Abstract: The inclusion of certain organic hydroxy acids, most notably citric acid, in the iron sulfate formulations of at least one prior art hydrophilic polymer delivery system followed by drying and crushing the product into particles has been found to significantly improve the efficiency and ease of application of iron source fertilizer materials for iron-sensitive plants growing on iron-deficient soils for periods exceeding one year. The dried particles most preferably may be selectively metered into soil in or near the seed row as a band application at or prior to planting or spot placed in the root zone of growing plants in soil. The dry band absorbs soil moisture to provide a unique environment which restricts contact of soluble iron fertilizers with the soil and provides for complexation of iron in the formulation with organic hydroxy acids also contained in the formulation, thereby minimizing the extent of chemical reactions with the soil that reduce the availability of the applied iron to plant roots.

Abstract: The inclusion of certain organic hydroxy acids, most notably citric acid, in the iron sulfate formulations of at least one prior art hydrophilic polymer delivery system followed by drying and crushing the product into particles has been found to significantly improve the efficiency and ease of application of iron source fertilizer materials for iron-sensitive plants growing on iron-deficient soils for periods exceeding one year. The dried particles most preferably may be selectively metered into soil in or near the seed row as a band application at or prior to planting or spot placed in the root zone of growing plants in soil. The dry band absorbs soil moisture to provide a unique environment which restricts contact of soluble iron fertilizers with the soil and provides for complexation of iron in the formulation with organic hydroxy acids also contained in the formulation, thereby minimizing the extent of chemical reactions with the soil that reduce the availability of the applied iron to plant roots.

Abstract: Inclusion of certain hydrophilic organic gel-forming polymers, notably polyacrylamides, with relatively inexpensive soluble iron sulfate [FeSO.sub.4 or Fe.sub.2 (SO.sub.4).sub.3 ] significantly improves the efficiency of iron source fertilizer materials for iron-sensitive plants growing on iron-deficient soils and can maintain supply of available iron to growing plants for periods up to about 12 weeks. These polymers may be mixed with iron-containing solutions to form suitable gels which are band applied in or near the seed row at or prior to planting or spot placed in the root zone of growing plants in soil. Other soluble fertilizers of micronutrients such as copper, manganese, or zinc also may be included instead of, or with, iron sulfates in hydrogels of these polymers.