Waves of late rains offer opportunities for faster biological breakdown of stalks

Several new stalk residue digester products are emerging in the marketplace. Your decision may well be not deciding whether to speed residue breakdown, but "which one is best?"  Farmers' demand is demonstrating their effectiveness. Although a strong cover-crop program also enhances your microbial diversity, the tonnage of cornstalks still presents a challenge.

September 27, 2018 — Many fields in the upper Midwest have abundant soil moisture this fall. That's a key ingredient to give munching microbes an early feast on heavy cornstalk residue, and set up your fields for easier planting next spring.

None of the long-established or new microbial residue breakdown products are promoted with a promise of immediate yield response. But this fall we measured a 2.63 bu. gain for soybeans fall-treated with Environoc 501, versus the untreated control. This was an average of only four random replications. Due to wide variability in test strip yields, the least significant difference in yield at the 95% confidence level was 3.84 bushels. (Even so, seed corn companies say that a 2-bu. average yield gain over their competitors indicates worthwhile value.)

All test plots in this trial were on ground where the 2018 cornstalks were flattened and crimped with a Yetter Devastator, a roller attachment which runs beneath the corn head. It cracks open stalks, allowing microbes early entry to the juices inside. Our recommendation: follow that crunching with an inoculation of a bacterial/fungal spray as soon as possible behind the combine. The granddaddy of these little livestock is Residuce, made by AgriEnergy Resources of Princeton, Illinois. Residuce has built a long list of loyal users over the years. Its success has attracted competitors, which is a real benefit for farmers.

Here are some of the advantages of a fall microbial booster for chewing through stalk residue:

1. Speeds conversion of stalk lignin and cellulose into active humus. This reduces spring and summer competition for nitrogen. When crops are growing, you don't want nitrogen diverted to decompose stalks; you want the growing crop to have all the nitrogen it needs.

2. Makes stalks more soft and fragile before planting. This helps your planter slice through heavy residue. Even if stalks haven't disappeared by the next May, they're usually more crumbly when the planter coulter hits. A few farmers find they don't need Trash Whippers to sweep aside residue — or even a no-till planter. A regular planter is adequate, with no hairpinning of tough stalks.

3. Helps achieve more uniform planting depth, without clumps of trash bouncing the planter unit. As you know, uniform depth is crucial to uniform emergence — which is crucial for uniformly high yields. Studies show that a corn plant emerging with a two or three-day delay has the equivalent of a 20- to 40-bu. yield penalty. That is, if all plants had that disadvantage, these runts would yield 40 bu. less than those which emerged on the same day.

Continuous-corn fields treated with Environoc 501 on the Dave Schwartz farm just west of Guthrie Center, IA digested their residue so quickly last fall that Dave reports most of the stalks had disintegrated by February. He does what we've long encouraged: Shred the stalks with a stalk shredder which carries a boom sprayer to apply the digester biologicals, plus a little nitrogen and perhaps some sugar or molasses to give the microbes an energizing breakfast.

The photo below is an example of a 2018 soybean field where (1) fall 2017 stalks were crunched with the Devastator, then (2) sprayed with 501 last fall, with (3) a followup of a second Biodyne USA product, Environoc 401, in-furrow on the soybeans this spring. Most of the heavy stalk residue has melted away.

For comparison, the photo below shows a section of the same field which was crimped with the Devastator last fall, but no biological accelerator was applied.  Stalks are gray and under fungal/bacteria attack, but still largely present.

We offer both Residuce from AgriEnergy Resources — a firm we've worked with 30 years — as well as the newcomer, Environoc 501, which also has excellent credentials. We're also on the trail of another newcomer to the stalkbusting market, which apparently is a blend which you can brew yourself. Sounds interesting. Call us for details.

Update Sept. 28: Biodyne USA will market a biostimulant for spring broadcast application.  Its name will be BD-Biocast since it is a broadcast application. Biodyne USA president Gil Farley e-mailed us with this note: "BD-Biocast  is a broadcast application for guys on beans who do not have in-furrow capability. Great results so far this year."

One advantage of BD-Biocast is that farmers can tank-mix it with early broadcast sprays of preplant herbicides or liquid fertilizers.

Renewable Farming can obtain BD-Biocast for you next spring.  

We continue to see positive response with in-furrow biologicals, which concentrate the beneficial critters right next to emerging roots.

Another management tool we encourage for heavy residue breakdown is a consistent cover-crop program, using several species of plants in your mix. Each species multiplies at least ten of its own favored microbes, says microbiologist Dr. Bob Kremer, ARS/USDA researcher at the University of Missouri. And diversity underground enhances the overall residue breakdown process.