Impact of land use change on nitrogen stocks in plinthosols of cerrado

The land use changes and different management forms promote modifications in soil organic matter (SOM), which imply the yield and sustainability of agricultural systems. SOM provides essential elements for plants, such as Nitrogen (N), one of its main constituents, and is also an indicator of soil quality. This study aimed to evaluate the dynamics of N levels and stocks in the soil of Plinthosol in the state of Tocantins, Brazil, under different uses (eucalyptus, corn, and pasture) compared to a natural ecosystem of Cerrado sensu stricto . Therefore, six trenches were opened in each study area to collect soil samples at 0-10, 10-20, 20-30, 30-40, and 40-50 cm soil layers, determining the contents and stocks (0-50 cm) of total N in the soil by dry combustion. The means were compared by the Tukey test at a 5% error probability level. N -S contents and stocks of the evaluated systems did not differ statistically from the reference area, except the eucalyptus area, which presented a higher average content, specifically in the 0-10 cm layer, and a higher average stock, considering the entire layer evaluated (0- 50cm). N -S stocks decreased in the following order across different land uses: eucalyptus > corn = pasture = Cerrado, probably indicating the effectiveness of the arboreal component in incorporating N -S as well as the importance of adopting conservation management practices that prioritize greater input and stabilization of organic matter in the soil.