Expect More Normal Yields from Irrigated Corn Plot

Irrigated soybeans demonstrate power of water.

Published on: Oct 8, 2007

Does irrigation pay if you have droughty soils? In case you needed proof, this year’s Corn Illustrated Plot project will undoubtedly provide it. This may be the extreme year on the dry side, but it will certainly underscore the value of irrigation.

Dryland plots have already been harvested, including a nitrogen rate field-size study and small plot, hand-planted plots testing various comparisons in production techniques. Results aren’t finalized, but yields topped around 90 bushels per acre. However, the irrigated plot on a different farm with similar soils has yet to be harvested. Harvest is estimated to occur within the next couple of weeks. The crop is drying down normally, and even though it’s planted at 32,000 and 40,000 seeds per acre, lodging isn’t a big concern so far, notes Jim Facemire, farmer- cooperator on the plot, located near Edinburgh in south-central Indiana.

Soybean harvest on the farm of both irrigated and non-irrigated fields this past week give some indication of the power of water. A full-season field of soybeans next to the corn nitrogen trial field, on the same soil type, yielded 14 bushels per acre, the worst Facemire has ever harvested in 35 years of farming these types of soils. He believes soybean yields were smacked harder than corn because only 0.4 of rain fell from August 1 through Sept. 10. All the while, temperatures climbed near or above 90 several days in a row.

Now Facemire reports that dry corners of the irrigated field where the high-yield Corn Illustrated corn plot is located also kicked out about 14 bushels of soybeans per acre. However, the irrigated soybeans there brought a sigh of relief. They averaged in the 50’s, relatively normal for soybeans under irrigation in a stress year.

That’s roughly a 40-bushel per acre increase in soybean yields for irrigation. With $8 beans, and some would argue you could get $9 per bushel with savvy marketing, that’s a difference of some $320 per acre. On 300 acres, that’s a $96,000 increase, before deducting irrigation expenses. While this is an extreme case, it’s obvious that if you have land that needs irrigation, and you have a source of water, it wouldn’t take very many years out of 10 even close to this one to pay for an irrigation rig and its operation.

So there’s still a chance that corn yields in the irrigated plot could be respectable. Actually, it’s a three-in-one plot. Part of it was irrigated from the beginning, according to a university irrigation scheduling program, and part was irrigated just after tasseling. Then a third part wasn’t irrigated at all. So this plot will feature full irrigation, semi-irrigation and no irrigation. That should make for an interesting comparison. Stay tuned!