Wheat harvest is underway in Eastern Washington. With cool spring weather and ample spring rainfall, it looks like it will be a bountiful harvest. Understandably, growers will be focused on getting their grain out of the field and into the bin, but this is also a good time to think about weeds – I’m always thinking about weeds.
The Aussies, who have perhaps the biggest issue with herbicide-resistant weeds of any country, identified the harvest operation as an underutilized opportunity for managing weeds. During harvest, weed seeds from plants that have survived earlier herbicide applications, enter the combine with the grain where they get sorted and either enter the bin with the grain or exit the combine in the chaff, which is then spread behind the combine. In effect, the harvest operation is rewarding these herbicide survivors by spreading them throughout the field, field borders, and even into the next fields to be harvested. The Aussies decided it would be a good idea to manage the chaff in such a way as to reduce the amount of weed seed that is added to the soil seed bank. The concept of Harvest Weed Seed Control (HWSC) was born.