Five tons of stalk and cob residue recaptured biologically after a 250-bu. corn harvest contain roughly 112 lbs. of N, 40 lbs. of P2O5 and 275 pounds of K2O. Growers who’ve learned how to unleash biological life in their soils can earn even greater values with water absorption and storage capacity, crop health and resilience against weather stress.
September 5, 2018 by Jerry Carlson — Stalks, leaves and cobs in a 150- to 200-bu. corn crop contain more than 1,500 lbs. of carbon, the essential ingredient of humus. On top of that, there’s almost equal biomass stored in corn roots.
Some Midwest farmers have been able to capture enough crop residue to raise their stored organic matter, primarily as active humus. A 1% increase in soil organic matter adds this many pounds per acre of nutrients: Nitrogen, 2,000 pounds. Phosphorus: 650 pounds. Potassium: 115 pounds. Another biggie is calcium: 700 pounds.
You can accelerate stalk recycling by fall-spraying stalks with bugs in a jug, but these are not the only tools available.
The granddaddy stalk digestion product we’ve used for years is Residuce. It was formulated in the 1980s by AgriEnergy Resources, and improved since. New bacterial and fungal combinations are brewing in several companies as they try to join the biological revolution.
Another promising new mix designed for fall application comes from Biodyne USA, called Environoc 501. A slightly different version is Environoc 801, which is a stalk residue digester designed for tank-mixing and broadcast spraying with liquid nitrogen, either in the fall or spring.
However, the most effective harvest of sunshine and nutrient recapture requires a synergistic combination of management tools:
1. The least practical tillage, to preserve underground fungal networks.
2. Cover crops to capture more days of sunshine energy, converting carbon dioxide to soil humus.
3. Added calcium and sulfur as gypsum, and soft rock phosphate, to accelerate beneficial soil organisms.
4. Manure and other carbon sources, such as humates. Let’s pause here for an example. A few days ago, our grandson Blake and I met a crop and livestock nutrition consultant, Brad Forkner, following the Farm Progress Show near Boone, Iowa. Brad focuses on the power of soil biological life. He owns the consulting firm Nutrient Management Specialists based in Cherry, Illinois.
Brad handed us a thumb drive with hundreds of scientific papers and presentations from many researchers, all of which anchor his consulting advice. (We are pursuing his insight on a particular kind of compost tea, which farmers can ferment fresh on their own farms and apply when the zillions of organisms per milliliter are fresh and hungry. More on this in future reports.)
In one of Brad’s PowerPoint presentations on that thumb drive, I found the photo below, taken by Brad on a client’s farm in Missouri:
That photo prompted a followup call to Brad: What happened here? Was this some radical new bio-brew the corn grower sprayed after harvest? He explained that the virtual meltdown in stalks on the dark side occurred in just 10 days of warm, damp weather after the corn combine hit those stalks on the left. Rains stalled further harvest for about ten days. Then the fresh, light-colored stalks on the right — under the same treatment as the left half — had been harvested just hours before this photo was taken.
Now the rest of this specific story: In the spring ahead of corn planting, the Missouri grower had spread 7 tons of chicken litter per acre on the entire field. Very likely it was at least partially composted, and probably came from a broiler house. Also, the grower had spread on the surface (without incorporating) 400 lbs. per acre of dry humic granules which Brad Forkner imports from Canada. Brad refers to the humic granules as “chips.” They are about the size of a BB. They quickly disperse when wet.
“That huge bloom of biological life was ignited by the chicken litter and fed by the fulvic and humic acids,” Brad told us. “It multiplied in the soil all summer and early fall. When the combine snapping rolls cracked those cornstalks, it opened up the sugars and other juices to the soil-borne organisms. Biological growth exploded during those warm, damp days.”
He has found that when the soil’s microbiome is optimum, you only need to add 0.37 lbs. of nitrogen per bushel of corn yield in corn following a soybean crop. That’s 200 bu. of corn on about 75 lbs. of applied nitrogen — spoon-fed as the crops needs it, not the fall before planting or all at once in early spring.
Remember that this rapid explosion of organisms occurred in Missouri. At our northern Iowa latitudes, farmers are challenged to get the corn out and apply residue digesters applied in time for fungi and bacteria to munch stalks on days above 50 degrees. Near Guthrie Center, Iowa (about the latitude of Des Moines), Dave Schwartz sprayed Environoc 401 and hit stalks with a flail shredder. By February, stalks were so fragile he could have planted without a no-till planter or trash whippers. Jim Mitchell of Eaton, Ohio solves that problem by lining up part-time help to run the sprayer virtually behind the combine.
In the past few years, “Soil Health” has emerged as a leading subject at Extension Service and agribusiness meetings with farmers. Not many years ago, scientists presumed that organic matter had no effect on the soil’s moisture-holding capacity. But in 1994, the Journal of Soil and Water Conservation by Berman Hudson confirmed: “In all soil texture groups, as organic matter content increased from 0.5% to 3%, available water capacity of the soil more than doubled.”
A common rule of thumb is that for every percentage increase in organic matter, the soil profile can sponge up and hold another four inches of rainfall until crop roots need it.
Brad sent the nearby table showing nutrients contained in a 250-bu. corn crop.
He adds these observations from his study and consulting experience:
“A good residue management system exposes plant disease organisms to winter conditions instead of allowing them to harbor with intact residue.
“If stalks aren’t mostly decomposed in the fall, microbial activity in the growing season will compete for nitrogen with the crop.
“Humates applied with a residue decomposition mix will feed the microbes. The humic and fulvic acids also pull heavy metals off the clay colloids, forming new stabilized compounds which move down through the soil profile. This frees up micronutrients and other nutrients that would normally be tied up in the clay.
“Humates can be applied in economical increments, and they persist in the soil. They’re a soil ‘savings account’ that grows.”
Nutrient Management Specialists also offers microbial/fungal residue digestion products.
Farmers who’ve spent years with cover crops and minimum tillage are in effect amplifying the number and diversity of residue-digesting microbes — in numbers far more vast than a quart or two of packaged organisms provide. One of our Indiana farmers who brews his own microbial tea considers a diverse mix of fall-planted covers as his “third crop.” He reports that he sees his stalk fields melting away much more rapidly than they did years ago — in spite of the high-lignin stalk composition of traited hybrids.
And now for a gentle closing reminder: Renewable Farming LLC can provide you with either Residuce from AgriEnergy Resources, or the Biodyne USA fall-applied digesters, Environoc 501 or 801. We’d be very interested to see one of our clients test them side by side, and also see if a 50-50 blend has a synergistic effect when applied together. Phone or e-mail us.
The nearby closeup photo showing the end view of stalks indicates again that biological activity can take off quickly under the right conditions. These stalks are in north central Iowa. We received the photos last October, and filed a report you can re-visit here.
It’s a dramatic example of the robust microbes that come in Environoc 501.
Our final photo shows a soybean field where an AgriEnergy Resources client applied Residuce in early fall before planting these beans the following spring. This is the classic photo which appears in AgriEnergy seminar presentations. It understates the speed with which Residuce digests the tough cornstalk tissue in the fall if the microbes get two or three weeks of daytime high temperatures in the 50s. The stalks become fragile, although they still look intact. By the following May, most have disappeared and they aren’t competing with crops for nitrogen and other nutrients.
Update Sept. 7: AgriEnergy sent an email to its clients and friends on this subject. We’ll post it here, unabridged:
Good residue management is an effective way to improve soil biology, by increasing the total numbers and diversity of beneficial soil organisms necessary for building organic matter and growing vigorous crops.
And speaking of numbers, let’s take a look at residue management by the numbers…
- 4 tons of residue per acre are left behind a modest 180-bushel corn crop
- 2.1 tons pounds of corn roots are left in each acre, too
- 80-30-190 – That’s the N-P-K contained in those 4 tons of residue
- 16 pounds of Sulfur, 35 pounds of Calcium, and 25 pounds of Magnesium are in those 4 tons, too
- 115 pounds of purchased nitrogen per acre – That’s the amount we SAVED per year, by farming biologically and managing residues wisely
- 3.9% organic matter – the soil on an Illinois farm where AgriEnergy Resources’ residue management plan had been followed for 25 years
- 2.9% organic matter – the soil just across the fence line from the AgriEnergy farm
- 1% organic matter – the biological farming difference! Wise residue management is the cornerstone of biological farming
1% organic matter allows the soil to store another 10,000 gallons of water/acre and contains 1,000# nitrogen/acre, 650# phosphate/acre, 115#potash/acre, and 700# calcium/acre.
While that 1% organic matter is huge, there are other benefits of a wise residue management program as well. Such as having less residue to till and plant into for the following crop. This means that less tillage is necessary to prepare a seedbed. In many cases it has meant that farmers can use a field cultivator rather than a disc. Having less residue to contend with means better spacing and placement of the seed and better seed-to-soil contact, both of which promote a more uniform stand. Less residue also allows the soil to warm up faster which means quicker emergence.
Another benefit of residue management is improved soil tilth. One of the byproducts of microbial respiration is the production of polysaccharides, a biological glue that forms and holds water stable soil aggregates together. The result is a “coffee grounds” soil tilth that allows better water and air infiltration. This improved soil tilth creates a superior seedbed. The improved tilth also means there is better gas exchange in the soil, allowing oxygen to go into the soil and carbon dioxide, methane and other gases to exit the soil.
AgriEnergy believes an important step in a good residue management program is using Residuce® – a package of live microbes known to break down crop residues. They are:
- *Residuce® Complete
- *Residuce® WS
- *Residuce® O
- Residuce® XT
- Residuce® CS
Products with an * are formulated for organic agriculture, however it is up to each certified organic grower to get approval from his/her certifying agency before using this product.