The N_2O content of soil air at different depths as well as its related content in and transport by seepage in lysimeter soils

摘要

Soils are one of the main sources of nitrous oxide (N_2O). Part of the N_2O formed in the soil may - owing to its good solubility in water - be transported by seepage into the groundwater. Lysimeters equipped with the necessary online analysis equipment and sampling devices are ideal for studying N_2O formation and discharge. We report on the N_2O content in the soil atmosphere at various depths of monolithic cores of an Eutric Cambisol and a Plithic Lixisol soil (each fertilized with organic manure), the N_2O emissions at the surface, and also the N_2O content of the seepage. Despite the high concentrations of N_2O in the deeper soil layers [up to 34 ppm(v)], the emissions were very low (mean 2.5-5.7 μg N/m2~*h) and discharge via leachate was rather low as well (max. 0.1 kg N/ha~*yr). The results differed remarkably between the two soils investigated.