Establishment and termination dates affect fall-established cover crops

In temperate climates, performance of fall-established cover crops is affected by establishment and termination date. This study evaluated the effect of mid-September to mid-October establishment dates on cover crop biomass production from early May to early June in Landisville (USDA Plant Hardiness Zone 6b) and Rock Springs (Zone 6a). Rye (Cereale secale L.), wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), annual ryegrass (Lolium multiflorum Lam.), hairy vetch (Vicia villosa Roth.), crimson clover (Trifolium incarnatum L.), and rape (Brassica napus L.) biomass was measured from 2003 to 2005. Early October established rye produced 1 to 7 Mg ha^-1 biomass in early May up to 12 Mg ha^-1 by early June. Early October established wheat produced 0.5 to 4 Mg ha^-1 in early May up to 9 Mg ha^-1 biomass by early June. Although they winterkilled in 1 yr, early October established barley and annual ryegrass produced up to 4 Mg ha^-1 biomass by early May and 9 Mg ha^-1 in early June. Mid-September established forbs did not successfully survive the winter in Rock Springs, but in Landisville, exceeded 1.5 Mg ha^-1 biomass in early May every year for hairy vetch, and in 2 out of 3 yr for crimson clover and rape. Biomass production was up to 7.5 Mg ha^-1 for hairy vetch, 4.3 Mg ha^-1 for crimson clover, and 6.9 Mg ha^-1 for rape. Annual ryegrass, crimson clover, and rape show potential as winter-hardy cover crops in southern Pennsylvania.