CONSERVATION SYSTEM AND LANDSCAPE EFFECTS ON SOIL STRENGTH IN A COTTON/CORN ROTATION.

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. [ABSTRACT FROM AUTHOR]