The use of synthetic iron (Fe) chelates in fertigation is the most common method to alleviate iron deficiency in crops. Several factors that determine the effectiveness of Fe chelates have been described such as the dosage applied and how theses crops are managed (García-Marco et al., 2006). Ethylene diamine tetra acetic acid (EDTA) is among the most commonly used chelating agents in southeastern Spain. However, the most effective chelating agent is actually diamino-di-(ortho-hydroxy phenyl acetic) acid (o,o-EDDHA) (Lucena, 2006), because the final amount of dissolved Fe obtained from Fe o,o-EDDHA is greater than that from Fe-EDTA (García-Marco et al., 2006), and the dissolved Fe obtained can be maintained in solution over a wide range of pH values (Alcañiz et al., 2004). However, as a result of the high cost, only cash crops are treated with these Fe chelates (Chen and Barak, 1982). Although several researchers have investigated ferric chlorosis and ways to remediate Fe deficiency in crops grown in soil (Marschner et al., 1986; Mengel, 1995) and in soilless crops, few have compared the effects of various synthetic Fe chelates available in the market (Assimakopoulou, 2006; Hernández-Apaolaza, 2007; Lucena and Chaney, 2007).
The total area of soilless crops in southeast Spain today is ≈5000 ha, half of which uses rockwool as the growing medium, whereas the other half uses perlite, sand, coir, and other minor soilless systems (Mazuela et al., 2005).
The aim of this study was to evaluate the effectiveness of Fe o,o-EDDHA in alleviating ferric chlorosis compared with EDTA in a soilless crop and its effects over production.
AlcañizS.CerdánM.JuárezM.JordáJ.D.BermúdezD.SánchezA.2004Uptake of Fe(o,o-EDDHA) isomers by strategy I and II plantsActa Hort.696535542
AssimakopoulouA.2006Effect of iron supply and nitrogen form on growth, nutritional status and ferric reducing activity of spinach in nutrient solution cultureSci. Hort.1102129
García-MarcoS.MartínezN.YuntaF.Hernández-ApaolazaL.LucenaJ.J.2006Effectiveness or ethylenediamine-N(o-hydroxyphenylacetic)-N′(p-hydroxy-phenylacetic) acid (o,p-EDDHA) to supply iron to plantsPlant Soil2763140
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UrrestarazuM.MartínezG.A.SalasM.C.2005Almond shell waste: Possible local rockwool substitute in soilless crop cultureSci. Hort.103453460