Oct 6, 2014
Nice note here from the International Plant Nutrition Institute on the patchiness of micronutrients in the field:
It's a pretty short article, but there is a very important point being made. Micronutrient deficiencies don't happen over the whole field and occur as a result of the spatial variability in soil characteristics that end up affecting micronutrient availability to the plant. These soil characteristics are things like pH, texture, organic matter, cation exchange capacity, EC and soil drainage.
The kicker for the grower or field practitioner is assessing the true extent of the micronutrient deficiency in the field since it is so patchy. Hard to make calls on something like this.