Yield trends under varying environmental conditions for sorghum and wheat across Australia

Abstract

Globally as well as nationally, food production is being exposed to increased climatic and market volatility. The trend in sorghum yield in Australia has been consistent and positive over the last 30 years, while yield trends globally for other cereals like wheat, maize and rice have slowed. Australia is of interest not only as a major exporter in world markets, but also because considerable research effort has been focused on developing crops and practices that help to reduce the risks of yield losses under drought conditions. This study examines sorghum and wheat yield trends over the previous three to four decades in Australia after realistically accounting for the effects of year-to-year climate variability. We quantified the yield trends within three distinct types of crop stress environments (i.e. DRY: ENVT1, MODERATE: ENVT2& WET: ENVT3). Overall trends in sorghum yields were 2.1% per year (44 kg/ha/year), which was nearly double that found for wheat (1.2% per year; 21 kg/ha/year). However, in dry environments, relative yield trends for sorghum were 3.6 times those for wheat, whereas in wet environments trends were similar. Likely technology and environmental factors underpinning these trends are discussed.