Nitrous oxide emissions in agricultural soils: a review

Abstract

The greenhouse gases concentration in the atmosphere have significantly increased since the beginning of the Industrial Revolution. The most important greenhouse gases are CO₂, CH₄ and N₂O, with CH₄ and N₂O presenting global warming potentials 25 and 298 times higher than CO₂, respectively. Most of the N₂O emissions take place in soils and are related with agricultural activities. So, this review article aimed at presenting the mechanisms of N₂O formation and emission in agricultural soils, as well as gathering and discussing information on how soil management practices may be used to reduce such emissions. The N₂O formation in the soil occurs mainly through nitrification and denitrification processes, which are influenced by soil moisture, temperature, oxygen concentration, amount of available organic carbon and nitrogen and soil C/N ratio. Among these factors, those related to soil could be easily altered by management practices. Therefore, understanding the processes of N₂O formation in soils and the factors influencing these emissions is fundamental to develop efficient strategies to reduce N₂O emissions in agricultural soils.