A newly established FLUXNET site for monitoring energy exchange and carbon budgets of agricultural cropping systems in Southern Italy

Gaseous emissions in the atmosphere in relation to anthropogenic activities are a growingmenace for the environment at the planetary level. Agriculture and forestry may play a positive role bysubstituting biomasses to fossil hydrocarbons as a source of energy and via sequestration of carbon in theterrestrial sinks. Monitoring C dynamics in agricultural systems is an urgent priority in view of compilingnational inventories of emissions and sinks. Due to the considerable incidence of arable land on emergedlands, the lack of directly measured data contribute to present uncertainties in the assessment of global Cbudget. The present experiment is aimed at monitoring CO2 and H2O net exchange of an irrigatedagricultural system in the course of several growing seasons, in a farm sited in Eboli (Salerno). Alfalfa ispresently grown, at its fourth year from establishment. Continuous monitoring of fluxes was started in July2002 and will be continued throughout all stages of growth. Following, the sod will be cultivated and newcrops established, so that C exchange in response to cultivation and management patterns will be evaluated.The eddy covariance flux monitoring apparatus has an open type configuration. A secondary station, logs ata frequency of 1 Hz the environmental variables needed to check energy balance closure and to model NEEresponse to environment. By adopting the Bowen ratio approach, an independent estimate of fluxes is made- to backup data during eddy station downtimes. Seasonal C budget are checked by destructive samplingsof aerial and below-ground biomass. The relevant soil and canopy variables - according with the ECCARBOEUROFLUX project database - are determined at periodical intervals. By the mean of a labellingtechnique (14C), soil carbon budget will be reconstructed via small scale experiment on monoliths. Thecombination of direct flux measurement and stable isotopes determinations (13C) allows for partitioning ofthe different ecosystem factors of C budget. Concurrent CO2 air concentration and isotopic compositionwill be used to assess sources and sinks of CO2 of the system, adopting the well-known Keeling plottheoretical approach.