Interannual variability of corn NEE in a Mediterranean cropping system

The study was carrried on in an irrigated croping system in Borgo Cioffi (BCIt, Salerno, Italy). The site was started in summer 2002, and turbulent exchange of mass and energy has been monitored continuously since then on alfalfa, Lolium grass and Florence fennel crops. Quality check and gap filling were performed according to standard CaroEurope procedures. In the present work, crop behaviour in terms of NEE, GPP, ecosystem respiration and their response to environmental drivers was compared across three consecutive years with fairly different weather conditions and management. Sub-optimal irrigation and consequent water availability was the main driver for the contrasting response throughout the crop cycles and the difference in final crop yield. On an annual basis though - when taking into account the contribution of the preceeding Florence fennel crop - a comparable mean NEE slightly exceeding 300 micromols m2 s-1 was recorded.