Stock to crop? Quantifying agricultural expansion in northern Australia and examining its drivers

Cuan Petheram , Peter Zund, Ian Watson

In recent decades, local, state, and federal governments have actively promoted irrigation and rainfed cropping expansion as a pathway to regional economic development for inland northern Australia (INA). This has created tension and competing narratives about development in the region. This study seeks to ground discussion in observed patterns of change by synthesising the cropping, horticulture and plantation forestry land use changes across INA between 1999 and 2023. Agricultural land use was mapped using the latest jurisdictional datasets and Sentinel-2A imagery in 2023 and Landsat-7 imagery in 1999. Land use was augmented by adding information on commodity type, land tenure, remoteness, irrigated water source and irrigation system. Irrigated agriculture grew from 32,904 to 60,303 ha, which is about 3% of the area of INA estimated as physically possible to irrigate based on coincidence of soil suitable for agriculture and water. Rainfed cropping and plantation forestry expanded from 28,811 to 134,362 ha. Drivers for this change in land use across the north are examined. Based on the results from the recent past we discuss what the future might hold. Future expansion is expected in regions with enabling infrastructure, cost-effective water and soils suitable for cropping.