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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]

Conservation tillage, crop intensification, sod-based rotations, and judicious application of fertilizers and herbicides are agricultural practices that are not only agronomically sound, but could increase soil C sequestration. These practices have great potential for adoption by cotton (Gossypium hirsutum L) producers in the southeastern USA. This paper reviews literature and discusses the impact and potential of best management practices by cotton producers to sequester C in the southeastern USA. The current political scenario and future probabilities for cotton producers to benefit from C sequestration, either directly through existing and proposed farm policies or indirectly through increased soil productivity are outlined. Current C prices are $3 per ton of C on the USA voluntary market. Carbon sequestration rates with adoption of no-tillage management of cotton production systems averaged 428 lb C acre-1 yr-1. In the future, a landowner could receive additional income by trading C credits or from government incentives like the Conservation Security Program. [ABSTRACT FROM AUTHOR]

Less frequent subsoiling could provide adequate loosening of compacted soil profiles for soils which are subject to severe soil compaction. However, most farmers practice annual subsoiling for fear that their soil could prematurely recompact and reduce cotton yields. An experiment was conducted in south-central Alabama using three subsoilers to determine their ability to maintain a loosened soil profile over a one, two, and three-year period. Results in the final year of the experiment didn't find any differences between cotton (Gossypium hirsutum L.) yields resulting from tillage three-, two-, and one-year previous. However, significantly reduced soil compaction was measured in the plots that were annually subsoiled. [ABSTRACT FROM AUTHOR]

Irrigation can positively influence cotton (Gossypium hirsutum L.) yield and fiber quality during periods of short-term drought. A cover crop in conjunction with conservation tillage can also benefit cotton yield and fiber quality by conserving soil moisture and potentially increasing plant available water. A split-plot experiment in a randomized complete block design was utilized to examine how interactions between irrigation levels and tillage systems affect cotton yield and fiber quality in the Tennessee Valley on a Decatur silt loam (fine, kaolinitic, thermic Rhodic Paleudults) from 2001-2003. Main plots were tillage systems and subplots were irrigation levels. The no-tillage system increased yields 13% in 2003 (normal rainfall year), while irrigation levels increased yields 46% and 32%, respectively in 2002 and 2003 over non-irrigated yields. Micronaire and staple were not affected by tillage system or irrigation level in 2001; however, micronaire and staple were influenced by tillage system and irrigation level in 2002. Only irrigation level influenced fiber quality in 2003. A no-tillage system, utilizing a cover crop combined with irrigation, can improve cotton yields in the Tennessee Valley. [ABSTRACT FROM AUTHOR]

For those soils that require deep tillage to alleviate soil compaction, subsoiling can be an expensive and time-consuming tillage event. Alternative tillage methods are needed which conserve natural resources without sacrificing cotton yields. An experiment was conducted in the Tennessee Valley Region of North Alabama to determine how frequently deep tillage is needed to alleviate soil compaction problems in these soils. Results over a two-year period that consisted of cotton (Gossypium hirsutum L.) yields resulting from tillage three-years previous, two years previous, and one year previous found no differences in crop yield. No differences between four tillage implements were also found with all tillage treatments resulting in similar yields. [ABSTRACT FROM AUTHOR]

After 106 cropping years, Alabama's Old Rotation experiment (circa 1896) continues to document the long-term effects of crop rotation and winter legumes on sustainable cotton production in the Deep South. For 100 years the experiment was under conventional tillage. However, since 1997, all crops planted on the Old Rotation have benefited from minimum tillage. Coincidentally, record yields of all crops grown on the Old Rotation have been achieved since conservation tillage techniques have been implemented. Long-term yields suggest that winter legumes are just as effective as fertilizer N in producing optimum cotton yields. Yields are also highly correlated with soil organic matter that reflect the long-term treatments. In the past, crop rotation benefits have had a small effect on cotton yields, considering yield levels and crop value. These benefits are apparently enhanced under conservation tillage. Soil quality differences, e.g., aggregation and soil tilth, due to rotations and cover cropping are dramatic and are likely to increase under conservation till age. [ABSTRACT FROM AUTHOR]

Over 70% of the cotton (Gossypium hirsutum L.) in the Tennessee Valley of northern Alabama is currently raised using conservation tillage techniques. High-residue small grain cover crops are becoming a common tool in these systems, but N immobilization may occurr causing previous N recommendations to be obsolete. A replicated 3-year field study was initiated in 1999 in the Tennessee Valley of Alabama on a Decatur silt loam (clayey, kaolinitic, thermic Rhodic Paleudult) to test a factorial arrangement of N source (ammonium nitrate and urea-ammonium nitrate), N rates (0, 40, 80, 120, 160 lb N/A), N application timing (all at-planting and 50-50 split between at-planting and first square), and N application method (banded or broadcast) for cotton grown in a high-residue rye (Secale cereale L.) conservation system. Preliminary results suggest that 120 lb N/A may be needed to optimize yields (781 lb lint/A in 2000, 1026 lb lint/A in 2001, and 875 lb lint/A in 2002). Generally, highest yields were obtained when N was applied at-planting (803 lb lint/A in 2000, 957 lb lint/A in 2001, and 863 lb lint/A in 2002). Ammonium nitrate applications resulted in greater yields when broadcast at-planting while UAN applications resulted in greater yields when banded, regardless of application timing. At current prices for AN and UAN, the preliminary data suggest the most efficient and economical practice for cotton grown in high-residue conservation systems would be to apply 120 lb N/A as UAN in a banded application at-planting. [ABSTRACT FROM AUTHOR]

For those soils that require deep tillage to alleviate soil compaction, subsoiling can be an expensive and time-consuming till-age event. Alternative tillage methods are needed which conserve natural resources without sacrificing cotton yields. An experiment was conducted in a field in Southern Alabama prone to soil compaction for three years to evaluate whether the concept of site-specific tillage (tilling just deep enough to eliminate the hardpan layer) would reduce tillage energy requirements and/or reduce cotton yields. Average cotton yields over this three-year period showed that site-specific tillage produced yields equivalent to those produced by the uniform deep tillage treatment while requiring 27% less tillage power. [ABSTRACT FROM AUTHOR]

The article discusses the threats of glyphosate resistant Palmer amaranth to conservation tillage in the U.S. It enumerate several potential solutions to the problem including the crop rotation intensification, integration of cultural solutions and the use of fall residuals on harvested fallow fields to minimize weed seedbank. It highlights a study which reveals the impact of the decline of redroot pigweed density on the increase tillage intensity. Futhermore, it stresses the need to have multiple strategies that involve the integration of cultural and chemical weed control to be able to overcome the threat.

The article presents an abstract of the study "Integrating Livestock in Cotton Production in the Coastal Plain: Influence of Winter Pasture and Tillage." The study was presented at the 2003 Beltwide Cotton Conferences which were organized in Nashville, Tennessee from January 6-10, 2003. The study was conducted in 2001 and 2002 in Alabama.

The article presents an abstract of the study "Spatial Variation of Cotton Yield: Influence of Soil Management and Terrain Attributes." The study was presented at the 2003 Beltwide Cotton Conferences which were organized in Nashville, Tennessee from January 6-10, 2003. The study revealed that soil conservation systems have more effect in dried years and in the zones with lower yield potential.