Watering the farm: Comparing organic and conventional irrigation water use in the Murray-Darling Basin, Australia

•Census and survey data of organic and conventional farm water use are compared.•Evidence of organic self-selection in regression model results.•Organic farms use less water overall than conventional farms.•Some organic farm industries seem to be less water efficient (water use/output produced).•Organic farms are more water use productive (water use/net farm income).

This study investigates the role that certified-organic farming systems play in irrigation water-use in the Murray-Darling Basin, where large-scale government policy has focussed on returning water from irrigation to key ecological sites. Information from Australia's agricultural census in 2011, as well as a specialized irrigation farm survey sample of 1499 observations, compared certified-organic and conventional irrigation water-use. Census and survey results found some evidence for some industries that organic irrigation farms are less water-use efficient (i.e. water use divided by tonne of output), but little significant difference in water-used per irrigated hectare was found overall (although for some industry sectors-notably horticulture-organic farms use less water on a per-hectare basis). After controlling for self-selection, regression model results also indicated that organic irrigation farms use less absolute water than conventional farms; use a smaller percentage of water received; and are more water-use productive (i.e. water use divided by net farm income). A lack of significance for the importance of irrigation infrastructure adoption, plus the importance of water-use charges in reducing water demand, suggests a need for governments to reorientate irrigation policy towards more multi-layered and inclusive practices that promote better soil conditions and water management, rather than focussing on providing subsidies for technology adoption.