In the latest episode of the Conservation Chat podcast, host Jacqueline Comito sat down with Dr. Bob Hartzler, Professor of Agronomy and Extension Weed Specialist at Iowa State University. Dr. Hartzler has spent decades studying weeds and helping Iowa farmers manage weeds. Most recently, Dr. Hartzler has been involved in the response to Palmer amaranth and its spread into 49 of Iowa’s 99 counties. The Palmer amaranth weed has been particularly difficult for farmers to control, as it has a similar appearance to waterhemp, a common weed in Iowa. Palmer amaranth, however, grows much more quickly than waterhemp, making early identification important (before the plant produces seed).
“We’ve gotten complacent with weeds, because, until recently it was so easy to control them with glyphosate and the other products. A lot of people don’t pay as close attention to the weeds as we would have 20, 30 years ago. If we want to stop Palmer amaranth, we need to pay attention to details again.”
The spread of Palmer amaranth is a reminder that we must implement more diverse weed management programs rather than relying exclusively on the power of herbicides. Dr. Hartzler speculated about whether the need for more comprehensive weed management plans might ultimately change our cropping systems.
“Whether we can continue the current production system relying solely on herbicides, I think that’s up in the air. We’re not discovering new herbicides like we were 20 years ago, so we’re running out of options. I think it is going to force us into a more diverse management program . . . It’s hard to believe that something as simple as a weed might force us out of the current production system that we have.”
In the current management system, “We’re relying almost entirely on the herbicides, so that make it very easy for the weeds to adapt,” Hartzler commented. “A more diverse crop rotation would be the best route to go. . . [the weed] has to find a way to survive in a crop that it’s not adapted to.” Tillage is another tactic that farmers have historically turned to for weed management; however, there are many benefits to no-tillage or minimum disturbance of the soil.
It’s clear that Dr. Hartzler has a deep passion for weeds, and for helping Iowa farmers find tools to eradicate weeds now and into the future. Tune in to this month’s chat and learn about Palmer amaranth and so much more – cover crops and weed suppression, monarch butterflies and milkweed habitat, and even herbicide carryover related to grazing.