Measurements of CO2 and N2O emissions in the agricultural field experiments of the MESCOSAGR project

Abstract

Soil organic matter (SOM) under agricultural management is a labile reservoir of C in the planet, and plays a key role in the production and emission to the atmosphere of two main greenhouse gases, CO2 and N2O. This chapter will overview one of the activities of the MESCOSAGR project that is the monitoring of CO2 and N2O emissions from soils under different agronomic treatments. The first part highlights the primary importance at global scale of SOM related to climatic change and agricultural management, including a description of processes involved in the CO2 and N2O evolution from soil. The state of the art of alternative techniques of SOM management in relation to CO2 and N2O emissions is discussed, also on the basis of the scarcity of literature data for Mediterranean croplands. The monitoring system of CO2 and N2O fluxes from field plots of the MESCOSAGR project indicated that compost additions were efficient in reducing fluxes from soils, especially for N2O and for the large compost rates. The role of the compost humified organic matter in exerting a hydrophobic protection against SOM mineralization was thus supported. However, the soil treated with the biomimetic catalyst showed no difference in gases emission from control plots, thereby indicating that the fraction of SOM that was not photo-polymerized continued to be microbially mineralized together with the carbon rhizo-deposited by crop root systems.