Agronomy •  2021-09-14

Post-harvest burndown yields big benefits for cereal farmers

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“Never do tomorrow what you can do today.” It’s an old saying to keep in mind when weighing the benefits of a post-harvest herbicide application or “burndown” this fall.

At the end of a long growing season, it can be hard to muster the energy to head back to the fields once your harvest is in, but doing a fall pre-seed ahead of the frost will help eliminate early weed competition next spring and save moisture and nutrients for vigorous seedling development.

Bottom line, post-harvest weed control provides the same benefits of a spring pre-seed while controlling winter annuals and the added workload and time management payback you’ll gain in the spring.

Weeds to watch out for

Several products are registered for fall pre-seed weed control that, when tank mixed with glyphosate, cover a wide spectrum of weeds. Winter annuals, dandelion and Canada thistle begin another life cycle in the fall.

Winter annuals left unchecked reduce soil moisture and nutrients throughout fall and in the spring, when they resume growth. Dandelion, with its large root system, is difficult to control; however, research has shown that fall is the best time to tackle this persistent weed.

Why post-harvest burndown works

Cooler conditions lead the weeds to translocate energy and nutrients down, carrying the herbicide into the root system and increasing the likelihood of complete control. Once the soil cools in the fall (≤ 10°C), certain products offer control that extends to the spring. The breakdown of the active is halted over winter, and early emerging susceptible weeds are controlled when activity restarts in spring. This is especially important for volunteer canola, which emerges in flushes in fall and spring and can be high in numbers.  

Fall pre-seed sets you up for a fast start next season by reducing spring weed populations and preserving soil nutrients and moisture.  

Set your cereal crops up for spring

With cereal crops specifically, applying a pre-seed herbicide in the fall is a real time-saver for spring as you can focus your efforts on getting your canola and pulse crop fields in the ground. Because your pre-seed weed control is already complete, your cereal crops can be seeded whenever conditions are optimal.   

Corteva Agriscience™ offers four cereal pre-seed herbicides with extended control: Korrex™ II, Paradigm™ PRE, PrePass™ XC and PrePass™ FLEX. Each solution provides extended control in the fall, and depending on time of application, extends into spring. The extended control also helps mitigate risk of reduced uptake due to low temperatures, as weeds generally recover quickly from overnight lows.

Finally, no matter what Mother Nature brings in the spring, your weed control will be taken care of and rainy, wet fields won't challenge your pre-seed weed control efforts. Whether you’re looking to start your cereal crops off without weed competition as it establishes in the fall, or set the table for a clean start next spring, here’s where you can find the right cereal pre-seed herbicide for your farm.