Influence of biotic and abiotic factors on the development of non-wetting soils and management approaches: A review

Non-wetting or hydrophobic soils occur around the globe and have impacts on infiltration rates, plant growth, and the hydrological cycle via evaporation, runoff, and soil leaching. These impacts may limit the productivity of the cropping areas, resulting in significant economic loss. Non-wetting of soil is a property whereby water pools on the surface of the soil instead of penetrating it, negatively influencing water movement. This phenomenon is caused by hydrophobic organic materials that bind to soil particles or aggregates within the soil pore spaces. This review examines the direct and indirect influences of biotic and abiotic factors on the development of hydrophobicity in soil. Biotic causes of non-wetting soils include microbial activity and type of vegetation. Abiotic factors such as the physicochemical properties of soil, climate, and fire are also examined in detail to determine their role in the development of soil hydrophobicity. A critical analysis of how and under what conditions these biotic and abiotic factors interact to cause non-wetting in soils is undertaken. Different physical, chemical, and biological management approaches are reviewed to understand better how non-wetting soils can be remediated. Given the existing remediation practices, it has been determined that a full understanding of hydrophobicity is lacking in the literature; therefore, more research is needed to identify the detailed mechanisms behind this phenomenon to develop a cost-effective and sustainable solution.