The clearance of vegetation for agriculture has had a large impact on the hydrology of native ecosystems. As a consequence, plants experience stress because of the large amounts of salt brought into the rhizosphere by rising saline groundwater. To attenuate this rise, and if possible restore the original hydrology, one strategy is to devise agricultural systems that mimic native systems. Knowledge of native systems is deficient in two areas in particular; water use and adaptation of root systems to ‘hostile’ soils. This research concentrates on the latter, in particular factors that affect root development of native vegetation on duplex or texture contrast soils.

Methods were investigated to visualise and calculate pore characteristics that are suspected to influence root proliferation in soil. Samples from a sodic duplex soils (yellow sodosol) were scanned with a medical CT (resolution of 1mm) and a micro CT (resolution of 40 μm). The cross section images were thresholded to separate the pores from the soil matrix and a total pore volume and a 3D skeleton of the pore structure were reconstructed. The porosity, pore distribution, numerical density, tortuosity and inclination of the pores were calculated from those reconstructions.

The results suggest that the porosity decreases in the E-B_tn horizon interface and increases again, deeper in the lower B_t horizon. The pores in the interface tend also to be more horizontal than in the upper sand layer and the lower B_t horizon. Some ‘coiling of the pores’ is also apparent.