Author
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Albano, Joseph |
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Submitted to: HortScience
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 5/2/2011 Publication Date: 8/1/2011 Citation: Albano, J.P. 2011. Iron-[S,S']-EDDS (FeEDDS) Chelate as an Iron Source for Horticultural Crop Production: Marigold Growth and Nutrition, Spectral Properties, and Photodegradation. HortScience. 46(8):1148-1153. Interpretive Summary: Chelating agents, like EDTA and DTPA are commonly used in soluble fertilizers to supply copper (Cu), iron (Fe), manganese (Mn), and/or zinc (Zn) to plants. Offsite runoff and contamination of surface waters with these chelating agents is of increasing concern due to their reported ability to remobilize heavy metals in sediments and their low susceptibility to biodegradation. The chelating agent EDDS is chemically similar to EDTA except that it is biodegradable. Information on the use of EDDS as a chelating agent in formulating soluble fertilizers for the production of horticultural crops is limited. Therefore, a series of studies were conducted with the objectives of evaluating FeEDDS as an Fe-chelate fertilizer agent in the production of marigold, and EDDS and/or FeEDDS spectral properties and vulnerability to photodegrdation. Marigold grown in peat-based media were fertilized with a nutrient solution containing 1 ppm Fe from FeEDDS, FeEDTA, or FeDTPA. There was no significant difference in foliar Fe or Mn between Fe-chelate treatments, averaging 140 µg/g and 88 µg/g, respectively, nor were there significant differences in leaf dry weight (2.30 g) between Fe treatments. EDDS and FeEDDS absorbed absorbed UV radiation, causing FeEDDS to degrade. Technical Abstract: Aminopolycarboxylic acid (APCA) complexones, commonly referred to as ligands or chelating agents, like ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) are commonly used in soluble fertilizers to supply copper (Cu), iron (Fe), manganese (Mn), and/or zinc (Zn) to plants. Offsite runoff and contamination of surface waters with these chelating agents is of increasing concern due to their reported ability to remobilize heavy metals in sediments and their low susceptibility to biodegradation. The APAC ethylenediaminedisuccinic acid (EDDS) is a structural isomer of EDTA with the [S, S'] stereoisomer of the complexone, a compound naturally produced by actinomycetes and is biodegradable. Information on the use of [S, S']-EDDS as a chelating agent in formulating soluble fertilizers for the production of horticultural crops is limited. Therefore, a series of studies were conducted with the objectives of evaluating Fe[S, S']-EDDS as an Fe-chelate fertilizer agent in the production of marigold, and [S, S']-EDDS (free ligand) and/or Fe[S, S']-EDDS spectral properties and vulnerability to photodegrdation. Marigold grown in peat-based media were fertilized with complete nutrient solution containing 1 mg/L Fe from FeEDDS, FeEDTA, or FeDTPA. There was no significant difference in foliar Fe or Mn between Fe-chelate treatments, averaging 140 µg/g and 88 µg/g, respectively, nor were there significant differences in leaf dry weight (2.30 g) between Fe treatments. Spectra of [S, S']-EDDS and Fe[S, S']-EDDS produced from ferrous or ferric sources of Fe absorbed maximally in the 210-230 nm and 238-240 nm range, respectively. The [S, S']-EDDS complexone used in the current study, a 30% assay solution, had chromaphoric properties, appearing light yellow in color. When exposed to light Fe[S, S']-EDDS quickly degraded at a rate at least twice that of FeEDTA. |
