Use of Iron Chelates

U s e of chelating agents--especially the new compound Fe 1 3 8 t o correct iron chlorosis by effectively supplying iron to plants has proved promising in a series of experiments. All plant species tested-but not all individual plants-responded to treatment, and some of the individuals within species did respond with retreatment. Treatment responses in the field have lasted from two to six months. Woody plants treated late in the summer have given good responses. Responses are more di5cult to obtain for large trees than for small trees and shrubs. Some large trees required several months following treatment to become green. None of the polyamine polyacetate chelates-of which EDTA is the best known-tested in the experiments has proved as e5cient in correcting iron chlorosis by soil applications in California as in Florida. The reasons for this difference have been intensively studied.