Renewable Farming

Our favorite way to melt down cornstalks for your “second harvest” of valuable crop nutrients

Rising fertilizer prices make it more profitable to capture all the phosphorus, potassium and organic matter you can from your corn crop. A 200-bu. corn crop totals about 4.5 tons of grain — and leaves about 4.5 tons of valuable stalks, leaves and cobs on the ground. That translates to 20 pounds of phosphorus, 80 pounds of potassium, and a rich array of other crop nutrients plus lignin and cellulose which can digest into moisture-holding humus. An Iowa State University article has details on the nutrients locked in corn stover.

Aug. 27, 2021 By Jerry Carlson   Back in the 1990s, one of the few microbial residue digesting blends was Residuce from AgriEnergy at Princeton, Illinois. In recent years, a widening array of biologically-based firms have developed competing combinations of hungry fungus and beneficial bacteria. They’ve also demonstrated other carbon-capture benefits such as smoother planting through crumbling residue the following spring. With a good job of stalk residue breakdown, many farmers report they can plant at uniform depth with no extra down pressure and no need for trash whippers. Ordinary disk openers slice through fragile stalks without hairpinning or bouncing.

Shredder and fall residue sprayer combo owned by Dave Schwartz
on his no-till farm in the hills west of Des Moines, Iowa

Seasoned veterans of fall stalk residue recapture often hire an extra driver — maybe a retired neighbor — to chase the combine with a residue-treating spray rig. Our favorite combination is a stalk shredder carrying tanks of residue treatment spray. Try to spray residue digester as early as possible after harvest, when daily highs are 50 or above and soil temps are still well above freezing. This gives fungus and bacteria a few days or weeks to multiply in the soft inner core of cornstalks.

Several years ago, we typically shredded test-plot stalks with an old $1,000 Brady shredder. We set the blades almost grazing the soil, and followed the shredder with a $2,000 pull-type field sprayer with a 60-foot boom. We had hardly any equipment investment for residue treatment on our 40-acre research operation.

It’s very difficult to apply a fall residue treatment program if you try to do it all yourself — waiting until the combine is put away. (For one thing, sprayers don’t like freezing nights with spray solution in pumps and hoses.) A spring application will still be helpful, though. It can accelerate residue breakdown before peak crop demand for nitrogen, so the residue is contributing nutrients instead of diverting them into breaking down last year’s stalks.


Biodyne’s Meltdown residue digester

Retail cost of Meltdown this fall is $44 per gallon in 265-gallon totes, and $46 per gallon in 2.5-gal. jugs. Application rate: 32 ounces per acre, for a per-acre product cost of $11. A Meltdown spraying pass is also an opportunity to piggyback an application of nutrients and fall residual herbicide. Meltdown includes the array of microbes in 501, plus 1% nitrogen and several organic acids to accelerate proliferation of residue-munching microbes.

Please visit this Biodyne product page for details on Meltdown residue digester


Biodyne’s 501 residue digester

Biodyne’s original residue digestion blend brought into the Midwest several years ago is labeled 501, intended for fall application. Its formulation of fungal and bacterial organisms has been refined since 1989 by microbiologist Dr. Fred Farley of Sarasota, Florida. Dr. Farley founded Biodyne World, working with a wide range of organisms for many purposes such as remediation of hydrocarbon spills worldwide. Several years ago Dr. Farley arranged with his nephew, Gilman Farley, to launch a Midwest manufacturing and marketing venture based at Ft. Wayne, Indiana. Its website is Biodyne USA, where you can review the company’s expanding product line. 

The Biodyne products which we retail here at Renewable Farming LLC are manufactured only two hours west of us at Fonda, Iowa, so we have ready access to the biologicals for our clients’ needs. (We manufacture WakeUP here in our own production plant on the farm.)

Biodyne’s 501 carries a retail price of $66 per gallon, but its application rate is only 16 ounces per acre. That’s a product cost of $8.25 per acre. 

The Biodyne 501 product page says, “Numerous land grant university studies have indicated that, based on fertilizer costs, the value of locked up nutrition contained within normal crop residue and stubble can range from $50 to $200 per acre.” A good job of mellowing hard lignin and cellulose into crumbling pre-humus can capture half or more of that over winter. Yet, the gradual decomposition of stalks allows a decent thatch on the surface to avoid serious soil erosion from fall and spring rains.

Please visit this Biodyne product page for details on 501 residue digester. 

Please get in touch with us for more details about fall residue recapture, and to place an early order for Meltdown or 501!