The full-season irrigated portion of the Corn Illustrated plots near Edinburgh, Ind., averaged 229 bushels per acre. Without irrigation, the yield was 88 bushels per acre. That's a whopping 141 bushel difference just for irrigation.
How does Jim Facemire, host farmer for the plots, know it was solely related to irrigation? Because the same rows ran all the way across the field, with one side irrigated, the mid-section irrigated starting two weeks after pollination, and the other end not irrigated at all! The mid-season irrigation section yield was almost directly in the middle between the other two, at 161 bushels per acre.
Facemire estimates it takes an investment of about $500 per acre to set up a center-pivot that's designated as a 160-acre pivot. He also estimates that his variable fuel costs for running the engines that powered his pump and irrigation rig amounted to just over $66 per acre this year for acres receiving irrigation all year long. He applied 11-acre inches in nine separate events on the full-season plots. He made the applications based upon the recommendation of a computerized irrigation scheduling program adapted for use in Indiana and Michigan.
"Jim could have paid for irrigation for every acre of his farm and covered variable operating costs at the same time, all in '07," says Dave Nanda, consultant for the Corn Illustrated project. Nanda is a corn breeder with more than 40 years of experience, developing hybrids for farmers in the Corn Belt. "But who knew it wasn't going to rain?"
Nanda makes his statement based on extra income Facemire could have netted on non-irrigated acres, based on plot results. If he sold corn at $4 per bushel, that amounts to $565 more gross revenue he could have carried off the field. That almost perfectly matches estimated installation and equipment costs, plus fuel costs for irrigating on his farm in '07.
You can't make decisions based upon one extreme year, Nanda realizes. But he notes that Facemire's example does illustrate how critical water is when it comes to going after high corn yields. He contends that it is far and away the most limiting factor in most dryland situations.
"I'm not recommending that everyone run out and invest in irrigation," he says. "But I think it is important to realize what water means to producing top corn yields."
Programs that allow you to calculate potential return for irrigation on average, wet and dry years are available. Gene Matzat, La Porte County, Ind., Extension ag educator, uses one prepared by Michigan Extension district staff when advising farmers on a potential investment in a new irrigation system. You can find it at www.msue.msu.edu/stjoseph. Look for the irrigation link under 'local information,' then scroll down to the Excel spreadsheet calculator near the bottom of the page. You can also find the irrigation scheduling program similar to what Facemire uses at the same location.