Glyphosate is the most widely used herbicide in the world. It is commonly known by its original trade name Roundup. Glyphosate is a non-selective herbicide, meaning it kills most plants. It stops plants from making certain proteins that are needed for plant growth. Glyphosate was first registered for use in the United States in 1974 and became more popular after Monsanto introduced glyphosate-resistant crops in the 1990s.
In recent years, concerns have grown over the health and environmental impacts of glyphosate. In 2015, the World Health Organization’s International Agency for Research on Cancer classified glyphosate as “probably carcinogenic to humans.” This sparked a debate over whether farmers should continue using glyphosate. Several countries have announced plans to ban or restrict the use of glyphosate.
Why are farmers moving away from glyphosate?
There are a few key reasons why many farmers are transitioning away from glyphosate to alternative herbicides and non-chemical weed control methods:
- Increasing weed resistance – Overreliance on glyphosate has led to more weeds developing resistance to it.
- Health concerns – Potential links between glyphosate and cancer have made some consumers wary of food grown with this herbicide.
- Environmental impacts – Glyphosate residues are frequently detected in soil, air, and waterways, raising questions over ecological effects.
- Regulations – Stricter government rules and even national bans on glyphosate are pushing farmers to switch to alternatives.
Growers are also moving away from monoculture farming systems dominated by glyphosate-resistant crops. Integrated weed management using cover crops, crop rotation, and targeted herbicide applications is becoming a preferred approach.
What are the leading alternatives to glyphosate?
Farmers are replacing glyphosate with both non-chemical methods and alternative chemical herbicides. The leading options include:
Organic herbicides
Naturally derived herbicides are growing in popularity. These include:
- Vinegar (acetic acid) – Vinegar is an effective option for total vegetation control on hard surfaces. Higher concentrations of acetic acid provide increased effectiveness.
- Citric acid – Made from citrus fruits, citric acid works by stripping away oils in plant cuticles that protect against dehydration.
- Corn gluten meal – A by-product of corn processing, corn gluten meal prevents root establishment and early seedling growth.
- Cloves and clove oil – Clove oil contains high levels of eugenol which act as a natural herbicide.
- Salt (sodium chloride) – Salt desiccates and kills plants by drying out cells and depriving them of water.
Organic acids and oils do not persist in the environment and break down quickly in soil and water compared to synthetic herbicides.
Synthetic alternative herbicides
For conventional farmers, new types of synthetic herbicides are replacing some glyphosate applications:
- Dicamba – A benzoic acid herbicide that kills broadleaf weeds. Commercial dicamba products include XtendiMax, Engenia, and Tavium.
- 2,4-D – One of the oldest selective herbicides, 2,4-D controls broadleaf weeds in cereals, corn, and grasslands.
- Glufosinate ammonium – Sold as Liberty and Cheetah, glufosinate is another non-selective herbicide for use on herbicide-tolerant crops.
- Clethodim – Used to control grass weeds in broadleaf crops like soybeans and vegetables.
- Indaziflam – A pre-emergent herbicide that provides residual control of grass and broadleaf weeds.
Using multiple modes of action helps prevent herbicide resistance.
Mechanical and cultural weed control
Farmers are also turning to non-chemical weed management approaches as glyphosate alternatives:
- Tillage – Turning over and stirring the soil buries weeds and prepares a clean seedbed.
- Mowing and trimming – Regular mowing keeps weeds from going to seed.
- Hand weeding – Manual removal of weeds is still commonly used, especially for large weeds.
- Mulching – Blocks light to prevent weed seed germination and growth.
- Cover crops – Cover crops like rye and buckwheat suppress weeds by competing for resources.
- Crop rotation – Rotating between crops prevents any one weed species from dominating.
- Competitive planting – Early and dense stands of crops shade out competing weeds.
Integrating multiple non-chemical techniques improves overall weed control and reduces reliance on herbicides.
What are the most promising glyphosate replacements?
The alternative weed management options with the most potential to sustainably replace glyphosate include:
1. Integrated weed management
Employing diverse chemical and non-chemical tools tailored to site-specific conditions prevents weed resistance and reduces herbicide volumes needed.
2. Cover cropping
Planting cereal rye, buckwheat, clover, and other cover crops provides a living mulch that smothers weeds throughout the off-season.
3. Smart herbicide application
Spot spraying individual weed patches or banded applications over crop rows enhance precision while decreasing overall herbicide use.
4. Crop rotation
Rotating between cash crops, cover crops, and green manures interrupts weed cycles and improves soil health.
5. Organic herbicides
Vinegar, citric acid, and clove oil provide organic farmers effective options without synthetic chemicals.
How do the costs of glyphosate alternatives compare?
Switching from glyphosate to other weed control methods initially causes costs to rise due to new equipment purchases and learning new techniques. But over the long-term, farmers can save money by reducing herbicide expenditures and building soil health.
Herbicide costs
| Herbicide | Typical cost per acre |
|---|---|
| Glyphosate | $3 – $15 |
| Organic herbicides | $15 – $35 |
| Synthetic herbicides | $7 – $30 |
Organic herbicides are more expensive per acre than glyphosate. But when used strategically in a diversified weed control program, overall herbicide costs can be reduced. The expense of synthetic alternatives can also be minimized by not relying on them exclusively.
Mechanical weed control costs
| Practice | Equipment cost | Labor hours per acre |
|---|---|---|
| Tillage | $50,000 – $500,000 | 1 – 3 |
| Mowing | $15,000 – $150,000 | 1 – 2 |
| Hand weeding | $500 – $2,000 | 20 – 60 |
Investing in equipment like tractors and mowers causes upfront costs. But this is balanced by reducing herbicide expenditures over time. More intensive practices like hand weeding require significantly more labor hours.
Cover crop seed costs
| Cover Crop | Seed Cost per Acre |
|---|---|
| Cereal Rye | $20 – $30 |
| Winter Wheat | $30 – $40 |
| Crimson Clover | $35 – $55 |
| Hairy Vetch | $70 – $90 |
Cover crop seed can cost $20 to $90 per acre depending on the species. This is more than offset by enhanced weed suppression and soil improvements that boost crop yields.
What challenges do farmers face in transitioning away from glyphosate?
Switching from heavy reliance on glyphosate to diversified weed management systems creates several challenges for farmers:
Knowledge gap
Most farmers lack experience with techniques other than spraying glyphosate. They need training in integrated weed management.
Increased complexity
Coordinating multiple approaches makes weed control more complicated than applying a single herbicide.
New equipment
Farmers need to invest in new machinery like advanced seed drills, high-residue cultivators, and robotic weeders.
More labor
Alternatives like hand weeding require more worker hours than spraying glyphosate.
Lower yields initially
It can take 3-5 years to optimize non-chemical tactics and rebuild soil, causing lower yields in the short-term.
Herbicide resistance
Overuse of alternatives like dicamba and 2,4-D could eventually select for resistant weeds.
Fewer herbicide options
Restrictions on paraquat, atrazine and other herbicides remove possible glyphosate replacements.
How can farmers successfully transition away from glyphosate?
Farmers can overcome challenges and successfully move away from glyphosate dependence by:
1. Starting the transition gradually
Phase out glyphosate use over 3-5 years to incrementally adopt new techniques and spread out equipment purchases.
2. Adding diversity through crop rotation
Rotating wheat-corn-soybean-cover crop interrupts weed lifecycles and improves soil.
3. Seeking expert guidance
Agronomists at university extensions and private crop consultants provide science-backed recommendations.
4. Building soil organic matter and fertility
Boosting soil health enables crops to better outcompete weeds and withstand stresses.
5. Banding and spot spraying herbicides
Strategic herbicide application minimizes usage while still controlling the worst weeds.
6. Investing in mulchers, cultivators and training
New equipment and worker education maximize the benefits of mechanical tactics.
7. Leveraging digital tools
Apps, drone imagery, and satellite data facilitate precise management.
8. Sharing experiences with other farmers
Peer knowledge exchange provides insights to smooth the transition.
Conclusion
Eliminating reliance on glyphosate is an evolving process for farmers. The most sustainable and economical approach integrates multiple alternative weed management methods. While the transition requires new expertise and upfront investment, reducing dependence on herbicides benefits the environment and society. Adopting integrated weed management powered by both novel techniques and time-tested cultivation practices helps ensure the continued productivity and resilience of agricultural systems.
