the effects of biological soil crusts on soil hydrologic properties in range land 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. therefore bscs cover the ground surface as a coherent layer, and influence primary processes such as carbon and nitrogen fixation and hydrologic status. this study carried out in qara qir rangeland of golestan province, northeast of iran, to investigate the effects of bscs on soil hydrologic indices. four sites including covered of bscs and without bscs cover areas were selected. infiltration rate, soil water content, available water content, organic carbon percent, and particle size distribution were measured in depths of 0-5 and 5-15 cm, with four replication. the gathered data were analyzed by nested plot, and the mean values comparison were done by duncan test. results showed that particle size distribution did not differ among areas covered by bscs and without bscs. infiltration rate, soil organic carbon, soil water content, and plant available water content were increased significantly in two mentioned depths due to the effects of bscs. in general it can be concluded that bscs improve soil hydrologic conditions.