Agriculture Reference
In-Depth Information
Figure 9.5
. Monthly A) ammonium and B) nitrate concentrations (µg N g soil
-1
) in MCSE
systems for 1989-1995. Mean ± SE for all measurements within each month.
via NO
2
−
reduction—effectively becoming denitrifying nitrifiers (Zhu et al. 2013,
Robertson and Groffman 2015).
Phillips et al. (2000a) found larger populations of nitrifiers in the MCSE
Conventional and No-till systems than in the Poplar and Early Successional sys-
tems, likely due to N fertilizer addition. However, nitrifier abundance, even when
high, still constitutes a relatively small proportion of the total microbial popula-
tion. Phillips et al. (2000b) found no detectable differences in the species composi-
tion of ammonia oxidizers in these systems—all were dominated by members of
