Heavy rains that inundated large swaths of Illinois farmland put growers in a holding pattern in early May, waiting to see what will become of their crops already in the ground as well as seed still in the bags.

An active weather pattern in late April produced more than a foot of rain in the span of a few days, leading to flooding, especially across the southern portion of the state. The majority of corn had been planted in most parts of Illinois, but there are concerns that some fields will need to be replanted.

“Southern Illinois is where the rains hit hardest,” said Jared Webb, an agronomist with Monsanto. “Corn was about 75 percent planted in many areas. I’m hearing that maybe 25 percent will have to be replanted. About 20 percent of the beans were planted too. Some of those are going to have to be replanted as well.”

Brad Conant, who manages the Illinois Farm Bureau office in Perry County, said there may be some replanting of corn in his neighborhood. But many farmers are hopeful they can coax a crop out of the fields.

Much may depend on when corn was planted.

“It’s a mixed bag. Stuff that was planted early and was up before the heavy rains turned a little yellow and had too much water,” Conant said. “But a lot of that is coming out of it. Most of that corn will probably be all right.

“In areas that were ponded, there could be some patching in on that early corn. The stuff that was planted days ahead of the 10 or 11 inches of rain we got here, there’s a lot of uncertainty. There will probably be a lot of that replanted.”

Webb said that though nearly all parts of the state were hit with some heavy rains, there is a lot of variability between regions.

“Northern Illinois hadn’t progressed as fast in terms of planting,” he said. “In the northern third, almost 50 percent was planted. And they didn’t get as much rain.”

During a visit to his father’s farm in southeastern Illinois, he saw first-hand how the corn was faring following the heavy rains and flooding. Variance in emergence is a concern.

“Some corn had turned yellow and pale. We’re seeing real unevenness at emergence,” Webb said. “You’re going to see a yield penalty in timing of emergence. One plant will be well ahead of the next plant. That presents between-plant competition.”

Some planting delays were likely due to hesitance by farmers anticipating the weather front, Conant said.

“The stuff that wasn’t in, the guys were probably waiting to see what was going on with the forecast,” he said. “They saw the writing on the wall and decided to delay.”

As is always the case, poorly drained fields pose the greatest problem. Webb has seen evidence of seed damage.

“This is varied across the field,” he said. “An area that might be higher, where the water was able to drain quicker from, there was a pretty good stand. Other areas had sporadic emergence. I dug up seeds that hadn’t emerged that were rotten. Without oxygen for so long, it suffocated the seeds.”

Leaching of nitrogen is another concern, depending on when it was applied, in what form, and whether the farmer used an inhibitor.

“Some areas received 12 to 15 inches of rain. Leaching could definitely be a concern,” Webb said. “Lack of oxygen can also cause some denitrification. We could see some losses that will show up later in the season.”

The Perry County area got a soaking rain on May 10 and 11 following several days that had dried the ground. That could actually be good for some of the crops there.

“That will probably help,” Conant said. “The ground didn’t get that hard crust over it. We’re waiting to see what will happen.”

Nat Williams writes for Illinois Farmer Today, a Lee Enterprises sister publication of The Southern Illinoisan.