Cotton Varietal Responses to Tillage Type in the Upper Southeastern US Coastal Plain

Current understanding of the effects of tillage systems on cotton growth and development of contemporary varieties is limited for producers of the Upper Southeast Coastal Plain of the United States. Tillage studies were conducted in Suffolk, VA, from 2013 to 2016 evaluating conventional, minimal, notillage, and strip-tillage systems on early season growth, soil compaction, and lint yield of four contemporary varieties using a split-plot design. Soil compaction was greatest in the no-till system with yearly depths to a root restrictive layer ranging from 8-26 cm. No-till resulted in shorter plant heights compared to other tillage methods in 2 out of 4 yr. Relative yield for no-till was 0.78, an 8% reduction compared to the other tillage systems. Deltapine 1321 B2RF was consistently taller than other varieties in all years; with significant varietal differences being present during all sampling intervals each year except 2013. Fibermax 1944 GLB2 was shorter than other varieties. In-season plant development was affected more by variety than tillage. Lint yield differed among varieties in 2013, 2014, and 2016. Deltapine 1321 B2RF produced the highest lint yields of 1746 kg ha(-1), 1467 kg ha(-1), and 693 kg ha(-1) in 2013, 2014, and 2015, respectively. Differences in lint quality parameters were influenced more by variety than tillage system. In the short term there was no significant growth or yield penalty associated with no-till cotton production as compared to other tillage systems. Variety selection and environment were the most important factors contributing to cotton yield during this four year study.