Determination of nitrogen mineralization in old and young spruce stands and adjacent grasslands area in Kafkasor region Artvin

Nitrogen mineralization has an important role in plant nutrition and nutrient cycle in soil. To present this numerically, we aimed to determin nitrogen mineralization under standard laboratory conditions for young spruce stands, old spruce stands, spruce rhododendron mixed stands and adjacent grassland in Artvin-Kafkasor region. For this aim, samples were taken from 0-15 cm depth soil in each sampling plot in 2010. Soil samples were taken with 15x15x15 cm steel cube cylinder.Soil texture(%), soil pH, organic matter content(% kg/ha), maximum water-holding capacity(%), and minarel nitrogen(kg/ha), net minarel nitrogen(kg/ha), total nitrogen(%-kg/ha) changes of soil samples were determined.In terms of average values, the highest values of sand content(%) was in spruce-rhododendron stands, clay content(%) was in young and old spruce stands, soil pH was in young spruce stand, maximum water-holding capacity(% mWHC), soil organic material(%-kg/ha), total nitrogen(%-kg/ha) was in young spruce stand. Mean highest net NH4+ value was found on 21st day in grasland, on 42nd day in spruce-rhododendron stand and on 63rd day in grassland. Average highest net NH4+ + NO3- value was found on 21st day in spruce-rhododendron stand, on 42nd and 63rd days in grassland.In respect to total nitrogen mineralization, it was higher in grassland than the other vegetation types. Total nitrogen mineralization was the lowest in spruce stands having rhododendron understory. Our results indicates that, rhododendron decreases nitrogen mineralization.Keywords: Total nitrogen, net mineral nitrogen, soil texture, organic material, Artvin-Kafkasor region