A growth disorder of cotton has been observed in irrigated cracking clay soils in fields at Galathera Creek, north of the Australian Cotton Research Institute (ACRI) for several years. The condition has since been found at other sites. Affected plants were stunted and grew slowly during the first half of the season and yielded poorly. Growth of stunted plants improved in mid-season but too late for substantial recovery of yield. Yield showed little or no improvement when P and Zn fertilisers were applied. Preliminary observations suggested that a lack of vesicular arbuscular mycorrhizal (V AM) development may have been adversely affecting cotton nutrition The aim of projects UNE7C and UNEl 7C was to determine the cause of the early season growth disorder (Galathera syndrome) and the role of VAM with regard to growth, development and yield of cotton