Solid and skip-row spacings for irrigated and nonirrigated upland cotton
Producers of upland cotton (Gossypium hirsutum L.) are interested in alternative row spacings and planting patterns to improve productivity. We conducted factorial experiments for 3 yr in adjacent irrigated and nonirrigated fields at Milan, TN, of cotton grown in 25-, 76- and 102-cm rows, each planted in a solid and 2 x 1 skip-row pattern. Narrower rows and solid plantings tended to close canopy earlier and more completely, to suppress weed growth, and to mature earlier than in wider rows and skip-row patterns. Incomplete canopy closure in wider skip-row spacings resulted in less weed suppression, but weed growth in skipped rows diminished with narrower row spacing. Skip-row cotton matured later than solid planting, but this effect also diminished with narrower rows. Without irrigation, row spacing and configuration for maximum lint yield depended on growing conditions of the particular year. Under irrigation, however, solid planted 76-cm rows consistently yielded more than either 25- or 102-cm solid or skip-row cotton. With or without irrigation, lint yields were 13 to 15% lower in 102-cm skip-row cotton than in 102-cm solid planting, but yields did not differ between solid and skip-row in narrower rows. Across years and treatments, plant density was the most influential yield component in nonirrigated cotton, but plant density and bolls plant–1 had similar influence under irrigation. Cotton producers interested in skip-row planting should consider rows spaced 76-cm or less to minimize weed problems and yield loss.