ABSTRACT The ecosystem respiration (R e ) is a key process of carbon from soil into atmosphere. It is highly sensitive to the changes in precipitation and nitrogen input (N i ), and plays a significant role in influencing warming. However, how annual precipitation and N i affect the R e and its temperature sensitivity (Q 10 ) in arid ecosystems remains unclear. Therefore, an in‐stiu N i manipulation experiment was conducted during both a humid year and a drought year in the desert steppe of western China. The results showed that R e exhibited an distinct unimodal trend in a humid year but not in a drought year, leading to marked different in Q 10 in 2 years. The Q 10 was higher in a humid year (1.9) rather than that in a drought year (1.1). The effect of N i on R e was variable, exhibiting both stimulatory and inhibitory effects, which overall resulted in no significant impact on R e . N i exerted a similar stimulatory effect in a humid year (31.0% ± 7.2%) and in a drought year (34.7% ± 6.1%), with an the increasing trend observed with higher N i levels. Meanwhile, the Q 10 was also showed an increasing trend with the with higher N i in a humid year (except at 1 g N m −2 year −1 ). In contrast, during the drought year, low N i level ( 6 g N m −2 year −1 ) increased Q 10 . Soil moisture exerted a threshold‐dependent regulatory effect on R e . In the humid year, R e initially increased and then decreased with rising soil moisture, whereas in the drought year, Re showed a significant declining trend as soil moisture increased. The results from the structural equation model showed that R e was primarily regulated by plant root biomass in a humid year, but by soil temperature in the drought year, and the annual precipitation exerted the most of important indirect effect on R e , primarily by influencing soil moisture, root biomass and soil temperature. In conclusion, R e and its Q 10 in this desert steppe was more sensitive to inter‐annual precipitation variability than to N i . In a humid year R e mainly mediated by root biomass, whereas in a drought year, it was largely governed by changes in soil moisture and temperature. These findings provided critical insights for the development of R e model in the Eurasian inland desert steppe.
Yue et al. (2026) studied this question.