Published on Friday, November 5, 2021
Beck’s Practical Farm Research (PFR)® data suggests 60 lb. to 90 lb./A. of cereal rye can effectively suppress waterhemp compared to the untreated check. In addition to knowing the proper rate to seed cereal rye, we need to determine how to terminate it. Crimping can lay the cover crop down, creating a mat, resulting in effective weed control. The timing and growth of the cereal rye will impact the success of the crimping. For the best results, wait for the cereal rye to head out. If terminated too soon, the crimper will not be successful because the cover crop will recover and continue to grow. Using glyphosate for chemical termination opens the window to earlier applications but will not get the mat of cover as with a crimper. Both methods can be utilized. Spraying the cereal rye and waiting 24 hours to crimp will allow for herbicide uptake to occur before the leaves are damaged with a crimper.
INFLUENCE ON WATERHEMP PRESSURE
Averaged across 30, 60, and 90 lb./A., crimping reduced the number of waterhemp plants by 52%, compared to chemical termination alone. Across the three cereal rye rates, chemical, crimping + chemical, and crimping averaged 3.3, 2.9, and 1.6 waterhemp plants/sq. ft., respectively. The rate of cereal rye had a bigger impact than the termination method. By increasing our cereal rye rate from 30 lb. to 60 lb./A., we saw a 64% reduction in waterhemp. However, once we reached 90 lb./A., we did not see as big of a response vs. 60 lb./A. Crimping + chemical reduced waterhemp control by 12% compared the chemical only treatment. This was slightly lower than stand alone crimper treatment, however, at the end of season it was still the best treatment. Explanation: In the stand alone crimper treatment it took longer for the cereal rye to die and because of this offered longer ground shade and waterhemp suppression. The chemical + crimp treatment achieved a quicker kill of the cover crop which caused it to degrade faster. However, becasue of the lingering competition from the ceral rye in the crimp only plot to the soybeans, we can conclude the chemical + crimp termination is the best combination. It provides a mat of protection while also ensureing 100% control of the cereal rye.
Cereal rye rate had a bigger impact than the termination method. By increasing to the proper rate of 60+ lb., we saw up to a 64% reduction in the number of waterhemp plants. However, by changing our termination method, we only had a 52% reduction in waterhemp plants. Though the crimping only treatment had the largest reduction in waterhemp, we did not have complete control creating competition with our soybean plants. Crimping + chemical reduced the number of waterhemp plants by 12% compared to chemical only. However, crimping + chemical termination created a mat of cover, while also ensuring the cereal rye was completely controlled.
Author: Jim Schwartz
Categories: Agronomy, Agronomy Talk
Tags: Agronomy, Herbicide, Cereal Rye, weed management