Food security and production is a major global issue faced by society. It has become essential to work the land efficiently, through better soil management and agronomy whilst protecting the environment from air and water pollution. The reduced ability of some soils to become wetted and absorb water - soil water repellency - is a major environmental problem in many parts of the globe. It can have serious environmental implications such as increased overland flow and soil erosion, poor uptake of agricultural chemicals, and increased risk of groundwater pollution due to the rapid transfer of contaminants and nutrient leaching through uneven wetting and preferential flow pathways. The initial degree to which water is repelled by the soil surface is usually assessed by measurement of the soil-water contact angle, whilst the time-dependent wettability is most commonly assessed by measuring the time taken for water drops to eventually penetrate the soil completely. Both chemical and physical factors play a role in determining soil water repellency. Organic compounds deposited on soil mineral or aggregate surfaces have long been recognised as a major factor, and the surface structure of the soil has also been implicated particularly in influencing soil-water contact angle. Here we discuss the environmental impact of soil water repellency, the factors and mechanisms which are thought to be important in causing repellency, the way repellency is measured and classified, and our current work on the significance of surface structure in influencing soil-water contact angles.
Helen M. Balshaw, Swansea University, UK
Peter Douglas, Swansea University, UK
Sujung Ahn, Swansea University, UK
Stefan H. Doerr, Swansea University, UK
Stream: Environmental Sustainability and Human Consumption: Food and Water
This paper is part of the ACSEE2015 Conference Proceedings (View)
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