Investigation of the microbial and soil invertebrates’ biodiversity indices of hard wood and soft wood plantations in west of Guilan province

This study was carried out to investigate the effect of different plantations on the activity of soil organisms, biodiversity indices and their relationships with the measured soil physical and chemical characteristics. Sampling of soil, soil organisms and microbial indicates were done in plantation of Populus deltoides, Pinus taeda and natural forest stand by random systematic method. In each mentioned tree stands, 40 places were selected and soil samples were taken from a depth of 0-20 cm.
The results showed that the highest microbial respiration, microbial biomass carbon, microbial biomass nitrogen and bacteria were observed in Populus deltoides and natural forests. Two indicators of metabolic and microbial also showed significant differences among the stands. The result of Pearson correlation between microbial indicators and different soil properties showed that there is a positive and significant correlation between these indicators and organic carbon and total nitrogen.
On the base of this study, it is declared that the variations of soil qualities properties and the diversity indices are proportional to the properties and the forest site productivity. Population of macrofauna, as an indicator of the site productivity, will be suitable indicators for evaluation of the forest management roles related to ecosystem conservation and permanency. Based on the results, Populus deltoides compared to the other forest stands showed favorable conditions to produce more organic matter and microbial respiration.