Soil acidification drives the negative effects of nitrogen enrichment on soil microbial biomass at the global scale

Abstract

Background and aims Nitrogen (N) deposition is a global driver of change that affects microbial biomass and ecosystem processes. However, it remains unclear whether N enrichment impacts microbial biomass in soil across ecosystems.Methods In this study, we synthesized 1,385 paired observations from 125 studies worldwide to evaluate the effects of N addition on soil microbial biomass. ResultsWe found that N enrichment substantially suppresses total microbial biomass, including bacterial, fungal, and arbuscular mycorrhizal fungi biomass. Importantly, we found strong negative effects on microbial biomass globally caused by N-enrichment-induced soil acidification. Moreover, N enrichment mainly shapes the acidification of soil through the increased concentration of ammonium and by changing exchangeable cations in soil, including magnesium, calcium, sodium, manganese, and aluminum ions.Conclusions Overall, our findings demonstrate that N-enrichment-induced soil acidification is a crucial factor to consider for preserving microbial communities and ecosystem function under future trends of increasing N enrichment.

Effect of Soil Acidification on Temperature Sensitivity of Soil Respiration

“…Secondly, soil pH serves an essential role in membrane-bound proton pumps and protein stabilization, affecting microbial physiological activities [27]. In addition, soil enzyme activities are dependent on pH, and low pH damages their activities, which in turn affect microbial activities [69,70]. Different microbial species have different sensitivities to soil pH changes during acidification, leading to different changes.…”