Living mulches between beds of polyethylene-mulched vegetable crops may suppress weeds and decrease surface and ground water contamination by pesticides. They should be either low growing or amenable to mowing and should withstand traffic. Twelve winter cover crops were planted in north (N.) and north central (N.C.) Florida in Fall 2004: black oats (Avena strigosa cv. Soilsaver), annual ryegrass (Lolium multiflorum cv. Gulf), rye (Secale cereale cv. Wrens Abruzzi), hard fescue (Festuca longifolia cv. Oxford), white clover (Trifolium repens cvs. Dutch white and New Zealand white), berseem clover (T. alexandrinum cv. Bigbee), crimson clover (T. incarnatum cv. Dixie), subterranean clover (T. subterraneum cv. Mt. Barker), arrowleaf clover (T. vesiculosum cv. Yuchi), a barrel medic (Medicago trunculata cv. Parabinga), and a disc × strand medic (M. tornata × M. littoralis cv. Toreador). Black oats, rye, and annual ryegrass established quickly and suppressed winter annual weeds. Canopy development of the other species was poor. Shoot biomass was greater in N. Florida than in N.C. Florida. The highest shoot biomass occurred with black oats. By 8 weeks after planting (WAP) rye and annual ryegrass had similar amounts of biomass, but by 16 WAP the yield of rye was greater. At some harvests, biomass with wheel traffic or mowing was lower than without, but black oats, rye, and ryegrass did not succumb to these treatments. Of the legumes, only crimson clover and `Toreador' medic in N. Florida produced sufficient biomass by 16 WAP to permit a harvest. Black oats, rye, and annual ryegrass appear to be the best living mulch candidates; however, black oats would require more frequent mowing.
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