1 Foliar iron fertilization of peach ( Prunus persica ( L . ) Batsch ) : effects of iron 2 compounds ,

18 Experiments to assess the capability of different combinations of Fe-compounds and 19 adjuvants to provide iron (Fe) via foliar application to Fe-deficient plants have been 20 carried out. A total of 80 formulations containing i) one of five Fe-compounds 21 (FeSO4.7H2O, Fe(III)-citrate, Fe(III)-EDTA, Fe(III)-DTPA, Fe(III)-IDHA), ii) a 22 surfactant (Mistol, alkyl-polyglucoside1 or alkyl-polyglucoside2) and iii) an adjuvant 23 (glycerol, methanol or glycine-betaine) were studied with respect to leaf wetting 24 ability and surface tension. From the initial formulations only 26 resulted in adequate 25 leaf wetting, 20 with alkyl-polyglucoside2 and 3 each with Mistol and alkyl26 polyglucoside1, and some of them (4 with alkyl-polyglucoside2, 1 with Mistol and 3 27 with alkyl-polyglucoside1) were found to have inadequate surface tension values for 28 use as foliar fertilizers. In a second experiment, 20 formulations containing alkyl29 polyglucoside2 and one each of the five Fe-compounds and adjuvants listed above, 30 were used for a foliar experiment with Fe-deficient peach trees (Prunus persica (L.) 31 Batsch) grown under field conditions. Iron-deficient shoots were sprayed only once 32 and leaf re-greening was assessed over 6 weeks for leaf chlorophyll content (via 33 SPAD measurements) and percentage of green leaf area (via image analysis). Foliar Fe 34