Micronutrients in sulfate form are typically recommended for dry broadcast applications to the soil. This form of micronutrients is also water soluble; although, copper sulfate may be problematic to mix with water depending on water properties.
Chelated elements are not recommended for use in foliar applications. Best results are seen when chelated micronutrients are placed in the soil with a starter fertilizer in-furrow or beside the row.
When it comes to plant availability and effectiveness of trace minerals in foliar sprays, the nitrate form sets the bar. As an added benefit, they mix well with International Ag Labs foliar products such as AMAZE and Bloomit®.