The organic approach to dealing with weeds is best described as ecologically based weed management or integrated weed management (IWM). IWM brings together a wide variety of strategies—from well-designed crop rotations to adjusting planting methods to novel techniques like flame weeding—that together offer an effective weed-management program. Iowa State University weed ecologist Matt Liebman refers to this as the "many little hammers" approach—going after weeds with many small, varied strategies instead of a one-shot approach, as with herbicides.
IWM emphasizes an ecological understanding of how weeds behave in farming systems. Virtually every field activity you engage in—from soil amendments to crop selection to tillage methods—can have an impact on your weed levels and how they interact with crops.
There are a few basic principles of IWM to keep in mind.
Don't let weed populations get out of hand. This means if you see a patch of weeds developing or if you notice that a certain field has become weedy, you need to increase the intensity of management in that area. This can be as simple as scouting and targeting patches of problem weeds or rotating a field into a weed-suppressive crop.
Don't let weeds get adapted to your operation. This means using multiple and diverse tactics to manage weed populations. Weeds can easily survive and persist if the same management practices are done at the same time of year every year.
The amount of damage weeds can do to a crop can vary. There are many ways to make crop plants more competitive so the negative impact on crop yield from weeds is reduced. Just as every field operation can affect weed levels, weed-crop competition can be affected as well. The key is to manage your system so that the crops are given as much of an advantage as possible over the weeds.
"Weed control really isn't a battle. It's about learning to understand soil structure and soil health."
~Gary Zimmer Blue Mounds, WI
