DEVELOPMENT OF A TECHNIQUE FOR THE MEASUREMENT OF ROOT GEOMETRY IN THE SOIL USING RESIN-IMPREGNATED BLOCKS AND IMAGE-ANALYSIS

A method is described that permits the measurement of roots in situ in the soil using computerized image analysis to process images obtained from planar faces cut from a resin-fixed pot. Soil sample pots are initially impregnated with rapid-curing epoxy resin. Blocks are then cut from the impregnated pot with a diamond saw to expose a planar face. Modification of the present resin-impregnation procedure is necessary as impregnation results were mostly unsatisfactory. Roots are contrasted from the soil matrix by enhancing autofluorescence using longwave ultraviolet light and appropriate filters. After image capture and segmentation to show regions of root material, measurements of volume fraction of roots, volumetric surface area, horizontal root length and horizontal root separation, were made with a larger resolution with soil depth than previously.