Assessing Short-Term Temporal Variability of CO2 Emission and Soil O2 Influx in Tropical Pastures and Regenerating Forests

Wanderson Benerval De Lucena 1, Kleve Freddy Ferreira Canteral 1, Maria Elisa Vicentini 1, Daniele Fernanda Zulian 2, Renato Paiva De Lima 3, Mario Luiz Teixeira De Moraes 2, Maurício Roberto Cherubin 4,5, Carlos Eduardo Pellegrino Cerri 4,5, Alan Rodrigo Panosso 1 and Newton La Scala Jr. 1

1Department of Engineering and Exacts Sciences, Faculty of Agricultural and Veterinary Sciences (FCAV), São Paulo State University (Unesp), Jaboticabal 14884-900, São Paulo, Brazil
2Department of Phytotechnics and Food Technology and Socioeconomics, School of Engineering (FEIS), São Paulo State University (Unesp), Ilha Solteira 15385-007, São Paulo, Brazil
3Agricultural Engineering College (FEAGRI), University of Campinas, Campinas 13083-876, São Paulo, Brazil
4Department of Soil Science, “Luiz de Queiroz” College of Agriculture (Esalq), University of São Paulo (USP), Piracicaba 13418-900, São Paulo, Brazil
5Center for Carbon Research in Tropical Agriculture (CCARBON), University of São Paulo (USP), Piracicaba 13418-900, São Paulo, Brazil

Abstract

Soil respiration, the exchange of gases between soil and the atmosphere (O2 consumption and CO2 production), plays a key role in ecosystem functioning and climate regulation. This study investigated the short-term temporal variability of soil CO2 emissions and O2 influx and their relationship with tropical climate conditions and soil attributes in the Cerrado region, Selvíria, MS, Brazil. Soil CO2 emissions were measured using the LI-8100 portable system, while soil O2 influx was estimated by linear interpolation of O2 variation inside the chamber using a UV Flux 25% (ultraviolet light) sensor. Soil temperature and moisture were measured simultaneously in three land use types: pasture (~11 years) and reforested areas with native species and eucalyptus (~35 years). Soils were classified as Oxisoils according to Soil Taxonomy. Significant short-term temporal variability was observed in CO2 emissions (mean 3.2 ± 0.5 µmol m−2 s−1), O2 influx (mean 1.8 ± 0.3 mg O2 m−2 s−1), soil temperature and moisture across the land use types. Pasture areas exhibited the lowest CO2 emission rates, associated with improved soil attributes (soil organic matter, sum of bases and pH) due to management practices, while reforested areas showed overlapping soil respiration patterns and higher temporal variability. Principal component analysis revealed strong coupling between O2 influx and CO2 emission in reforested soils. These findings highlight the influence of land use on short-term soil respiration dynamics and underscore the importance of sustainable pasture management and reforestation in the Brazilian Cerrado. The results also support public policies aimed at restoring degraded pastures, reducing deforestation and burning, and enhancing soil carbon sequestration to mitigate climate change.
Keywords
soil respiration; pastures; reforested areas; land uses; nature-based solutions