During a summer when Georgia corn farmers have relied heavily on their irrigation systems working effectively, many struggled with equipment malfunctions that may have reduced crop yields. University of Georgia Cooperative Extension irrigation specialist Wes Porter believes that those problems can be avoided in the future if producers make necessary modifications after the growing season.

“If farmers haven’t employed a good maintenance plan, ensured good uniformity in their irrigation systems, and done a good job fixing leaks and stopped-up nozzles, it was noticed during the 2019 season. We had such a hot and dry time from mid-May to mid-June when our corn was in peak tassel, we’ve seen a lot of streaking. That’s usually attributed to poor uniformity,” Porter said.

Streaking refers to a section of a field where the crops have been underwatered and the effects are visible in the form of smaller plants, wilted plants exhibiting stress, and those with a canopy that is not fully developed.

A number of irrigation issues can lead to streaking, including clogged nozzles that can’t apply an adequate amount of water; leaks that affect the uniformity of water being applied; and pumps that are not pumping at peak capacity due to aging equipment.

“Usually when we get to the point where we start seeing these maintenance type of issues in a normal year, we have had enough rainfall to mask some of the problems. This year, we’ve had such hot, dry weather that those problems have shown up,” Porter said.

According to this year’s UGA Extension Corn Production Guide, corn needs the most water — approximately 0.33 inches per day — during pollination. While producers prefer Mother Nature to supply the needed moisture, irrigation systems are in place to satisfy water requirements not met by natural precipitation. However, if malfunctions exist and corn doesn’t receive the right amount of water at the right time, the amount and size of the corn kernels could be impacted.

“Many of our growers can see there’s water coming out of the system, but they can’t tell that it’s not flowing at the correct rate,” Porter said. “We’re irrigating, we’re just not getting the exact rate we think we’re applying.”

Beginning the weekend of May 11, Georgia fields received little to no rainfall for a three-week span. The dry spell intensified when temperatures reached 100 degrees Fahrenheit right after Memorial Day weekend in south Georgia, according to the UGA Weather Network at www.georgiaweather.net.

“I think we got into a comfort zone the past couple of years where we had been getting adequate rainfall for our crops. This year we got very little rainfall through most of the state in late spring and, on top of that, we’ve had excessive heat. Suddenly those maintenance issues that farmers may have been neglecting are showing up really quickly, and it may be unfortunate, but some of these issues will show up in yield maps,” Porter said. “It will be easy to tell if there was an irrigation system problem on the yield map, as the yield reductions will follow irrigation system patterns.” 

Porter recommends farmers thoroughly inspect their irrigation systems and make needed repairs once harvest season is done.

For more information about corn production in Georgia, see the UGA Grain Crops Team website at grains.caes.uga.edu.