Investigation of microbial biomass content change and determination of chemical and physical properties of soils in oriental spruce stands and adjacent grasslands in Kafkasör region, Artvin.

The objectives of this study were to determine changes in some soil properties and soil microbial biomass in Spruce stands regenerated during 1984-2005 planning term and in adjacent grasslands. These soil properties will be determined in 3 sampling points(total 12 points) taken from each of young spruce stands, old spruce stands, old spruce stands with a Rhododendron ponticum L. understory and grassland areas. Microbial biomass will be determined by Chloroform Fumigation-Extraction method on soil samples taken from 0-15 and 15-30 cm soil depths in summer and autumn. Microbial biomass carbon of study areas were found between 138,06 μg g-1 and 2318,66 μg g-1 in topsoil, 5,11 μg g-1 and 511,80 μg g-1 in subsoil and also decreased with depth. Besides mean values were observed highest in old spruce stand with understory and lowest in young spruce stand and either increase or decrease from summer to autumn were observed in study areas. Microbial biomass nitrogen of study areas were found between 82,36 μg g-1 and 429,66 μg g-1 in topsoil, 10,45 μg g-1 and 136,10 μg g-1 in subsoil and also decreased with depth. Besides mean values were observed highest in grassland and lowest in young spruce stand and increase in grassland and decrease in all spruce stands were observed from summer to autumn. Positive correlations between microbial biomass carbon with Corg, Ctotal and Cmic/Corg and between microbial biomass nitrogen with organic matter, Ntotal and Nmic/Ntotal were observed. The results obtained showed that carbon and nitrogen reserve may increase during the vegetation period and organic matter has a stability but converse of these by microorganisms activity is related to substrat quality and availablity in soils of study area.