Mass Spectrometric Investigation on Denitrification

Kinetic Formulation of the Denitrification Process in Soil

“…Multiplying R on the numerators and the terms on the right-hand side of eq. 7 on the denominators of equation group 6 results: Cho and Sakdinan (1978) are well described by the kinetic model shown in Fig. 1 Fig.…”

Kinetic formulation of oxygen consumption and denitrification processes in soil

“…The kinetic expressions presented above describe the experimentally observed (Cho and Sakdinan 1978;Cho 1982;Dendooven et al 1994) or rewriting…”

“…However, the minimum concentration of O 2 at which the inhibitory effect is expressed is unclear (Firestone 1982). The work of Cho and Sakdinan (1978) indicated that the formation of N 2 O from a soil supplemented with finite amounts of NO 3 -and O 2 under wellshaken conditions did not commence until all the O 2 had disappeared from the closed system. Since their investigation was a dynamic experiment, the concentration of O 2 was constantly decreasing with time.…”

“…Their expression was based on a constant denitrification intensity, defined to be the sum of production rates of NO 2 -, N 2 O and N 2 from their immediate precursors. The model of Cho and Mills (1979) explains several important observations made by many workers (Blackmer and Bremner 1978;Cho and Sakdinan 1978;Gaskell et al 1981). These include i) the apparent inhibition of N 2 O reduction by high concentrations of NO 3 -and NO 2 -, ii) the lag in the reduction of N 2 O prior to the exhaustion of NO 3 -, iii) influence of C 2 H 2 upon the disappearance of NO 3 -, and iv) the change in the disappearance rate of NO 3 -due to gaseous escape of N 2 O from the system.…”

“…The composition of the population at steady state and the resulting electron demand will likely be different under O 2 -stressed vs. O 2 -rich conditions. This difference was demonstrated by examining the change in CO 2 production rate in the presence and absence of O 2 under well-shaken conditions (Cho and Sakdinan 1978). Since the apparent inhibitory effect of O 2 could also result from competition, where there are large differences in the affinity for electron competition among the electron acceptors, the effect of O 2 upon denitrification could also be expressed as a competition phenomenon.…”