Antagonistic interactive effects of CO2 and nitrogen on microbial community enhance the persistence of soil C storage

To study long-term elevated CO2 and enriched N deposition interactive effects on microbial community and soil ecoprocess, here we investigated soil microbial community in a grassland ecosystem subjected to ambient CO2 (aCO2, 368 ppm), elevated CO2 (eCO2, 560 ppm), ambient nitrogen deposition (aN) or elevated nitrogen deposition (eN) treatments for a decade. There exist antagonistic CO2×N interactions on microbial functional genes associated with C, N, P S cycling processes. More strong antagonistic CO2×N interactions are observed on C degradation genes than other genes. Remarkably antagonistic CO2×N interactions on soil microbial communities could enhance soil C accumulation. Samples were collected under four different carbon dioxide and nitrogen treatment (aCaN,eCaN,aCeN and eCeN) in each of the four plant species richness levels:1, 4, 9, 16 ; In plots with 1 plant species, each treatment has 32 replicates ; In plots with 4 and 9 plant speices, each treatment has 15 replicates ; In plots with 16 plant species, each treatment has 12 replicates.