Future climate change in the Mediterranean area: implications for water use and weed management

Results obtained within research activity from the Climesco Italian Project are summarized. These results suggest that in regards to the impact of climate change in the Mediterranean area, a decrease of water availability and a more frequent occurrence of drought periods are expected. In order to describe the main effects of climate change on water use in some agro-ecosystems in the Mediterranean area we showed that the Penman-Monteith equation can be modified to simulate future changes in reference evapotranspiration by recalibration of the crop resistive parameter. Moreover, the use of adjusted crop coefficients (Kc) can help quantify the climate change impact on water use for irrigated crops grown in Southern Italy and elsewhere in the Mediterannean. For this region temperature rise and the concomitant expected rainfall reduction may lead to an increase yearly potential water deficits. For autumn-spring crops a further increase of water deficit is not expected. In contrast for a significant increase of water deficit, and thus of irrigation needs, is expected for spring-summer crops. Another aspect considered in this review is how in the Mediterranean area, drought conditions and warmer temperatures will alter the competitive balance between crops and some weed species. We report experimental data showing how weed aggressiveness and competition is already increasing due to warmer temperatures in the Mediterranean region.