Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 1/8/2008
Publication Date: 5/27/2008
Citation: Raper, R.L., Arriaga, F.J., Balkcom, K.S., Shaw, J.N., Reeves, D.W., Schwab, E.B. 2008. Conservation system and landscape effects on soil strength in a cotton/corn rotation. In: Boyd, S., et al, editors. Proceedings of the National Cotton Council Beltwide Cotton Conference, January 8-11, 2008, Nashville, Tennessee. p. 1603-1607. Interpretive Summary: Soil compaction reduces cash and cover crop yields throughout much of the Southern United States by limiting root growth to near the soil surface. During our common short-term droughts, plants are starved of moisture. The causes of soil compaction that have been identified are vehicle traffic and natural variability. Landscape variability is another cause that was identified through this multidisciplinary study on a large field-site in South Central Alabama. More soil compaction was found on the lower elevations where past runoff events had deposited soil particles. Continued research in this area should assist with determining whether or not tillage of these zones would reduce their compacted soil conditions.
Technical Abstract: Soil compaction often limits crop yields in the Southeastern U.S., particularly during periods of drought which have been prevalent the last two growing seasons. However, conservation technologies including cover crops and in-row subsoiling reduce the negative effects of soil compaction. The relative benefit of these technologies on large fields where terrain varies has not been studied. A 22.5-acre field with varied soil landscapes in the Coastal Plain was used to evaluate how soil strength changes after conservation technologies were used. This field was severely degraded from annual conventional tillage for more than 30 years, but has shown great improvements in soil quality and productivity on every landscape position after conservation technologies were used. Soil bulk density, soil moisture, and cone index measurements were taken in different landscape positions and in conventional and conservation tillage systems to evaluate how these treatments had changed soil strength. Results showed that the most important factor in predicting soil compaction was still row position, with the highest soil strength found underneath the trafficked row middle. Landscape position also greatly affected measurements of soil compaction. Treatment effects were not as large as the two previous factors, complicating the finding of easy solutions to soil compaction problems.