Resumo

RIVERA-ORTIZ, Patricio; CASTRO-MEZA, Blanca I  e  DE LA GARZA-REQUENA, Francisco R. Iron Chlorosis in Citrus Trees and Leaf Fertilization. Terra Latinoam [online]. 2009, vol.27, n.1, pp.11-16. ISSN 2395-8030.

Yield of citrus trees growing on calcareous soils is often low. This is related to an insufficiency of available soil iron and low contents of the element in the plant, which exhibit yellowing leaves, a disorder called iron chlorosis. With the aim of correcting iron deficiency, the response of chlorotic orange trees Valencia (Citrus sinensis) and Italian lemon (Citrus limon) to foliar application of iron compounds in solution was studied. The individual spraying of ferrous sulfate 0.25%, chelate FeEDTA 0.25% and ferric citrate 0.25% produced slight re-greening in leaves and a significant increment of leaf iron concentration, but chlorosis was not corrected. When ferrous sulfate mixed with dispersant oil, 0.5% emulsified citrulline, was sprayed on chlorotic orange trees, re-greening and leaf iron content increased significantly. Lemon trees had the same response to mixtures of ferrous sulfate and ferric citrate in dissolution. This suggests that emulsified citrulline and the citrate ion improved leaf uptake of sprayed iron and that both mixtures could be very useful in reducing iron chlorosis in citrus.

Palavras-chave : iron deficiency; ferrous sulfate; FeEDTA; ferric citrate; citrulline.