Effect of broadleaved tree species on chemical and microbial soil properties in plain forest of Noor

Forest soil characteristics can be strongly influenced by tree species and seasons. A few studies have been carried on the effect of single trees in different seasons on soil characteristics. Therefore, in this study, the effect of Parrotia persica (DC.) C. A. Mey., Ulmus minor Miller, Quercus castaneifolia C. A. Mey. and Populus caspica Bornm. species on some of chemical and microbial features of topsoil were considered in the fall (November 2016) and summer (August 2018) seasons in plain forest of Noor city (Mazandaran province, northern Iran). Five replication of each species was regarded; soil samples were taken from 15 cm of depth under tree canopy cover from four sides of the tree trunk and kept at 4° C for experimentation. Afterward, some chemical characteristics [i.e. organic carbon (C), total nitrogen (N) and C/N ratio], and microbial indices [i.e., basal respiration, microbial biomass carbon (MBC) and nitrogen (MBN) and their ratio] were measured and calculated. Two-way ANOVA and the Duncan multiple tests were employed to analyzing statistical characteristics. Results showed that seasonal changes, in spite of significant differences in microbial indices, had no effect on chemical characteristics. The highest MBC, MBC/MBN ratio, and organic carbon content were observed in the soil of Q. castaneifolia, while MBN and total N content were higher in soil of P. caspica. The findings indicated that P. caspica due to having the highest MBN, total N, and lowest C/N ratio, creates better conditions for microbial activities than other species and can be considered to improve soil quality in the region.