Petiole and leaf blade analyses as nutritional status indicators of 'solo' and 'formosa' papaya trees

Abstract

The absence of a literature consensus about parts of leaves, blade or petiole which would be most indicative of the nutritional status of papaya trees, has hindered the use of foliar analysis as a diagnosis tool for this crop. An experiment was carried out to compare the nutricional status evaluated using blades and petioles of 'solo' and 'formosa' papaya groups. A completely randomized block design was used to test six varieties, three of each group. Leaves were sampled every three months in five occasions. Recently matured leaves were separated in petioles and blades for the evaluation of N, NO3-, P, K, Ca, Mg, S, B, Cl, Fe, Mn and Zn concentrations. These concentrations were compared to those reported in the literature for this crop. The nutritional status diagnosis of the papaya plants, when made by means of blade or petiole leaves, led to different diagnoses showing the need of the definition of a single pattern. Blade has shown to be more effective than petiole for the diagnosis of the nutritional status, better differentiating the papaya tree varieties in relation to N, P, K and Cl, and not differing in relation to the other nutrients. It is here recommended to use the blade as indicator of the nutritional status of papaya plants.