Physical, chemical and microbiological soil attributes influence soil greenhouse gases fluxes in Atlantic Forest and pine (Pinus taeda) plantations in Brazil

Abstract

AbstractForest soils can be sources or sinks of greenhouse gases (GHGs) depending on soil attributes that affect biomass and activity of soil micro‐organisms involved in GHGs fluxes. In this work, we tested the hypothesis that soil physical, chemical and microbiological attributes, under different forests ecosystems, affect the soil GHGs [nitrous oxide (N2O), carbon dioxide (CO2) and methane (CH4)] fluxes. The study was carried out in two locations in southern Brazil in 2019, with three experimental plots of 900 m2 in native forests of the Atlantic Forest biome and in loblolly pine (Pinus taeda) plantations. Air samples released from the soil surface were analysed for concentration and flux of CO2, N2O and CH4. Soil samples were analysed for chemical attributes, density (Ds), soil microporosity (MiPs), soil macroporosity (MaPs), total porosity (TP), water‐filled pore space (WFPS), microbial biomass carbon (MB‐C), basal respiration (BR), microbial (qMic) and metabolic (qCO2) quotient and activities of soil urease and β‐glucosidase enzymes. The seasons influenced the CO2 and N2O emissions, probably because of the changes in seasonal conditions. However, native forests consumed more CH4 than pine plantations. Meanwhile, the native forests presented soils with lower Ds (average 21.5% lower), more TP (average 12.5% higher) and more moisture (average 33% higher), which improved the microbiological attributes of the soil (20% to 60% more MB‐C, 67% higher urease activity and 30% higher β‐glucosidase activity) compared with pine plantations. Native forests contributed more intensely to CH4 consumption than pine plantations because they present better physical, chemical and microbiological soil conditions. Therefore, it is possible that forestry practices that improve soil physical attributes are likely to contribute to increase CH4 consumption, and to reduce GHGs emissions in forest ecosystems.