Novel Fe(III) chelates, with N,N'-bis(2-hydroxy-5-methyl-benzyl) ethylenediamine-N,N'-diacetic acid and N,N'-di(2-hydroxybenzyl)etylenediamine-N,N'diacetic acid as chelating agents were studied for protonation and stability consts. and successfully used in field trials for efficient supply of Fe to nectarine and peach (Spain) as well as mandarin and lemon (Morocco) trees. The chelates were more efficient than the corn. Fe(III) chelates of ethylenediamine-N,N'-bis(2-hydroxyphenylacetic) acid used for comparison.