Arbuscular mycorrhizal fungi alleviate the negative effect of nitrogen deposition on ecosystem functions in meadow grassland

Abstract

Nitrogen (N) deposition can reduce plant species richness and cause grassland degradation, thus affecting grassland ecosystem stability. Arbuscular mycorrhizal (AM) fungi play an important role in ecosystem stability. However, the influences of AM fungi on grassland ecosystem stability under N deposition remain unclear. We need more information on the impacts of N accumulation on the interactions between AM fungi and the plant community. To test the contribution of AM fungi to grassland stability under N deposition, a 5‐year field experiment was conducted in a temperate meadow with two manipulated factors, namely, N addition and AM fungi suppression. The plant species richness and diversity, biomass stability, litter decomposition, and greenhouse gas emissions were quantified. Under N addition, AM fungi did not affect the plant species diversity and richness but altered the coverages of different functional groups and increased the aboveground productivity and biomass stability. Litter decomposition increased under N addition and increased more in the treatment where AM fungi were not suppressed. The emissions of N2O and CH4 in the AM fungi suppression treatment were much higher than those in the nonsuppression treatment under N addition. Our results suggest that AM fungi can alter the plant community structure, increase plant productivity and community biomass stability, accelerate litter decomposition, and reduce the soil total N concentration and emissions of N2O and CH4 under N addition. Our results highlight that the conservation of AM fungi should be considered to alleviate grassland degradation and maintain grassland ecosystem multifunctionality in the future considering global change.

Nitrogen Addition Affects Ecosystem Carbon Exchange by Regulating Plant Community Assembly and Altering Soil Properties in an Alpine Meadow on the Qinghai–Tibetan Plateau

“…There were differences in the sensitivity of different functional groups to N addition because of the difference in the N utilization capacity of plant roots and leaves ( Kang et al, 2019 ). Some previous studies in alpine ( Bassin et al, 2007 ) and subalpine grasslands ( Soudzilovskaia and Onipchenko, 2005 ) reported that sedges were characterized by high respiration efficiency and growth rates ( Aerts, 1999 ; Shane et al, 2006 ; Mcclean et al, 2011 ), which will make sedges have a higher resource competitiveness than the other functional groups in alpine meadow ecosystems.…”

“…A long-term N addition affects the plant biomass and community composition in grassland ecosystems by increasing soil N availability ( Bai et al, 2008 ; Yang et al, 2012 ; Xu et al, 2014 ; Shen R. N. et al, 2022 ). For example, a long-term N addition could promote the functional groups of grass by negatively impacting forb in alpine grasslands ( Zhang L. et al, 2020 ), which is an effect related to the different mycorrhizal distributions, N absorption amounts and utilization mechanisms between grasses and forbs ( Wang et al, 2015 ; Kang et al, 2019 ). Chronic or excessive N addition can also reduce the species richness and diversity when soil N exceeds the saturation threshold ( Xia and Wan, 2008 ; Li S. et al, 2019 ).…”

Effects of arbuscular mycorrhizal fungus inoculation on the growth and nitrogen metabolism of Catalpa bungei C.A.Mey. under different nitrogen levels

“…Evidence suggests that AMF can transfer a large amount of N to host plant cells, improve the utilization efficiency of N in the soil, reduce the input of chemical fertilizer, and make a virtuous cycle of the soil ecosystem, thus playing an important role in plant N nutrition (Govindarajulu et al, 2005;Savolainen and Kytöviita, 2022). At present, this has been confirmed in vegetables (Roussis et al, 2022), crops (Tanaka and Yano, 2005) and forage grass (Kang et al, 2020;Khan et al, 2021), but the researches on trees are relatively few. Moreover, the effects of AMF on plant N metabolism and its regulatory mechanism are rarely reported.…”

Negative effects of phosphorus addition outweigh effects of arbuscular mycorrhizal fungi and nitrogen addition on grassland temporal stability in the eastern Eurasian desert steppe

“…Certain soil microorganisms, especially specific soil mutualists, are known to be important in temporally stabilizing plant communities, as shown in several field and greenhouse experiments (Wagg et al, 2021; Yang, 2021; Yang, Liu, et al, 2021; Yang, Mariotte, et al, 2021; Yang, Shen, et al, 2018; Yang, Wagg, et al, 2018; Yang, Zhang, et al, 2021). Arbuscular mycorrhizal fungi (AMF) are a type of fungus that forms a symbiotic relationship with host plants, and enhance the stability of plant productivity (Jia et al, 2022; Kang et al, 2020; Yang et al, 2014; Yang, Liu, et al, 2021; Yang, Mariotte, et al, 2021; Yang, Zhang, et al, 2021). Jia et al (2021) reported that AMF can increase plant diversity (according to the Shannon–Wiener diversity index) and improve the stability of ANPP in an arid grassland, while the input of N had opposite effects in this environment.…”