of their pastures.