This year's corn crop is seeing widespread uneven growth causing farmers to question the cause.

University of Kentucky Extension Agronomist Lloyd Murdock attributes the uneven growth to a combination of things, many having to do with the weather. No-till fields are showing the majority of unevenness, he said.

"We froze completely the last few days of November and stayed frozen all the way through December and the first part of January," he said. "When it did thaw, it stayed cool and stayed dry so there wasn't much chance for decomposition. Last year's herbicides didn't continue to break down and we didn't get mineralization from residues that were left from last year to release nutrients, especially nitrogen."

Then, when spring came, it warmed very, very rapidly but was dry. In tilled soils there was enough warmth and moisture to get mineralization, he said. But, in no-till fields the mineralization did not occur, so there wasn't much nitrogen release from the soil.

Corn planted during the dry spell in May resulted in uneven emergence, said James Herbek, UK Extension grains specialist. Those dry conditions also resulted in slow root growth making it difficult for the plant to get to the nitrogen farmers applied after planting.

Recent rains have allowed roots to grow and are now reaching the nitrogen supply, Herbek said.

There's not much a farmer can do now to even out his stand, Murdock said.

Some farmers have asked if they should apply additional nitrogen, but Murdock said he did not believe that was necessary.

Generally, farmers can apply no nitrogen at planting and sidedress later. But there are times, such as this year, when that's not the right thing to do, Murdock said.

"We recommend putting down a third of the nitrogen at planting and sidedress with the remainder," he said. "If we'd have done that this year, then we would not be seeing the unevenness in most cases."

The really severe cases will see yield reductions, Murdock said. But, in general, it's still a pretty good crop and looks about as bad now as it's going to look all season.

Herbek said many of the uneven crops are beginning to look better and will do well as long as they continue to get moisture. Moisture has been variable across the state but there generally is enough to sustain the crop as long as timely rains continue.

The state's subsoil moisture is still well below normal levels, especially in the western area. If rainfalls aren't timely and adequate enough to sustain the crop, then it could curtail growth, he said.