15.15.15 + ZN ZINC ADDITIVE COMPOSITE FERTILIZER – BASE FERTILIZER Zinc additive compound fertilizer is used to eliminate zinc deficiency, which is common in all fruit trees, especially citrus fruits, vegetables and some field crops such as corn, potatoes, sugar beet. Zinc has a positive effect on the yield increase and quality by improving the root system and vegetative parts of the plant and regulating hormonal enzyme activities.