The Economic And Agronomic Value Of Micronutrients

Growers can look beyond N-P-K to improve yield without increasing their budget

Published online: May 12, 2024 Articles
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St. Johns, Mich. – Nitrogen (N), phosphorus (P) and potassium (K) are the foundation of every crop nutrition program – but they’re not the only nutrients growers should pay attention to when building their program. 

“Historically speaking, we’ve thought of these nutrients in their own little silos,” says Reid Abbott, an agronomist for AgroLiquid. “We know through a lot of years of research that nutrients like calcium (Ca) and sulfur (S) are as important to crop health and yield as nitrogen, phosphorus and potassium.” 

“Calcium has its role in the soil as well as the plant, improving nutrient movement and assimilation,” Abbott says. “We like to see 65-75 percent of our base saturation or cation exchange sites occupied by calcium in the soil, and that allows all of the other nutrients to function most ideally. On the plant side, calcium does a lot to bring nutrients into the plant, make the metabolic process more efficient and improve the utilization of other nutrients.” 

Abbott adds that in-season foliar applications can ensure plants have calcium available when they need it. 

“Concentrating your application on leaf tissue so the nutrients don’t have to go through the soil system and risk getting tied up or lost could lead to a better response,” he says. “Some of it has to do with timing and some of it has to do with application methods, but there are tools out there for however you’re set up to apply these nutrients. It’s about making sure we apply them at the right rate and the right time.” 

Some growers consider sulfur the fourth macronutrient for its ability to balance the soil and improve its fertility. In addition, Abbott says the need for sulfur is growing in part because of the Clean Air Act and other legislation that has led to fewer deposits of sulfur on the ground. 

“For sulfur, you need a ratio of one part to every 10 to 14 parts of nitrogen,” he says. “As we’re moving up in yield, we’re starting to see greater deficiencies. So the more nitrogen you’re putting on, the more you need to maintain that 10:1 ratio and build that sulfur. We’re even seeing responses up to 8:1 in some of our research.”

Abbott notes growers don’t have to increase their crop budget to incorporate micronutrients and secondary nutrients. 

“For years, we’ve probably been overapplying nitrogen in many of our fields,” he says. “Consider turning that down and using the money to add some of these other nutrients for a more effective crop nutrition program.” 

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