Alternatives to chemical herbicides
Here at PlantCatalyst® we’re passionate about agriculture and we love to read articles about a variety of agricultural practices, issues and trends. To that end we’ve begun asking writers to submit blogs that our followers might find interesting. This third blog in our series continues on last week’s blog about the phenomenon known as “dicamba drift” which has become a recent problem for famers here in South Dakota. Once again, we hired South Dakota based writer Samantha Petit to help us write something about it. The following was written by Samantha and our CEO John Willard III. We hope you enjoy it!
Last week our PlantCatalyst® blog focused on some of the problems associated with using chemical herbicides, especially when GMO crops are involved. While we don’t claim to have all of the answers we do hope that growers will start to consider alternatives to chemical herbicides. This is especially important when one realizes that Mother Nature is having her say and an increasing number of new weed strains are developing natural resistance to chemical herbicides. Without further adieu, here’s a good list of some alternatives to controlling weeds without chemicals. Enjoy!
The use of herbicides comes down to convenience. There are a number of techniques, that when used together, can control weeds. Many of these techniques also improve the quality of the soil and can potentially increase yields, without the harmful environmental effects associated with herbicides. Even large scale farms can incorporate techniques to control weeds without the use of chemical herbicides.
Alternative techniques include a combination of preventative and physical means. While I could write for days on these topics, I will briefly touch on three of the most common techniques used in herbicide-free weed control.
By looking into the ecology of weeds, farmers can gain a sense of what crop sequences are going to have the biggest impact on minimizing weeds. The following techniques have been documented with success by many farmers:
- Include fallow periods into the rotation to deplete perennial root systems and to destroy annual weeds.
- Follow crops that are prone to weeds with crops that easily prevent the weeds from going to seed.
- Cultivate crops that allow weed seed production to be prevented before crops that poorly compete with weeds.
- Rotate crops that are cultivated during different growing seasons.
- Rotate between perennial and annual crops.
- Work cover crops into rotation between cash crops instead of leaving soils bare.
- Avoid using cover crops that tend to promote weed production in your specific area.
While cover crops are excellent at suppressing weeds they must be manage properly to be effective. To successfully implement cover crops and maximize weed control farmers should choose cover crops based on your climate and seasons, source high quality seed, and optimize planting depths, seeding rates, and sowing techniques. Basically you should treat the cover crop as if it were a cash crop.
Cover crops help suppress weeds in a number of ways including creating competition, preventing germination of weed seeds, altering the microbial communities in the soil that puts weed species at a disadvantage, and through the release of plant growth-inhibiting substances.
Cover crops increase soil quality by adding organic matter when mowed, tilled, or rolled into the soil. The residual plant matter can act like mulch hindering the germination of weed seeds, releasing growth-inhibitors during decomposition, and promoting the growth of fungi that inhibit the growth of weeds.
Intensive Grazing Systems
Intensive grazing systems are a great addition to any weed management program. Increasing stocking rates of sheep, cattle, goats, and/or chickens and adjusting grazing times, reduces selective grazing and can help control weeds. For example by introducing sheep into a cattle system or goats into a sheep system, farmers and ranchers can control many types of weeds.
Many people don’t realize it but chickens are excellent at weed control, especially when rotated behind or with other livestock. Animals can also be used to graze cover crops before they are incorporated into the soil.