Published online by Cambridge University Press: 15 October 2004
Introduction. The lack of information in the literature regarding the most adequate sampling time and leaf for the assessment of the nutritional status of carambola trees limits the use of leaf analysis as a diagnostic method for this species. Therefore, we determined seasonal variations in the leaf mineral composition of carambola trees cultivated on acid soil and submitted to lime application in order to define criteria for the indication of the diagnostic leaf and the adequate sampling time. Materials and methods. The experiment was set up in a typic Hapludox in Bebedouro, São Paulo, Brazil, with lime doses of (0, 1.85, 3.79, 5.56 and 7.41) t·ha–1 applied in August 1999. Grafted carambola tree seedlings (cv. Malaysia) were planted in December 1999. To assess the nutritional status of the plants, the leaf’s macro- and micronutrient concentrations were determined in the third and sixth leaves, including the petiole, in flowering branches without fruits located in the middle third of the plant. Samples were collected throughout 2002, except for January and February due to the lack of flowers. Results and discussion. The results showed that the sixth leaf was more effective than the third leaf for the assessment of the nutritional status of carambola trees, with better differentiation of the lime effect on the levels of Ca, Mg, Mn, Zn, Cu and Fe, especially during the sampling period from August to October. Conclusion. In the area concerned with this study, the sixth leaf collected during the flowering peak from August to October appears ready to allow a nutritional diagnosis of carambola trees.