TILL-IT® DUO ZINC 9% is designed for application to the soil. TILL-IT DUO ZINC 9% is highly effective under adverse soil conditions unlike inorganic zinc compounds that are tied-up and unavailable to the plant. These adverse conditions include: high phosphate soil levels, high pH (alkaline), high salinity, high carbonate levels, and clay soils (adsorption). EDTA products may be applied separately or in combination with fertilizers or pesticides.