Changes in Soil Nitrous Oxide and Carbon Dioxide Dynamics after the Application of Digested Liquid Cattle Manure

抄録

The aim of this study was to clarify the changes in N₂O and CO₂ emission from the soil surface, their concentrations in soil gases, and gas diffusion fluxes after application of digested liquid manure (DL) produced by anaerobic digestion of cattle manure slurry. N₂O emission increased more and faster after application of DL compared to after the application of conventional inorganic fertilizer. The N₂O emission rate from the DL was 0.25% of the applied nitrogen. CO₂ emission after the DL application also increased, and the CO₂ emission ratio from the DL was 33% of the applied C. Soil N₂O concentration increased after DL application. The highest soil N₂O concentration occurred earlier than the largest N₂O emission. The increase in CO₂ concentrations near the surface was small. The largest N₂O diffusion flux was observed near the surface, and a negative flux was observed in deeper layers 14 days after DL application. The difference in the CO₂ flux between deeper and surface layers flux was smaller than that in the N₂O flux, which suggests that the contribution of CO₂ generation in deeper layers is larger than that of N₂O.