INTERACTION BETWEEN NITROUS-OXIDE FORMATION AND METHANE OXIDATION IN SOILS - INFLUENCE OF CATION-EXCHANGE PHENOMENA

Ammonium (NH4+) inhibits the microbial oxidation of methane (CH4), and gives rise to the formation of nitrous oxide (N2O) in aerobic soils. However, the NH4+ concentration in the soil water is not necessarily p roportional to the total NH4+ concentration in the soil, due to cation exchange or fixation phenomena. It was found that introducing the con cept of ion exchange or fixation in kinetic models on CH4 consumption and N2O formation can increase our knowledge on these processes in soi ls. A fit of these kinetic models with experimental data showed a stan dard deviation of slightly more than 10%. The effects of NH4+ on CH4 o xidation and N2O formation can only be compared in soils with the same cation exchange capacity (CEC).