Translocation of soils to stimulate climate change: CO₂ emissions and modifications to soil organic matter

The effect of climate change on CO₂ emissions was studied on undisturbed soil monoliths (40-cm diameter, 25-cm high), which were translocated to warmer zones than their place of origin. Thirty-two months after the translocation, a climatic factor deduced from the moisture content of the soil and from the effective mean temperature (temperatures in excess of 5°C) revealed that translocation increased the potential of the climate to enhance the biological processes by between 73% and 26% compared with what the soil would support in its place of origin. At the end of the study, the transported soils had lost a large proportion of both total carbon and nitrogen (between 20 and 45%). During the experiment, the CO₂ emissions from the soils, measured under field conditions, were quite variable, but were usually greater than from soils in situ. The variation in labile C in the soil throughout the experiment was calculated from a first-order kinetic equation for organic matter decay. The relative CO₂ emissions, expressed in terms of the labile carbon fraction in the soils, were clearly greater in those translocated soils that underwent the most intensive climate change, which indicates that the variations in emissions over time are basically a function of the size of the labile organic matter pool.