Nitrogen and phosphorus addition interactively affected the abundance of soil nematodes in a Tibetan alpine meadow

Abstract

There has been a significant increase in atmospheric nitrogen (N) and phosphorus (P) deposition since the Industrial Revolution, profoundly affecting the structure and function of terrestrial ecosystems. Nevertheless, the interactive effects of N and P enrichment on soil nematode community composition remain poorly understood. Here, we conducted a three-year controlled experiment on the Tibetan Plateau to investigate the mechanisms underlying nutrient-induced shifts in soil nematode communities. Our findings revealed that nitrogen and phosphorus enhanced soil nematode community abundance by 36.76 % and 12.17 %, respectively. Furthermore, we identified significant N × P interactions affecting both nematode abundance and specific trophic groups. Phosphorus addition counteracted the negative effects of nitrogen addition on the abundance of nematode community (from −0.03–87.92 %), plant parasites (from −39.50–70.82 %), fungivores (from −15.62–20.66 %), and omnivores-predators (from −34.78–21.67 %), while enhancing the positive effects of nitrogen addition on bacterivores (from 31.47 % to 119.71 %). Soil nematode abundance variations in the meadow ecosystem were mainly regulated by changes in soil pH. These findings highlight the critical role of nutrient interactions in soil micro-food webs and underscore the need to integrate pH-mediated mechanisms into predictions on ecosystem responses to global change.