Andisols of deserts in Iceland

Desert areas cover 35 to 45 000 km(2) of Iceland or about 35 to 45% of the country. These surfaces have very low vegetation cover as a result of several environmental factors and anthropogenic impacts. A good understanding of the soils of the deserts is a key factor for successful restoration of these ecosystems. Very limited data has previously been published about the soils of Icelandic deserts and limited research has been reported on soils that form in basaltic tephra materials under similar conditions elsewhere in the world. The purpose of the research reported here was to gain a basic understanding of properties, variability. and classification of the soils of Icelandic deserts. Eight soil pedons, representing a variety of desert surfaces, were described, sampled, and analyzed for key physical and chemical properties. The morphology was generally characterized by a frost-heaved gravel layer at the surface, with finer subsurface horizons with abundance of volcanic glass. The soils had low organic content (< 10 g kg(-1)), and very low levels of N. Water holding capacity was generally < 50 g kg-1 at 1.5 MPa. Phosphorus retention is 24 to 93% in A and B horizons. The soils were near neutral in reaction but the pH in NaF solution was commonly around 10. Mineralogy was dominated by volcanic glass, but allophane and ferrihydrite are also present. The results of this study show that most Icelandic deserts soils are Typic Virtricryands according to soil taxonomy. Icelandic Andisols combined are 5 to 7% of the world's Andisols.