Long‐term nitrogen fertilization decreases bacterial diversity and favors the growth of Actinobacteria and Proteobacteria in agro‐ecosystems across the globe

Abstract

Long-term elevated nitrogen (N) input from anthropogenic sources may cause soil acidification and decrease crop yield, yet the response of the belowground microbial community to long-term N input alone or in combination with phosphorus (P) and potassium (K) is poorly understood. We explored the effect of long-term N and NPK fertilization on soil bacterial diversity and community composition using meta-analysis of a global dataset. Nitrogen fertilization decreased soil pH, and increased soil organic carbon (C) and available N contents. Bacterial taxonomic diversity was decreased by N fertilization alone, but was increased by NPK fertilization. The effect of N fertilization on bacterial diversity varied with soil texture and water management, but was independent of crop type or N application rate. Changes in bacterial diversity were positively related to both soil pH and organic C content under N fertilization alone, but only to soil organic C under NPK fertilization. Microbial biomass C decreased with decreasing bacterial diversity under long-term N fertilization. Nitrogen fertilization increased the relative abundance of Proteobacteria and Actinobacteria, but reduced the abundance of Acidobacteria, consistent with the general life history strategy theory for bacteria. The positive correlation between N application rate and the relative abundance of Actinobacteria indicates that increased N availability favored the growth of Actinobacteria. This first global analysis of long-term N and NPK fertilization that differentially affects bacterial diversity and community composition provides a reference for nutrient management strategies for maintaining belowground microbial diversity in agro-ecosystems worldwide.

Phosphorus and Nitrogen Drive the Seasonal Dynamics of Bacterial Communities in Pinus Forest Rhizospheric Soil of the Qinling Mountains

“…Similar results have been reported based on the researches on other mountain forest rhizospheric soil (Rasche et al, 2011; Dai et al, 2018). Some species of Proteobacteria and Actinobacteria were reported as the copiotrophic bacteria and exhibited the opposite variation pattern, whilst, some species of Acidobacteria were tended to be more fastidious oligotrophic bacteria (Fierer et al, 2007).…”

Scientists’ warning to humanity: microorganisms and climate change

“…This proportion is predicted to increase, leading to substantial changes in soil cycling of carbon, nitrogen and phosphorus, among other nutrients. Furthermore, these changes are associated with a marked loss of biodiversity 206 , including of microorganisms 207 . There is increasing interest in using plant-associated and animal-associated microorganisms to increase agricultural sustainability and mitigate the effects of climate change on food production, but doing so requires a better understanding of how climate change will affect microorganisms.…”

Soil microbial restoration strategies for promoting climate‐ready prairie ecosystems

“…Nowhere is this disruption more obvious than in the tallgrass prairie ecosystems that once dominated the Midwestern United States. Beginning in the 1830s, European settlers expanding westward altered much of this ecosystem by suppressing fire (Briggs et al 2005) and replacing native plants and animals with agricultural crops (e.g., Herkert natural to agricultural ecosystems dramatically altered soil microbial communities through long-term tilling and fertilization (Fierer et al 2013, Dai et al 2018, House and Bever 2018, and changed soil physical and chemical parameters resulting in substantial carbon loss to the atmosphere (Post and Kwon 2000). In sum, an estimated 80-99.9% of tallgrass prairies and their accompanying soils have been altered by human activity, making it the most impacted ecosystem in North America Knopf 1994, Sampson et al 2004).…”

“…Through decades of fertilization, tilling, and agrochemical use, soil microbial communities in agricultural systems have become so altered that they are thought to reach an alternative stable state (Jangid et al 2010, Fichtner et al 2014. For example, nitrogen fertilization causes a consistent decrease in soil bacterial diversity and microbial biomass carbon, independent of nitrogen application rates or crop types (Dai et al 2018). Nitrogen fertilization is also related to increased relative abundances of Proteobacteria and Actinobacteria (Ramirez et al 2010, Zhou et al 2017, Dai et al 2018, which include taxa that are adapted to high nitrogen demand and labile carbon pool metabolism (Fierer et al 2007, Collins et al 2016.…”

“…For example, nitrogen fertilization causes a consistent decrease in soil bacterial diversity and microbial biomass carbon, independent of nitrogen application rates or crop types (Dai et al 2018). Nitrogen fertilization is also related to increased relative abundances of Proteobacteria and Actinobacteria (Ramirez et al 2010, Zhou et al 2017, Dai et al 2018, which include taxa that are adapted to high nitrogen demand and labile carbon pool metabolism (Fierer et al 2007, Collins et al 2016. Conversely, in North American remnant prairies, where plant organic material inputs control the growth of these copiotrophic taxa, Verrucomicrobia, which are thought to specialize in recalcitrant carbon degradation, are more predominant members of the community (Fierer et al 2013).…”