As the Kentucky corn crop begins to show some height, some plants are showing signs of potassium deficiency, which might be due to sidewall compaction.

The compaction is likely the result of producers planting in less-than-ideal conditions this spring when record rainfall caused significant planting delays across the state.

Sidewall compaction makes it difficult for plants to establish root systems to get the nutrients they need from the soil. In a sidewall compaction situation, roots grow in the planting furrow, along the rows.

With a potassium deficiency, lower plant leaves will turn yellow first. The yellowing begins at the tip and travels along the outside plant leaf margin, eventually causing the leaves to turn brown and die.

“The plants are likely lacking in more than just potassium, but the potassium deficiency usually shows up first,” said Lloyd Murdock, Extension soil specialist with the University of Kentucky College of Agriculture.

Murdock said there’s little producers can do to alleviate sidewall compaction on their own, as penetrating the compacted soil would likely destroy the plants. But, Mother Nature may be able to provide relief, especially in cases where roots are starting to break through the compacted soil.

“In most cases, the plants’ roots will penetrate the soil with time, especially if we have good moisture,” he said. “Rains moisten the soil, making it easier for plants to penetrate the compacted wall.”

In contrast, dry conditions could exacerbate the problem.

“If it dries off, recovery will be really slow, if at all,” he said.

He noted, in a few cases, the soil compaction may be too severe and the plants may not recover, even with timely rainfall.