Two Causes for Runoff Initiation on Microbiotic Crusts: Hydrophobicity and Pore Clogging

Infiltration and water retention of biological soil crusts on reclaimed soils of former open-cast lignite mining sites in Brandenburg, north-east Germany

“…Chen et al, 2014;Colica et al, 2014;Fischer et al, 2010;Katznelson, 1989;Kidron et al, 1999;Malam Issa et al, 2009;Mazor et al, 1996;Rossi et al, 2012) was mentioned as one reason for the decreasing infiltration and higher water repellency. However, cyanobacteria always dominated the crusts studied there.…”

“…On the other hand, investigations showed a promoted run-off by soil crusts (e.g. Kidron et al, 1999;Malam Issa et al, 2009). Run-off generation on soils with biological soil crusts was also caused by hydrophobic polymers and extracelluar secretions (Fischer et al, 2013), which reduced the size of pores formed by cyanobacteria (Mazor et al, 1996;Verrecchia et al, 1995) and induced run-off (Malam Issa et al, 2009).…”

“…They modify the water run-off infiltration balance (Kidron and Yair, 1997) and alter water re-distribution on different scales (Eldridge et al, 2002;Kidron, 2014). Increased porosity, enhanced aggregate stability and an improved physical structure have been reported to cause higher infiltration (Mager and Thomas, 2011;Menon et al, 2011;Rossi et al, 2012), while water repellency and clogging of pores led to a reduced infiltration (Kidron et al, 1999;Malam Issa et al, 2009). Also an influence of soil crusts on infiltration can be masked by soil properties like structure or texture.…”

Biological soil crusts cause subcritical water repellency in a sand dune ecosystem located along a rainfall gradient in the NW Negev desert, Israel

“…The modifications in hydrological surface properties are due to a multitude of factors associated with the BSCs, including texture (Fischer et al, 2013), surface roughness (Rodríguez-Caballero et al, 2012), vesicular porosity and capillary barriers , pore clogging and swelling of organic crust components (Fischer et al, 2010;Kidron et al, 1999) as well as water repellency (WR) (Drahorad et al, 2013b;Fischer et al, 2010). Recently the importance of the single factors have not been characterized systematically, as the complex interactions between them make it difficult to state general claims on their importance.…”

A Field Guide to Biological Soil Crusts of Western U.S. DrylandsA Field Guide to Biological Soil Crusts of Western U.S. Drylands

“…Scanning electron microscopy shows sufficient openings in sandy loam soils for water flow (Belnap and Gardner 1993), but concentration of silt and clay particles in the crust, in combination with swelling, may restrict infiltration even in sandy soils when they are wet (Verrecchia et al 1995). Some authors speculate that the hydrophobic nature of some crustal components contributes to soil surface sealing (Bond 1964;Dulieu et al 1977;Walker 1979;Rutin 1983;Jungerius and van de Meulen 1988); however, others have shown crustal organisms at some sites are highly hydrophilic (Kidron et al 1999).…”