Quantitative and visual assessments of climate change impacts on South Australian wheat production

Abstract

The outputs of Global Climate Models (GCMs) were nested with the DSSAT3.5 CERES-Wheat model to explore the potential effects of climate change on South Australia's wheat production for the 2080s with CO2 fertilisation effect taken into account. A stochastic weather generator: LARS-WG was employed to generate daily climate change scenarios. The simulated results were fed into Arc/View to produce regional impact maps for visual assessment and spatial analysis under different climate change scenarios and CO2 levels through an interface of AEGIS/WIN. Two sowing dates were employed to look at the potential impact of future climate change and atmospheric CO2 increase on wheat production. Simulated results show that (1) Wheat yields increase under all CO2 levels. Yields increase under different climate change scenarios in most cases. However, the increase is less than that under corresponding CO2 levels due to the adverse effects of climate change. Wetter sites benefited less compared with drier sites under climate change scenarios. (2) Grain nitrogen content decreases under all CO2 levels and under most of climate change scenarios, but the decrease under climate change scenarios is less than that under corresponding CO2 level due to increased temperature which enhanced soil nitrogen mineralisation. Grain protein content decreased more at drier sites. The combined effects of climate change and increase of atmospheric CO2 concentration will downgrade wheat quality at least one class at drier sites. (3) Grain yield at planting date of 30 June was significantly enhanced compared with that of planting date of 30 May under the same environmental change condition (same climate change scenarios plus their corresponding CO2 levels).