As crop margins continue to tighten, growers want to see more from the fertility dollars they're already spending, and some agronomists say micronutrients deserve a closer look.
Stephanie Zelinko, national agronomist for AgroLiquid, says micronutrients can improve the efficiency of a standard nitrogen, phosphorus and potassium program. She notes that in some cases, micronutrients allow growers to reduce those macro inputs without sacrificing performance.
"The individual micronutrients can actually make a better return on investment than some of the key macros like nitrogen," Zelinko said. "If they all work together, we can cut back nitrogen or even phosphorus and get more value out of the micronutrients added to the program."
Reid Abbott, also an agronomist for AgroLiquid, says the relationship between phosphorus and zinc is one of the more important pairings to manage. Without adequate zinc, phosphorus uptake is limited regardless of application rate. He also recommends maintaining a two-to-one ratio of iron to manganese for proper balance in the plant. Sulfur, manganese and iron all support nitrogen in key metabolic processes, which means they can extend the value of a nitrogen program when applied correctly.
Soil pH and composition are the top factors in determining what nutrients crops actually access. Abbott notes that even iron-rich soils may have an iron deficiency in high-pH environments. High organic soils tend to be low on manganese, and boron is prone to leaching in sandy conditions.
"The only way to know what's really available is to get a current soil test," Zelinko said.
Mid-season, tissue testing and sap sampling are the most reliable tools for finding deficiencies before they affect yield. Many micronutrient deficiencies may show similar symptoms, making an accurate diagnosis critical, especially before applying any corrective measures.
"Many micronutrient deficiencies can look similar to one another, so you want to make sure that if you're going to make an adjustment, that you're applying the right nutrient," Zelinko said. "Tissue testing and sap sampling are the best ways to go about that, so we know what we are working with."
For more information, visit agroliquid.com or watch Crop Nutrition Week content at cropnutritionweek.com.
