Key Learnings from 2024: Best Practices for Pre-Drilling Glyphosate Use
Utilizing glyphosate for weed elimination before drilling paves the way for residual herbicides, effectively managing future weed germination in crops. However, reports of ineffective control surfaced last spring.
Creating stale seed beds and ensuring proper cleaning are crucial components of herbicide strategies, especially this autumn as farmers contend with increased seed returns due to inconsistent control from the previous season.
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Bayer agronomist Roger Bradbury shares insights from last spring’s experiences to assist farmers in optimizing their results this season.
Effective Application
Last spring, Bayer received several reports indicating that weed control did not meet expectations.
“Upon investigation, we discovered various factors, including application timing, conditions, and dosage, contributed to the subpar control,” Roger explains.
He notes that there were limited spray opportunities, allowing weeds to grow significantly between the recommendation and the application, resulting in inadequate rates.
“In limited conditions, farmers often applied herbicides too quickly, exceeding the recommended speed of 12 km/h to cover more ground,” he adds.
Additionally, the notably wet conditions in early spring placed stress on target plants, hampering glyphosate’s translocation within the weeds.
Roger also points out that some applications were postponed until stem extension, which limits glyphosate’s reach to the roots, risking regrowth.
However, this issue does not apply to autumn applications.
Guidelines for Autumn
Roger stresses the importance of correct rates and conditions for autumn applications.
“Ensure you use an adequate rate of Roundup: at least 720g/ha glyphosate for blackgrass and 1,080g/ha for brome, ryegrass, and couch,” he advises.
One of the biggest risks is attempting to cover ground too quickly. Speeds exceeding 12 km/h can lead to turbulence and drift, especially when using higher boom heights and on uneven terrain.
This inconsistency can cause some areas to receive less than the intended dose.
“Since the target weeds tend to be small in autumn, improper application can easily result in missing some plants,” Roger warns.
Farmers are encouraged to assess the outcomes of all glyphosate applications to confirm effective control.
Herbicide Stewardship
Achieving effective initial control with Roundup is vital for sustaining the long-term efficacy of the herbicide. Insufficient glyphosate doses increase the potential for developing resistance.
“Always apply the correct rate for the target weed, ensuring that the right amount reaches the plant. If performing two applications in the same field, incorporate cultivation between sessions as an alternative weed control method,” he recommends.
Bayer is particularly concerned about farmers lowering herbicide rates and adding agents like citric or fulvic acid to compensate.
“Our research indicates that this practice diminishes control and poses a stewardship risk,” he cautions.
Maria Sanchez completed her Bachelor’s degree in Plant Sciences from the University of California, Davis, in the USA. Her studies focused on plant genetics and biotechnology, with an emphasis on developing disease-resistant crop varieties. Maria has contributed to several research projects aimed at improving crop resilience to climate change and is now pursuing her Master’s degree in Plant Breeding.