I have a couple plots that are part of ag fields. Pigweed wasn't an issue in these plots previously, but evidently got spread by the combine last year. The plots were planted in oats and crimson clover last fall and left fallow this summer. A fairly heavy stand of goosegrass and barnyard grass volunteered this summer and apparently shaded out any pigweed from sprouting.

Around the first of August the farmer sprayed these plots with Liberty while spraying beans. The plots were completely dead two weeks ago, but as of yesterday they have sprouted several patches of Palmer amaranth pigweed. Plants are 12-14" tall and already have flower heads on many of them. In other places I'm seeing more plants that have sprouted but not gotten as big.

I'm trying to figure out what is the best way to keep them from producing viable seed and also not release any more seed that is in the seedbank. I plan to plant oats and crimson again in about a month, but from what I understand, the pigweed will have produced viable seed by that time.

Options appear to be spray it now and possibly again before planting, disc it up now and again before planting or is there something else I can do to keep from making the situation worse?