Baled cornstalks are being actively sought in many parts of the state for livestock feed. But what's it worth?
There are labor and costs associated with baling cornstalks and there are the hidden costs.
Is the price of the cornstalks or other crop residues enough to offset the lost nutrients that the decaying stalks would have added to the soil? And what about the conservation benefits the crop residue would contribute? Will it increase soil loss and erosion?
According a recent Natural Resources Conservation Service worksheet, custom baling costs about $11.50 per large round bale. If you harvest several bales from an acre, harvesting costs may add up to $60-$70 per acre. If a bale weighs about 1,200 pounds, that's about $20 per ton.
According to Charles Wortmann, University of Nebraska nutrient management specialist, every 40 bushels of corn or grain sorghum produced leaves about one ton of crop residue behind. A ton of cornstalks contains about 17 pounds of nitrogen, 4 pounds of phosphorus, 50 pounds of potash, and 3 pounds of sulfur, he says. Adjusted to last spring's fertilizer prices, that's about $26 in nutrients per ton of stalks.
If you harvest five or six round bales per acre, that's between $75 and $100 per acre in nutrients leaving the field with the stalks.
The University of Nebraska has a new NebGuide for calculating the value of cornstalks. It includes formulas so that in today's volatile marketplace, you can plug in your own values for the various nutrients, Wortmann says. It can be accessed online at: www.ianrpubs.unl.edu/sentIt/g1846.pdf.
Crop residue also helps reduce soil erosion. The NRCS says producers who want to harvest stalks from highly erodible land, or HEL, need to check with their local NRCS office to see if stalk removal is workable under their conservation plan.
Cornstalks and other crop residue also contribute to soil organic matter, says Charles Shapiro, UNL extension soils scientist. Soil organic matter has an impact on nutrient availability, nutrient- and water-holding capacity, infiltration, and drainage. It also provides carbon and energy for soil microorganisms.
Soil residue reduces soil-moving by raindrops and improves infiltration. It also keeps the soil cooler and reduces evaporation and it traps snow on the field.
A recent Kansas recent study of crop residue cover indicates that good cover can save about 3.5 inches of soil water. In a dryland situation, each inch of soil water can produce 12 bushels more corn. In an irrigated field, the savings can reduce irrigation costs, too.