Cultivar and soil effects on growing season and production-scaled N2 O emissions from Prairie Potato systems

Abstract

Agricultural soils are a significant source of nitrous oxide (N2 O), a potent greenhouse gas. Potatoes, with their low nitrogen use efficiency (NUE) and high nitrogen (N) demand, present a high risk of N2 O emissions. Investigating factors influencing N2 O production, including crop cultivar and soil environment, is needed to reduce emissions from Prairie potato production. This 2-year study in Saskatchewan monitored N2 O emissions from three potato cultivars (Clearwater Russet, Dark Red Norland, and Sangre) on two sites (clay loam and sandy loam), and evaluated the effect of soil micro-topography by measuring emissions from hill and furrow positions. Daily N2 O flux, cumulative growing season emissions, yield-scaled, and tuber N-scaled emissions were quantified. Cumulative growing season emissions ranged from 164 to 848 g N2 O N ha−1, aligning with other Prairie research but lower than more humid regions, likely due to lower precipitation on the Prairies. Although cultivars produced similar cumulative emissions, production-based analyses revealed Dark Red Norland and Sangre had 35%–67% lower yield-scaled N2 O than Clearwater Russet. Emissions were higher from hills than furrows at three of four site-years, suggesting variability in N2 O production processes, likely related to substrate availability and moisture. This study highlights the complexity of soil and environmental interactions —encompassing differences in soil micro-topography, growing seasons, and soil characteristics——in driving N2 O emissions. Significant negative relationships were found between NUE (tuber NUpE) and N2 O emissions, demonstrating that selecting cultivars for agronomic performance (high yield and high NUE) may be a practical strategy to reduce production-based N2 O emissions from potato production.