Nitrous oxide emissions and yields from potato production systems as influenced by nitrogen fertilization and irrigation: A meta-analysis

Potato (Solanum tuberosom) is a globally significant crop in relation to the scale of its consumption, being the third most consumed worldwide. The overall sustainability of global agriculture is increasingly of concern, specifically in relation to increasing anthropogenic emissions of the greenhouse gas nitrous oxide (N₂O) emissions from nitrogen fertilizer additions to croplands and its contribution to climate change. Against this backdrop, a meta-analysis of 119 experimental comparisons from 18 studies—spanning 19 study sites in 10 countries—was employed to investigate the impact of irrigation, cumulative water input, N fertilizer application rate, soil pH, and soil texture on cumulative N₂O fluxes and tuber yield in potato production. Compared to non-fertilized controls, N₂O emissions from fertilized potato production decreased by 34% when irrigation provided 61%–90% of total water input (corresponding to averages of 321–473 mm). Likewise, N₂O emissions increased by 53% with 200–475 mm seasonal water input and by 37% with N fertilization rates of 101–200 kg N fertilizer ha⁻¹. Furthermore, soil pH between 7.1 and 7.5 reduced emissions by 6%, while medium-textured soils showed an increase of 2%. Conversely, tuber yields from fertilized potato production were comparatively maximized under 31%–60% of water input as irrigation (7%) and 751–1025 mm cumulative seasonal water input (28%). Alongside 201–300 kg N fertilizer ha⁻¹ (97%), soil pH of 7.1–7.5 (48%), and in coarse-textured soils (49%). Overall, these findings underscore the importance of considering irrigation and N fertilization options specifically in optimizing potato production for reduced N₂O emissions and enhanced tuber yield.