Submitted to: Communications in Soil Science and Plant Analysis
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/27/2011
Publication Date: 10/5/2012
Citation: Busscher, W.J., Khalilian, A., Jones, M.A. 2012. Tillage management for cotton in southeastern coastal soils during dry years. Communications in Soil Science and Plant Analysis. 43(19)2564-2574. Interpretive Summary: Tillage can be necessary for some soils that have deep compaction from large equipment or that compact easily. But tillage, even tillage that does not invert soil, can be one of the most expensive operations for agricultural producers and, depending on fuel costs, tillage can become prohibitively expensive. With this in mind, we revisited the need to till sandy coastal soils in cotton production. Previous research had shown that some coastal soils may not need to be tilled every year. This research showed a marginal decrease in soil strength and increase in yield with annual tillage after a dry year when reconsolidation of the soil would not be as complete as under normal rainfall. It also showed that under some conditions soil water content can affect strength more than tillage and may mask differences among tillage treatments. The producer will have to take all these conditions into account when determining whether it would be profitable to till or not. Future research could develop decision tools that help the producer make this decision but it would have to include the producer’s experience in a field which is likely to be as important or more important that any calculation.
Technical Abstract: With rising energy costs, deep tillage carries an increasing cost to many Coastal Plain management systems; therefore, deep tillage needs to be reevaluated in terms of frequency and implement type. In 2002 and 2003, 3 implements in 4 tillage treatments were evaluated for effectiveness in increasing cotton (Gossypium hirsutum L.) yield at two sites when non-inversion deep tillage was performed annually or not. The 4 treatments used a straight-legged subsoil shank with bedding, a straight-legged subsoil shank and strip tillage without bedding, a Paratill and strip tillage without bedding, and a Terra-Max and strip tillage without bedding. In the second year of the experiment, treatments were split; half of each plot was tilled again and half was not. Treatments were compared to a control that was not tilled. Tillage generally decreased soil penetration resistance and improved yield but differences were significant only about half of the time. No single tillage treatment significantly reduced penetration resistances better than the others at both sites or for both years. Treatments that were tilled the first and not the second year did not significantly reduce penetration resistance probably because of lack of re-compaction based on an exceptionally dry first growing season. Tilling the second year improved yield but only marginally. Producers would do well to decide whether or not to till after a dry year (and possibly subsequent years) on a case-by-case basis, basing their decision on re-compaction.