Soil & Tissue Tests for Micronutrients
Because micronutrients concentrations are very low in both soils and plant tissue, it is hard to judge sufficiency levels based on soil or plant tissue tests alone. The general recommendation is to test both soil and tissue from both “good and “problematic areas” where micronutrient deficiency is suspected. The comparison of the micronutrients concentrations of the samples will help determine if the problem is caused by micronutrient deficiency.
It is important to know the testing methods or extractions used by testing labs and the methods reported used on the tables when evaluating sufficient levels of nutrients. Additionally, it is critical to observe the units to be sure that comparisons are equal.
The following tables are micronutrients guidelines provided by Oregon State University Extension and Montana State University Extension. However, the decisions on micronutrient fertilization should be made based on knowledge of crop response to micronutrients in the local area. We recommended that growers conduct on-farm trials for >2 years to determine if micronutrient fertilization is beneficial.