“Other than herbicides, the toolbox of available weed management practices is the same for all growers,” he says. “Effective weed control requires an integrated approach based on knowledge of each crop and the weeds that threaten it.”

In a survey conducted online by researchers at Rodale Institute, 85 percent of the organic growers responding use at least three weed management strategies – and most use six. The top six practices are hand weeding, mechanical control, mulches, cover crops, crop rotation and dense planting. These practices remove weeds, prevent them from being competitive or, in the case of crop rotation, inhibit weeds that prefer the growing conditions associated with certain crops.

But some of these techniques also have drawbacks. Farmers who rely on hand-weeding know it is a labor-intensive process. And the disadvantages of extensive mechanical control (tillage) are well-documented in some types of crops and fields. Tillage can promote soil erosion and rob the soil of moisture. According to the National Sustainable Agriculture Information Service (ATTRA), it also can disturb soil biology, increase runoff, decrease water infiltration, damage soil structure and even invite weeds by exposing bare ground. Such drawbacks heighten the need for scientific research focused on sustainable weed management alternatives.

“Research that advances our knowledge of the biology, ecology and management of weeds is fundamental to success on any farm, and it is vital that we do more of it,” Fennimore says. “Scientific investigation gives us a broader base of tools that can be used successfully — regardless of the size of the operation or whether a farmer chooses conventional or organic growing practices.”