Audit identifies grain drying, nitrogen as energy hogs

By Jean Caspers-Simmet

LAPORTE CITY, Iowa — When Shannon Gomes and the three other crop consultants who make up MGT Envirotec decided to work with the Natural Resources Conservation Service to develop an energy audit spread sheet, they thought it would show farmers how they could save diesel fuel by switching to no-till.

What they found as they developed the cropping system audit was that while there were savings by switching to no-till, the real energy "hogs," were nitrogen fertilizer and corn drying.

"By switching from conventional tillage to no-till you will save at most two gallons of diesel fuel per acre," said Gomes, who owns Cedar Basin Crop Consulting in Waverly. "But to go from harvesting 20 percent moisture corn to 18 percent, the energy savings is 10 to 12 gallons of diesel fuel equivalent per acre."


With the energy audit spread sheet, the developers converted all energy to gallons of diesel fuel equivalent so they would have a common platform.

They found it takes a lot of energy to manufacture anhydrous ammonia.

"For the farmers using manure, that manure is real valuable," Gomes said.

The intent in designing the software was to create a tool for farmers to look at their present situations and at management alternatives.

The spread sheet has drop down menus where farmers select the energy usage for their cropping systems.

Drying 200 bushel corn harvested at 20 percent moisture to 15 percent moisture costs 13 gallons of diesel fuel equivalent. If the corn is harvested at 17 percent moisture, energy use drops to 5 gallons of diesel fuel equivalent.

"Farmers could look at hybrids with better dry-down characteristics as opposed to hybrids harvested wet," Gomes said. "This spreadsheet allows them to quickly go through some ‘what if’ scenarios."

Applying anhydrous ammonia at a rate of 140 pounds of nitrogen per acre uses 22 gallons of diesel fuel equivalent. Reducing that to 100 pounds drops energy consumption to 15.6 gallons.


Funding for development of the energy audit came from the Natural Resources Conservation Service and Cedar Valley and Prairie Partners RC&D through a partnership with MGT Envirotec. The audit’s implementation has been supported by the Iowa Soybean Association’s Certified Environmental Management Systems for Agriculture program, with funding form the Iowa soybean checkoff.

MGT Envirotec wants to look at the energy consumption involved in livestock production. The audit currently assigns zero for the energy involved in producing manure. It does consider the energy required to agitate, pump, transport and apply manure.

"Most farmers who put down manure don’t buy nitrogen, phosphorus or potassium so the energy audit looks really good for them, but it’s not a true picture of the entire energy cost," Gomes said.

"A lot of farmers were shocked by what they learned from the energy audit," said Michael McNeil, owner of Ag Advisory Ltd, in Algona and a co-owner of MGT Envirotec. "They had no idea that planting a later variety of corn or putting on that extra 30 pounds of ntirogen was taking that much energy. Many also didn’t realize how much energy they were saving by using animal manure as a source of fertilizer."

The spread sheet will be available free at NRCS offices and from the Iowa Soybean Association.

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