UGA Research: Weed Control in Organics

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By Clint Thompson

University of Georgia research may have yielded a new way for growers to manage weeds in organic production.

Photo courtesy of Tim Coolong/UGA: Shows buried drip tape being used in his research trials.

Tim Coolong, associate professor in the University of Georgia (UGA) College of Agricultural and Environmental Sciences, is researching the effect of irrigation combined with different cultivation tactics to control weeds. He is studying shallow sub-surface drip tape placement for weed control in sweet corn compared to overhead irrigation combined with various cultivation techniques. His objective was to examine weed growth in the different trials.

“We did the same thing last year when we had more rain. This year when it was dry – June was like super dry – what we found was that with the buried drip tape, essentially, we got the same amount of weed control with a low input cultivation regime as we did with a high input regime with overhead (irrigation). What it showed us was here’s a tool that an organic grower can use,” Coolong said.

“It obviously reduces weed growth because you’re not wetting the surface of the soil. It’s a tool that you can use to help reduce weed pressure. Maybe you’re not on top of weeds as much as you should be, so this can help you.”

Tim Coolong

Organic Systems

According to the U.S. Department of Agriculture, produce can be labeled organic if it’s certified to have grown on soil that had no prohibited substances applied for three years prior to harvest. These substances include fungicides, herbicides and pesticides that are normally implemented in conventional production systems.

Organic growers have to think ‘outside the box’ to determine the best method to control weeds. Coolong’s research would help producers manage weeds that are prevalent in Southeast soils. He direct seeded corn during his spring trial to use as a model crop. Coolong plans to transplant broccoli as part of his fall trial.

Hand weeding is an option for organic farmers, but it can be expensive depending on how many acres are being produced.