48th TWC, Tob. Work. Conf., 2018, abstr. 66

Cover crop management for conservation tillage tobacco

(1) University of Kentucky, Lexington KY USA; (2) Kentucky Department of Fish and Wildlife, Frankfort KY USA

Cover crops provide a host of benefits including protection from soil erosion, scavenging of nutrients, suppression of weed growth, conservation of soil moisture, and the addition of organic matter to the soil. Historically tobacco growers have used cover crops consisting primarily of winter annual small grain species. Recently, cover crops consisting of a mixture of species have been promoted for improved soil health and increased agricultural productivity. To achieve the full benefit of mixed species cover crops producers must allow the crops to grow long enough to produce a large amount of biomass. Heavy biomass residues can interfere with tobacco transplanting operations and reduce the growth of tobacco thus an appropriate balance must be achieved between biomass production and manageability. The objectives of this study were to determine the value of mixed cover crops relative to monoculture cover crops, and to evaluate the impact of cover crop management on cash crop performance. Mixed cover crops and winter wheat cover crops were terminated with paraquat early (4 to 6 weeks before transplanting) and late (1 to 2 weeks before transplanting) and late with above ground residue removal. Early termination resulted in less overall biomass and lower C:N ratios compared to late kill.  The late kill treatment resulted in significant stand reduction at one site/year location. Mixtures that included a small grain tended to be dominated by the small grain, although more nitrate was available in soil as measured by plant root simulator probes under mixed covers than mono- cultures. Additional work is needed to optimize cover crop management to maximize potential benefits while minimizing negative impacts on cash crop growth. (Reprinted with permission)