|Terra, J - AUBURN UNIVERSITY|
|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: May 9, 2005
Publication Date: December 20, 2005
Citation: Terra, J.A., Reeves, D.W., Shaw, J.N., Van Santen, E., Raper, R.L., 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: Soil management practices like conservation tillage must be evaluated at the field scale because producers are reluctant to adopt management recommendations derived from small plots. 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 management practices on yield, soil water, and indicators of drought stress for cotton grown in a 20 acre field in Alabama. Conventional systems 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. Management practices were arranged so as to cross the maximum landscape variability in the field. Conservation systems had greater rainfall infiltration, improved water use efficiency and less drought stress, resulting in 14% higher yields compared to conventional systems. Yearly variations in yields were also reduced with conservation systems. The study showed conclusively, even at the scale of operations used by producers, that conservation systems using no-tillage and high-residue producing cover crops minimized drought stress, reduced economic risks from yield variations, and increased cotton yields. 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: Soil management impacts on cotton (Gossypium hirsutum L.) water relationships and productivity have rarely been evaluated at field-scale level. We evaluated soil management practices effects on cotton yield in a 9-ha Alabama coastal plain field (Typic and Aquic Paleudults) during 2001-2003. Soil water content (0-30-cm depth), stomatal conductance and canopy temperature were assessed during bloom (2001-2002). Treatments were established in a randomized complete block design in strips traversing the landscape in a corn (Zea mays L.)-cotton rotation. Treatments included a conventional system with or without dairy bedding manure (CTmanure or CT), and a conservation system with and without manure (NTmanure or NT). In conventional systems, tillage consisted of chisel plowing/disking + in-row subsoiling; no cover crop was used in winter. The conservation system consisted of no surface tillage with non-inversion in-row subsoiling and winter cover crops. Data were analyzed with mixed models accounting for spatial correlation. Conservation systems had greater soil water content (0.140 vs. 0.119 m3 m-3), higher stomatal conductance (0.45 vs. 0.33 mol m-2 s-1) and lower canopy temperature (31.8 vs. 32.9 ºC) compared with conventional systems. Averaged over years, conservation systems improved seed cotton yield compared with conventional systems (2710 kg ha-1 vs. 2380 kg ha-1, respectively). For degraded soils in warm humid climates, conservation systems including no-tillage and high-residue producing cropping systems minimize drought risk and increase cotton yield.