Evaluation of a custom residue manager to manage cover crops and its effects on cotton population and yield in a no till system

Abstract. Cover crops are important part of no-till conservation agriculture and these crops must produce an optimum amounts of biomass to be effective in protecting soil surface from erosion, and runoff, conserve soil water and provide a physical barrier against weeds. Because of the large amount of residue produced by cover crops, they must be managed appropriately as not to create planting problems for producers. A study was conducted at the E.V. Smith Research and Extension Center (EVS) in central Alabama to determine the effect of commercially available DAWN^® row cleaner and different experimental residue managers on cotton (Gossypium hirsutum L.) stand, emergence rate, and seed cotton yield. A randomized completely block design with four replications was used for this study. Presented results illustrate two growing and harvest seasons (2012 and 2013). Rye (Secale cereale L.) was chosen as a cover crop as it has been a popular cover crops for Alabama producers. Standing rye without rolling down was chosen to study treatment effects of different residue managers. Rye was chemically terminated using Roundup (glyphosate) and after complete rye desiccation, cotton was planted directly into standing rye residue cover. During cotton planting, cover crop residue amount accumulated on the no till planter and the time to clean planting units from residue were also measured. Data showed that in both growing seasons treatments did not affect cotton yield, however different weather and different amounts of residue affected cotton yield. Cotton stand was affected by residue manager treatments in 2012, but not in 2013, however significant differences in cotton stand were observed between two growing seasons, and cotton stand was significantly lower in 2013 as affected by large amounts of cover crop residue in 2013. In both growing seasons, residue management treatments affected the amount of residue of the planting units. The highest residue accumulation was observed with V-type divider and was related to the presence of winding weeds (hairy vetch) interlocking with rye and the rye stalks with weeds were pulled by the divider. The second largest residue accumulation was observed with a standard DAWN^® row cleaners with coulters due to rotation of the row cleaning wheels and wrapping rye residue around row cleaners and required a significantly greater time to clean up residue from the DAWN^® row cleaners compared to other residue managers. Overall, residue manager can be successfully used in situations where cover crops are not generating a large amount of residue and the standing cover crop is not lodged in many directions.