Biocrusts Influence on Soil Infiltration in Aridlands:
A Case Study of Turkmen Steppe, Iran

A. Tavili & M. Jafari

Faculty of Natural Resources, University of Tehran, Karaj, Iran
e-mail: atavili@ut.ac.ir

Abstract

Biological soil crusts occur as assemblage of lichens, mosses, liverworts and cyanobacteriaes. Lichens and mosses are the two important components of biological soil crusts, especially in arid and semiarid rangeland environments, where vascular plants vegetation is poor. Available information indicates that biological soil crusts contribute to a variety of ecological functions such as soil stabilization and vascular plants establishment, but their role in infiltration is not well understood and results of reported researches have been conflicting. Current study was conducted to show effects of biological crusts on soil infiltration on Qara Qir rangelands in Turkmen steppe, with an annual precipitation of 240 mm. For this, double ring method was used to determine infiltration rate under crusted and uncrusted soil conditions during a 90 minutes time. The time intervals were considered as 0, 10, 30, 45, 60, and 90 minutes. Since research was performed at one site with the same climate, topography, vascular plants, and soil texture, so the difference of understudy points was related to absence and presence of lichens and mosses. Infiltration of crusted and non-crusted soils was compared using t- test. Results showed that due to increasing soil surface roughness, infiltration was significantly higher in crusted soil compared to uncrusted one. Infiltration of crusted and uncrusted soils at the starting and ending times of measurement were 6.2 versus 3.2 and 1.6 versus 0.7 mm/min, respectively. Therefore, one can conclude that presence of lichens and mosses in Qara Qir rangelands is important in view point of soil-water relations.

Keywords: Biological soil crusts, Moss, Lichen, Infiltration, Double ring, Rangeland, Qara Qir