Magnetic resonance imaging of soils and plant roots

Abstract

Magnetic Resonance Imaging, or MRI, has been proposed as a tomographic tool in the study of soil dynamics and soil structure because it is a non-destructive way to view internal structure in opaque materials such as soils. A natural extension of this application of MRI is the study of plant root dynamics such as growth and water uptake from a surrounding soil. Traditionally, MRI has been used to study fluid samples, or fluid saturated samples, most notably the human body. There are severe drawbacks to studying solid or solid-like materials with MRI, especially heterogeneous materials such as soils, mainly arising from the rapid loss of signal from such samples. Using a technique developed at UNB called SPRITE, an acronym for "Single-Point Ramped Imaging with T1-Enhancement", these drawbacks can be circumvented, and images of rigid and semi-rigid samples, such as concrete and compact bone, can be acquired. This thesis presents results from tests done on soil and plant root samples which, using the SPRITE method, have been imaged to study soil water migration (drying) and water uptake by roots in soils.