Over the last three years, tissue samples in corn reveal surprising nutrient deficiency trends for Derek Emerine, National Agronomist for Helena Agri-Enterprises. No, it’s not deficiencies in nitrogen, phosphorus and potassium.
“They’re macronutrients for a reason,” says Emerine.
Instead, it’s how those nutrients rank from most to least deficient. Helena’s data shows potassium is actually more deficient than nitrogen, with phosphorus coming in third. Perhaps an even bigger surprise is the prevalence of magnesium deficiencies in corn across the country.
“Agronomically, you typically think about magnesium deficiencies showing up in sandy soils. We’ve seen that historically when we go into the Carolinas or Georgia as well as West Tennessee or North Alabama.”
Derek Emerine
“What this data is telling us, which is a little bit different, is we're seeing magnesium show up all across the corn belt.”
The numbers back up what Helena agronomists across the Midwest have shared anecdotally for years. According to Emerine, depending on growth stage, a significant number of samples by growth stage are deficient in magnesium. This secondary nutrient is a central component of chlorophyll, which is necessary for photosynthesis, and therefore, important for creating carbohydrates and sugars.
Moving beyond the big takeaways and breaking down the data by growth stage can shed light on other deficiencies and help corn growers prioritize nutrition throughout the season. Early in the season, prior to V4, it’s a given corn will need more phosphorus. Cold, wet soils are known to inhibit phosphorus uptake at this time. The second highest deficiency is magnesium. A similar trend continues into mid-season growth stages, with nitrogen, phosphorus and potassium leading the way and magnesium rounding out the top deficiencies once again. At reproduction, sulfur comes into the discussion.
“A lot of people know they need sulfur, but we’re finding they may not be applying enough, and that’s something to be aware of,” says Emerine.
Zinc is another micronutrient to remember during reproduction. For a lot of corn producers, zinc applied with pre-plant fertilizers is the norm and a practice Emerine says to continue. However, because zinc impacts pollen formation and protein production, it’s a micronutrient to keep an eye on as uptake ramps up later in the season as well.
Looking at Extractor® data broadly reveals the most common problems corn growers are facing across the country. For some, it might be time to modify fall or spring commodity fertilizers, while others need to incorporate certain foliar-applied nutrients into their mid-season sprays. Finding the right answer requires understanding the needs of your own crop. To measure nutrient levels in your field this season, contact your local Helena representative to get started with Extractor. Hear more insight from Derek Emerine on nutrition in corn, soybeans, cotton and wheat this season by tuning in to Episode 32 of the FieldLink® Podcast available on YouTube and wherever you listen.