Utilizing Nutrient Ratios for Assessing Macro Nutrient Deficiencies in Corn.

Increasingly corn leaf tissue analysis has been used to diagnose nutrient deficiencies in the Midwest.  Observation analysis of corn ear leaves at growth stage VT of fields in western Indiana over a three year period across a range of corn varieties, plant populations soil types and management systems indicate significant nutrient ratio relationships.   Ear leaf N:K, N:Mg and N:Ca ratios all increased with decreasing leaf K content, and were similar across years.  These results were in agreement with published nutrient ratios for corn earl leaves published in the 1980s.  Results will be presented on ear leaf macro nutrient ratios and threshold deficiency levels for corn will be proposed.