The implantation of species that perform soil fertility beneficial processes, such as green manures, allows the best crop development, and it becomes possible to maintain the productivity of this resource. The present work aims to evaluate the physical, chemical and biological attributes in soil under influence and without influence of guandu bean canopy in two sampling periods, having soil comparison area in secondary vegetation conditions at two different depths, in order to to determine the possible influence of the Cajanus cajan (L. Millsp.) guandu bean canopy on the organic matter (MO) mineralization, and on the better nutrient availability to the soil. The analyzes were performed at Fazenda Semper Verde, in Pacajá, PA. The experimental design was completely randomized, applying the ANOVA and Tukey test in areas with three different treatments, being T1-area of secondary vegetation, T2-area under influence of guandu bean crown and T3-area without influence of guandu bean. Physical attributes were evaluated: soil density (SD) and particle size, chemical: pH in water, total nitrogen (N), organic matter (OM), organic carbon (Corg), carbon and nitrogen ratio (C/N), and Biological: identification and quantification of bacterial colonies through the bacterial colony forming unit (CFU). Undisturbed soil physical samples were collected with Uhland auger by the aid of volumetric ring, and for particle size, chemical and biological with Dutch auger at depths of 0-20 and 20-40 cm, in February (rainy season) and October (period In general, the higher soil moisture content collected during the rainy season had a negative numerical influence on the highest values for density, lower values of hydrogen potential (pH), nitrogen and positively for higher carbon contents. Organic (Corg) and Organic Matter (MO). The DS was numerically decreased for area under influence of the guandu bean canopy, when the soil was collected in the dry season, demonstrating the importance of the legume root system for the soil decompression process. The pH and N values increased statistically at both depths and all treatments. The area under influence of guandu beans showed better results when compared to the other areas for N input in the 0 to 20 cm layer with 16.5 g / kg and 20 to 40 cm 11.5 g / kg, higher. CFU number at dilution10ˉ² with 0.743 CFU, reduction of C / N ratio in the 0 to 20 cm layers, from 5 to 0.3 and from 20 to 40 cm 10 to 0.2, making this culture recommended for improvement of these parameters and enabling the improvement of soil fertility reducing financial costs to the producer.
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