Water and Energy Consumption by Agriculture in the Minqin Oasis Region

Abstract

Water used in agriculture consumes much energy, mainly due to pumping water for irrigation, but the water-energy nexus is always neglected in arid and semi-arid areas. Based on hydrological observation data, irrigation data and socio-economic data over the past 50 yr, this study has derived a detailed estimate of greenhouse gas (GHG) emissions from agricultural water use in the Minqin Oasis. Results show that the decreasing water supply and increasing demand for agriculture has caused severe water deficits over the past 50 yr in this region. The groundwater energy use rate rose by 76% between 1961 and 2009 because of the serious decline in groundwater levels. An increase in pump lift by an average 1 m would cause GHG emission rates to rise by around 2%. Over the past 10 yr, the GHG emissions from groundwater accounted for 65-88% of the total emissions from agricultural water. GHG emissions for diverted water varied from 0.047 to 0.074 Mt CO2e as the water input increased. Long distance conveyance and high pump lifts need more electricity input than groundwater abstraction does. Government policies have had a favorable effect on total emissions by reducing water abstraction. But groundwater depletion, exacerbated by a growing population and an expansion in arable land, remains the principal energy-water nexus challenge in the region. In response to the increasing water-energy crisis, energy-saving irrigation technology, matching to cost efficiencies, and better coordination between different infrastructural agencies could be feasible ways of rendering the water and energy sectors more sustainable over the long term.