|Terra, J - INIA URUGUAY, AUBURN UNIV|
|Shaw, J - AUBURN UNIVERSITY|
|Van Santen, E - AUBURN UNIVERSITY|
|Mask, P - AUBURN UNIVERSITY|
Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 14, 2005
Publication Date: December 5, 2005
Citation: Terra, J.A., Shaw, J.N., Reeves, D.W., Raper, R.L., Van Santen, E., Schwab, E.B., Mask, P.L. 2005. Soil management and landscape variability affects field-scale cotton productivity. Soil Science Society of America Journal. 70:98-107. Interpretive Summary: Cotton producers need to understand the impacts of landscape variability on cotton productivity in order to tailor soil management practices for optimum efficiency. ARS scientists at the J. Phil Campbell Sr. Natural Resource Conservation Center, Watkinsville, GA and the Soil Dynamics Research Unit in Auburn, AL, cooperated with Auburn University scientists to determine the impact of soil management practices on cotton yield in a 20 acre field. Both conventional and conservation systems were tested. In conventional systems, tillage consisted of chisel plowing/disking + in-row subsoiling; no cover crop was used in winter. Conservation systems consisted of only non-inversion in-row subsoiling plus winter cover crops to provide 4 to 6 tons/acre of residue for complete soil coverage. Slope, bulk soil electrical conductivity, soil carbon or organic matter, and clay content explained 16 to 64% of the variability in cotton yields, but their relative importance varied among management practices and growing seasons. Conservation systems had 14% higher yields compared to conventional systems over the entire field, and reduced yield variability across years compared to conventional systems. When the field was delineated into management zones using soil and landscape properties identified as affecting yield, the conservation system was more productive than the conventional system in 87% of the zones across growing seasons. This information can be used by State Cooperative Extension Systems, USDA-NRCS, crop consultants, and producers to promote the use of environmentally and economically sustainable conservation practices on the 3.1 million acres of cotton grown in the Southeast.
Technical Abstract: A better understanding of interactions between soil management and landscape variability on cotton (Gossypium hirsutum L.) productivity is needed for precision management. We assessed management practices and landscape variability effects on seed cotton yield in a 9-ha AL field (Typic and Aquic Paleudults) during 2001-2003. Treatments were established in replicated strips traversing the landscape in a corn (Zea mays L.)-cotton rotation. Treatments included a conventional system with or without dairy manure, and a conservation system with and without manure. Conventional systems consisted of chisel plowing/disking + in-row subsoiling without cover crops. Conservation systems combined no surface tillage with in-row subsoiling and winter cover crops. A soil survey, topography, soil electrical conductivity (EC), soil organic carbon (SOC) and soil texture were used to delineate five zones using k-means clustering. Conservation systems improved cotton yield compared to conventional systems (2710 kg ha-1 vs. 2380 kg ha-1). Slope, EC, SOC and clay content were correlated with yield in all treatments. Soil and terrain attributes explained 16-64 % of yield variation, however, their significance fluctuated between years and treatments. Factor regression suggested that in dry years, variables related with soil quality and field-scale water dynamics had greater impacts on CT yields than NT yields. The conservation system was more productive than the conventional system in 87 % of the cluster×year combinations. Our data suggests that for our site, cluster analysis using terrain variables is more suitable for delineating management zones in conservation than conventional systems.