By Scout Nelson
As the 2026 harvest season comes to an end, farmers can begin preparing their weed management plans for the 2027 growing season. Planning ahead helps producers identify weed problems, select suitable herbicides, and choose effective control methods.
Along with purchasing crop seeds, fertilizers and other farm inputs, reviewing the previous season's weed management results is an important step toward protecting crop health and improving yields.
Eric Jones, Assistant Professor and SDSU Extension Weed Management Specialist, along with Philip Rozeboom, Jill Alms, and David Vos, highlighted important questions farmers should consider while preparing their weed management plans.
Reviewing field conditions, weed species, and previous control methods can help producers make better decisions for the next growing season.
Review the Previous Year's Weed Management Results
Farmers should first review how well their weed management plans worked during 2026. They can identify successful practices, areas that need improvement, and factors that affect herbicide performance.
Dry conditions across much of South Dakota early in the season may have reduced the activation of preemergence herbicides. Although weather conditions are beyond farmers' control, herbicides must be applied before rainfall can activate them.
Using two or more different herbicide groups in preemergence applications can improve weed control and reduce the risk of herbicide resistance. Farmers should select products based on the weed species found in each field.
Postemergence herbicides may also provide weaker control during dry conditions. Adding a soil residual herbicide can help control later weed growth. Fields with a history of heavy weed problems may benefit from this approach. Farmers should consider using a different herbicide group from the one applied before crop emergence.
Product selection, application rates, soil type, crop rotation, and weed species also affect herbicide performance. Since fields have different soil conditions and weed populations, farmers should develop plans based on individual field needs.
Identify Fields with Heavy Weed Problems
Farmers should record fields where weeds emerge late, herbicide applications are delayed, or weed control is poor. These areas need regular scouting and closer attention during the next growing season.
Fields with a history of heavy weed growth should receive stronger management plans. Early identification helps farmers take timely action before weeds produce seeds and spread further.
Identify Weed Species in Each Field
Understanding which weed species are present helps farmers choose the right herbicides and control methods.
Wet conditions during 2025 encouraged the growth of weeds such as barnyardgrass and smartweed. Dry conditions during 2026 may have supported weeds such as kochia. These weed populations can affect fields during the 2027 growing season.
Farmers should select preemergence and postemergence herbicides based on the weeds present in each field. The latest South Dakota Pest Management Guides and herbicide labels provide useful information about approved products and the weed species they control.
Use Non-Herbicide Weed Control Methods
Herbicides are important weed control tools, but combining them with other methods can improve results. Non-herbicide practices also help reduce the development of herbicide-resistant weeds.
Some useful methods include:
- Tillage: Use suitable tillage practices, including targeted tillage or no-till systems.
- Narrower crop rows: Consider drill-planted soybeans or 20-inch corn rows to help crops compete with weeds.
- Fertilizer management: Support healthy crop growth so plants can compete better with weeds.
- Mowing: Control weeds along ditches and fence lines before they produce seeds.
- Hand weeding: Remove small and isolated weed patches before they spread.
Farmers can apply these practices in specific problem areas instead of using them across the entire farm.
Consider Changes in Crop Rotation
Crop rotation provides opportunities to use different herbicides and weed control methods. Growing crops with different life cycles can also interrupt weed growth and reduce weed populations.
Small grains are planted before many summer annual weeds emerge. Their growth can help cover the soil and limit weed development. After harvesting small grains, farmers can use additional control methods to prevent weeds from producing seeds.
Perennial crops such as alfalfa can also help manage serious weed problems. Frequent cutting and continuous plant cover make it harder for many summer annual weeds to grow and produce seeds.
However, farmers should carefully select crops for fields with difficult weeds. Conventional soybeans may have limited herbicide options for controlling weeds such as kochia and waterhemp. Similar concerns apply to crops such as sunflowers. These crops are better suited to fields with fewer weed problems and where farmers can apply timely management practices.
Watch for Possible Herbicide Resistance
Poor weed control does not always mean herbicide resistance. Weather conditions, incorrect application rates, and application mistakes can also affect results. However, repeated control failures require attention.
Farmers should rotate herbicide groups, use different products in preemergence and postemergence applications, and select approved herbicide mixtures. If weeds continue to survive properly applied treatments, producers should report the problem for further testing.
South Dakota State University Extension is also surveying the state to understand the spread of herbicide-resistant weeds. Farmers can learn more through Suspect Herbicide Resistance in Your Fields? SDSU Can Help!.
Prepare Early for the 2027 Growing Season
Weather conditions and weed populations during the 2027 growing season remain uncertain. However, farmers can improve their chances of success by preparing for different conditions.
A strong weed management plan combines herbicides, crop rotation, field scouting and non-chemical control methods. Changing control practices regularly also helps reduce weed adaptation and resistance.
Photo Credit: gettyimages-zoomtravels
Categories: South Dakota, Crops