The practice of intercropping cotton and melons has increased significantly in south Georgia, from about 40 acres in 2010 to several thousand acres this past year. Like with more common cropping systems, a major impediment to further growth has been the management of glyphosate-resistant Palmer amaranth pigweed.

“One of the major issues in Georgia is glyphosate-resistant Palmer amaranth pigweed, and it can impact watermelon production significantly,” says Peter Eure, a member of the University of Georgia research team looking at solutions for the problem. “If we don’t maintain early season control of resistant Palmer amaranth, we’ll be battling it throughout the season, and most of the time we lose. We also want to reduce the amount of hand-weeding required by our growers who are battling this weed pest.”

Eure explained that research was conducted to identify herbicide systems to manage troublesome weeds in watermelon-cotton intercropping production and to determine the profitability of watermelon-cotton intercropping versus a monoculture of watermelon or cotton.

A small group of innovative growers in south Georgia began the intercropping experiment, he explains, and it has since gained in popularity.

“Traditionally, spring-planted watermelons in south Georgia are harvested by July, allowing that land to be planted to sorghum. However, returns on sorghum following watermelon are often marginal, prompting growers to seek other potential crops and strategies that may generate greater revenue; one such strategy is a watermelon-cotton intercropping system,” says Eure.

Land preparation, fertilizer and irrigation are already in place for the watermelons, he says, so intercropping cotton could potentially increase resource efficiency and improve grower profit. However, a major impediment to intercropping systems in Georgia is the management of glyphosate-resistant Palmer amaranth following watermelon harvest.