Nutrição e desenvolvimento da brotação de eucalipto em função de fontes e doses de fósforo

Abstract

The management of eucalyptus forests through the chisel has been the most viable in relation to the reforms, due to the decrease in the production costs, however the knowledge regarding the influence of the phosphated fertilization on the system is still limited. The objective of this dissertation was to evaluate the influence of the source and dosages of phosphated fertilizer on the initial development of Eucalytus ssp sprouting in postharvest fertilization, in the region of Catalao-GO. The experiment was developed on Fazenda Olhos D’agua, Copebras 26 reforestation project, belonging to Anglo American Fosfatos Brasil Ltda., located in the same municipality. The soil of the experimental area is classified as dystrophic red-yellow latosol. The experiment was installed with randon block delineation in incomplete factorial arrangement with six repetitions, and 32 plants per part. The treatments were conducted with two phosphorus sources: monoammonium phosphate (MAP) and ammoniac single superphosphate (SSGA), in four dosages (50; 100; 150 and 200 kg ha-1 of P2O5), a testimony treatment without phosphated fertilization and an additional testimony, with triple superphosphate (TSP) at standard dosage of 120 kg ha-1 P2O5. The fertilizers application conducted was in top-dressing and sowing, without incorporation. At the age of 19 months, the plants’ growth, the characteristics related to the productivity, as well as the content of leaf nutrients, were analyzed. The MAP and SSGA phosphated fertilizers used on the nutritinal reposition of the forests through the management of chisel, at the age of 19 months, presented a greater Agronomic Efficiency Index – IEA than the triple superphosphate. The best results were obtained between the dosages of 117 kg ha-1 and 145 kg ha-1 . From the leaf analyzis was possible to verify that there was absorption of the phosphorus applied according to the dosages, reaching the conclusion that the nutrient was available to the plant and at the right proportion to its development.