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Title: PHOTODEGRADATION OF FEDTPA IN NUTRIENT SOLUTIONS I. EFFECTS OF IRRADIANCE, WAVELENGTH, AND TEMPERATURE

Author
item Albano, Joseph
item MILLER, WILLIAM - CORENELL UNIVERSITY

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/19/2000
Publication Date: 4/1/2001
Citation: Albano,J.P.,Miller,W.B. 2001. Photodegradation of FEDTPA in nutrient solutions I. effects of irradiance, wavelength, and temperature. Hortscience.36:313-316.

Interpretive Summary: Iron-diethylenetriaminepentaacetic acid (FeDTPA) is used in nutrient solutions to maintain Fe in a soluble form (i.e., a form available for uptake by the plant) in the growth medium. Irradiation of FeDTPA-containing nutrient solutions by a fluorescent plus incandescent light source resulted in the loss of both Fe-chelate and soluble Fe, the formation of a precipitate that was composed mostly of Fe, and a rise in pH. The rate of Fe-chelate photodegradation in solution increased with irradiance intensity and with solution temperature under irradiation, but irradiance had the greater effect. Fe-chelates absorb in the blue and UV regions of the spectrum. Removal of these wavelengths with a spectral filter eliminated photodegradation. The results of this research are important to plant nutrition researchers, producers of water-soluble fertilizers, and to growers as we have demonstrated that failure to protect such solutions from light could result in the destruction of the compound.

Technical Abstract: Irradiation of FeDTPA-containing nutrient solutions by a fluorescent plus incandescent light source resulted in the loss of both Fe-chelate and soluble Fe, the formation of a precipitate that was composed mostly of Fe, and a rise in pH. The rate of Fe-chelate photodegradation in solution increased with irradiance intensity and with solution temperature under irradiation, but irradiance had the greater effect. Fe-chelates absorb in the blue and UV regions of the spectrum. Removal of these wavelengths with a spectral filter eliminated photodegradation. Chemical names used: ferric diethylenetriaminepentaacetic acid (FeDTPA).