Extension Communications
3614 Administrative Services Building
Ames, Iowa 50011-3614
(515) 294-9915
4/10/00
Contacts:
Mark Hanna, Extension Agricultural and Biosystems
Engineering, (515) 294-0468, hmhanna@iastate.edu
Elaine Edwards, Extension Communication Systems, (515)
294-5168, eedwards@iastate.edu
Limit Spring Tillage for Farm Fuel Savings
AMES, Iowa -- Increases in diesel fuel prices along with conserving soil moisture has some farmers thinking about limiting spring tillage operations.
"Total diesel use for all field operations, including tillage, planting and harvest, is typically four to six gallons per acre. Eliminating a deep, primary tillage operation can save one gallon per acre, and eliminating a secondary tillage operation can save one-half gallon per acre or more," said Mark Hanna, Iowa State University Extension agricultural and biosystems engineer. "Fuel savings are in addition to savings on wear and tear on machinery and labor requirements."
When tractors are used, Hanna advised paying attention to several key points to minimize fuel consumption. Tractor engines and transmissions should be well maintained. Make sure inflation pressure in rear and front tires is correct for tractor axle loads. For mechanical front-wheel assist tractors, closely match front tire size with rear tire size as detailed in the operation manual. Although well-maintained diesel engines are efficient, if possible match tractor horsepower to the required load or task. If a large tractor must be used for a smaller drawbar load, shift the transmission up to a higher gear and reduce engine speed by throttling back.
The tractor must be properly ballasted to be most energy efficient when pulling heavy drawbar loads. A properly ballasted tractor under drawbar load will generally have 5 to 10 percent wheel slip on firm surfaces or soil and about 10 to 15 percent slip on looser tilled soil. Slip is often not visually noticed until in excess of 20 percent. Proper ballasting should be according to manufacturer's recommendations in the operator's manual or from the dealer. Two-wheel drive tractors may have a total tractor weight of 115 to 135 lb. per PTO horsepower and four-wheel drive tractors about 90 to 105 lb. per PTO horsepower. Static weight splits between rear and front axles, respectively, will be approximately 75 percent/25 percent for a two-wheel drive tractor, 60 percent/40 percent for a mechanical front wheel assist tractor and 45 percent/55 percent for a true four-wheel drive tractor.
In addition to field operations with the tractor, trucks should be well maintained (engine, tires, transmission). Some trips may be able to be combined or eliminated with advance planning, Hanna said.
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