Effective Management of Alfalfa and Goldenrod: Non-Herbicide Approaches and Roundup Ready Alfalfa Considerations

[MikePhua]

Alfalfa, a widely cultivated forage crop, often faces challenges from weed species such as goldenrod. Managing these weeds without damaging the alfalfa crop itself is a common concern for farmers and land managers. Additionally, the advent of Roundup Ready alfalfa has introduced new possibilities and questions around herbicide use and weed control. This article explores the detailed methods for controlling goldenrod in alfalfa stands without herbicides, the implications of Roundup Ready alfalfa, and practical experiences from the field.
Understanding Alfalfa and Goldenrod
Alfalfa (Medicago sativa) is a perennial legume valued for its high protein content and nitrogen-fixing ability, contributing significantly to livestock nutrition and soil fertility. Goldenrod (Solidago spp.), on the other hand, is a perennial weed known for its aggressive growth and ability to spread rapidly via rhizomes and seeds, often invading pastures and reducing forage quality.
Goldenrod is particularly challenging due to its resilience and tendency to dominate spaces where the desirable forage has weakened or is absent. It also flowers late in the season, attracting pollinators but complicating timing for effective control.
Non-Herbicide Control Methods for Goldenrod in Alfalfa
Non-herbicide control of goldenrod in alfalfa relies heavily on cultural and mechanical strategies, focusing on maintaining the health and competitiveness of the alfalfa crop.

• Frequent Mowing or Cutting: Regular cutting of goldenrod before seed set can reduce its spread. Repeated mowing weakens the root system over time, reducing vigor.
  
• Mechanical Removal: Pulling or digging out goldenrod patches can be effective on small scales, though care must be taken as any root fragments left can regrow.
  
• Soil Fertility and pH Management: Maintaining optimal soil fertility helps alfalfa outcompete goldenrod. Goldenrod often thrives in poorer soils, so balanced fertilization with adequate phosphorus and potassium supports alfalfa dominance.
  
• Crop Rotation and Overseeding: Introducing competitive grasses or rotating with other crops can reduce goldenrod populations by interrupting its lifecycle.
  
• Shade and Canopy Management: Dense alfalfa stands with adequate canopy closure reduce light reaching goldenrod seedlings, suppressing their growth.
  

These methods, while labor-intensive, avoid chemical inputs and promote long-term pasture health.
What About Roundup Ready Alfalfa?
Roundup Ready alfalfa is genetically engineered to tolerate glyphosate, a broad-spectrum systemic herbicide. This innovation allows farmers to spray glyphosate directly over the alfalfa stand to control weeds like goldenrod without harming the crop.
Benefits of Roundup Ready Alfalfa

• Simplified Weed Control: Glyphosate effectively kills a wide range of weeds, including goldenrod, when applied correctly.
  
• Reduced Tillage: With chemical weed control, mechanical soil disturbance can be minimized, helping soil structure and reducing erosion.
  
• Improved Crop Establishment: Clean fields free of competing weeds support healthier alfalfa stands.
  

Considerations and Concerns

• Resistance Management: Overreliance on glyphosate can lead to herbicide-resistant weed populations, including glyphosate-resistant goldenrod or other species.
  
• Market Acceptance: Some livestock producers and markets may prefer non-GMO or organic forage, limiting Roundup Ready alfalfa adoption.
  
• Regulatory and Stewardship Issues: In some regions, planting Roundup Ready alfalfa requires compliance with specific stewardship plans to prevent gene flow to non-GMO alfalfa fields.
  
• Environmental Impact: Glyphosate use has been scrutinized for potential effects on non-target plants and soil microbiota.
  

Field Experiences and Case Studies
Many farmers report success controlling goldenrod with glyphosate applications on Roundup Ready alfalfa. One common practice is to apply glyphosate post-emergence when goldenrod plants are actively growing but before flowering. Timing is critical to prevent seed dispersal and minimize crop stress.
In contrast, non-herbicide approaches, while slower and more labor-intensive, often result in more sustainable pasture conditions over the long term. For example, a dairy farmer in the Midwest successfully controlled goldenrod by implementing a strict cutting schedule combined with soil amendments that favored alfalfa growth, reducing goldenrod infestation over three seasons.
Glossary of Key Terms

• Alfalfa: A perennial legume used as forage.
  
• Goldenrod: A perennial weed species, often invasive in forage fields.
  
• Glyphosate: A broad-spectrum systemic herbicide, active ingredient in Roundup.
  
• Roundup Ready: Genetically engineered crops tolerant to glyphosate.
  
• Rhizomes: Underground stems that allow some plants to spread.
  
• Canopy Closure: The coverage of plant leaves over the soil surface.
  
• Stewardship Plan: Guidelines to manage the use of genetically modified crops.
  

Summary of Control Options

• Non-Herbicide Methods:
  • Frequent mowing before seed set
    
  • Mechanical removal of patches
    
  • Soil fertility management to support alfalfa
    
  • Crop rotation and overseeding
    
  • Maintaining dense alfalfa canopy
    
• Herbicide Methods with Roundup Ready Alfalfa:
  • Targeted glyphosate application
    
  • Reduced tillage farming practices
    
  • Requires management to prevent resistance
    

Final Thoughts
Successfully managing goldenrod in alfalfa fields requires an integrated approach tailored to farm goals, resources, and local regulations. Non-herbicide methods prioritize ecosystem health and long-term sustainability but require patience and labor. Roundup Ready alfalfa offers convenience and effective weed control but comes with stewardship responsibilities and market considerations. Many farmers find a hybrid approach combining cultural practices with judicious herbicide use delivers the best balance between productivity and environmental care.
A local story highlights how a family farm transitioned from heavy herbicide reliance to integrating mowing and soil health improvements, resulting in reduced goldenrod issues and better forage quality. This approach underscores the value of knowledge sharing and adaptive management in modern agriculture.
This comprehensive view on alfalfa and goldenrod management equips farmers and land managers with the knowledge to make informed decisions that optimize forage production and sustainability.