Adubação com N, P2O5 e K2O apenas em cobertura no crescimento de Eucalyptus urograndis na região do Pontal do Paranapanema-SP

Abstract

In a study performed at the field level by sector, we studied the effect of different levels of fertilization with nitrogen, phosphorus and potassium on the growth of Eucalyptus urograndis in relation to diameter at breast height (DBH), total height (H) and increase annual average (IMA m3.ha-1). The work was carried out at New District, Cuiaba Paulista-SP, in the region of Pontal, on the 05th of November 2007. The experimental design was a randomized block design with four replications in factorial scheme (3 x 3 x 3) to nitrogen (0, 30 and 60kg ha-1 of N), phosphorus (0, 40 and 80kg ha-1 of P2O5) and potassium (0, 30 and 60 kg ha-1 of K2O), in an area already planted, no fertilizer, with 6 months of age. The treatments were composed of 15 plants, of which only three plants were measured. Measurements in relation to the DAP was a tape measure and the total height of the plant with dendrometric clipboard. Evaluations were performed at 6 and 24 months after implantation, respectively in May 2008 and November 2009. Statistical analysis consists of analysis of variance by the Tukey test at 5% probability to compare the treatment means. There was also no influence on the calibration of different doses fertilization rates, P, K, NxK interaction, interaction Nx P and P x K interaction significantly in the variables already listed. Studies calibration of NPK in relation to the location and time of application are suggested. The non-response from the application of N, P2O5 and K2O, 6.0 months in the cover, is probably not located at fertilization, especially of P2O5, a soil with very low levels of this nutrient (2mg.dm-3 resin), and secondarily to the late implementation of treatment, associated with its incorporation to 15cm deep.