Wednesday, November 15, 2006 - 1:05 PM

Causes and Alleviation of Soil Water Repellency.

Coen J. Ritsema, Alterra - Wageningen University, Droevendaalsesteeg 3, Wageningen, 6708 PB, Netherlands


Best management practice for sport fields and turfgrass systems should amongst others aim at preventing the rooting zone to become water repellent. When water repellency develops, it is extremely difficult to rewet the dry, water repellent soil pockets as water will by-pass these regions through surface runoff and preferential flow processes. This will result in irregular wetting of the rooting zone of the soil, and in the long term reduced turf performance.

In this presentation causes of the development of water repellency in soils will be discussed and illustrated, as well as its overall effect on flow and transport processes. Based upon numerous automated TDR measurements in various water repellent soils, animation examples of infiltration events will be shown which provide revealing evidence of the complex nature of flow and transport processes under natural field conditions. Special attention will be given to the formation and dissipation of preferential flow paths, the occurrence and persistence of dry spots, and lateral flow components over time.

Also the use of regular surfactant treatments to prevent and remediate soil water repellency will be discussed based upon extensive field trials. Generally, regular surfactant applications result in improved soil wettability, increased soil water holding capacity, a reduction in irrigation water requirements, and better turf quality compared with untreated plots.