Simulating Agronomic Adaptation Strategies to Mitigate the Impacts of Climate Change on Wheat Yield in South-Eastern Australia

Rising air temperature and change in rainfall patterns are expected to have impact on agricultural production. The impact of climate change on wheat production was investigated and agronomic adaptation strategies were evaluated for two emission scenarios of Representative Concentration Pathway (RCP4.5 and RCP8.5) and three projection periods (2030, 2050 and 2070) using a climate model ensemble in the bio-physical model Agricultural Process SIMulator (APSIM). Early and late maturing wheat varieties were tested under six sowing time scenarios. Under RCP4.5, growing season rainfall would decrease by 9%, 15% and 19% in 2030, 2050 and 2070, respectively, and temperature would increase by 0.7 degrees C, 1.2 degrees C and 1.4 degrees C, respectively. For RCP4.5, the wheat yield would decrease by 9%, 15% and 19% in 2030, 2050 and 2070, respectively. Under RCP8.5, the yield would decrease by 9%, 18% and 27%, respectively. Short-season cultivars would be suitable for the low-rainfall environments and long-season cultivars for the high-rainfall environments. In 2050, for RCP4.5 at a low-rainfall site, the yield of early maturing variety would decrease by 11% and 31%, while at a high-rainfall site, these values would show a 9% decrease and 1% increase, respectively. At the low rainfall site, yield reduction for early sown variety would be 14% and 23% when late sown, while late maturing wheat would have a much higher yield reduction. At the higher rainfall site, yield reduction for early and late sown early maturing variety would be 3% and 15%, while for late-maturing wheat these values would be only 1% and 2%. Generally, the future climate is expected to have significant impact on wheat yield and changes in agronomic practices can mitigate the impacts on yield.