Impact of Row Spacing and Variety on Cotton Fruit Distribution and Yield

Cotton (Gossypium hirsutum) in Mississippi has been traditionally planted on a 97-102 cm row spacing.  These row widths were originally utilized as a means to accommodate the width of a mule, which were utilized prior to mechanized agricultural implements. 

In recent years, cotton producers have experimented with 76 cm row spacing in order to consolidate the amount of necessary implements for crop production.  Corn (Zea mays) and soybean (Glycine max) are often planted on 76 cm rows and, if efficacious, planting cotton on 76 cm row spacings would reduce equipment cost and increase efficiency.

Additionally, cotton distribution within each plant and total seed cotton yield varies widely across varieties planted in a given geographic region.  Therefore the objective of this research is to investigate the effect of alternate row spacings and multiple cotton varieties on cotton distribution within the plant and on total seed cotton yield.

A field experiment was conducted during the 2019 growing season across four locations: Starkville, and Stoneville, Mississippi, Belle Mina, Alabama, and Jackson, Tennessee.  Phytogen 350 W3FE and PX3B07 W3FE were planted on row spacings of 102, 97, and 76 cm.  Stand counts were recorded at 21 DAP, and height, node, and total nodes above white flower were recorded at first bloom.  Additionally, height, node, and nodes above the uppermost cracked boll were recorded at defoliation.  Finally, box mapping was utilized to map cotton distribution within the plant. In each plot, 3.04 m^-1 of cotton was hand harvested by clipping plants at the soil surface. The node and position of each cotton boll within the plant was then recorded.  The objective of this research is to make recommendations to producers regarding row spacing and variety selection in order to maximize profitability and yield.  This experiment will be conducted again during 2020 growing season.