Dataset for 'Atmospheric N deposition as a key driver of soil nitrate production and accumulation in temperate forests under semi-arid climate' in Geophysical Research Letters

Anthropogenic nitrogen (N) deposition profoundly influences the soil N cycling in forests, especially for soil nitrate accumulation that is derived from both atmospheric N deposition and microbial N transformation. Using the novel 17O isotope anomalies, we traced the source contributions and microbial production to soil nitrate across semi-arid forests in northern China experiencing high N deposition. Results show that forests under higher N deposition retain more atmospheric nitrate and exhibit higher microbial nitrification rates. Unexpectedly, deposited N pollutants, rather than moisture supply, were the main drivers of soil nitrate production and accumulation across semi-arid forests where moisture limitation persists. This finding reveals a predominance of anthropogenic N inputs in regulating soil nitrate dynamics in semi-arid ecosystems. Our work enhances the understanding of forest N biogeochemistry under climate changes and anthropogenic N loading, with implications for sustainable forest water and nutrient management.