EVALUATION OF NET NITROGEN MINERALIZATION RATES AT Pinus brutia TEN. FORESTS AND MAQUIS SHRUBLANDS IN SOUTHERN TURKEY

摘要

The current study aimed to illuminate net nitrogen mineralization rates at different aged and originated Pinus brutia Ten. forests under Mediterranean climatic conditions. With this intention, we sampled 7 different locations covering ages from 2 to 70 years old forests which are planted or naturally regenerated. Additionally, we sampled a maquis land on which the vegetation is mainly comprised by Quercus coccifera, Juniperus excelsa, Olea europea var. sylvestris, Philyrea latifolia and Pistacia terebinthus. The sampling was conducted in 2009 for laboratory incubation and basic soil properties, such as pH, soil total nitrogen, soil organic carbon, texture and CaCO_3 contents which were determined to investigate their relations with the net N mineralization and net N nitrification rates. The net N mineralization amounts were significantly higher at younger stands with 8.48 and 4.49 mg NH/-N kg(-1) mo_(-1) at 7 and 2 years old pine plantations, respectively. In conclusion, we found that stand age has the major effect on net N mineralization. We have detected only limited amount of net nitrification at 2 years old naturally regenerated forest sites. We can conclude that mineralization rates at Mediterranean ecosystems are considerably affected by stand age and structure.