With more weed resistance at play, does cold steel have a place again? That’s the key question in a swirling debate among farmers, their crop advisors and Extension and industry workers. Weed resistance won’t go away. Does tillage have a fit once more? Part of the answer may depend on which weed you’re battling. For example, a study in the Midwest and upper Delta showed that a no-till system can more efficiently deplete the “seed bank” compared to varying degrees of tillage. The study looked at small-seeded broadleaf weeds, such as waterhemp, and the research was conducted by weed scientists Larry Steckel at the University of Tennessee and Christy Sprague with Michigan State University, among others. Because waterhemp is small-seeded with a relatively thin seed coat, it is more susceptible to decay and predation in a no-till system, says Sprague. “Over time, that seed can be exposed to more fluctuations in temperature and moisture as long as it remains in the shallower soil profile,” Sprague explains. “Under those circumstances, decay could happen sooner compared to burying the seed more deeply with tillage.” It’s important, she adds, to follow best herbicide practices with any no-till system. That includes:
- Choosing pre-emergent herbicides that give good residual control early in the season.
- Making sure post-emergent herbicides are applied on a timely basis.
- Using an array of herbicides with multiple sites of action to gain control if resistance is an issue. That further reduces the chance that resistant seedlings will escape.
“We really want to eliminate any of those weeds from going to seed,” she emphasizes. “And if you have a few escapes here and there, it makes sense to rogue those plants.”
To download a copy of the Sprague/Steckel study, click here. Also, use the Nufarm AgPro University site to read up on recent articles related to this topic. For example: Dr. Bryan Young from Purdue University, “Should Tillage be Used to Control Resistant Weeds?”