Nail down your perfect termination timing

Due to recent harsh environmental conditions, you might be struggling with poor cover crop termination. We’re here to help with some tips on nailing down termination timing.

The 2024 growing season is getting close and you might be reflecting on some of the conditions you faced in 2023. If that reflection gives you some anxiety, you’re not alone. Growers across the country were faced with various challenges including extreme drought conditions. One consistency we’ve been seeing across the country is the struggles farmers are facing when it comes to cover crop termination. When harsh environmental conditions hit early in the season, the limited plant available moisture can have a huge impact on yield.

Remember these helpful tips:

• Two of the most important factors when planting a crop, especially with drying conditions and excessive residue, include:
  • Proper seeding depth.
  • Seed-to-soil contact.
• As conditions change, seeding methods must change with them. Make sure to get out of the cab and dig behind the planter to ensure the seeding furrow is being formed properly.
• It's extremely important to your termination timing and success that you are conscious of the current moisture conditions on your farm and what the current weather outlook is.

As we head into the new growing season, our team wanted to share some of the main concerns we observed in spring 2023:

1. It's extremely important to properly terminate your cover crop to efficiently grow your cash crop.

Getting your crop started on the right foot is the most important part of the growing process and many of the lessons we learned this past year stemmed from improper termination methods and timing. As we learn and grow together, we can fine-tune these practices.

In wet or normal years, our concern is that terminating a cover crop too soon will create a matted layer of residue that traps moisture and prevents the sun from helping to warm and dry out the surface. For this reason, many growers will decide to terminate cover crops later in the spring after the plants have had a chance to pull excess moisture from the soil through their roots. In the spring of 2023, however, many areas saw this moisture quickly disappear and not be replenished for several weeks. The water that was absorbed by the cover crop left the soil profile lacking the moisture necessary for germination and early growth of the cash crop.

2. The lack of moisture this past growing year also impacted termination applications, limiting control of cover crops. This limitation brought up a new challenge to growers who ended up fighting through sporadic plant growth that made planting conditions extremely variable. With drought conditions continuing through most of the summer fo 2023, we also experienced a lack of available nutrition in some of the growing crops across the Midwest.

3. As you remember, we often speak about the importance of maintaining a healthy C:N ratio ahead of a corn crop as this will provide early-season plants with enough available nitrogen that won't be tied up in breaking-down residue. With a delayed response to the chemistries that were used for burndown in 2023, more of this residue from the cover crop needed to be broken down. Applied fertility was lost to feed the microorganisms responsible for the breakdown. There was also less nutrient movement through the soil and limited root growth occurring under the dry conditions we experienced, which resulted in plant nutrient deficiencies.

When are conditions right for effective cover crop termination?

You might have noticed that most product labels of the herbicides commonly used for cover crop termination require plants to be “actively growing” during application. This means that the days leading up to the application, as well as the days following the application, need to maintain specific temperatures for the application to be successful. Many of the acres that we witnessed having chemical termination issues in 2023 came down to crop growth during application. Applications were made with chemical rates that were thought to be sufficient but were applied at a time when we experienced daytime temperatures of at least 50 degrees Fahrenheit and lower nighttime temperatures. We experience some temperature swings in April and May every year that send the growing conditions of our cover crops into periods of active growth and dormancy. During these temperature swings, it is important to pay attention to the nighttime temperatures. Providing that cover crop two to three days of growth where nighttime temperatures stay above 40-45 degrees Fahrenheit is important to get them back in a state of active growth. It is equally important that these conditions are forecasted to continue after the application.

Another consideration to take into account is what kind of environmental stresses your current cover crop is under due to moisture restraints. A cover crop is like a cash crop in that its growth is slowed when it is under drought conditions. We must be mindful of this and ensure our chemical program is designed correctly to terminate a potentially stressed cover crop due to moisture restraints or slower growth due to cooler conditions. As always, be sure to follow recommended use rates, tank mixes, and use of surfactants that are detailed on herbicide product labels.

A good cover cropping system brings dying soil back to life through its living roots and provides the armor a soil needs to protect itself from the changing environment around it. One of the biggest lessons we learned from 2023, however, is that a good cover cropping program is only as good as its termination plan. Application timing, application rates, and adaptability to changing environments and weather patterns are extremely important when working to limit water and nutrient loss. Remember, it is better to have a more risk-averse mindset when working towards your final goal and have a contingency plan for terminating your cover crop.

Stay tuned as next month we will take a deep dive into our top recommendations for cover crop termination.