The Ability of Fungal Surface Properties to Alter Soil Water Repellency in Sandy Soils.

Soil water repellency (SWR) is a significant problem affecting large areas of land and wide array of ecosystems.  It has a drastic impact on soil quality, which includes reduced water infiltration, increased runoff, leaching of nutrients and agrochemicals, reduction of plant growth and increased soil erosion.  Numerous factors may cause SWR including fire, soil moisture, organic matter, plant compound and exudates.  Additionally hydrophobic microbial structures and exudates can also cause SWR.  However, microbial community examinations to date identify fungi as the dominant microbial group which causes water repellency in soil.  However, distinguishing between fungal strains that alter water repellency has yet to be examined.  The functional significance of fungal surfaces is known to provide an ecological adaption to dry conditions, but the implication of this property on SWR has yet to be determined.  This study was conducted to determine whether SWR could be manipulated by fungal surface properties.  The effect of fungal surface properties on SWR was investigated by inoculation of sandy soils with three types of fungi (low, shifting and high hydrophobic strains).  Assessing the change in repellency and hydrophobicity of fungal surface properties was determined using a water repellency index (ratio of ethanol sorptivity over water sorptivity) and contact angle measurements respectively.  The low hydrophobic strain showed no increase in SWR, while the shifting hydrophobic and high hydrophobic strains both showed an increase.  The ability of fungi surface properties to decrease SWR may improve soil quality.