Plants reduced nitrous oxide emissions from a Northern Great Plains saline/sodic soil

AbstractThe slowly establishing salt‐tolerant perennial grasses reduced nitrous oxide (N2O‐N) emissions from saline/sodic soil compared to barren areas. Other salt‐tolerant species may accelerate vegetative establishment and reduce N2O‐N emissions. In a greenhouse study, barley (Hordeum vulgare L.), Florida broadleaf mustard (Brassica juncea L.), and Kernza intermediate wheatgrass [Thinopyrum intermedium (Host) Barkworth & D. R. Dewey] were grown for 63 days to compare shoot biomass and chemical composition, N2O‐N emissions, and the soil microbiome between saline/sodic and productive (non‐salt impacted) soils. Emissions were measured six times daily from 1 to 22 and 42 to 63 days after planting (DAP). Shoot and soil microbial biomass and communities were quantified 63 DAP. N2O‐N emissions were 87% greater from no‐plant saline/sodic than no‐plant productive soil (p < 0.05). N2O‐N emissions were reduced from planted treatments soon after plant emergence. N2O‐N emissions reductions from saline/sodic soil during the first 22 DAP were 84%, 76%, and 61% for barley, mustard, and Kernza, respectively. Barley had the greatest shoot biomass and impact on the soil microbial community, increasing the fungi to bacteria ratio from 0.063 to 0.094 in the productive soil and from 0.056 to 0.076 in the saline/sodic soil. Plant‐induced changes to the soil microbiome, and decreased soil inorganic N and water, contributed to N2O‐N emission reductions. Archived field samples from grass‐established saline/sodic soil areas had a fourfold increase in nos‐Z gene copy number compared to no‐plant controls, which may, in part, explain decreased N2O‐N emissions. Establishing these vigorous species may aid in restoring multiple ecosystem services to saline/sodic areas.