Eliminating Herbicides in Cabbage
Adequate weed control can be achieved by combining cultivation and interseeded cover crops
Good news on the IPM front came this year from a project on weed control in transplanted cabbage. Herbicide applications were eliminated. Weeds were managed instead by a combination of cultivation and the planting of a cover crop between the cabbage rows. Robin Bellinder, a fruit and vegetable science faculty member, found that as long as moisture conditions are adequate and the cabbage is given enough nitrogen, yields in the fields using these IPM methods are equivalent to those in fields treated with herbicides.
Variations on the theme included two cultivations versus three, plus either hairy vetch or spring oats as the cover crop; two cultivations versus three, with no cover crop; and one application of nitrogen fertilizer versus two. These treatments were compared to hand weeding, herbicide applications with no cultivation or cover crop interseeding, and no weed control at all (a check plot). Here is a summary of what was learned:
- the second nitrogen application increased cabbage yields for all treatments by an average of six tons per acre
- three cultivations, either with or without interseeded cover crops, provided control equivalent to herbicides
- two cultivations were insufficient as a weed management strategy, whether or not they were combined with a cover crop
- cabbage interseeded with oats suffered the greatest yield reductions, about 30 percent less than yields in the herbicide-treated plots
Bellinder is hopeful that this picture could look even brighter: "With further study focused on proper timing, I think we may see that two cultivations will be enough, meaning both cost and herbicide reductions."