Data from:[Minor temporal responses of grassland soil carbon fluxes to decade-long nitrogen enrichment]

Understanding long-term effects of nitrogen (N) enrichment on soil respiration (Rs) is essential for prediction of impacts of ongoing anthropogenic global change on belowground carbon dynamics. However, temporal impacts on grassland Rs metrics of long-term N addition are unclear. We quantified responses of Rs and its autotrophic and heterotrophic components to decadal inputs of contrasting levels of N in a Tibetan alpine grassland and found minor temporal variations among the responses, which contrast with direction and magnitude of those reported for forest ecosystems. The responses in Rs metrics reported here may be explained by combined effects of biogeochemical processes, i.e., decreased temperature, increased moisture and ammonium content in soils, and minor variations in root and microbial biomass. Our results did not support predictions that long-term, high-level N-addition exacerbates temporal reductions in Rs and highlight the challenge of effective prediction of long-term belowground responses to global environmental change in grassland ecosystems.