INFILTRATION INTO SOILS, WITH PARTICULAR REFERENCE TO ITS VISUALIZATION AND MEASUREMENT BY MAGNETIC-RESONANCE-IMAGING (MRI)

This article draws attention to the potential of magnetic resonance im aging (MRI) for studies of patterns and mechanisms of water infiltrati on into soils, and stresses the vitally important need for collaborati on between hydrologists, soil physicists and MRI experts. A brief intr oduction of the principles of MRI is given. This is followed by a revi ew of the literature relating to nonpreferential infiltration, prefere ntial infiltration exhibiting fingering and preferential infiltration involving a wide range of macropore flow. These differing degrees of c omplexity of infiltration dynamics require the employment of noninvasi ve and nondestructive techniques for their detailed investigation. Fin ally, an overview of applications of MRI to the detection of the spati al and temporal distribution of soil moisture and its changes is given . General conclusions are drawn from previous and current research, an d the potential of the application of MRI to infiltration studies is s ummarized.