New Fact Sheet: Herbicide Rotation Restrictions in Forage and Cover Cropping Systems

Please check out our new factsheet Herbicide Rotation Restrictions in Forage and Cover Cropping Systems.

Here is a short excerpt:

Designing effective herbicide programs while following pesticide label restrictions can be challenging in any cropping system. With rotations that include forage and cover crops, the challenge can be increased-especially when a planned cover crop might be needed as supplemental or emergency forage. In this case, the best approach is to be aware of crop rotation restrictions ahead of time and plan the most effective solutiuon for all possible scenarios.

For more information on this topic, please see another WCWS article- Is it legal to use a cover crop as a forage crop? Maybe not.

The Interseeder: Adding flexibility to cover crop seeding

In Wisconsin, it is not easy to get your cover crop seeded after corn silage, corn grain, or soybean harvests. From Penn State, researchers have been working on equipment modifications to seed a cover crop while side-dressing a corn crop with nitrogen and applying a POST herbicide.

Rolling and Crimping Cover Crops

Under Cover Farmers is a video featuring farmers discussing how they use cover crops and specifically rolling-crimping for termination in a conventional system. The video is 28 minutes in length and was produced by the USDA-NRCS.

It’s worth taking a long coffee break and hearing what these farmers have to say.

Resource: 2014 Pest Management in Wisconsin Field Crops Guide

Don’t miss this year’s Pest Management in Wisconsin Field Crops guide from University of Wisconsin Extension.

New updates to the weed managment section include:

  • Another glyphosate-resistant weed from Jefferson County has been confirmed.
  • Several active ingredient name changes.
  • New herbicides have been added to the corn and soybean chapters.

For more update details, go to page 301. To obtain a print copy of the guide, go here. For a free electronic copy in pdf format, go here for the download.

New York Times Features Illinois Corn Farmers

Farmers in Illinois are paying attention to the growing Buy Local and farm-to-school campaigns sweeping through their communities and finding ways to diversify their farm income. The New York Times article “The Seeds of a New Generation” features several Illinois farmers who have alotted some of their acreage to new fruit orchards and vegetable production. To read the article, go here.

GM crops: True or false

The introduction and continued use of genetically modified crops has sparked furious debates. The scientific journal Nature, a preeminent publication, has a series of articles with a relatively balanced evaluation of transgenic crops including a very good article evaluating the myths and truths swirling around popular case studies.

Expanding the Seeding Window for Cover Crops

Are you looking for ways to expand your cover crop* seeding window? Here in Wisconsin, the cover crop species options after harvest are rather limited. For instance, this year in Columbia county, planting a cover crop into a field planted in corn for grain on June 1 with a projected harvest date of October 15 results in only one choice with no freeze risk to establishment according to the Midwest Cover Crops Council selector tool- cereal (winter) rye.

Seeding a cover crop into an existing corn crop before harvest is a strategy to extend the number of cover crop species that will establish good stands before frost. Farmers in Indiana have been using modified high-clearance sprayers to seed cover crops before the main crop harvest. Want to learn more? Dan Perkins, an Indiana Extension agent, provides a detailed discussion in his video.

*What is a cover crop? It is a crop planted between main crops that is NOT intended for harvest. For a discussion of the benefits and drawbacks of different cover crop species, consult the Midwest Cover Crops Council website or “Managing Cover Crops Profitably”, for a free pdf copy go here. Also, the Midwest Cover Crops Council in partnership with the Purdue Crop Diagnostic Training and Research Center have produced a handy pocket guide to cover crops. To purchase, visit this site.

Resources for Wisconsin Farmers, Part III

Wisconsin’s Department of Agriculture, Trade, and Consumer Protection produces The Wisconsin Pest Bulletin at weekly or semi-monthly intervals. For email notifications, go here. The bulletins are archived and available as printable pdf documents.

What information can you find in the bulletin?

  • Degree day accumulations for towns located throughout Wisconsin.
  • A pest forecast with scouting guidelines for different pests.
  • Scouting reports for several cropping systems arranged by the following categories: forages and grains, corn, soybeans, fruit, nursery and forest, and vegetables.

Weed Control Considerations for a Late Spring

News flash, it’s been a late, wet, challenging spring for a number of reasons. Okay, that’s not much of a news flash. The USDA-NASS Wisconsin Crop Progress report released today indicates that as of May 26, 64% corn is planted with 27% emerged, and 29% soybean is planted with 5% emerged. I’m certain that many of those fields were planted right between rain storms. Since that means roughly ¼ of our corn and soybean acres in the state will have seed in the ground without plants emerged, and many of those fields may have been too wet for herbicide and/or fertilizer applications, I suspect there are a lot of critical weed control decisions that could be encountered in the next week, particularly when ‘Plan A’ didn’t work out well.

Considerations for planted corn fields needing herbicide

In corn, some common scenarios for ‘Plan A’ likely included a nitrogen application before the corn was planted. Secondarily, the plan may also have been to apply nitrogen in the form of Urea Ammonium Nitrate (UAN) as a carrier with a preemergence (PRE) herbicide. Those are a couple of traditional practices and there are a lot of PRE herbicides that can be applied before and after corn plants emerge, and a lot of PRE herbicides that can be applied with UAN as a carrier. However, if you chose an herbicide and nitrogen program with the full intention that the applications would be made before plants emerge, and now you find yourself needing to accomplish these applications after plants are emerging, there are some considerations that should be double-checked to avoid problems.

For starters, the maximum growth stage at which an herbicide application can no longer be applied postemergence (POST) is different for every product. Of particular importance, though, is that there are some herbicide products like Fierce, Sharpen, and Verdict (as examples) that cannot be made to emerged plants. Second, there are products that can be applied with UAN after corn plants emerge, but the risk of crop injury is greatly increased with these combinations. Please be cautious and double check the label for recommendations regarding limitations on crop stage, tank-mix combinations including adjuvant interactions, and rates of both herbicides and UAN. If you planned to apply 100% of your nitrogen needs as UAN, you may have to consider side-dressing applications to reduce the up-front nitrogen rate mixed with herbicide if the crop has emerged.

Considerations for planted soybean fields needing herbicide

In soybean, there are also some herbicides that can be applied before and after plants emerge, but there are many more products that CANNOT be applied once the plants start to emerge, and some are further restricted to applications no more than 3 days after planting. These products include (but may not be limited to): Authority Assist, Authority First, Authority MTZ, Authority XL, Enlite, Envive, Gangster, Lorox, Metribuzin, Optill, OpTILL Pro, Sharpen, Sonic, Valor, and Valor XLT.

Moreover, another consideration that may soon be encountered is whether soybean can be planted in fields that were planned for corn. If there have already been herbicide applications made in preparation for corn, the labels of those products will need to checked to make certain it is possible to plant soybean there. There are a few herbicides that can be used at similar rates ahead of both corn and soybean, but in many cases this will be a limiting factor. If corn herbicides have been used that restrict soybean planting, I’m afraid you are ‘locked’ in for corn. Options in this scenario would include proceeding with corn with reduced yield expectation or exercising preventive planting options. For more information about corn agronomic considerations of late planting visit the UW Extension Corn Agronomy web page and for more information about regarding insurance considerations consult a recent article by Ag Economist Dr. Paul Mitchell.

Considerations for fallow fields from prevented planting

If a grower is considering the option of taking a preventative planting payment for not establishing a crop, there are a couple of considerations about weed control that should be taken into consideration. First, an obvious statement, fallow ground will be a haven for weeds to flourish for the rest of the season. An important component in an integrated management system will be to limit any seed production of weeds during the fallow year. Options will include repeated herbicide applications, repeated tillage applications, a cover crop, or some combination of these options. The most immediately important point I want to make is that all of these options will cost money and should be factored into the financial equation during the decision process of whether to take a preventive planting payment without establishing a crop.

Weed control with herbicide:

Why did I say ‘repeated’ herbicide applications? First, there may be several herbicide options to choose from to manage weeds all season, but make certain if you use residual herbicides they are appropriate choices for your rotational crop. Second, don’t expect that a residual herbicide, which provides season-long control in a crop will also provide season-long control on fallow ground. It’s likely that even many expensive residual herbicide programs would need a second application at the end of the season without the help of a competitive crop. Also, realize that striving for fields completely free of vegetation all summer-long may be a tremendous risk to soil erosion. From this perspective, allowing weeds to occupy the field for some vegetative growth may not be a bad thing as long as they are terminated prior to flowering. Unfortunately, if you violate weed size limitations on the labels of non-selective herbicide products, it would not only be accepting tremendous risk of ineffective control, but it would also provide tremendous selection pressure for herbicide resistance. So, to rely on non-selective herbicides that don’t have residual activity will also likely necessitate multiple applications.

Weed control with tillage:

Perhaps the most straight-forward discussion is of repeated tillage applications with tillage equipment, probably a disc, to keep vegetation from going to seed. The only comment here is that this could, depending on soil type, be a tremendous risk to soil erosion or other soil properties.

Weed control with a cover crop:

Establishing a crop to aid the suppression of weeds in this scenario is a great idea. However, keep in mind there are different considerations for establishing a ‘cover’ crop and establishing a ‘forage’ crop. A cover crop will be grown the rest of the year but not harvested. In this case, the major consideration is whether there are possibly any herbicide residues in the soil that would inhibit getting the cover crop species established. However, if you have any intentions of harvesting the crop for any kind of grazing or haying later in the year, that crop is a forage crop. Under this scenario, make certain you understand the implications for crop insurance, and secondarily make sure the following crop planted is allowed as a rotational crop on the pesticide labels that have been used in that cropping system for at least the previous 3 years. There are several herbicides that would prevent a large number of forage crops to be harvested and fed to livestock for as long as 40 months following herbicide application.

Lists of product names mentioned in this article were not meant to be all inclusive or as any product endorsement. As always, read and follow the label directions for all products you are using in a cropping system. Last, good luck and think safety first in this challenging season.

Vince M. Davis, Cropping Systems Weed Scientist

Apps for Ag

Attention Tablet and Smartphone Users!

Universities and private companies have developed an array of applications for agriculture. Here at the University of Wisconsin, the Integrated Pest and Crop Management program has produced three apps: Wisconsin’s Corn Nitrogen Calculator, Nitrogen Price Calculator, and the IPM Toolkit.

Other free apps:

  • ID Weeds by the University of Missouri Extension for Android and iPhone. For the web page, go here.
  • Aphid Speed Scout by the University of Nebraska.
  • Ground Spray by the University of Nebraska for Android and iPhone.
  • PeRK by the University of Nebraska, an app for pesticide record keeping available for Android and iPhone.
  • SoilWeb for Android and iPhone. The California Soil Resource Laboratory designed this app to use data from the USDA-NCRS to identify your soil type based on your phone’s GPS location. If you haven’t bought a smartphone, you can still access the data at the Web Soil Survey.
  • Nitrogen Calculator, University of Illinois, covering Iowa, Illinois, Indiana, Michigan, Minnesota, Ohio, and Wisconsin.
  • Extreme Beans developed by the United Soybean Board.
  • MixTank by Precision Laboratories is free but a fee is charged for integrated weather data.
  • The Northern Plains Integrated Pest Management Guide was developed collaboratively between University of Minnesota Extension, South Dakota State University, Kansas State University, Iowa State University Extension, North Dakota State University Extension, University of Nebraska Lincoln Extension, and the North Central Integrated Pest Management Center.
  • Farm Fuel Budget by North Dakota State University for Android only.
  • FuelLog, by Simon Morgenthaler, will track fuel consumption, miles, maintenance and much more for your vehicles. Free and fee versions available.