IWRA Proceedings

Abstract The monitoring and quantification of CO2 released to the atmosphere by the rural production systems is an uprising need when facing the actual challenge of global warming. It is known, that in the last decade the change of land use and silviculture activities have contributed in a significant manner in the net emissions of CO2 to the atmosphere. However, is not quite clear the magnitude of the contribution of each individual ecosystem, and even it is least known the contribution of the separate action of the soil-plant system components. There are three methods for monitoring and quantifying the CO2 flux in an extensive open area condition: i) Open or close use of interchange gas chambers; ii) Using the technique of the Bowen Relation Method; and iii) Using the Eddy Covariance Method. In this experiment, the last mentioned was used for its high reliability in the measurements of mass and energy flux in extensive land conditions. The experiment was carried out at Rancho “Los Angeles” Municipality of Saltillo, Coahuila, México (25º 6.650’ N and 100º 59.413’ W). It was measured the CO2 flux, in plots of 2.4 ha after removing the native vegetation, dominated by three families (Chenopodacea, Euphorbacea y Asteraceae), using two tillage treatments: vertical tillage by chiseling (VT) and conventional tillage by disc ploughing (CT), the flux was measured as well in a reference plot without tillage treatment (NT). In all plots it was determined the magnitude of flux for each component at the soil- plant system. The results showed that under the predominant climatic conditions at Autumn 2006, when separating the components of the soil-plant system from the CO2 total flux monitored (FCO2tm), the more important contribution came from the soil at both tillage methods used (FCO2sLV=66 % and FCO2sLC=74 %).