Wednesday, November 7, 2007
308-5

Cotton Response to Herbicide Technologies, Row Patterns, and Tillage Systems.

Kipling S. Balkcom1, Andrew J. Price1, Francisco J. Arriaga1, Dennis P. Delaney2, and Jason S. Bergtold1. (1) USDA-ARS, 411 S Donahue Drive, Auburn, AL 36832, (2) Alabama Coop. Ext. System, 106 Extension Hall, Auburn University, AL 36849-5633

Cotton producers must make decisions related to cotton varieties, herbicide systems, tillage systems, and row patterns. A study was conducted to compare a conventional variety, a glyphosate tolerant variety, and a glufosinate tolerant variety in both conventional tillage and conservation tillage systems for standard row (102-cm) and narrow row (38-cm) cotton planting patterns during the 2004-2006 growing seasons at the E.V. Smith Research Center, Field Crops Unit near Shorter, AL. Data collection included plant populations, plant biomass at 1st square and mid-bloom, and lint yields. Plant populations were 22% higher for 38-cm cotton compared to 102-cm cotton, reflecting a 35% higher seeding rate in 38-cm cotton plots. Plant biomass measured at 1st square and mid-bloom was also affected by growing season with 38-cm cotton plant biomass averaging 34% greater in 2004 and 2005, however, the effect of tillage system was contradictory during the same growing seasons. In 2006, plant biomass was greater for 38-cm cotton at mid-bloom. Throughout the study, lint yields and net returns were influenced more by the growing season than row spacing, variety, or tillage system. In general, costs of production were greater when using the 38-cm row spacing, a conventional tillage system, and/or herbicide resistant cotton varieties. Differences among plant growth parameters were observed between 38-cm and 102-cm cotton production systems, but these differences did not translate into an economic advantage for the narrow row production system during the 2004-2006 growing conditions of Central Alabama.