Joseph P. Albano and William B. Miller Department of Horticulture, Clemson University Download the Adobe Acrobat version of this document. Introduction In crop production, a grower must consider many factors in fertilization, including formulation and application frequency. Often not considered, however, is the manner that the fertilizer solution is stored, especially if prepared as a concentrated stock. Research has indicated that iron-chelates are affected by light. Precipitated iron in the agar is insoluble and unavailable to the plant, and limited soluble iron significantly reduces plant growth and may alter plant physiology.
Many plants respond to iron-deficiency stress by modifying root physiology.
These physiological reactions are collectively referred to as iron- efficiency. These bonds occur in a ring structure around the metal ion. Chelates are capable of maintaining iron in a soluble form in chemical environments where iron would otherwise precipitate. Therefore, chelates like EDTA and DTPA are commonly added to fertilizer. These chelates have a high affinity for Iron and generally form stable complexes with the metal across a pH range from 4 to 7.