Here we investigate how cardoon (Cynara cardunculus L.), energetic crop cultivated under Mediterraneanclimate in rainfed conditions, is adapted to the environment. Two main resources used for producingbiomass are analysed in detail: water (H2O) and carbon dioxide (CO2). Following micrometeorologicalapproach, the eddy covariance technique has been used for monitoring H2O and CO2exchanges betweencanopy and atmosphere in order to investigate the dynamics of the cardoon growth at field level andto compute the Gross Primary Production (GPP). The dynamics of canopy CO2assimilation in termsof GPP, evapotranspiration (ET) and water use efficiency (WUEGPP, as ratio between seasonal GPP andseasonal ET and WUEagroas ratio between yield and seasonal ET) were analysed during three successivegrowth seasons in a south Italy site. The environmental drivers of CO2assimilation and ET were analysedat instantaneous scale. The crop showed increasing resource use efficiency along the three seasons ofexperiment for all considered resources: in particular, for the last two seasons cumulated GPP increasedand cumulated ET decreased. It seemed to require a season for its establishment to the environment,improving the use of water and CO2assimilation in the second and third season.