Influence of Mulch, Tillage, and Diphenamid on Weed Control, Yield, and Quality in No-Till Flue-Cured Tobacco (Nicotiana tabacum)

Field experiments were conducted to determine the effects of various densities of four fall-seeded small grain mulches and diphenamid (N,N-dimethyl-α-phenyl benzeneacetamide) on weed control, yield, and quality in no-till flue-cured tobacco (Nicotiana tabacumL. ‘McNair 944’). A greenhouse study investigated the effects of non-soil-incorporated mulch from the same small grains plus alfalfa (Medicago sativaL.) on various growth parameters of tobacco (‘Speight G-70’). None of the mulches used in the greenhouse study adversely affected growth of the tobacco. Mulch from rye (Secale cerealeL. ‘Abruzzi’) killed about 2 weeks before transplanting plus diphenamid provided better annual broadleaf weed control (85%) than wheat (Triticum aestivumL. ‘McNair’), barley (Hordeum vulgareL. ‘Keowee’), and no mulch. Oat (Avena sativaL. ‘Brooks’) mulch resulted in 80% broadleaf weed control. There were no differences in annual grass control (which was short lived) among mulches but control was lower in the no-mulch treatment. Rye mulch resulted in a 22% increase in the control of broadleaf weeds compared to no-mulch. Yield of the no-till tobacco did not differ among mulches and averaged 82% of that conventionally grown. The quality was not affected. The rye mulch did not affect the yield or quality of tobacco when compared to a nonmulch, noncultivated treatment. The 18% decrease in the no-till yield was apparently the result of the lack of tillage and increased weed interference and was not due to adverse effects from the rye.