A substituição da floresta por outro tipo de uso do solo pode levar a perdas significativas na matéria orgânica do solo, alterando sua dinâmica e como consequência alterando as entradas e saídas de nutrientes do sistema. Neste trabalho o objetivo foi avaliar o estoque de nutrientes em diferentes sistemas de uso de solo em Colorado do Oeste-RO. Os sistemas avaliados foram o agroflorestal (teca e cacau), florestal (teca com cinco anos), teca com oito anos, agrossilvopastoril (teca, cacau e pasto) e pastagem tendo a mata nativa como referência. Em cada sistema foram abertas três minitrincheiras, nas quais foram coletadas amostras deformadas e indeformadas nas profundidades de 0 a 5, 5 a 10, 10 a 20 e 20 a 30 cm. Nessas amostras foram determinados os nutrientes: N, P, K, Ca e Mg, a matéria orgânica, a densidade do solo e os teores de argila. The replacement of forest by other land use can lead to significant losses in soil organic matter, changing its dynamic and the nutrients inputs and outputs of the system. The objective of this study was to assess nutrient stocks under different land use systems in Colorado do Oeste-RO. The agroforestry (teak, and cocoa), forestry (teak with five years), teak for eight years, farming areas (teak, cocoa and pasture) and pasture were the systems evaluated and the native forest was taken as reference. In each system three small trenches were dug, in which deformed and undeformed soil samples, at depths of 0 to 5, 5 to 10, 10 to 20 and 20 to 30 cm were taken. In these samples the nutrients N, P, K, Ca and Mg, organic matter, bulk density and clay content were determined. A completely randomized design with split plots and, three replications in each system was adopted. Differences were observed in soil nutrient stocks among the usage systems and with depth. The concentration of nutrients was influenced by the system. Ca was the nutrient most stored (2912.86 to 5188.48 kg ha -1 ) in all systems and K was the least(17.33 to 46.22 kg ha -1 ). The system of teak five years is the system which is closer to the forest, for the storage of nutrients.

Aims: The objective of this work was to evaluate the performance of agrometeorological models for estimating the yield potential of corn in municipalities of the State of Mato Grosso, referring to the 2014/2015 harvest period. Location and Duration of the Study: Due to their great potential on corn crop cultivation, four cities were chosen within the State of Mato Grosso: Nova Mutum, Lucas do Rio Verde, Sorriso and Sinop. 2014/2015 harvest period. Methodology: The yield data were obtained by the Farming Economy Institute of Mato Grosso-IMEA. The physiological ripening cycle considered was 120 days and the seeding period 02/02/2015 and harvest 01/06/2015. In order to calculate yield and the water stress, it was necessary to gather data from meteorological stations near the cities where the work was produced, these data were available at the National Institute of Meteorology. The estimated potential yield data were compared among the agrometeorological models, as well as the real yield obtained in the selected municipalities. Results: The estimated potential yield data were compared among the agrometeorological models, as well as the real yield obtained in the selected municipalities. There were variances between the agrometeorological models studied, on average estimated 5413.68 kg ha-1 at model 1 and 6766.45 kg ha-1  аt the model 2 (Table 3). It was observed that Model 1 estimated greater yield for Nova Mutum, followed by Sinop, Sorriso and Lucas do Rio Verde, and yet the Model 2 estimated greater potential for Lucas do Rio Verde, followed by the municipalities of Sinop, Sorriso and Nova Mutum (Picture 1 and Table 3).   In this regard, the model 2 has characterized the closest potential yield, from the environment yield reality. Conclusion: The Model 2 has characterized the potential yield closer to the reality of production environment. The difference of all potential yield of corn from all municipalities studied were all directly related to factor interaction which interferes on its growth and development, consequently the difference among these environments. Taking into account the effects of water conditions, the chosen period for seeding can harm the corn yield in the municipality of Lucas do Rio Verde.