What is in this article?:
- How to kill weed seeds before they get started in your fields
- Weed management toolbox
- Cover crops comeback?
Adam Davis, an ecologist with USDA’s Agricultural Research Service at the University of Illinois, offers five ways to manage the weed seedbank.
Weed management toolbox
Davis conducted that early research to evaluate a valuable option for growers who want to manage hard-to-control weed populations: Manage the weed seedbank to prevent weeds from getting started.
The key to weed seedbank management is to reduce the ability of the seeds to germinate. Then growers either don’t have the weeds to control or they have fewer weeds to handle with other weed management tools. Here are Davis’s suggestions for managing a seedbank:
- Reduce seed production by either competitive crop varieties or through agronomic practices.
- Kill newly formed seeds by harvesting and removing weed seeds from the field with modified harvest machinery. Modified combine harvesters have been developed for removing weed seeds, and a practice known as “spray topping” uses herbicide to kill developing seed.
- Look at diversifying crop rotations. Crops with different growing patterns and canopy structure can also increase seed predation.
- Delay primary tillage. To increase weed seed predation, delay primary tillage to give predators time to eat seeds on the soil surface. Avoid deep tillage so seeds are not protected deep in the soil profile.
- Encourage germination of weed seeds and plan on controlling the emergence flushes completely with a stale-seedbed approach. A stale seedbed can be made through either physical (field cultivation) or chemical means. “Field cultivation is usually more effective, since it not only kills the emerged weeds, but brings new weeds to the surface to be killed in a second pass a week or two later,” Davis says.