Interpreting Micronutrient Test Results
When foliar analysis indicates a micronutrient deficiency, treat those results with caution advises University of Nebraska Extension.
April 5, 2012
What if foliar analysis indicates a micronutrient deficiency? Such results are often used to promote micronutrient application. Treat these results with caution.
First, foliar nutrient concentration can vary with rate of growth, growth stage, variety, weather conditions, and time of day. With many samples taken and several nutrients considered, there is potential for seeing occasional low levels, even with high soil fertility conditions.
Second, labs and service companies differ greatly in their interpretation of foliar analysis results with some considering low to be anything below an average result, and others basing their interpretation on research relating plant response to nutrient application relative to the tissue nutrient levels. Foliar analysis for agronomic crops in Nebraska should be used to guide soil testing and additional foliar analyses for future crops but, it is not a sole justification for a nutrient application.
Could you have an exceptional situation for response to micronutrients? Such claims are common, often with a high level of certainty. If you are doubtful, do your own trials, but don't limit yourself to a mere one time, side-by-side comparison which many find to be convincing. Spatial technology makes replicated on-farm trials often easy to conduct. Even with such trials, repetition on three or more fields or years is encouraged for confidence in small yield effects. Extension Educators can help you design such a trial and interpret the results.