Soil Texture-Greenhouse Gas-Leachate Linkages Reveal Liming Effects on C and N Cycling

Liming is an important agricultural practice for mitigating soil acidification and potentially reducing N2O emissions. Although lime can act as either a CO2 source or sink depending on proton donors driving dissolution i.e., strong acids vs. carbonic acid, IPCC assumes it as a 100% CO2 source. Soil leachate and shallow groundwater chemistry can reveal the dominant proton donors governing these reactions; however, previous studies have primarily focused on gas emissions alone. To address this knowledge gap, we conducted a two-month mesocosm experiment with spring barley using 13C-labeled carbonate and 15N-labeled fertilizer in acidic sandy (pH = 5.42) and clayey soils (pH = 5.45), incorporating three simulated rainfall events. Lime and fertilizer were homogeneously mixed with the soil, and gas samples were collected immediately following setup (Day 0).In lime-treated soils, both CO2 and N2O fluxes were elevated prior to crop emergence and peaked on Day 0, whereas in control treatment, CO2 and N2O slightly increased on Day 0 and peaked after the first rainfall event. This suggests that liming and tillage stimulate initial greenhouse gas emissions. Consistent with previous studies, about 13% of lime-derived C was emitted as CO2, and N2O emissions were low (N loss