Papers

Summary

The spatial and temporal variation of soil CO₂ emission is influenced by several soil attributes related to CO₂production and its diffusion in the soil. However, few studies aiming to understand the effect of topography on the variability of CO₂ emissions exist, especially for cropping areas of tropical regions. The objective of this study was to evaluate the spatial and temporal changes of soil CO₂ emission and its relation to soil attributes in an area currently cropped with sugarcane under different relief forms and slope positions. Mean CO₂ emissions in the studied period (seven months) varied between 0.23 and 0.71, 0.27 and 0.90, and 0.31 and 0.80 g m^–2 h^–1 of CO₂for concave (Conc), backslope (BackS) and footslope (FootS) positions, respectively. The temporal variability of CO₂ emissions in each area was explained by an exponential relation between the CO₂ emission and soil temperature and a linear relation between CO₂ emission and soil water content. The Q₁₀ values were 1.98 (± 0.34), 1.81 (± 0.49) and 1.71 (± 0.31) for Conc, BackS and FootS, respectively. Bulk density, macroporosity, penetration resistance, aggregation and oxidizable organic carbon content explain the changes in soil CO₂ emission observed, especially when the Conc position was compared to BackS. The effect of relief form and topographic position on soil CO₂ emission variation was dependent on the time of measurement