CO ₂ and N ₂ O emissions and microbial community structure from fields that include salt‐affected soils

Although salinity and sodicity are worldwide problems, information on greenhouse gas (GHG) emissions from agricultural salt-affected soils is scarce. The CO2–C N2O–N were quantified three zones intertwined within a single U.S. northern Great Plains field: highly productive zone (electrical conductivity with 1:1 soil/water mass ratio [EC1:1] = 0.4 dS m–1; sodium adsorption [SAR] 1.8), transition (moderately salt-affected; EC1:1 1.6 SAR 4.99), saline/sodic (EC1:1 3.9 22). In each zone, measured every 4 h for 7 d in four randomly placed chambers that treated two N rates (0 224 kg ha–1). experiment was conducted 2018 2019 during similar seasonal periods. Soil samples taken treatments after GHG measurement analyzed soil inorganic N, microbial biomass different communities using phospholipid fatty acid analysis. Real-time polymerase chain reaction used to quantify the number of copies some specific denitrification functional genes. had highest CO2–C, lowest emissions, greatest biomass, whereas biomass. Within urea application did not influence emissions; however, urea-treated 84 57% higher than 2019, respectively. copy nitrite reductase gene, nirS, 42-fold soil, suggesting high potential denitrification. These findings suggest could be reduced by applying zones.