Effect of Afforestation on Soil Carbon and Nitrogen Content on a Mediterranean Island (Lampedusa, Italy)

During the 20th century, large surfaces in the Mediterranean countries were subject to afforestation activities, mostly affecting abandoned agricultural lands. Under semi-arid climate conditions, Pinus spp. were the most frequently used species for these activities. The effect of pine plantations on soil organic carbon (SOC) and nitrogen (N) content in Lampedusa Island (South Italy) was investigated. SOC and soil N content under pine plantations of different ages (14, 24 and 43 years since plantation) were compared with SOC and soil N content in garrigue communities, which were dominated by shrubs, subshrubs and perennial herbs. The results showed that SOC content is affected by plantation age, with values of 26.5, 41.3 and 44.4 Mg ha-1 in soils under pines planted 14, 24 and 43 years ago, respectively. There were no significant differences in SOC and N between pine afforestations and garrigues. Our results contribute to improve knowledge on the effect of pine afforestations on soil carbon (C) stocks, aimed to evaluate the optimum management strategies of abandoned agricultural land (spontaneous secondary succession versus plantation) in semi-arid environments.