Increased Water Savings in Rice Crops Under Aerobic Irrigation Conditions: A Case Study in the Riverina Region, Australia

Rice (Oryza sativa) is a high water-demand crop, with yield strongly dependent on irrigation water availability, particularly in the semi-arid Riverina region of Australia. Enhancing the drought resilience of rice production therefore requires improved water management strategies, such as Aerobic Rice (AR) as an alternative to the traditional Continuous Flooding (CF) strategy. To better characterize AR water-saving potential, the main components of the water balance were measured under these systems. Net irrigation was measured using the Agriflo XCi ultrasonic Doppler sensor, and evapotranspiration (ET) with the LI-710 Eddy Covariance sensor. Three commercial-scale rice farms during the 2024–2025 season in the Riverina region were monitored. The analysis focused on three aspects: (i) rice crop development, (ii) water management and water balance, and (iii) rice performance and water productivity indicators. Water savings associated with AR were estimated at 18.4% in a side-by-side comparison. In addition, final harvested yield increased by 5.5%, resulting in a 29.5% increase in water productivity. ET from the AR paddock was 6.5% higher than under CF. Nevertheless, AR reduced Deep Percolation (DP) by 59.0% compared with CF. Two other CF paddocks were also monitored across the region, and water use from 13.0 to 14.5 ML ha^-1 has been observed as the baseline irrigation water requirement for permanent ponded rice paddocks in this region. These findings provide evidence that AR can deliver meaningful water savings while improving water productivity in commercial-scale rice paddocks in this semi-arid region of Riverina.