Gerald Reinken*, Sharad P. Kale** and Fritz Fuehr*
* - Institute of Radioagronomy, Forschungszentrum Juelich GmbH, Juelich, D 52425, GERMANY
** - Nuclear Agriculture Division, Bhabha Atomic Research Centre, Trombay, Bombay 400 085, INDIA.
e-mail: g.reinken@kfa-juelich.de
Soil organic carbon, SOM, Organic matter, Oat straw, Lysimeter, Soil column, Soil horizon, Silty soil, Sandy soil, Preferential flow, Macropores, Chemical translocation, Leaching, Dye movement, Adsorption pattern, Fingering structure, Transport mechanism, Modelling
The understanding of heterogeneous transport phenomena in unsaturated natural soils is limited. Especially for estimating ground water contamination and for interpreting soil leaching in lysimeter studies, the preferential flow is an important transport mechanism. In a short-time lysimeter experiment the tracer dye Brilliant Blue (BB) was applied on an undisturbed soil monolith to simulate a heavy rainfall event of 30 mm in 3 h under a high initial soil water content. Preferential pathways with a characteristic fingering structure were identified in the typical silty soil of the Rhineland in Germany. Soil organic matter (SOM) is known to be one of the highly heterogeneous fractions of soils. The distribution pattern of organic matter seems to be a characteristic factor for the preferential flow of chemicals in this structured silty soil, since SOM and BB show similar distribution patterns.