Metal Chelates in Coffee

Clay fixation of metal chelates as a factor in their usability by soil application to correct micronutrient deficiencies

“…A similar Fe effect was observed in an earlier study Wallace, 1956) in soil where Fe chelates, in contrast to some acid chelate forms, resulted in lower Mn in plants. An effect similar to that of the presence of a chelating agent was reported by Medcalf and Lott (1956); Fe, Zn, Mn, and Cu chelates of EDTA each resulted in sufficiently less Mn absorption by coffee plants to ameliorate Mn toxicity and increase yields. Shannon and Mohl (1956) obtained somewhat similar results in solution culture with beans (Wallace et al, 1957).…”

“…This effect may, however, be partly the result of reactions within the plant rather than reactions in the soil, as discussed later in this paper. It has been frequently observed that plants have a lower Mn content following a soil application of Fe chelate (Holmes and Brown, 1955;Medcalf and Lott, 1956;Wallace and Lunt, 1956;Wallace, 1956). While this may be due in part to the chelation of available Mn and subsequent fixation on clay, the evidence indicates at least two other factors that interfere with the absorption of Mn following a chelate application.…”

Efeito de três fertilizantes acidificantes sobre a concentração de alumínio e de manganês em folhas e raízes de cafeeiros

“…No cafeeiro, a absorção excessiva de manganês pode induzir o aparecimento de sintomas de carência de ferro, segundo MEDCALF & LOTT (10). Pode, também, de acordo com GONZALES (6) e ARZOLLA (2), diminuir a absorção de zinco, provocando o aparecimento dos sintomas conhecidos por "café macho".…”

Estudos sobre a alimentação mineral do cafeeiro: VI Efeitos das deficiências de micronutrientes em Coffea arabica L. var. Mundo Novo cultivado em solução nutritiva

“…21;PEREZ, 1957;MÜL-LER, 1959), ferro, Fe (LOUÉ, 1955;MEDCALF & LOTT, 1956;CULOT et al, 1958;MÜLLER, 1959), manganês, Mn (GONZALEZ et al, 1953;DROSDOFF, 1956;CULOT et al, 1958;MÜLLER, 1959) e zinco, Zn (GONZALEZ et al, 1953;FRANCO & MENDES, 1954;PEREZ, 1957;MÜLLER, 1959;JONES et al, 1960). Não foi possível encontrar na literatura referência alguma aos sintomas provocados pela falta de cloro (Cl), cobre (Cu), e molibdênio (Mo).…”