Four genes were less abundant in NT compared to one or more of the others soils (nifH, nirK, nirS, norB).In conclusion, the microbial communities involved in nitrogen metabolism were sensitive to different agricultural practices, which in turn, likely has implications for N 2O emissions.

Based on nirS/nirK ratios, CT represents the highest N 2O consumption potential in four soils. Diversity and richness values were higher for four of the nine genes ( napA, narG, nirA, nirB). The relative abundance of nirS was significantly higher in the CT treatment compared to the others.

The abundance values of napA, narG, nifH, nirA, and nirB were not significantly different between NT and CT. The relative abundance of four genes ( nifH, nirK, nirS, and norB) were significantly lower in the NT treatment compared to one or more of the other soils. The data generated were statistically compared between the four management practices. Additionally, the genes associated with nitrogen metabolism (defined by the KEGG hierarchy) were examined. For each gene, relative abundance values, diversity and richness indices, and taxonomic classification were determined. The work involved examining soil shotgun sequencing data for nine genes ( napA, narG, nirK, nirS, norB, nosZ, nirA, nirB, nifH).

The current study investigated the abundance and diversity of genes involved in nitrogen cycling (primarily denitrification) under four agricultural management practices (no tillage, conventional tillage, reduced input, biologically-based). Although the reduction of N 2O to nitrogen gas can control emissions, the factors impacting the enzymes involved have not been fully explored. Nitrogen fertilizer results in the release of nitrous oxide (N 2O), a concern because N 2O is an ozone-depleting substance and a greenhouse gas.

Xlstat wayne state university