Sintomas de deficiências minerais no cafeeiro

Abstract

<abstract language="eng">Coffee plants (Coffea arabica L.) were grown in nutrient solutions for the purpose of studying deficiency symptoms of the following elements : nitrogen, phosphorus, potassium, magnesium, calcium, sulphur and iron. The methods employed in the growing of coffee plants in the nutrient solutions are described. After preliminary tests with several nutrient solutions Hoagland's formula was selected as most suitable for the present tests. However, the quantity of phosphate employed in the basic nutrient solution was reduced to one third of that given in Hoagland's formula. This reduction in phosphate was made because of the previous results obtained by Jacob which seemed to indicate that the coffee plant requires only very small amounts of phosphorus. In the present tests phosphorus deficiency symptoms were obtained and these results suggest that Jacob's failure to obtain phosphorus deficiency symptoms may be ascribed to use of Shive's solution, which has a very high phosphate content. While growing in this complete nutrient solution his plants may have stored enough phosphorus to supply their needs later when they were transferred to the solution lacking this element. In the course of the present investigation it was found that in the nutrient solutions containing KH2PO4 and having a pH higher than 5.5, the coffee plant absorbs insufficient iron. This difficulty of iron absorption by the coffee plants grown in nutrient solution was overcome by a technique previously described that is, when iron deficiency symptoms appeared on plants being tested for other deficiencies the nutrient solution was changed and the new solution used contained no phosphate. The plants were allowed to grow in this solution for two to four days and then the phosphate was added. In this way the plants absorbed sufficient iron for their requirements. The present paper describes and the color plates illustrate the symptoms on coffee plants that were associated, in the present studies, with nutrient solutions deficient in the various elements listed

Título en español.

“…. 4. Highly significant correlations were found between relative yields and leaf-magnesium values in both summer and fall leaf samples.…”

“…Los rendimientos máximos guardaron relación con los altos contenidos de magnesio en la hoja. 4. Se obtuvieron correlaciones altamente significativas entre el rendi miento y el contenido de magnesio en las hojas de las muestras recolectadas en el verano y el otoño.…”

Clorose das fôlhas do cafeeiro excelsa

“…Os sintomas da clorose se assemelham àqueles devidos à deficiência de ferro nas folhas (2). Para determinar se esse tipo de clorose era devido a alguma deficiência, trataram-se as folhas cloróticas de cafeeiros excelsa com soluções de sais de ferro e de outros elementos, a fim de verificar se algum deles promovia a recuperação da côr verde normal das folhas.…”

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

“…Não foi possível encontrar na literatura referência alguma aos sintomas provocados pela falta de cloro (Cl), cobre (Cu), e molibdênio (Mo). Do mesmo modo, os trabalhos feitos em solução nutritiva não mencionavam os efeitos das carências de Cl, Cu, Mo e Zn; só foram descritos nessas condições os sintomas de falta de boro (MALA-VOLTA & DIAS, 1953;CIBES & SAMUELS, 1955;LOUÉ, 1957), ferro (FRANCO & MENDES, 1952;MALAVOLTA & DIAS, 1953;CIBES & SAMUELS, 1955;LOUÉ, 1957) e manganês (MALAVOLTA & DIAS, 1953;CIBES & SAMUELS, 1955;MENARD, 1956;LOUÉ, 1957).…”