Soil fungal community assembly processes under long‐term fertilization

Abstract

Understanding the processes that regulate communities of microorganisms is a key issue and focus in microbial ecology. Although fungi play a critical role in soil biogeochemical cycling, their community assembly processes remain largely unknown, especially in agricultural soils. In this study, we investigated the relative importance of five community assembly processes (variable selection, homogeneous selection, homogeneous dispersal, dispersal limitation and an undominated process) in soil fungal communities under long‐term (28 years, 1990–2018) fertilization management consisting of 12 different treatments in triplicate field plots. Using Illumina MiSeq sequencing of the 18S rRNA eukaryotic gene, we observed that fungal communities in manure treatments were all structured primarily by homogeneous dispersal, whereas the communities in chemical fertilizer treatments were structured primarily by homogeneous dispersal and an undominated process. Soil calcium played an important role in shaping the soil fungal community, whereas soil organic matter concentrations had a considerable impact on the soil fungal phylogenetic community composition. Overall, our results suggest that fertilization management should be considered as a key factor driving microbial community assembly processes in farmed soils.Highlights Soil Ca played a key role in shaping eukaryotic microbial community Chemical fertilization resulted in homogenous selection and undominated processes. A combination of chemical and manure fostered homogenous selection processes.

Adaptation of Soil Fungal Community Structure and Assembly to Long- Versus Short-Term Nitrogen Addition in a Tropical Forest

“…Additionally, the hyphal networks of fungi and the roots of their hosts limit the dispersion of fungal species (i.e., dispersal limitation), since most of the dominant trees in the forest are EcM or arbuscular mycorrhizae ( Lu et al, 2018 ; Gurmesa et al, 2019 ). Our results support the view that stochastic processes predominate in the fungal community assembly ( Shi et al, 2019 ; Zhao J. et al, 2019 ; Jiao and Lu, 2020 ). Furthermore, the neutral community model explained a relatively large fraction ( R 2 > 0.5) of fungal community variation, indicating that the fungal community was more influenced by neutral (or stochastic) processes.…”

How Do N Addition Affect Soil Fungal Community Assembly: Short- Versus Long-term Effects?

“…Additionally, the hyphal networks, forming between fungi and the roots of their hosts, limit the dispersion of fungal species (i.e., dispersal limitation), since most of the dominant trees in the forest are ectomycorrhizal or arbuscular mycorrhizae [39,63]. In general, our results are supported by prior studies reporting that stochastic processes predominate in fungal community assembly [13,18,21]. Furthermore, the neutral community model explained a relatively large fraction (R 2 > 0.5) of fungal community variation, indicating that the fungal community was more influenced by neutral (or stochastic) processes.…”

“…Nitrogen enrichment can also affect the processes underpinning fungal community assembly but inconsistent results have been reported. For example, stochastic processes dominate under the fertilization treatment in some studies [20,21], whereas deterministic processes were found to have a larger relative importance with fertilization in other studies [31,33]. Moreover, nitrogen fertilization resulted in tightened network associations among fungal, bacterial and protists communities in diverse agricultural soils [34], indicating increased importance of deterministic biotic interactions in shaping microbiome.…”

“…While these are conceptualized processes, new theoretical frameworks and experimental/analytical methodologies are being developed to associate them with measurable ecological and evolutionary processes, such as competition, predation, phylogenetic signals, network interactions and trait variables [7,15,16]. In doing so, it is possible to quantify the relative contribution of these assembly processes for different ecosystem types, geographic scales and microbial categories [17][18][19], and to assess how the dominance of the assembly process is affected by global or regional environmental changes [20][21][22].…”

Dominant Tree Species Shape Soil Microbial Community via Regulating Assembly Processes in Planted Subtropical Forests

“…Some studies have proposed an increasing proportion of deterministic processes along the chronosequence of long-term disturbances, though emphasis has been given to the stochastic processes at the initial stage of disturbance [10,11]. Although soil microbiota is jointly shaped by the deterministic and stochastic processes under anthropogenic disturbances, such as fertilization [12], climate warming [11], and land use changes [10], the relative importance of these two processes is still unclear.…”