Extension Communications
3614 Administrative Services Building
Ames, Iowa 50011-3614
(515) 294-9915
11/12/99
Contacts:
Mark Hanna, ISU Extension Agricultural and Biosystems
Engineer, (515) 294-0468, hmhanna@iastate.edu
Elaine Edwards, Extension Communication Systems, (515)
294-5168, eedwards@iastate.edu
Fall Tillage Options
AMES, Iowa -- Open weather has many Iowa crop producers tilling soil and others considering fall tillage. Producers should carefully consider options before heading to the field with tillage equipment, according to Mark Hanna, Iowa State University Extension agricultural and biosystems engineer.
In field areas where a documented compaction problem exists, dry soil conditions allow tillage equipment to more effectively fracture and loosen the soil.
"Costs of subsoiling for fuel, equipment depreciation and maintenance, and labor range from $5 to $10 per acre so producers should make sure there's a reason for the operation," Hanna said.
When loosening a compacted layer, tillage should be no deeper than required to avoid unnecessary fuel use and wear on equipment. "Soil that has been opened up by deep tillage allows rainfall to infiltrate the soil more quickly," he said. "However, if significant rainfall does not occur, soil that has been opened up will become drier. Most tillage operations reduce residue cover, allowing the potential for greater erosion by water or wind."
Crop producers should not confuse difficult pulling of tillage implements in dry soil conditions with compacted soil. Because of limited moisture, soil in many fields has become much stronger and requires more tractor drawbar horsepower even though it may not be denser or compacted. In fact, cracks in many fields due to drying soil have loosened soil by natural processes.
"To detect compaction, producers should look for evidence of reduced crop rooting, slow water infiltration and soil that is more difficult to penetrate than in nearby uncompacted areas," he said. Plants may have appeared shorter during the growing season in compacted areas.
"Field areas with heavily traffic during wet soil conditions are the most likely places to find compaction," Hanna said. "Traffic on dry soils such as occurred this fall causes little compaction. Producers may want to consider tilling only those portions of the field that will benefit from soil loosening."
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