Water-Energy-Food (WEF) nexus in agricultural systems

Water-Energy-Food (WEF) nexus in agricultural systems

Water and energy are often the two limiting factors in agricultural production in Australia which has also incurred considerable greenhouse gas (GHG) emissions. From a Water-Energy-Food (WEF) nexus perspective, agricultural water, land and energy uses, and crop production are intertwined. As such, this study develops a WEF nexus model to optimize resource uses, economic and environmental performances in an irrigated agricultural system with multiple scenarios designed in contrast to basic situations in the study area. In a baseline scenario, the optimized irrigated areas of wheat (72%; 7,768 ha) are remarkably higher than those of cotton (28%; 3,003 ha) under cotton irrigation application rate of 7.74 ML/ha and wheat irrigation application rate of 2.02 ML/ha. The gross margins per ha irrigated area are AU$4,132/ha in cotton cultivation, being higher than AU$1,584/ha in wheat cultivation. GHG emission intensities are also higher in cotton (3.25 tCO2e/ha and 0.52 tCO2e/t) than those in wheat (2.69 t CO2e/ha and 0.45 tCO2e/t). In comparison, for different crop prices the highest profits (approximately AU$32 million) are generated in the specific scenario involving cotton lint price over AU$650/bale and wheat price below AU$400/t. For alternative energy sources in irrigation, solar-powered irrigation can generate higher profits, AU$25.61 million, and lower total GHG emissions (27 ktCO2e). For methods in disposing crop residues, the economic performances are the best in the combustion scenario (total profits AU$38.44 million). The best environmental performances are in a mulching scenario (28 ktCO2e). For other influential factors, rainfall and power feed-in tariffs show more complex influences than the other factors. Across all scenarios, the maximal total profits (AU$60.77 million) are in the scenario involving combustion with an assumed efficiency of power generation being high (70%). This study contributes to the sustainable management of water, energy, land resources, and also effective crop residue disposals. It can be adopted as a generic model, applicable to a farm scale and extended to incorporate climate change and residue management in other agricultural systems that require more cost-effective production and sustainability.

File reproduced in accordance with the copyright policy of the publisher/author/creator.