The best farm-level irrigation strategy changes seasonally with fluctuating water availability

Around the globe farmers managing irrigated crops face a future with a decreased and more variable water supply. To investigate generic adaptation issues, a range of on-farm strategies were evaluated for apportioning limited water between fields and enterprises using a typical case-study farm from Australia’s Riverina region. These strategies are compared for a range of seasonal water availability levels. The analysis did not address investment in new irrigation technologies or new crops, but focussed on irrigation intensity and crop choice amongst existing enterprises. Participatory engagement and whole-farm simulation modelling were our primary tools of research. The adaptation options found to best suit irrigation farming in years of high water availability were substantially different to those when water supplies were low. This illustrates strategic differences between irrigation farming in land-limited circumstances and water-limited circumstances. Our study indicates that the cropping and irrigation strategy leading to greatest farm returns changes on a season-by-season basis, depending primarily on the water availability level.