Soil Respiration From Degraded and Managed Pasture in Southeast of São Paulo State, Brazil.

Soil respiration is a process by which the carbon dioxide is released inside soil either by microorganisms or plant roots and delivered to atmosphere (Rochette et al., 1991). However, soil respiration is characterized by a high spatial and temporal variability (Currie 1974), and relation with management practices. This research aimed to study the differences and similarities of soil respiration (FCO₂) from degraded and managed pasture in southeast of São Paulo State, Brazil. FCO₂ was measured simultaneously in both areas in 08 days, during the mornings, with two portable LI-COR systems (LI-8100, Lincoln, NE, USA). In each of those areas a grid having 100 m × 100 m with 102 measurement points was installed, with points distributed at distances from 5–20 m apart. Degraded pasture (DP) is characterized as an area which receives no appropriate management practice in the last 5 years. Managed pasture (MP) is described here as the area that has been managed under crop rotation after sugarcane, with maize and later with Brachiaria brizantha for the last 3 years, in addition with paddock grazing rotation (6 head ha^-1). Our results show average emissions of 8.73 (± 0.86) and 5.96 (± 0.69) µ mol m^-2 s^-1 for DP and MP, respectively. Higher FCO₂ in DP, where plants height and ground cover were lower compared to MP, could point to higher soil C losses in degraded conditions.