Iron is one of 16 essential elements for plant growth and reproduction. Most annual plants have a requirement for Fe on the order of 1 to 1.5 lb Fe per acre, compared with nitrogen (N) at 80 to 200 lb per acre. This 8-page fact sheet provides a detailed basic understanding of soil science and plant physiology for diagnosing and correcting Fe problems in plants and soils. Written by George Hochmuth and published by the UF Department of Soil and Water Science, August 2011.
http://edis.ifas.ufl.edu/ss555