[Effect of inorganic nitrogen on CH4 oxidation in soils]

The effects of N inputs, including N fertilizer applications and atmospheric N depositions, on CH4 oxidation by soils were determined by CH4-oxidizing bacteria, N inputs and soil factors. These effects were inhibitory or stimulative, but inhibition was more popular than stimulation, and the inhibition of NH4+ was more popular than that of NO3-. Wealthy experiments in different soils and climate regions are required to monitor and evaluate how N inputs influence CH4 oxidation in soils. Generally, CH4 oxidation in soils following N inputs showed multiple inhibition patterns, i.e., immediate or direct inhibition, delayed inhibition, and absence of inhibition. Some researchers explained the inhibition mechanism through using competition between CH4 and NH4+ for the same enzyme sites, elevated threshold, salt effect and ion-exchange, and N turnover rate and N concentration. However, the inhibitory mechanism is still unclear. Therefore, inhibitory mechanism is one of the main research concerns in future.