Greenhouse gas emissions from irrigated crop production in the Canadian Prairies

Abstract

Irrigated agriculture in the Canadian Prairies is in a position to play a prominent role in addressing global food demands imposed by a growing world population. Particularly within Saskatchewan there is potential to see large increases in the number of irrigated hectares, due to the large irrigable land base and supply of freshwater resources. Yet, how this increase will influence the agricultural greenhouse gas (GHG) balance is not well understood. Through the quantification and comparison of GHG emissions from a typical irrigated and dryland cropping system in Saskatchewan, this research aimed to better understand the role of irrigated agriculture on GHG dynamics in this region. A field-scale analysis of irrigated soil conditions and resulting soil greenhouse gas emissions identified that soil N availability was likely the dominant factor influencing soil N2O emissions from irrigated systems. Soil moisture was also a key factor in soil GHG fluxes, governing seasonal CH4 uptake and episodic N2O and CO2 emissions. The development of system-specific GHG budgets—incorporating on-site GHG sources and sinks—identified electricity as irrigated cropping’s largest contributor of global warming potential (GWP). Emissions from soil and diesel-combustion sources were less intensive under irrigated production; yet overall greenhouse gas intensity (GHGI) was greater from irrigated cropping. This research provides a first look into GHG dynamics from irrigated agriculture in Saskatchewan and identifies areas for potential mitigation as irrigated crop production expands in the Province.