Sugarcane farming practices contribute to global warming
(PhysOrg.com) -- The global market for sugarcane is expanding, and new research at UQ is informing improved farming practices to reduce its environmental footprint.
In the study, a UQ team, in collaboration with Department of Environment and Resource Management, analysed greenhouse gas emissions from an experimental sugarcane farm near Jacobs Well, 45km south-east of Brisbane.
Emissions of nitrous oxide (N2O) from soil were considerable when "higher-than-recommended" nitrogen fertiliser rates were applied and when soil became waterlogged during flood-irrigation.
Nitrous oxide is a potent greenhouse gas with a global-warming potential 300 times higher than carbon dioxide, the Earth's most problematic climate warmer.
"Nitrous oxide originates from nitrogen stored in the soil. Concentrations of nitrous oxide in the atmosphere are rapidly increasing and contribute 10 percent to global warming. Much of the increases in atmospheric N2O are being caused by nitrogen fertilisers applied in all of agriculture," said Dr Susanne Schmidt, from the School of Biological Sciences.
"Our study demonstrates that N2O is emitted from sugarcane soil early in the growing season. Approximately one percent of fertiliser-nitrogen is emitted as N2O, but this emission can increase to be five times higher when high amounts of nitrogen fertiliser are applied.
"Our study gives clear guidance of how N2O emissions can be effectively reduced. Sugarcane growers who apply less nitrogen fertiliser will reduce emissions. Avoiding accumulation of soluble nitrogen in the soil, the precursor for N2O, and preventing water-logging, strongly reduces emissions.
"Growers are aware that sustainable practices are key to future productivity and efficiency. There has been a significant change in the industry in addressing environmental issues and adopting sustainable farming practices."