ASK Jeff: The Rodale Institute’s farm manager, Jeff Moyer, answers your hardcore farming questions

How can I manage weeds in a no-till system without herbicides?

Posted January 12, 2007

What Jeff brings to the table

Jeff Moyer, who’s been the farm manager here at the 333-acre Rodale Institute research farm for more than a quarter of a century, receives lots of mail from farmers just like you asking for advice. Jeff’s hands-in-the-dirt experience over the past 26 years has run the gamut from refining the farm's cover cropping and crop rotation systems (including managing 270 acres in a rotation of corn, small grains, hay, and edible soy beans for a Japanese market) to overseeing The Rodale Institue Farming Systems Trial®, the world’s longest running side-by-side comparison of organic and conventional agriculture. We thought it would be fun and informative to share some of these farmer-to-farmer exchanges, and Jeff’s practical wisdom, with our NewFarm.org readers … and we’ll be doing it on a regular basis.

Got a question of your own? Click here to send it to Jeff.

Dear Jeff,

How can I manage weeds in a no-till farming system without herbicides?

Carlos Brigard
Colombia


Dear Carlos,

Thanks for the question on weeds in no-till and for reading New Farm. The question you ask is really the most important one of all and gets to the heart of why we till the soil in the first place. We till the soil for two main reasons: first, to get good seed-to-soil contact; second, to help us manage competition from weeds.

As conventional ag has moved in the direction of reduced tillage, it has increased its reliance on herbicides to help manage weed pressure. As organic farmers consider reducing or eliminating tillage from their system, they need to think about increasing their use and management of cover crops. These cover crops will really be the key to the success or failure of the no-till system.

In order to be successful, you'll need to select cover crops that match up in timing with your cash crops. An example of this would be using a legume like hairy vetch as a cover crop to plant corn into. As the vetch matures and flowers in late spring, it can be killed mechanically with a tool like the one we designed here at The Rodale Institute, and the corn can be planted directly into the rolled mat of vetch. In this example the vetch needs to be planted the fall before the corn, it needs to be a thick stand, and it needs to be established with the same care you would expect to give any cash crop. This cover crop will then supply all the nitrogen for the corn and suppress the weeds through a smothering and mulching effect.

Weeds are very opportunistic. They will not grow when a dense stand of an established crop is in place. They are also generally small-seeded, need access to light to stimulate their germination and will have trouble breaking through the thick mat of the rolled cover crop. Keep in mind that any place in the field where bare soil is exposed, weeds will germinate and break through the protective layer of mulch.

You can read much more about this on our No-Till Plus page or in our no-till forum section. Also checkout the FAQ section to get more insight into how this system works.

Jeff