EFECTO DE LA INCORPORACIÓN DE RESIDUOS ORGÁNICOS Y DOS TIPOS DE LABRANZA SOBRE LA ACTIVIDAD DE LA UREASA EN UN ALFISOL

 Palabras clave: AbstractA study was performed in order to evaluate the enzimatic acti-vity (urease) on an Oxic Haplustalf of the agricultural area of the Yaracuy valley (Yaritagua, Estado Yaracuy, Venezuela). The soil tillage was done with minimum and conventional til-lage operations and maize was planted. Three kinds of organic residues (Crotalaria juncea, Pennisetum purpureum y Pha-seolus lunatus) were incorporated. Sampling was made (every 15 day) two depths (0-10 cm and 10-20 cm) and urease activity was determined. Urease activity varied from 91 to 156 ìg urea.g soil-1.h-1 in the first 10 cm, and 66 to 109 ìg urea g soil1. h-1 at 0-20 cm depth in the different treatments. The variation in the enzimatic activity was possibly due to changes in the soil moisture level.Key words: Organic residues, urease, Yaracuy, tillage &nbsp