Growers can control weeds in their potato crops by applying herbicides, via tillage or a combination of the two practices. As herbicides are costly, growers are looking at options to reduce herbicide use without compromising on weed control. Ivany (Can. J. Plant Sci. 2002) showed that reducing herbicide application (metribuzin preplant + clethodim post-emergence) to a 1ft wide band applied directly over the row provided excellent weed control (better than 90%) when combined with a single post-emergence tillage operation to take out the unsprayed weeds growing between the rows. The timing of the tillage step (crop at ground crack, 3″ or 6″ tall) had no impact on weed control. By comparison, a single tillage operation provided only 30-40% weed control. The weeds growing in the hills reduced yields in the tillage-only treatments by over 30%. By contrast, the combination of band applied herbicide+a single tillage produced yields equivalent to when the entire field was treated with herbicide, but at a cost savings of 66%. The relative efficacy of band application + tillage will vary with weed type and cropping conditions but the idea is worth thinking about for next spring.
Source: Ivany (2002) Can. J. Plant Sci.