Electromagnetic (EM) surveys in combination with computer models, like Sodium-SaLF, and chloride mass balance models have been used to estimate deep drainage under irrigated soils with high clay content (Wills and Black 1996; Triantafilis et al. 1998; Zischke and Gordon 2000). In addition to these surveys and models we can also add field lysimeters. These have been used in southeast Queensland and northwest NSW to monitor nutrients that leach below the root zone of cotton crops (Zischke and Gordon 2000). This form of evaluating nutrient leaching is accurate, however, it is also expensive and requires a lot of time to install. They are a permanent fixture in the field to be studied and cannot be readily relocated to monitor multiple locations across a field.