Renewable Farming

Inexpensive way to amplify the benefit of biological residue digesters this fall

Converting this fall’s cornstalk carbon to nutrients for next year’s crop becomes more profitable when you use the synergy of crimping and shattering stalks before applying a microbial residue digester. A combine header attachment, the “Devastator” by Yetter Equipment, is accumulating some promising data and farmer reviews.

Oct. 20, 2017 — The Devastator has been on the market a few seasons. Yetter is refining this roller-crimper, which attaches under your combine head, for more aggressive action. The unit we watched in action yesterday at Steve Schmidt’s field near Dunkerton, IA has both crimping blades and round bars to crush and split stalks. Here’s Steve and the Devastator, a six-row unit which cost him about $4,000 after some highly competitive shopping around.


Current version of the Yetter “Devastator.” The vertical blades on the rollers
are a variation from earlier models.

The roller-crimper achieves the tire-saving benefit of a Stalk Stomper unit, plus a more aggressive stalk shattering action that allows faster moisture and microbe penetration into the stalk pith. A corn-on-corn yield study shows increased yields in no-till fields the year following use of this implement, versus no stalk crimping. You can watch a brief 2016 video by Beck’s Hybrids, shot near us at Marion, IA at this YouTube link. Stick with the video to the last couple of minutes where field studies indicate improved yield results. The Beck’s research reporter mentions a “carbon penalty,” probably referring to the fact that undigested carbon in stalks competes for microbial attention and nutrients during a critical early part of the growing season. In our book that’s a penalty for failing to convert stalks with a high carbon:nitrogen ratio as quickly as possible into mellow, crumbling humus and glomalin. This amplifies a full bloom of beneficial microbes to feed your following crop.

A header attachment like the Devastator just might do almost as well as a stalk shredder in cracking cornstalks and opening them up for an application of AgriEnergy’s Residuce or the more recently introduced Environoc 501 from Midwest Biodyne. The photo below shows farmer Steve Schmidt and Renewable Farming’s Blake Carlson checking out stalks flattened and crimped with the Devastator.  We hope to get a field study going this fall with Steve, comparing residue breakdown with and without the Devastator, in combination with microbial stalk digesters. Steve will follow the corn with beans, and perhaps we can even detect a yield difference there in 2018.


Most flattened stalks are also at least crimped and cracked by the Devastator.

We’ve long advocated shredding stalks along with applying a microbial residue digestion spray plus “starter” nutrients as early as possible after harvest. This imposes even more workload at harvest, and hardly anything can drag a farmer out of a combine to do other fall fieldwork before freezing nights arrive. Of course, overnight freezing threatens any spraying operation; nobody wants to risk a sprayer pump broken by a freeze-up.

Residue-treatment advocates who’ve learned the yield benefits — and fertilizer savings — often retain a retired farmer or other friend  each season to chase the combine with the residue digestion sprayer. It doesn’t take a $200,000 GPS, high-clearance, self-compelled sprayer for this job. A utility tractor and a used pull-type sprayer with a Raven controller can keep up with a combine easily. A good sprayer with a 750-gallon tank, dual wheels and 60-foot boom can be found for around $2,500. The residue mix is simple and safe to handle. Drift concerns are minimal. 

Here’s a link to an earlier Renewable Farming article explaining how cash-crop farmer Jim Mitchell gets the residue treatment done on time without constraining the combine.