Which part of your operation uses the most energy?

Many growers would say tillage trips are their farm's energy hog. Conventional tillage requires about 4.5 gal./acre more than no-till or strip-till, but surprisingly it's not the largest energy user.

Crop drying is actually the energy villain in Corn Belt operations, according to a study of 50 Iowa growers.

So says Shannon Gomes, who co-created a farm energy audit spreadsheet. He is owner of Cedar Basin Crop Consulting, Waverly, IA, and co-owner of MGT Envirotech, a consortium examining on-farm efficiencies and sustainability. Gomes is secretary of the National Alliance of Independent Crop Consultants (NAICC) and past president of the Iowa NAICC.

To simplify decisions, the energy audit translates all farm energy use to gallons of diesel fuel equivalent (GDFE).

“The surprising thing was that the two biggest energy consumers are drying costs and nitrogen (N) fertilizer for corn,” Gomes says. “They represent 10 times the potential energy savings of tillage. This was a real eye-opener.

“My advice to farmers after analyzing this data is to select hybrids with maximum drydown at harvest. If you can save two percentage points (moisture) on 200-bu. corn, that's worth about $16-20/acre savings just from better genetics of drydown,” he says.

“If you split your N application between fall and preplant, you can save the equivalent of roughly 5-10 GDFE/acre in fuel,” Gomes says.

Changing tillage equipment is more expensive, making less dramatic savings. “Farmers can save maybe a few gallons per acre switching to no-till versus 10-20 GDFE/acre with hybrid selection and N management,” Gomes says.

He believes that, long term, growers would be wise to think beyond energy costs to energy availability.

The 50-farm audit's development was funded by the Iowa Natural Resources Conservation Service and Cedar Valley and Prairie Partners RC&D through a partnership with MGT Envirotech. The audit's implementation was supported by the Iowa Soybean Association's Certified Environmental Management Systems for Agriculture (CEMSA) program, with funding from the Iowa soybean checkoff.

A final analysis of the on-farm results will be available in March at www.iasoybeans.com.

The energy audit spreadsheet was shared with crop consultants nationwide at the NAICC annual meeting in January for potential use on all crops and geographies.

ON-FARM ENERGY EVALUATION

“I need to plant more soybeans,” says Waverly, IA, grower Mark Mueller (left) after reviewing his farm's energy assessment. “Corn uses a lot of energy. I had been leaning that way anyway, this just quantifies it.” His 2008 rotation of half beans, half corn will be an adjustment from last year's rotation of ¾ corn. “It's been at least a decade since we were at half beans, half corn,” says Mueller, who is active with the Iowa Corn Growers Association. “We like growing corn, but I just priced anhydrous ammonia, and bean prices have come up since last year.” His crop consultant and energy audit inventor Shannon Gomes found that Mueller's energy use is lower than most other farms studied due to lower-moisture hybrid selection. The 50-farm average for continuous corn using conventional tillage was 54 GDFE.

adds, “This exercise illustrates the rapid increases in input costs for nitrogen, phosphorus and potassium. It underscores the true value of manure.”

MANURE SAVES 77%

Reuben Skow's hog manure saves him approximately 77% of his energy costs involved in using nitrogen (N) on corn, according to the energy audit. “I've been able to get enough from my custom feeding operation to supply all of my N, phosphorus and potassium for the last 10-12 years, and stay within DNR environmental guidelines,” says the Wesley, IA, grower. That amounts to about $85.90/acre in direct and indirect energy costs, according to his energy audit results.

“These numbers refer to the energy use involved with fertilizing our corn crop,” says Michael McNeill, Skow's crop advisor. “I've calculated how much energy it takes to manufacture N from natural gas, transport it to the farm and apply it to the land. On the manure side, I took the amount of energy it took to agitate the manure, pump it from the barn and transport it and apply it to the land. It's a brand new type of calculation.”

Skow has used N tests and weigh-wagon tests for the last four years to quantify the value of his manure. His corn yields the past four years have topped 200 bu.

He also selects corn hybrids for both yield and fast drydown, allowing him to skip propane drying for the past three or four years. “I realize I took a slight discount for the 17% moisture, but my yield covered that cost,” he says.

Even before his energy audit, Skow cut back his spring and fall tillage trips to one each. “In the fall I just deep-till my corn stalks with one pass, without chopping stalks or disking ahead of that. In the spring, it's one pass with a field cultivator, and I use a trash whipper on the planter to move the trash out of the seedbed,” he says.

Skow estimates that neighboring farmers have cut about 25% of their fuel use over the past 10 years, judging from his perspective as director of his local fuel co-op. “The problem is, though, the total energy bill has doubled, or worse,” he says.