Row spacing, tillage system, and herbicide technology affects cotton plant growth and yield

Cotton (Gossypium hirsutum L.) producers are faced with numerous production choices including cotton varieties, herbicide technology, tillage systems, and row spacing. A study was conducted to compare cotton production across conventional, glyphosate-tolerant, and glufosinate-tolerant varieties in both conventional and conservation tillage systems for standard row (102 cm) and narrow row (38 cm) cotton planting patterns. The experiment was conducted during the 2004–2006 growing seasons at the Field Crops Unit, E.V. Smith Research Center, near Shorter, AL in long-term tillage plots. Data collection included plant populations within row spacings, plant biomass and height at 1st square, mid-bloom, and lint yields. Plant biomass measured at 1st square and mid-bloom was 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 within the growing season. Mid-bloom plant biomass also varied across growing seasons with 21% more plant biomass recorded in 38 cm rows averaged across all three growing seasons. Plant heights were shorter for 38 cm cotton compared to 102 cm cotton, regardless of growth stage or tillage system. No differences in cotton development were observed across varieties. Cotton planted in 38 cm rows yielded equivalent to 102 cm cotton during two of the three experimental years and was superior to 102 cm cotton the remaining year, which corresponded to the best growing season observed during the experimental period. These results indicate that 38 cm cotton production can produce yields that are at least equivalent to standard 102 cm cotton, despite differences in plant development. The productivity of a narrow row cotton production system may be attractive to some growers, but economic evaluations are required to determine if the system is profitable on a large scale based on equivalent or marginal lint yield increases.