Increased adoption of no-tillage wheat seeding in the Coastal Plain area of Virginia has prompted many farmers to ask whether wheat cultivars perform differently in no-till than they do in conventional-tillage.
To answer this question, Virginia Tech Extension Agent Paul Davis began a research study three years ago evaluating 12 popular, or newly released cultivars, under conventional-tillage, reduced-tillage, or no-till.
Tested varieties have included lines from UniSouth Genetics Inc., Vigoro Seeds, Southern States, Featherstone Farms, Pioneer Seeds, Virginia Tech, Coker Seeds, Renwood Farms, and Hubner Seeds.
Each year, wheat was planted in rotation behind corn and the conventional-tillage plots were either moldboard plowed or deeply disked, the reduced-tillage plots were lightly disked to a depth of four inches and planted, and the no-till plots seeded directly into mowed corn stubble.
Grain yields for the site varied from a low of 60 bushels per acre in 2003 to a high of 74 bushels per acre in 2002. Yields in 2004 were between those at 71 bushels per acre.
Nitrogen rates over the years were typically 120 to 130 pounds per acre. Biosolids at a rate of 160 pounds plant available nitrogen per acre were applied in the spring prior to the first year of the study and as a result, total in-season nitrogen applied to wheat in 2001-02 was only 95 pounds per acre.
Lodging, which occurred in only the first season, was greatest in conventional-tillage, and was probably due to excess available nitrogen from biosolids applied the previous spring.
Tillage system had no affect on grain yield except in 2002 when the more severe lodging in the conventional-till plots made harvesting all the grain from these plots with a combine impossible.
Although numerous cultivars were consistently tested in all three years, the lack of yield differences due to tillage indicates that none did particularly well or particularly poorly under any tillage system.
Overall, the tillage treatment didn't have a consistent effect on grain yield, lodging, or grain test weight. High-yielding cultivars in conventional-tillage or reduced-tillage should perform similarly under no-tillage.
Cultivar testing need not consider tillage as a performance factor. Cultivar recommendations should not be made separately on the basis of tillage systems.