friendly than mineral fertilizers, the disturbance caused by animal
manure application might also impose some risks. An important
aspect of organic fertilization is the introduction of high loads of
exogenous microbes in soil
In modern agriculture, mineral and organic fertilization account for most of the global anthropogenic
N2O emissions. A strategy to prevent or to reduce emissions of greenhouse gases such as N2O is the use of
nitrification inhibitors, which temporarily inhibit the microbial conversion of soil ammonium to nitrate.
However, information about the magnitude and duration of disturbance caused by organic fertilization
with nitrification inhibitor on the microbial community is lacking. Here we examined N dynamics and
how potentially active soil microbial communities changed through time by the addition of
dicyandiamide-treated swine slurry and mineral fertilizers. A field experiment (corn/cereal succession
under no-tillage system) was carried out using the following treatments: (I) unfertilized control, (II)
surface application of mineral nutrients, (III) surface application of swine slurry, and (IV) surface
application of swine slurry with dicyandiamide. Soil samples were collected at 0, 3, 6, 11, 25 and 50 days
after start of experiment. Total RNA was extracted, synthesized to cDNA and used as template to amplify
and sequence the 16S rRNA. Nitrous oxide emissions were also quantified. The organic fertilizers were
the main drivers on changes in microbial community structure. Slurry application decreased microbial
diversity and changed the microbial structure temporarily but the metabolically active microbial community
was resilient, recovering to the original status 50 days post-fertilization. DCD had no effect on
metabolically active microbial community and was pathway-specific, having impact only on nitrifiers
during a short-term period, which in turn reduced the N2O emissions.