Nitrous oxide (N$2$O) is a potent greenhouse gas, produced by pastures, fields and other agricultural land. It is released during nitrification and denitrification due to tillage and fertiliser application combined with factors related to soil. This affects changes in microbial communities, mainly bacteria, fungi and the genes involved in N2O production. The intensity of emissions is estimated indirectly based on the presence of genes of the denitrification pathway (nirK, nirS, nosZI and nosZII), but the connections between them and N2O emissions are not clarified, since emissions are influenced by other factors in addition to the genetic potential of the community. Studies have shown that, in soils that have been untreated for a long time, the abundance of the nirS and nirK genes is lower and the abundance of the nosZ gene is higher. However, emissions are not always lower than theoretically expected. Therefore, the impact of tillage should always be adjusted to soil and climate characteristics. The use of mineral and organic fertilizers has different effects on the growth and structure of microbial communities and gene expression. Fertilization with organic fertilizers to a certain extent affects the growth of denitrifiers due to greater availability of organic carbon, but the effect is not uniform for all types of fertilizers. Similar changes occur in organic systems, where the abundance of the nosZ gene is significantly higher than in conventional systems.
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