|VAN SANTEN, EDZARD|
Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: 11/3/2003
Publication Date: 11/3/2003
Citation: Terra, J.A., Reeves, D.W., Shaw, J.N., Raper, R.L., Van Santen, E., Mask, P.L. 2003. Conservation system and soil landscape unit impacts on corn and cotton yield variability [abstract].ASA-CSSA-SSSA 2003 Meeting. CDROM
Technical Abstract: We evaluated yield responses of a corn (Zea mays L.)-cotton Gossypium hirsutum L.) rotation to soil management and terrain attributes in a 10-ha field in AL. Soil samples in a 18 x 9-m grid were analyzed for organic carbon (SOC) and texture. Soil survey, topography, and electrical conductivity (EC) maps were used to define management zones (MZ) by cluster analysis. Treatments were established in a RCB design with 6 replicated strips. Treatments were a conventional system with (CTM) or without manure (CT), and a conservation system with (NTM) or without manure (NT). In CT and CTM, tillage consisted of chisel plowing/disking + in-row subsoiling; no cover crop was used. The NT and NTM consisted of no-tillage with in-row subsoiling and winter cover crops. Mixed models, regression analysis and geostatistics assessed treatments effects across the landscape. Conventional system seed cotton yield was 10% lower than conservation ones in 2001 (2.84 vs. 3.12 Mg ha-1) and 19% lower in 2002, a drier year (1.32 vs. 1.63 Mg ha-1). Conservation systems had the highest yield in all MZ in both years. In corn, no differences were found in 2001, but in 2002 yield was 29% higher in conservation than conventional systems (9.29 vs. 7.19 Mg ha-1). Slope, EC, SOC and clay explained 45% of cotton and 65% of corn yield variation. Conservation systems had greater impacts in a drier year and in MZ with lower yield potential for both crops. Fewer and simpler MZ may be needed for conservation systems.