Soil CO2 emissions under different land-use managements in Mato Grosso do Sul, Brazil

Abstract

Understanding the variability of soil CO2 emission across several land use and cover (LULC) classes and biomes and its relationship with climate variables is important to drive strategies that contribute to meeting local and international demands for sustainable development and low carbon agriculture. The hypothesis of this research is that soil CO2 emission in situ (FCO2) is variable between LULCs across different biomes and that there may be an association between soil CO2 flux and environmental variables such as temperature and soil moisture. This study evaluated FCO2, measured by a portable EGM-5 CO2 gas analyzer, CO2Flux model (obtained by remote sensing approach), soil moisture (SM), soil temperature (ST) and relationship between these variables in different LULC classes. We identified LULCs can contribute to carbon neutralization actions over the Cerrado, Atlantic Forest and Pantanal biomes located in State of Mato Grosso do Sul (MS), Brazil. Four LULC classes were evaluated in each biome: agriculture (soybean cultivation), pasture, eucalyptus plantation, and native vegetation. A principal component analysis (PCA) was performed to verify the relationship between biomes and LULC classes with the variables evaluated, and a Pearson correlation plot was created to assess the relationship between the variables evaluated. The lowest FCO2 values were found in eucalyptus and soybean crops, regardless of biome. Our findings reveal the existence of soil CO2 flux variability between the different LULCs and biomes. Pasture in Pantanal and Atlantic Forest biomes exhibited the highest FCO2 values. Eucalyptus cultivation and native forest showed negative CO2Flux values, regardless of biome. Lower FCO2 values were also observed for soybean cultivation. Such findings reinforce that native vegetation function as carbon sinks and that, therefore, their conservation is vital for the mitigation of CO2 emissions. However, soybean and eucalyptus farming can be strategic for low carbon agriculture in MS and carbon neutralization projects by simultaneously contribute to economic and sustainable development of the regions covered by the biomes evaluated here.