Nonylphenol induces nitrous oxide production in agricultural soils by facilitating gross nitrogen mineralization

Nonylphenol (NP) is commonly used as a plasticizer and pesticide emulsifier in agriculture. However, its presence in soil can pose a serious threat to soil ecosystems. A series of experiments were conducted to investigate the effects of NP on soil nitrogen cycling. This study revealed that NP contamination increased the mineralization of organic nitrogen and lead to higher nitrous oxide (N₂O) emissions in soil from different regions of China. It was also observed that NP significantly decreased the total nitrogen (TN) content in agricultural soil while increasing the content of soil total dissolved nitrogen (TDN), nitrate nitrogen (NO₃^--N), and ammonium nitrogen (NH₄⁺-N). Furthermore, the study evaluated the kinetics of enzyme-catalyzed reactions and found that the increase in nitrite reductase activity could contribute to the observed increase in N₂O emission in agricultural soil contaminated with NP. In addition, it was found that NP exposure resulted in the promotion of bacteria involved in denitrification (Nocardioides, Haliangium, Micromonospora, Pedomicrobium) and altered the network complexity of the bacterial community involved in nitrogen conversion. These findings underscore the significance of NP in N₂O emissions and provide insight into its influence on the nitrogen geochemical fractions and cycling in soil.