Download or read book Emissions de compos s organiques volatils COV par quatre esp ces v g tales m diterran ennes ligneuses written by Romain Olivier and published by . This book was released on 2010 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biogenic volatile organic compounds (BVOC) are atmospheric gases originating from the secondary metabolism of plants and sometime stored in their leaves under oil forms. Once released in the air, they contribute to chemical reactions leading to the formation of different polluting compounds, including ozone, a greenhouse gas. BVOC emissions are regulated by some environmental parameters among which soil nutrient status showed a non-negligible but still unclear influence. For some years, sewage sludge compost spreading have been tested in Mediterranean shrubland, in order, on the one hand, to restore lands degraded by frequent and mostly anthropogenic fire, and on the other hand, to find a recycling alternative to these wastes whose production keeps increasing. Since these Mediterranean ecosystems are composed of many BVOC emitting species, our study aimed at assessing, through several experimentations, the impact of sewage sludge compost, and more widely fertilizers, on BVOC emission rates and therefore on atmospheric pollution processes. In a first plant nursery study, we assessed the effect of a chemical fertilization on pot-grown Quercus pubescens isoprene emission, in shade or full sun growth conditions. This study showed a significant diminution of isoprene emissions under the highest fertilizer dose, whatever light growth conditions. In two other studies, we assessed the effect of sewage sludge compost spreading in a Mediterranean shrubland, under two doses, on BVOC emissions and contents of Rosmarinus officinalis, Cistus albidus and Quercus coccifera. Seasonal observations were also monitored for this last species. Both studies presented a relatively weak effect of compost on plant nutrition and BVOC emissions. The different studies of this project showed that the predominant effect on plants of fertilizer or amendment supply was the increase of their growth, especially their leaf emitting biomass. Thus, at the landscape scale, these practices may induce, via a better growth of emitting species, an increase of BVOC emissions much more higher than that observed at the leaf level.