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Overseeding dormant bermudagrass [Cynodon dactylon (L.) Pers.] ‘Tifton 85’ with cool-season annuals in the southeastern United States could provide winter and spring forage or bioenergy feedstock. We overseeded cool-season annual legumes and grasses in monocultures or mixtures into dormant Tifton 85 and compared aboveground dry matter (DM) and N yields of single harvests at peak biomass production and a multiple harvest forage system. We also measured first-cut spring Tifton 85 yields. Wheat (Triticum aestivum L.) yielded as much or more (P £ 0.05) biomass in a single-harvest system than other grasses only during a dry cool season. Well-distributed precipitation, in combination with multiple cool-season grass legume harvests, resulted in lower yields than the single harvest system, whereas the reverse occurred when precipitation was erratic. Hairy vetch (Vicia villosa Roth) matured later in the spring, and monocultures or mixes with it yielded more (P £ 0.05) DM and N than the more precocious crimson clover (Trifolium incarnatum L.). A drier cool season followed by a spring with good precipitation, as well as repeated cool-season grass and legume harvests, resulted in more (P £ 0.05) spring first-cut Tifton 85 DM regrowth. Results provide several management options to maximize cool-season, annual legume, and grass bioenergy feedstock or forage while minimizing negative and maximizing positive effects on subsequent early spring Tifton 85 regrowth. J.A. White, Dep. of Plant & Soil Sciences, Mississippi State Univ., Mississippi State, MS; J.P. Muir, Texas A&M AgriLife Research, Soils & Crop Science, 1229 North US Hwy 281, Stephenville, TX 76401; B.D. Lambert, Tarleton State Univ., Stephenville, TX 76401. Received 5 Sept. 2017. Accepted 4 Dec. 2017. *Corresponding author ( j-muir@ tamu.edu). Assigned to Associate Editor Jose Dubeux. Abbreviations: DM, dry matter. Published in Crop Sci. 58:964–971 (2018). doi: 10.2135/cropsci2017.09.0530 © Crop Science Society of America | 5585 Guilford Rd., Madison, WI 53711 USA This is an open access article distributed under the CC BY license (https:// creativecommons.org/licenses/by/4.0/). Published January 18, 2018