Role of Soil Organic Matter on Water Repellency

ROLE OF SOIL ORGANIC MATTER ON WATER REPELLENCY 

Most mineral compounds that constitute soil are hydrophilic however, the modification of organic matter coating the soil particles is instrumental for the transformation of these hydrophilic surfaces to hydrophobic soils (Doerr et al., 2000 Mainwaring et al., 2013). SOM is considered to be a byproduct of plant and animal residues at various stages of decomposition, root exudates, cells and tissues of soil organisms, and substances produced by fungal or soil microbial activity (Llewellyn et al., 2004). Attempts to find correlations between the level of SOM and SWR have to date yielded inconsistent results. 

The formation of such films are favored by (1) bulky head groups, (2) more than one polar group, (3) more than one hydrocarbon chain orientated in different directions from the polar part of the molecule (e.g., esters), (4) bent hydrocarbon chains such as ds-unsaturated acids, and (5) branched hydrocarbon chains. 

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