Tips for rye termination after a short growing season

ICYMI – A recent article from Iowa Farmer Today highlights tips from ISU Extension and Outreach for terminating a rye cover crop following a reduced growing season.

Given the limited fall growth and persistent cold weather this spring, there will likely be less cover crop growth compared to recent years. This could lead to termination challenges for those that are not prepared.  With three methods of termination, there are options for producers to choose from to find the best fit.  These methods include: herbicide (most widely used), rolling/crimping (after pollen shed) and limited tillage.

Here are some keys for successful herbicide termination:

  • Translocated herbicides, like glyphosate, work best on actively growing plants
  • Spray on sunny afternoons when daytime temperatures are 60°F or above & nighttime temperatures stay above 40°F
  • Avoid spraying in the early morning or evening hours

Timing of termination recommendations:

  • Ahead of corn = terminate 10-14 days before planting
  • Ahead of soybeans = terminate 1-2 days before planting to maximize spring growth

For more tips, check out our earlier post Cover Crops: Tips for Termination!

Liz Juchems

Dr. Bob Hartzler Talks Weeds on Conservation Chat Podcast

Bob_labelIn 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 Bob_am_label2identification 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.”

Palmer vs waterhemp_labelIn 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.

larvae3_labelIt’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.

If you’re on the go, take the Conservation Chat podcast with you – find it on iTunes or search for “Conservation Chat” on the podcast app of your choice!

Julie Whitson

Breaking Down the Cover Crop Workshop Series Highlights

Last fall offered ideal conditions for cover crop establishment and growth, with adequate moisture and growing temperatures. Great fall growth helped protect the soil during heavy rain events, but could present challenges this spring if farmers are not prepared with a termination plan and equipment adjustments.

DSC_0192I am pleased to report that we had 350 attendees at our six spring cover crop management workshops across the state in late February and early March. Roughly 61% of attendees identified as farmers/ landowners looking for information as they prepared for spring.

Attendees were highly engaged and asked many questions of the speakers who shared tips on spring management of cover crops. I want to share with you a few of the frequently asked questions from the workshops and resource links to learn more.


In our long-term on-farm project, farmer partners reported that in 49 of 53 site-years, properly managed cover crops had little-to-no effect on corn and soybean yield (and actually increased soybean yield in 7 site-years).


Scout early to minimize potential impacts. Check out this podcast with ISU entomologists Matt O’Neal, Erin Hodgson, as they invite grad student, Mike Dunbar, to share his experience of true armyworm in a cornfield with a cereal rye cover crop.


ISU field agronomist Meaghan Anderson provided tips for planning to terminate cover crops this spring using herbicide, rolling/crimping and/or tillage in a recent Integrated Crop Management article.


ISU research data indicates no change is needed for nitrogen application rates following a cereal rye cover crop. However, you may want to apply starter fertilizer prior to corn.  Research summaries can be found on the ISU Soil Fertility website.


In addition to conservation purposes, cover crops can provide forage for livestock. It is important to consider restrictions on labels of herbicides used earlier in the growing season if you intend to use the cover crop as a forage source.

We want to thank everyone who helped make these workshops possible:
Carl Pederson, Mark Hanna, Tom Kaspar, Meghan Filbert, Stefan Gailans, Sarah Carlson, Angie Rieck-Hinz, Joel DeJong, Rebecca Vittetoe, Shane Wulf, and Justin Bisinger.

— We have three cover crop field days coming up next week and there is still time to register to or 515-294-5429.

Liz Juchems