The addition of one summer crop – it didn’t really matter which one – to the winter wheat-fallow cropping system made a huge difference in the fight against these troublesome winter annual grass weeds. Staying out of winter wheat for two years rather than one resulted in a significant decline in the soil weed seedbank. The 1996 Farm Bill, which decoupled government support payments from base acres planted, allowed growers to add summer crops to their rotations without risking the loss of government payments. This resulted in an increase in adoption of summer crops in the rotation. In 2000, generic glyphosate became available, which made no-till an economically attractive option that resulted in even greater adoption of summer crops. Growers were managing their winter annual grass weeds and reducing the amount of fallow in their operations. I felt good about my educational efforts on managing winter annual grass weeds in wheat. The problem was not solved, but things had become manageable.
However, it was not long before the Clearfield wheat production system was introduced. This was quickly followed by the introduction of Maverick and Olympus herbicides. The ability to selectively control these winter annual weeds, which I had been saying was very unlikely, had come to pass. Growers could now control these weeds in wheat without the need of crop rotation. Many of the growers who had adopted the winter wheat-summer crop-fallow rotation primarily for weed control, returned to the winter wheat-fallow rotation. For nearly 20 years, this worked for them.
In 2012, I was lured to WSU by an Endowed Chair position funded by the Washington Grain Commission. I was welcomed by the same three winter annual grass weeds that I had worked on in Nebraska, along with rattail fescue, Italian ryegrass, and wild oat. I also found a very wheat-centric cropping system with very little crop diversity. This worried me because there were already signs that the herbicides we had been relying on for annual grass control in wheat for more than a decade were beginning to lose their efficacy.