Cotton production in Australia occurs mainly in cracking clay soils. In the past, it was widely assumed that deep drainage was negligible in these soils (Hearn, 2000).

Many Australian cotton growers sow rotation crops after irrigated cotton assuming that they will improve soil quality, reduce pest and disease incidence, and maintain profitability of cotton.

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 Bla

Water use efficiency is a key issue for the Australian cotton industry. For the individual producer the focus is to maximise returns from a limited resource.