Managing the soil seedbank
Wouldn’t it be great if we could just kill every weed seed in the soil and not have to worry about them becoming next spring’s headaches? Since that’s not possible and weeds seem to thumb their leaves at whatever herbicides we throw at them, the best we can do is prevent the seeds from reaching the soil.
Kevin Bradley is an extension weed scientist at the University of Missouri. He says this takes a multi-pronged approach that includes an herbicide program integrated with cultural practices to keep the Palmer amaranths and waterhemps from going to seed.
"And so, what I’m talking about is like cover crops plus pre-herbicides plus post-herbicides all with effective modes of action. Row spacings, any kind of things that we can integrate, mesh together to basically just try to keep that field weed free as much as possible," says Bradley. "That’s what we’re shooting for right now."
There will be escapes, which is often what runs through the harvester and gets spread back out on the field. Until we can figure out a way to prevent that, keep a garbage can in the combine and do some good old-fashioned hand-pulling when you see them poking their heads above the canopy of the cash crop.
"If you just have a seed head here or there, why wouldn’t it be worth your time to go out there and pull it up and get it out of your field? That one plant can produce anywhere from 300,000-500,000 seeds. All that seed’s going to go back into your soil," he says. "I know it’s easy for me to say and I’m not the one who has to go do it but, it is an option and probably going to be worth your time."
Harvest the weed-free areas first and weedy spots last.