Because of the importance of meteorological variables in different processes that occur in the soil, the objective of this work was to evaluate the kinetics of carbon dioxide evolution (microbial activity) associated with the meteorological elements in areas in caatinga in the semiarid conditions of Paraiba. The experiment was set in the field, in the Bacia Escola/CCA/UFPB, municipality of São João do Cariri - PB. The daytime microbial activity, measured by the release of CO2, was evaluated monthly from January to December 2008, in three adjacent areas of Caatinga corresponding to the treatments: T1 (10 animals - 1 animal/3,200 m²), T2 (5 animals - 1 animal/6,400 m²) and T3 (control - no animals). The total area of the experiment was 9.6 ha and for each treatment it was used an area of 3.2 ha. Six points of collection (set at random)were selected from each treatment. The treatments were distributed in completely randomized block design arranged in sub-divided plots (3×12×6), and 3 stocking rates (Plot), 12 periods of evaluation (sub-plots) and 6 hours of evaluation (sub-subplots) and 3 blocks. The methodology was based on the principle that the CO2 released by an area of soil is absorbed by a solution of 0.5 N KOH and determined titrimetricallyc with HCl 0.1 N. The evolution of CO2 varied throughout the day in function of weather factors, mainly temperature. The rate of CO2 tended to release more in the afternoon. Due to the importance of soil and air temperatures in many processes that occur in soil, more studies are needed in the semiarid region of Brazil.
