Parent material influences soil abiotic N₂O production from chemical oxidation of hydroxylamine

Abstract. Hydroxylamine (NH₂OH) and nitrite (NO₂^-) represent pivotal nitrification intermediates that substantially govern soil abiotic N₂O production. Yet, the intricate factors influencing the abiotic formation of N₂O from chemical reactions involving NH₂OH and NO₂^- remain uncertain. This study was designed to reveal the impacts of land use type and parent material on soil abiotic N₂O production in response to NH₂OH and NO₂^- amendments. Our investigation revealed that land use type exerted no significant influence on abiotic production of N₂O with NH₂OH and NO₂^- addition. Nevertheless, the parent material exhibited a notable (P < 0.01) effect on N₂O production intrigued by NH₂OH addition. Specifically, a markedly higher abiotic N₂O production from NH₂OH was observed in soils developed from Quaternary red clay than those derived from granite. Subsequent analysis demonstrated that the soils originating from Quaternary red clay displayed significantly higher manganese (Mn) content in comparison to those originating from granite. This finding consistently aligns with the close correlation between the abiotic N₂O production via chemical oxidation of NH₂OH and Mn content of soil. Furthermore, the site preference (SP) values for N₂O arising from NH₂OH and NO₂^- addition were 25–30 ‰ and around 20 ‰, respectively, aligning with the expected ranges characterizing ammonia oxidation and chemodenitrification processes. Our findings provide valuable insight into the distinct influence of parent material on soil abiotic N₂O production via chemical oxidation of NH₂OH, contributing to a better understanding of the underlying mechanisms, and highlight the significance of soil factors in regulating abiotic N₂O production within soil ecosystems.