Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/16/2008
Publication Date: N/A
Interpretive Summary: Farmers on sandy soils in the southeastern U.S. must manage soil compaction when growing cash crops on their land. Soil compaction in this area of the country can occur from natural processes and the movement of farm machinery across the field, reducing crop yields. Two methods of reducing compaction of soils are controlling field traffic and in-row subsoiling. Subsoiling or deep tillage disturbs the soil underneath the surface, allowing crop residues to remain on the soil surface to prevent soil erosion. The distance between subsoiling and planting operations in the field can significantly affect cash crop performance. A study was conducted in south-central Alabama to determine the effectiveness of using automatic steering systems for subsoiling to provide the most benefit from subsoiling operations. Automatic steering can help control traffic on the field and make sure field operations occur in the same spot each year, reducing compaction of soils. Results of the study show that as the accuracy of doing subsoiling right next to the planted row decreases cotton yields were reduced by as much as 24 to 52 percent and net revenues from cotton production by as much as 38 to 83 percent. In addition, larger farms may benefit from highly accurate automatic steering systems, while smaller farms may need to go with cheaper alternatives, such as foam markers.
Technical Abstract: Producers in the Coastal Plain of the southeastern U.S. manage soil compaction in conservation tillage systems by in-row subsoiling prior to planting. However, planting directly over the loosened zone of soil can be difficult in high-residue conservation tillage systems where cover crop production is maximized. Tractors with automatic steering capability could assist with placement of deep tillage in close proximity to planting operations, but little is known about the accuracy necessary to maximize rooting development, reduce succeeding soil compaction, and optimize crop production. An experiment was conducted in south-central Alabama to evaluate the distance deep tillage can be from the cotton row and still affect cotton yield and economic performance. Results showed as distance between the planted row and tillage pass increased seed cotton yields were reduced by as much as 24 to 52 percent and net revenues from cotton production by as much as 38 to 83 percent. An economic analysis of on-farm adoption showed that auto-guidance systems with accuracy of less than 2.5 cm may be the most profitable for larger farms, while systems with less than 10 cm accuracy may provide a better economic alternative for smaller farms.