Decomposição de esterco bovino e de biomassa de Gliricídia sepium em Neossolo Regolítico.

The use of organic wastes such as manure, crop residues and green manuring to improve soil fertility and agricultural productivity is one of the strategies used by family farmers in the Brazilian semi-arid. In this context, the objective of this study was to evaluate the dynamics of N, P and K after the incorporation of manure or biomass of gliricídia (Gliricídia sepium). The work was conducted within an area with gliricídia rows spaced 6 m between each other and 1 m between trees in a Neossolo Regolítico, in Esperança, PB. The experimental design was a randomized split-plot with two main treatments (with or without gliricídia) and three secondary treatments (fertilization with manure, gliricídia prunnings and control) with four replications. In the experimental plots was measured mineralization of N, P and K in situ in the field for 120 days at 0-20 cm. No significant loss of mass and N, P, K of the decomposition bags of organic fertilizers among the SA and CA systems. The greatest losses of N, P and K occurred during the first two weeks, being higher in the treatment compared to treatment G E, except that the release of K had a similar pattern in both organic fertilizers. Both the SA system, such as CA, throughout the incubation period there was net N mineralization, however there were significant effects of additions of Gliricídia or manure and the control. [ABSTRACT FROM AUTHOR]