Abstract:
Controlled-release Nitrogen Fertilizers (CRNFs) are an effective fertilization technique by
minimizing nutrient loss and making Nitrogen (N) available to plants as they grow. Biochar-based
CRNF (BCRNF) technologies have been demonstrated very promising in increase of corn yield.
Despite the beneficial effects of BCRNFs, their impacts on prokaryotic and fungal soil communities
are not well evaluated. Different formulations of BCRNF were developed to investigate their effects
on corn productivity. We analyzed the soil microbes and their functional potential under different
BCRNF regimes using amplified V3–V4 region of 16s rRNA for determining prokaryotic, and ITS
genes for fungal communities. The soil prokaryotic diversity was similar across the treatments,
with differences in prokaryotic genera with relative abundance of 0.1% or less in the soil (p < 0.05).
In contrast, the fungal community diversity was different only for unfertilized soil. It had a high
relative abundance for Aspergillus. Genus level comparison showed that Pseudofabraea was higher in
Bioasphalt-based BCRNF compared to other treatments. Moreover, the N-fixing communities in soil
were also similar across the treatments. At genus level, Microvirga, Azospirillum, and Methyloprofundus
were highest in no-fertilizer control. The functional potential predictions using PICRUSt2 portrayed
a consistent N-cycling functions across the treatments. However, the predicted gene functions related
to nitrous-oxide reductase (nosZ) and hydroxylamine reductase (hcp) were significantly lower in soil
receiving BCRNF containing biosolid. Overall, BCRNF treatments previously identified to increase
corn yield displayed minimal shifts in the soil microbial communities. Thus, such novel fertilization
would enable increased crop yield without affecting soil communities leading to sustainable crop
production.
