Temperature regulation of soil carbon dioxide production in the Humid Pampa of Argentina: estimation of carbon fluxes under climate change

Our objectives were to quantify the effect of abiotic factors on CO₂ emissions in the Humid Pampa of Argentina and estimate the potential increase in CO₂ fluxes from this agricultural soil as a consequence of climate change. The experimental site was located at Pergamino (33°56'S, 60°34'W), on a fine, illitic, thermic Typic Argiudoll soil. In situ CO₂ production presented an exponential relationship with air temperature. C liberated annually by mineralization was estimated by integration of monthly respiration measurements and amounted to 8.4 t C ha^-1 year^-1. Future monthly CO₂ fluxes were calculated for the climate change scenario (doubled atmospheric C concentration) using mean monthly temperatures predicted for Pergamino. An increase of around 50% in CO₂ emission from agricultural soils in the Humid Pampa could be expected as a consequence of climate change. The effect of the climate change scenario projected by the global climate models for the Humid Pampa indicates a reduction of the biomass production of cereal crops. Consequently, the predicted decrease in C inputs to soil for this region and an important increase in soil C mineralization would result in marked future C losses.