La Mineralización del Nitrógeno libera a la solución de suelo NH + y NO - los cuales son tomados e inmovilizados por la planta. Con la hipótesis que el uso de Abonos verdes (AV) y Compost (CO), aumentan la disponibilidad de estas formas inorgánicas de N, de forma semejante a los fertilizantes nitrogenados de síntesis industrial, se establecieron bloques completos al azar con cinco tratamientos y tres repeticiones: Testigo absoluto: cultivo con manejo local sin ninguna adición (T), Fertilización química (FQ), Incorporación de una mezcla de AV (AV), Incorporación de Compost (CO) e incorporación de una mezcla AV y Compost (AVC) evaluados en cinco muestreos. Se evaluó el efecto de incorporar dos AV sobre los contenidos de nitrógeno del suelo, las poblaciones de bacterias nitrificantes, las tasas de mineralización neta (Totales y Puntuales) y las tasas de nitrificación neta y se relacionaron con el rendimiento de Maíz Zea mays L. en Palmira, Colombia. Las poblaciones se calcularon con el método del Número más probable, N-NH4, N-NO3 y N Total mediante espectrometría, CIAT 2006. Los resultados se analizaron mediante SAS versión 9.1.3. Los contenidos de N amoniacal, nítrico, inorgánico total, orgánico, total y las poblaciones de nitrificantes no presentaron diferencia significativa entre tratamientos. Las tasas de mineralización neta (Totales y Puntuales) y las tasas de nitrificación neta tampoco presentaron diferencia significativa entre tratamientos.//Abstract: Based on the hypothesis that the use of green manure and compost increases availability of inorganic forms of nitrogen in a similar way to that of industrially synthesized nitrogenated fertilizers, complete randomized blocks were established using five treatments replicated three time as outlined below. These forms of inorganic N, namely NH + and NO -, mineralized from organic N are releases into the soil solution and then absorbed and immobilized by the plants. The field trial had a control treatment; locally managed maize Zea mays crop with any addition of fertilizer or manure (CT), a treatment including chemical fertilization (CF), a treatment with a mix of two green manure (GM), another with compost (CO) and a treatment where the soil was amended with a mix of green manure plus compost (GMC). Soil samples was taken at five different stages from crop located in the municipality of Palmira, Colombia. The effect of incorporating two different kinds of GM on the populations of nitrifying bacteria, on soil nitrogen (Inorganic, Organic and Total) contents and on the mineralization rates (Overall and Specific) and nitrification net rates, was evaluated. Pearson correlation coefficients were determined between the earlier sources of variations on soil and the yield of maize crop. The population sizes of nitrifying bacteria were calculated using the most probable number method MPN and N-NH4, N-NO3 and total N determinations were made by spectrometry with autoanalyzer (CIAT 2006). The results were analyzed using the 9.1.3 version of the SAS software package.