Weed Management Via Harvesting Order

By Eric Jones and Clarence Winter et.al

The 2025 growing season was warm with a lot of precipitation that resulted in several flushes of weed germination. Later emerging weeds can be seen in some crops now, but these weeds likely did not cause a yield loss (Figure 1). Unfortunately, the only means to manage these weeds now is to hand pull and remove them from the field as viable seed is likely present (Figure 2). If weeds are to remain in the field until harvest, the seed should remain within the field.

Determining Harvest Order

Despite The warm and wet growing season that promoted continuous flushes of weed germination, weeds are usually present at the time of harvest. The severity of weediness can vary from “clean” to “weedy mess” (Figure 3). Careful consideration should be taken to determine the order of fields to be harvested. What fields are “clean” and a “weedy mess” should be determined by preharvest scouting. Fields that are very weedy should be harvested last. If weedy fields are harvested first, the weed seeds can become lodged into cervices of the combine and be transported to other fields (Figure 4).

If the next field harvested happens to have low numbers of weeds present, the weed seeds deposited on the combine could be dislodged and added to the soil seedbank. If the field with low weed pressure was harvested first, the field would have less weeds to control in the subsequent growing season. If a weedy patch is encountered in a field, this area can be avoided and combined later. Minimization of weed seed transportation via a combine is especially important if the field has herbicide-resistant weeds or weed species not common to other fields. If weed patches are small and isolated, then these areas can be hand weeded and removed from the field to ensure weed seeds are not returned to the soil or transported by the combine. If weedy patch is unavoidable, the combine should be cleaned before entering a different field.