Studying The Effects of Biological Soil Crusts on Soil Saline-Sodic Properties (Rangeland of Qare Qir, Golestan Province)

Biological soil crusts (BSCs(result from an intimate association between soil particles and cyanobacteria، algae، fungi، lichens and mosses in different proportions، which live on the surface، or immediately in the uppermost millimeters of soil. Biological soil crusts، are important from the ecological view point and their effects on the environment، especially in rangeland، and desert ecosystems. These effects have encouraged researchers to have a special attention to this components of the ecosystems. The present study carried out in Qara Qir rangeland of Golestan province، Iran، to investigate the effects of BSCs on Soil saline-sodic properties. In the study area، four sites were selected which included sections with and without BSCs. Soil sampling was carried out in each section for depths of 0-5 and 5-15 cm، with four replication. The gathered data from soil samples were analyzed by nested plot. Results showed that BSCs than non-BSCs، significantly decrease the amount of soil acidity، calcium carbonate and soil saline-sodic properties such as electrical conductivity، sodium، calcium and magnesium concentration، sodium adsorption ratio، and exchangeable sodium percentage at both depths. In general، it can be concluded that BSCs enhance soil infiltration rate and available water content، that together their bioaccumulation properties، leads to decreasing soil saline-sodic properties. Potassium concentration did not differ among areas covered by BSCs and without BSCs. But infiltration rate and available water content were increased significantly in two mentioned depths on sites covered with BSCs than without BSCs. In general، it can be concluded that BSCs enhance soil infiltration rate and available water content، that together their bioaccumulation properties، leads to decreasing soil saline-sodic properties.