Post-harvest weed control is a crucial aspect of maintaining crop health and ensuring a successful growing season. Implementing effective strategies during this period can provide a clean start for next spring, setting the stage for optimal crop growth and yield.
One of the most effective methods for post-harvest weed control is incorporating a burndown herbicide application with glyphosate and a soil-active herbicide.
Post-harvest weed control
Weed management is an ongoing battle for farmers, and weeds left uncontrolled after harvest can become a significant problem in the following growing season. Weeds can deplete soil nutrients, harbour pests and diseases and interfere with crop emergence, leading to reduced yields. A fall herbicide application is a proactive approach to weed management that targets weeds after the harvest and before the soil freezes.
A fall burndown application helps control weeds that are still actively growing. Adding a soil active herbicide either as a tank-mix or as a second sprayer pass in the fall before freeze-up creates a protective barrier in the soil to help prevent new weeds from emerging early in the spring. This strategy not only provides immediate weed control but also sets the stage for a cleaner, more productive start to the next growing season.
Benefits of using glyphosate and soil-active herbicides
Glyphosate is a non-selective, systemic herbicide widely used for controlling a broad spectrum of weeds. When combined with a burndown product, such as BlackHawk® EVO and a soil-active herbicide, such as Fierce® EZ, the effectiveness of the burndown application is enhanced, plus the residual properties of the soil active herbicide provide up to eight weeks of control after activation.
Using glyphosate with a product such as BlackHawk EVO in a fall burndown application offers several advantages:
- Comprehensive Weed Control: Glyphosate effectively targets both annual and perennial weeds, reducing the weed population before they have a chance to spread and establish.
- Multiple Modes of Action:: BlackHawk EVO features multiple modes of action to control challenging broadleaf weeds like kochia (including Group 2-, 4- and 9-resistant biotypes), cleavers (including Group 2- and 9- resistant biotypes), narrow-leaved hawk’s-beard (including Group 2- resistant biotypes) and volunteer canola (including all herbicide-tolerant biotypes).
- Enhanced Soil Health: Controlling weeds after harvest helps preserve soil nutrients and moisture to support a healthy crop in the following season.
Tips to maximize your fall herbicide application
To ensure your fall herbicide application is as effective as possible, it is important to consider several key factors, including timing, water quality, environmental conditions, and application techniques. Here are some tips to help you maximize the effectiveness of your fall burndown:
Timing is Crucial
The timing of your fall soil active herbicide is one of the most critical factors for success. The optimal time to apply a fall soil active is after harvest and before the soil freezes. Applying herbicides such as Fierce EZ or Valtera® EZ when soil temperatures are below 10° C can help maximize residual activity into the following spring.
Glyphosate and burndown products such as BlackHawk EVO are most effective on weeds that are actively growing. Consider spraying these products later in the morning or early in the afternoon when temperatures favour plant growth. If there has been a frost it’s best to wait one to two days before applying glyphosate and BlackHawk EVO.
Water Quality and Quantity
Water is a vital component of any herbicide application, and the quality and quantity of water used can significantly impact the effectiveness of your fall burndown. Nufarm recommends using at least 10 gallons of water per acre for optimal coverage. For soil active herbicides, this ensures that the herbicide is evenly distributed across the field and available for uptake. Additionally, it is essential to check the pH of your water. A water pH above 5.5 is ideal for maximizing herbicide solubility, which enhances the herbicide’s effectiveness and ensures that it remains active in the soil for an extended period.
10 gallons of water per acre is also recommended for BlackHawk EVO. This helps ensure good herbicide coverage on the target weed species.
Adapt to Environmental Conditions
Environmental conditions will affect the success of your fall burndown application. It is important to adjust your spraying techniques based on the conditions in your field. Since soil residual herbicides form a protective layer in the soil, reaching the ground is a top priority. In windier conditions, consider using coarser low-drift sprays, which help ensure that the herbicide hits the soil rather than being carried off by the wind. This adjustment can improve the coverage and effectiveness of the herbicide, leading to better crop protection in Canada.
Be Prepared for Weather Changes
Weather conditions can change rapidly in the fall, and it is essential to be aware of the forecast before applying your herbicide. If cold weather is expected, particularly if there are short periods of freezing temperatures at night, it is important to take precautions. Adding UAN (urea ammonium nitrate) to any leftover spray solution can help prevent the solution from freezing in the sprayer booms and nozzles. After spraying, purge the system to remove any remaining herbicide solution before shutting down. The next day, refill the sprayer with water and herbicide to ensure a consistent and effective application.
Minimize Soil Disturbance
One of the advantages of Nufarm’s soil active herbicides is that they do not require incorporation into the soil. After applying the herbicide, there is no need to disturb the soil with tillage or other operations. It’s also important to use minimum or zero-till drills for seeding in the spring. By leaving the herbicide undisturbed, you allow it to form a consistent protective barrier in the soil for controlling weeds.
Post-harvest weed control is a critical component of successful crop management, and incorporating a fall burndown with glyphosate and a soil-active herbicide can provide the cleanest start for the following growing season. By carefully considering factors such as timing, water quality, environmental conditions and application techniques, you can maximize the effectiveness of your fall burndown and ensure that your crops have the best possible start in the spring.
