Cooler soil temperatures typically found in no-tilled corn fields, as opposed to nearby conventionally tilled soils can be responsible for zinc deficiency development, especially if the planting season is cooler than normal

While zinc is classified as a micronutrient and is used only in small quantities by corn (usually less than 0.5 lbs/A), it plays a major role in photosynthesis, various enzyme reactions, DNA transcription and auxin activity. Of all the micronutrients, zinc is the most likely to be deficient in corn and most likely to show a yield increase when applied as a fertilizer.

Early Recognition Pays

Rasel Parvej, Louisiana State University Extension specialist, explains zinc and phosphorus are highly immobile elements in the soil, so seedling roots must grow to both the micronutrients for proper uptake.

“When plants aren’t growing quickly, they can’t take in zinc or phosphorus, which is why we often see phosphorus-induced zinc deficiency when it’s cold,” he says. “Nearly 50% of zinc accumulated by the corn plant is acquired by the silking or R1 growth stage, so recognizing and correcting zinc deficiency early in the season can be critical to producing optimum yields.”

Parvej also says if soil pH levels are high (7.0 or higher), zinc is likely to be unavailable for plant use. Growers who use in-furrow application of 10-34-0 are particularly at risk of seeing these conditions.

“An ideal pH for corn production is 6-6.5 and zinc availability should be adequate even when applying phosphorus fertilizers. But if the pH is 7.0…