Soil texture is an easily overlooked factor affecting the temperature sensitivity of N₂O emissions

As a potent greenhouse gas, soil nitrous oxide (N₂O) is strongly stimulated by rising temperature, triggering a positive feedback effect of global warming. However, its temperature sensitivity varies greatly among soils with different physical and chemical characteristics, while associated mechanisms remain unknown. Here we performed a meta-analysis of the effect of warming on N₂O emission and found distinctions in the response of N₂O to temperature increase in soils with different textures. Then, we conducted an incubation experiment on 11 arable soils with varying textures sampled across China. The results show that the temperature sensitivity of N₂O emissions was lower as soil texture became more clayey and was consistent with the outcome of meta-analysis. Further analysis was conducted by classifying the soils into clay and loam subgroups. As shown in the clay soil subgroup, N₂O emission was significantly correlated with both inorganic nitrogen contents and potential denitrification and nitrification activities. Correlation analysis and partial least square (PLS) path model revealed that temperature mediated N₂O emission by regulating nosZ gene abundance indirectly. In loam soils, however, the indirect effect of temperature on N₂O production was achieved mainly through nirS gene abundance. Additionally, soil DON content strongly correlated with N₂O emission in both subgroups and affected N₂O emissions by influencing the abundance of denitrifiers under warming conditions. Our findings suggest that (i) soil texture was an important factor affecting temperature sensitivity of N₂O emission and (ii) variable efficacy of warming in soil N₂O production might originate from the enriching DON and nitrate content and its different indirect effects on nirS- or nosZ-type denitrifiers.