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On-line version ISSN 1806-9088
CHAVES, Roselene de Queiroz and CORREA, Gilberto Fernandes. Macronutrients in the soil- Pinus caribaea Morelet system with yellowing of the needles followed by senescence and death. Rev. Árvore [online]. 2005, vol.29, n.5, pp. 691-700. ISSN 1806-9088. http://dx.doi.org/10.1590/S0100-67622005000500004.
This study was carried out to diagnose senescence and pine trees death (Pinus caribaea Morelet), observed after yellowing and progressive necrosis of the needles in the Brazilian Cerrado in western Minas Gerais. The varieties caribaea and hondurensis, planted between 1977-82 were compared. In the three sites studied samples from twenty trees were collected; ten with yellowing of the needles and ten without symptoms. From each tree, phloem and xylem tissue from root segments and needles were collected and the contents of N, P, K, Ca, Mg and S were analyzed. The considered sites is formed by a Yellow Latosol (Typic Acrustox) with high clay content and the presence of positive charges (acric soil). Soil sampling was performed at the following depths: 0-5, 5-10, 10-20, 20-40, 40-60, 60-80, 80-100, 100-150, 150-200, 200-250 and 250-300 cm. Soil analysis was carried out to evaluate the contents of organic matter, concentration of Ca, Mg, P and K as well as pH in water and in KCl. The mean concentration of N, P, K and S did not differ significantly in the green and yellow needles but Ca and Mg contents were significantly lower in the yellow needles. Visual symptoms and laboratory tests revealed complex deficiency symptoms involving Ca and Mg.
Keywords : tropical pine; plant soil relations; nutritional deficiency; Brazilian Savanna (Cerrado); afforestation.