Diversity Of Soil Fungal Communities Research Articles

Effects of Maize/Peanut Intercropping and Nitrogen Fertilizer Application on Soil Fungal Community Structure

Maize/peanut intercropping may improve soil health through reducing nitrogen (N) fertilization. However, the effects of maize/peanut intercropping combined with reduced N fertilization on the soil fungal community structure have not been well reported. Using a long-term localized micro-zone experiment, we investigated the combined effects of intercropping and N fertilizer application on soil fungal community diversity and composition. Three cropping patterns (maize/peanut intercropping, maize monoculture, and peanut monoculture) and three N application levels (0 kg·hm−2, 150 kg·hm−2, and 300 kg·hm−2) were assessed. The results showed that the total numbers of fungal species and unique species (operational taxonomic units, OTUs) in both maize and peanut soils tended to first increase and then decrease with increasing N application. Compared with monoculture, the numbers of total OTUs and unique OTUs in intercropped maize soil decreased by 4.14% and 12.79%, respectively, but the total numbers of OTUs and unique OTUs in peanut soil increased by 1.08% and 3.78%, respectively. With increasing N application, the soil fungal Ace and Chao indices of maize soil first increased and then decreased, while the fungal Shannon, Ace, and Chao indices of peanut soil decreased. Compared with the monoculture system, intercropping significantly reduced the maize soil fungal Ace and Chao indices but increased the peanut soil fungal Shannon, Ace, and Chao indices. Nitrogen application and intercropping significantly altered the fungal community structure of maize soil, while N application had no significant effect on the fungal community structure of peanut soil, though intercropping significantly changed the fungal community structure of peanut soil. At the phylum level, Ascomycota, Basidiomycota, Mortierellomycota, unclassified_k_Fungi, and Chytridiomycota were the dominant taxa. Redundancy analysis (RDA) showed that soil nitrate (NO3−) content was the main environmental factor shaping the soil fungal community. In conclusion, excessive N fertilization (300 kg·hm−2) can reduce soil fungal community diversity; maize/peanut intercropping reversed the negative effect of N application on fungal community of peanut soil, but not that of maize soil. Soil NO3− content is the primary environmental driver of soil fungal communities.

The Impact of Artificial Restoration of Alpine Grasslands in the Qilian Mountains on Vegetation, Soil Bacteria, and Soil Fungal Community Diversity

To understand how the soil microbial community structure responds to vegetation restoration in alpine mining areas, this study specifically examines the grassland ecosystem in the Qianmalong mining area of the Qilian Mountains after five years of artificial restoration. High-throughput sequencing methods were employed to analyze soil bacteria and fungi microbial characteristics in diverse grassland communities. Combined with modifications in vegetation diversity as well as soil physicochemical properties, the impact of vegetation restoration on soil microbiome diversity in this alpine mining area was investigated. The findings indicated that the dominant plants were Cyperus rotundus, Carex spp., and Elymus nutans. As the extent of the grassland’s restoration increased, the number of plant species, importance values, and plant community diversity showed an increasing trend. The plant functional groups were mainly dominated by Cyperaceae, followed by Poaceae. Plant height, density, plant cover, frequency, and aboveground biomass showed an increasing trend, and soil water content (SWC) increased. While soil pH and soil electrical conductivity (EC) exhibited a declining trend, available phosphorus (AP), total phosphorus (TP), total nitrogen (TN), nitrate nitrogen (NO3-N), soil organic carbon (SOC), and soil water content (SWC) showed an increasing trend. The dominant bacterial communities were Actinobacteriota, Proteobacteria, Acidobacteriota, Chloroflexi, Firmicutes, and Gemmatimonadota, while the dominant fungal communities were Ascomycota, Mortierellomycota, Basidiomycota, unclassified_k_Fungi, and Glomeromycota. Significant differences were detected within soil microbial community composition among different degrees of restoration grasslands, with bacteria generally dominating over fungi. SWC, TP, and TN were found to be the main soil physicochemical factors affecting the distribution of soil bacterial communities’ structure; however, SOC, TN, and NO3-N were the primary factors influencing the soil distribution of fungal communities. The results of this study indicate that different degrees of vegetation restoration in alpine mining areas can significantly affect soil bacterial and fungal communities, and the degree of restoration has varying effects on the soil bacteria and fungi community structure in alpine mining areas.

Effects of slow-release nitrogen and urea combined application on soil physicochemical properties and fungal community under total straw returning condition

Under the system of full straw returning, the relationship between soil fungal community diversity and soil physiochemical properties, and the combined application of slow-release nitrogen and urea is unclear. To evaluate its effect and provide an effective strategy for sustainable agricultural production, a 2-year field positioning trial was conducted using maize as the research object. The experiment was designed with two factors: straw treatment(S) and nitrogen fertilizer treatment(N),Six experimental treatments were set up,S1N0,S1N1,S1N2,S1N3,S1N4,S0N2,respectively.Analysis of 54 soil samples revealed 15 fungal phyla and 49 fungal classes. The composition of fungal communities in each treatment was basically the same, but there were significant differences in species abundance. Under total straw returning conditions, the combined application of slow-release nitrogen fertilizer and normal nitrogen fertilizer significantly increased the relative abundance of Ascomycota. During the jointing stage, tasseling stage and maturity stage, S1N4, S1N3 and S1N2 increased by 25.76%, 22.97%, 20.74%; 25.11%, 30.02%, 23.64% and 22.47%, 28.14%, 22.71% respectively compared with S0N2.The relative abundance of Basidiomycota was significantly reduced. Alpha diversity analysis showed that the straw returning mode significantly increased the Shannon index and decreased the Simpson index, which was obvious in the jointing stage and tasseling stage. The principal coordinate analysis analysis results showed that the fungal communities formed different clusters in the horizontal and vertical directions at the three growth stages of corn jointing, tasseling and maturity. At the jointing stage and tasseling stage, the communities of the straw return treatment and the straw removal treatment were separated, and the community distribution of each treatment was not significantly different in the mature stage. Total straw returning combined with slow-release fertilizer significantly (P＜0.05) increased the soil organic carbon, nitrate nitrogen and ammonia nitrogen content in each growth period, and increased the soil total nitrogen and hydrolyzable nitrogen content (P＞0.05).After the straw was returned to the field, the combined application of slow-release nitrogen fertilizer and common urea had a significant impact on soil urease, catalase, and sucrase activities. Among them, the three enzyme activities were the highest in the S1N3 treatment at the jointing stage and maturity stage, and the S1N4 treatment at the tasseling stage had the highest enzyme activity. Fungal community composition is closely related to environmental factors. Soil organic carbon, urease and catalase are positively correlated with Ascomycota and negatively correlated with Basidiomycota.

Intercropping changed the soil microbial community composition but no significant effect on alpha diversity.

Enhancing the planning of the forest-agricultural composite model and increasing the efficiency with which forest land is utilized could benefit from a thorough understanding of the impacts of intercropping between forests and agriculture on soil physicochemical properties and microbial communities. Populus cathayana × candansis cv. Xinlin No.1 and Glycine max intercrop soils, along with their corresponding monocrops, were used in this study's llumina high-throughput sequencing analysis to determine the composition and diversity of soil bacterial and fungal communities. The findings indicated that intercropping considerably raised the soil's total phosphorus content and significantly lowered the soil's carbon nitrogen ratio when compared to poplar single cropping. Furthermore, the total carbon and nitrogen content of soil was increased and the soil pH was decreased. The sequencing results showed that intercropping had no significant effect on soil alpha diversity. Intercropping could increase the composition of fungal community and decrease the composition of bacterial community in poplar soil. At the phylum level, intercropping significantly increased the relative abundance of four dominant phyla, i.e., Patescibacteria, Proteobacteria, Patescibacteria and Deinococcus-Thermus. And the relative abundances of only two dominant phyla were significantly increased. It was found that soil total phosphorus and available phosphorus content had the strongest correlation with soil bacterial community diversity, and soil pH had the strongest correlation with soil fungal community diversity. The results of this study were similar to those of previous studies. This study can serve as a theoretical foundation for the development of a poplar and black bean-based forest-agricultural complex management system in the future.

Dynamic Shifts in Soil Fungal Functional Group Characteristics across Distinct Vegetation Types during Ecological Restoration in Degraded Red Soil Regions

The red soil region in southern China has become the second-largest soil erosion area after the Loess Plateau. The evolutionary trajectory of soil fungi during vegetation restoration in acidic red soil regions remains a subject of inquiry. The investigation focused on the restoration process of an ecosystem facing intense degradation in the southern regions of China by studying four distinctive vegetation types: barren land (BL), pure Pinus massoniana forest (CF), mixed coniferous (CBF), and broad-leaved forest (BF). The outcomes revealed considerable enhancements in soil properties’ attributes, evident through a gradual reduction in the bulk density of soil (SBD) and a corresponding increment in soil moisture content (MC), total nitrogen (TN), total carbon (TC), total potassium (TK), soil organic matter (SOM), and available potassium (AK) as vegetation restoration advanced. An intriguing trend emerged where the relative abundance of Ascomycota fungi displayed a declining trajectory, whereas Basidiomycota fungi exhibited an ascending trend with the progression of vegetation restoration. Specifically, broad-leaved forests exhibited a significantly greater relative abundance of Penicillium fungi compared to other stages of vegetation restoration. The diversity of soil fungal communities increased in tandem with vegetation restoration. A redundancy analysis illuminated a strong and positive relationship between the abundance of major soil fungi and soil pH, TN, and TC (key influencers of acidic red soil fungal populations). This study provided additional evidence of an elevation in ectomycorrhizal and saprophytic trophic fungi, signifying a transition that enhances the vegetation’s ability to capture water and nutrients. This, in turn, contributes to the overall enrichment and diversity of vegetation communities during the progression of restoration.

Effects of continuous cropping on fungal community diversity and soil metabolites in soybean roots.

Microbial community imbalance is the main cause of soybean intercropping, but the mechanism of soybean soil fungal community diversity change induced by continuous cropping is still unclear. This study analyzes the fungal community diversity and the change of fungal communities in compartments of different root systems of intercropped soybeans by high-throughput sequencing (endosphere, rhizoplane, and rhizosphere) between continuous cropping and maize-soybean rotation. The results showed that the community composition and the diversity of compartments of different root systems of intercropped soybeans are different, and fungal diversities showed a decreasing trend from rhizosphere to endosphere. Continuous cropping significantly increased fungal community diversities in different root compartments and changed their formation, enrichment, and depletion processes. Continuous cropping brings about the enrichment of soil pathogens, but only partial soil pathogens could colonize from the rhizosphere to the endosphere. All these suggested that root compartments had selective effects on root-associated fungal community diversity. Additionally, metabolomics assay revealed that continuous cropping soybean markedly altered soil metabolic profiling. Correlation analysis results showed that fungal community diversity was significantly correlated with soil metabolites. To sum up, under different planting patterns, the diversity and the functional mode of soybean soil microbial community have changed. Continuous cropping has increased the abundance of pathogenic fungi in soybean soil, resulting in changes in the correlation between soil fungi and metabolites, and then changed the soil metabolic spectrum.IMPORTANCESoybean yield can be affected by soybean soil fungal communities in different tillage patterns. Soybean is an important food crop with great significance worldwide. Continuous cultivation resulted in soil nutrient deficiencies, disordered metabolism of root exudates, fungal pathogen accumulation, and an altered microbial community, which brought a drop in soybean output. In this study, taking the soybean agroecosystem in northeast China, we revealed the microbial ecology and soil metabolites spectrum, especially the diversity and composition of soil fungi and the correlation of pathogenic fungi, and discussed the mechanisms and the measures of alleviating the obstacles.

Diversity and Structure of Soil Microbial Communities in Chinese Fir Plantations and Cunninghamia lanceolata–Phoebe bournei Mixed Forests at Different Successional Stages

Cunninghamia lanceolata is an important species in plantations and is widely planted in sub-tropical regions of China because of its fast-growing and productive characteristics. However, the monoculture planting is carried out in the pursuit of economic value. This planting mode has led to problems such as the exhaustion of soil fertility, decrease in vegetation diversity, and decrease in woodland productivity. In order to restore soil fertility and increase timber production, the introduction of broad-leaved tree species to plantations is an effective transformation model. Understanding how forest age changes and stand structure differences drive the composition and diversity of soil microbial communities is helpful in understanding the trend of soil–microbial changes in plantations and evaluating the effects of the introduction of broad-leaved tree species in soil–plant–microbial ecosystems in plantations. Therefore, the purpose of our study is to investigate the effects of forest age and pure forest conversion on C. lanceolata–P. bournei-mixed forest soil microbial community structure and diversity by detecting soil nutrients, enzyme activities, and soil microbial 16S and ITS rRNA gene sequencing. According to the findings, the diversity and abundance of bacterial communities in C. lanceolata plantations of different ages increased first and then decreased with the increase in forest age, and the max value was in the near-mature forest stage. The fungal abundance decreased gradually with stand age, with the lowest fungal diversity at the near-mature stand stage. During the whole growth process, the bacterial community was more limited by soil pH, nitrogen, and phosphorus. After introducing P. bournei into a Chinese fir plantation, the abundance and diversity of the bacterial community did not improve, and the abundance of the fungal community did not increase. However, soil nutrients, pH, and fungal community diversity were significantly improved. The results of these studies indicate that the introduction of broad-leaved tree species not only increased soil nutrient content, but also had a significant effect on the increase in the diversity of soil fungal communities, making the microbial communities of mixed forests more diverse.

Effects of Fractal Dimension and Soil Erodibility on Soil Quality in an Erodible Region: A Case Study from Karst Mountainous Areas

Soil aggregate stability and soil erodibility (k) are crucial indicators of soil quality that exhibit high sensitivity to changes in soil function. Therefore, it is of great significance to explore the quantitative relationship between these indicators and soil quality for effective ecosystem monitoring and assessment. In this study, soil samples were collected from eight altitude gradients in a karst mountainous area; we analyzed 11 soil physical, chemical, and biological properties, and assessed soil quality using the minimum data set (MDS) method. The results revealed that soil aggregate stability, bulk density (BD), pH, and fungal community diversity exhibited a unimodal altitudinal pattern, whereas the soil organic carbon (SOC), total nitrogen (TN), and C:N ratio showed an increasing trend. Among the factors considered, SOC, BD, soil pH, mechanical composition, and fungal community diversity were found to explain the most variation in soil aggregate stability and soil erodibility (k). Principal component analysis (PCA) identified soil fungal community diversity, C:N ratio, coarse sand, and macro-aggregate (MA) content as highly weighted indicators for MDS. The integrated soil quality index (SQI) values, ranging from 0.30 to 0.62 across the eight altitude gradients, also exhibited a unimodal altitudinal pattern. The analysis indicated a significant linear relationship between the fractal dimension (D) and soil erodibility of the EPIC model (Kepic) with SQI, suggesting that D and Kepic can serve as alternative indicators for soil quality. These findings further enhance our understanding of the response of soil properties to altitude changes, and provide a novel method for assessing and monitoring soil quality in karst mountainous areas.

Effects of Naphthalene Application on Soil Fungal Community Structure in a Poplar Plantation in Northern Jiangsu, China

The soil food web is essential for the functioning of terrestrial ecosystems. The application of naphthalene is a commonly employed experimental treatment for expelling soil fauna to examine faunal effects on litter decomposition processes, for which is it assumed that naphthalene has negligible effects on soil microbial communities. An experiment was conducted to examine the potential soil-fauna-repellent effect of naphthalene application (100 g/m2/month, TR) on a soil fungal community during litter decomposition. The results showed that TR greatly suppressed the abundance and taxonomic richness of soil fauna by 83.7 ± 14.2% and 48.1 ± 17.2%, respectively, and reduced the rates of poplar leaf litter decomposition compared to the control (CK, without naphthalene treatment). Among the fungal communities, the abundance of Thelephorales in the TR soil was suppressed, while the abundance of Capnodiales was stimulated, although TR did not significantly alter the carbon and nitrogen content in the soil microbial biomass nor the diversity of soil fungal communities and the most abundant fungal phylum. Thus, both the suppressed soil arthropod abundance and altered soil fungal community might contribute to the observed slowdown in litter decomposition. These results suggest that naphthalene, as a soil fauna repellent, can alter the abundance of specific taxa in a soil fungal community, thereby impeding the effort to elucidate the contribution of soil fauna to ecosystem functioning (e.g., with respect to litter decomposition).

Effect of elevation on composition and diversity of fungi in the rhizosphere of a population of Deyeuxia angustifolia on Changbai Mountain, northeastern China.

Soil fungi are a key component of terrestrial ecosystems and play a major role in soil biogeochemical cycling. Although the diversity and composition of fungal communities are regulated by many abiotic and biotic factors, the effect of elevation on soil fungal community diversity and composition remains largely unknown. In this study, the soil fungal composition and diversity in Deyeuxia angustifolia populations along an elevational gradient (1,690 m to 2020 m a.s.l.) were assessed, using Illumina MiSeq sequencing, on the north-facing slope of the Changbai Mountain, northeastern China. Our results showed that soil physicochemical parameters changed significantly along with the elevational gradients. The Ascomycota and Basidiomycota were the most dominant phyla along with the gradient. Alpha diversity of soil fungi decreased significantly with elevation. Soil nitrate nitrogen (NO3--N) was positively correlated with fungal richness and phylogenetic diversity (PD), indicating that soil nitrate nitrogen (NO3--N) is a key soil property determining fungal community diversity. In addition to soil nitrate content, soil pH and soil moisture were the most important environmental properties determining the soil fungal diversity. Our results suggest that the elevational changes in soil physicochemical properties play a key role in shaping the community composition and diversity of soil fungi. This study will allow us to better understand the biodiversity distribution patterns of soil microorganisms in mountain ecosystems.

13 Cycles of Consecutive Tomato Monoculture Cropping Alter Soil Chemical Properties and Soil Fungal Community in Solar Greenhouse

Consecutive tomato monoculture cropping (CTM) obstacles severely restrict the development of facility tomato industry in China. However, the effect of CTM on the soil fungal community in greenhouses is still unclear. Here, we aim to identify the variation of soil chemical properties and soil fungal community associated with CTM for 1, 3, 5, 9 and 13 cycles. The results indicated that CTM led to a significant increase in soil total phosphorus (TP) and soil electrical conductivity (EC) value. CTM, though, significantly increased soil fungal community diversity, yet also led to the imbalance of soil fungal community compositions. Specifically, a beneficial soil fungus, Chaetomiaceae, decreased significantly at CTM13, while several soil pathogenic fungi, including Fusarium and Cladosporium, increased significantly at CTM13. A redundancy analysis (RDA) indicated that soil EC value, pH and TP had a greater impact on soil fungal community structure. Structural-equation-model (SEM) analysis indicated that, when compared with CTM3–CTM9, the decline of tomato fruit fresh weight per plant (TFFW) at CTM13 might be related to the significant increase in soil EC value, soil Fusarium and Cladosporium. Thus, appropriately decreasing soil EC and soil pathogenic fungi and enhancing soil beneficial fungi under a CTM system is crucially important for sustainable tomato production in greenhouses.

Soil fungal diversity and assembly along a xeric stress gradient in the central Namib Desert

The Namib Desert of south-western Africa is one of the oldest deserts in the world and possesses unique geographical, biological and climatic features. While research through the last decade has generated a comprehensive survey of the prokaryotic communities in Namib Desert soils, little is yet known about the diversity and function of edaphic fungal communities, and even less of their responses to aridity. In this study, we have characterized soil fungal community diversity across the longitudinal xeric gradient across the Namib desert (for convenience, divided into the western fog zone, the central low-rainfall zone and the eastern high-rainfall zone), using internal transcribed sequence (ITS) metabarcoding. Ascomycota, Basidiomycota and Chytridiomycota consistently dominated the Namib Desert edaphic fungal communities and a core mycobiome composed of only 15 taxa, dominated by members of the class Dothideomycetes (Ascomycota), was identified. However, fungal community structures were significantly different in the fog, low-rainfall and high-rainfall zones. Furthermore, Namib Desert gravel plain fungal community assembly was driven by both deterministic and stochastic processes; the latter dominating in the all three xeric zones. We also present data that suggest that the inland limit of fog penetration represents an ecological barrier to fungal dispersal across the Namib Desert.

Mixing planting with native tree species reshapes soil fungal community diversity and structure in multi-generational eucalypt plantations in southern China.

The continuous planting pattern of eucalypt plantations negatively affects soil quality. A mixed planting pattern using native species implanted in pure plantations has been considered a preferable measure for this problem. However, the impact of this approachon the structure and function of fungal communities is not clear. Here, harvesting sites that had undergone two generations of eucalypt plantations were selected to investigate soil fungal community structure and the co-occurrence network characteristics in response to two silvicultural patterns involving the third generation of eucalypt plantations (E) and mixed plantations of Eucalyptus. urograndis × Cinnamomum. camphora (EC) and E. urograndis × Castanopsis. hystrix (EH). Compared with the first generation of eucalypt plantations (CK), E markedly weakened enzyme activities associated with carbon-, nitrogen-. and phosphorus-cycling. Reduced soil fungal alpha diversity, and elevated the relative abundance of Basidiomycota while decreasing the abundance of Ascomycota. In contrast, EC and EH not only enhanced fungal alpha diversity, but also reshaped fungal composition. At the class level, E caused an enrichment of oligotrophic Agaricomycetes fungi, classified into symbiotroph guild, while EC markedly decreased the abundance of those fungi and increased the abundances of Sordariomycetes, Dothideomycetes, Eurotiomycetes, and Tremellomycetes fungi, which were classified into saprotroph or pathotroph guild. Moreover, fungal network complexity and robustness topological attributes were higher or significantly higher in mixed plantations soils compared with those of pure eucalypt plantation E. Furthermore, fungal diversity, structure, and functional taxa were significantly affected by soil organic matter, pH, total nitrogen, and nitrate nitrogen.

Effects of Different Topdressing Nitrogen Rates on Soil Fungal Community Structure and Ecological Network in Wheat Field Under Crop Residue Retention

Crop residue retention and fertilizer application are the main sources of soil nutrient input in fields. Crop residue retention combined with appropriate fertilizer application rates could provide necessary nutrients for crop production under the premise of environmentally friendly conditions. The aim of this study was to clarify the influence of different topdressing nitrogen rates on the soil fungal community in a wheat field under crop residue retention and to evaluate the rationality of nitrogen fertilizer management in winter wheat from the perspective of soil ecological function. On the basis of full straw retention and 150 kg·hm-2 basal nitrogen, treatments with five topdressing nitrogen rates (0, 37.5, 75, 112.5, and 150 kg·hm-2) were set up. The abundance, diversity, structure, and ecological network of soil fungal communities were analyzed using real-time fluorescence quantitative PCR and high-throughput sequencing, and the main soil physical and chemical factors driving the change in soil fungal communities were explored. The results showed that, compared with the no topdressing nitrogen and low topdressing nitrogen rate treatments, high topdressing nitrogen rate treatments increased soil total nitrogen and mineral nitrogen and decreased soil pH, total phosphorus, available phosphorus, and available potassium. Compared with the no topdressing nitrogen treatments, the 37.5-150 kg·hm-2 topdressing nitrogen treatments significantly increased soil fungal community abundance (P<0.05), whereas there was no significant difference among different topdressing nitrogen treatments (P>0.05). The Heip index and Shannon index of soil fungal communities decreased gradually with the increase in topdressing nitrogen rate, and the Sobs index, Heip index, and Shannon index of soil fungal communities in the treatment with 150 kg·hm-2 topdressing nitrogen were significantly lower than those of 0-75 kg·hm-2 topdressing nitrogen treatments (P<0.05). Principal component analysis and similarity analysis showed that there were significant differences in soil fungal community structure under different topdressing nitrogen rate treatments (P<0.05). With the increase in topdressing nitrogen rate, the number of network edges and average number of neighbors of soil fungal ecological network increased first and then decreased, and the network complexity of 37.5 kg·hm-2 topdressing nitrogen treatments was the highest. Compared with 0-75 kg·hm-2 topdressing nitrogen treatments, 112.5 kg·hm-2 and 150 kg·hm-2 topdressing nitrogen treatments increased the characteristic path length of the soil fungal ecological network, whereas it decreased the network density. With the increase in topdressing nitrogen rate, the relative abundance of soil saprotrophs gradually increased, and the pathotroph-saprotroph-symbiotroph relative abundance gradually decreased. Redundancy analysis showed that soil pH, total phosphorus, mineral nitrogen, available phosphorus, and available potassium were the main soil physicochemical factors affecting the soil fungal community structure in the wheat field under different topdressing nitrogen rate treatments. In conclusion, on the basis of straw retention and basal nitrogen, topdressing nitrogen at the wheat jointing stage could change the diversity, structure, and species composition of the soil fungal community, in turn affecting the soil fungal ecological network and function, and high topdressing nitrogen rates could reduce soil fungal community diversity, ecological network complexity, and network density.

Altitudinal pattern and driving factors of soil fungal community in the tropical forest of Jianfengling, Hai-nan, China

Fungi are an important group of soil microorganisms. Exploring the altitudinal pattern and driving factors of fungal composition and diversity is an important topic in the field of biodiversity and ecosystem function. We employed the Illumina high-throughput sequencing technology to investigate the variation and environmental control of fungal α-diversity and β-diversity at the topsoil (0-20 cm) and subsoil (20-40 cm) across an altitudinal gra-dient of 400-1500 m in a tropical forest of Jianfengling Nature Reserve. The results showed that Ascomycota and Basidiomycota dominated soil fungal community, reaching a relative abundance of more than 90%. Fungal α-diversity at the topsoil exhibited no obvious altitudinal pattern, and that of the subsoil decreased with the increases in altitude. Higher fungal α-diversity was observed in the topsoil. Soil fungi β-diversity was significantly affected by altitude. Morover, temperature was the driving force of the altitude pattern of fungi β-diversity. The similarity of fungal community decreased significantly with the increases in geographical distance, but did not change with the increases in environmental distance. The similarity of rare phyla (Mortierellomycota, Mucoromycota and Rozellomycota) was significantly lower than that of rich phyla (Ascomycota and Basidiomycota), indicating that diffusion restriction determined the differentiation of fungal community structure along the altitude gradient. Our study demonstrated that the diversity of soil fungal community was affected by altitude. The rare phyla, rather than rich phyla, determined the altitudinal variation of fungi β-diversity in Jianfengling tropical forest.

Moss-dominated biocrust-based biodiversity enhances carbon sequestration via water interception and plant-soil-microbe interactions

We investigated a nature-based solution (NbS) via incorporating biocrust into alfalfa-maize intercropping system to test carbon sequestration in seriously eroded agricultural soils. Field investigation showed that the NbS (moss-dominated biocrust+ intercropping) massively lowered surface soil erosion by 94.5% and soil carbon (C)and nitrogen (N)loss by 94.7 and 96.8% respectively, while promoting rainwater interception by 82.2% relative to bare land (CK). There generally existed positive interactions between biocrust and cropping in the integrated standing biodiversity system. Enhanced plant biomass input into soils substantially promoted soil fungal community diversity and abundance under NbS (p<0.05). This enabled NbS to evidently improve soil macroaggregate proportion and mean weight diameter. Critically, topsoil carbon storage was increased by 2.5 and 10.7%, compared with CK and pure intercropping (p<0.05). Conclusively, the standing diversity under such NbS fostered soil C sequestration via water interception and plant-soil-microbe interactions in degraded agricultural soils.

Long-Read Sequencing Analysis Revealed the Impact of Forest Conversion on Soil Fungal Diversity in Limu Mountain, Hainan.

Soil fungi are essential to soil microorganisms that play an important role in the ecosystem's soil carbon cycle and mineral nutrient transformation. Understanding the structural characteristics and diversity of soil fungal communities helps understand the health of forest ecosystems. The transition from tropical rainforest to artificial forest greatly impacts the composition and diversity of fungal communities. Hainan Limushan tropical rainforest National Park has a large area of artificial forests. Ecologists have conducted in-depth studies on the succession of animals and plants to regenerate tropical rainforests. There are few reports on the diversity of soil fungi and its influencing factors in the succession of tropical rainforests in Limu Mountain. In this study, 44 soil samples from five different stands were collected in the tropical rainforest of Limushan, Hainan. High-throughput sequencing of rDNA in its region was used to analyze fungal communities and study their α and β diversity. Analysis of variance and multiple regression models was used to analyze soil variables and fungal functional groups to determine the effects of interaction between fungi and environmental factors. A total of 273,996 reads and 1290 operational taxonomic units (OTUs) were obtained, belonging to 418 species, 325 genera, 159 families, eight phyla, 30 classes, and 73 orders. The results showed that the composition of soil fungal communities in the five stands was similar, with ascomycetes accounting for 70.5% and basidiomycetes accounting for 14.7%. α and β diversity analysis showed that soil fungi in Limushan tropical rainforest had high abundance and diversity. Multiple regression analysis between soil variables and functional groups showed that organic matter, TN, TP, TK, and AK were excellent predictors for soil fungi. TP was the strongest predictor in all functional groups except soil saprotroph. Organic matter and total nitrogen were the strongest predictors of soil rot. The transformation from tropical rainforest to artificial forest in Limushan did not change the soil fungal community structure, but the richness and diversity of soil fungi changed. The forest transformation did not lead to decreased soil fungal abundance and diversity. Different vegetation types and soil properties affect the diversity of soil fungal communities. We found that Caribbean pine plantations can improve soil fungal diversity, while long-term Eucalyptus spp. plantations may reduce soil fungal diversity.

Decay of fallen wood and elevation affects soil fungal community assembly and indirectly controls community diversity

Fallen wood has a pivotal role in the forest ecosystem and acts as an important intermediary for material cycling and energy flow between vegetation and soil. A keystone of the forest ecosystem is the soil fungal community which performs a crucial role in regulating the internal functions of the system. Nonetheless, the characteristics of soil fungal community diversity and the process of community assembly beneath fallen wood remain unclear. Here We investigated two subtropical forests at different elevations, and selected three fallen wood of different decay classes and a control soil without fallen wood in each stand. The soil underneath the fallen wood was collected for analysis to explore the effects of decay on soil fungal diversity and community assembly processes. The 18S rRNA amplicon sequencing was used to determine fungal diversity and calculate normalized stochasticity ratios (NST), whilst the underlying soil ecological factors were measured to predict the possible drivers of fungal diversity along with the driving mechanisms. The results revealed that elevation and fallen wood decay had a significant interactive effect on soil fungal alpha diversity as well as beta diversity. Outcomes of tNST (taxonomic Normalized Stochasticity Ratio) suggested that fallen wood decay at high-elevation made stochastic processes progressively more important in the assembly of soil fungal communities, while the opposite occurred at low-elevation, yet the results calculated by the pNST (Phylogenetic Normalized Stochasticity) method tended to indicate a predominance of stochastic processes in both two elevations. Fungal diversity was strongly positively correlated with NST values, but soil ecological factors were only strongly associated with NST values. The partial least squares path model (PLS-PM) further indicated that elevation and fallen wood decay did not directly regulate changes in fungal community diversity, but indirectly controlled fungal community assembly processes by affecting soil ecological factors, anon varied fungal diversity as well as community structure. This work will generate fresh insight into the patterns of soil fungal diversity and community assembly processes in forest ecosystems.

Pattern and drivers of soil fungal community along elevation gradient in the Abies georgei forests of Segila mountains, Southeast Tibet

Soil fungi are a diverse group of organisms extremely crucial to forest nutrient cycling and carbon (C) storage. The elevational pattern of soil microbial diversity has been widely studied, but how soil properties, elevation, and their association affect fungal community in subalpine forests remain to be explored. Here, soil fungal community diversity was investigated using high-throughput sequencing along an elevation gradient (3500–4300 m a.s.l.) in the Abies georgei var. smithii forests, a typical subalpine forest type in the Segila Mountains of Southeast Tibet. Elevation significantly affected the soil properties. Available phosphorus (P), total nitrogen (N), and soil organic C (SOC) increased whereas pH decreased with elevation. A U-shaped pattern for fungal diversity was found in topsoil while a slight monotonically decreasing pattern in subsoil layer across the elevation gradient. Basidiomycota, Ascomycota, and Mortierellomycota were the top three dominant phyla, and ectomycorrhizal fungi were the dominant functional fungi group in the A. georgei forest soils. Significant negative correlations were observed between fungal OTUs richness and NO 3 - ( r = −0.431, p < 0.01), indicating that soil N availability is an important factor for fungal diversity. Based on redundancy analysis, soil factors explained 32.1% of the total variations in composition structure of fungal community. Soil pH, moisture, and fertilities (i.e., SOC, TN, TP, NO 3 - ) were independent factors affecting the fungal community composition. Collectively, the alterations in soil environmental factor across elevations are essential in shaping the soil fungal diversity and community composition in the A. georgei forests in Segila Mountains, Southeast Tibet. • Elevation significantly increased soil organic C and nutrients while decreased pH. • Topsoil fungal richness showed a U-shaped pattern with increasing elevation. • Ectomycorrhizal fungi (EcM) were the dominant functional group across elevation. • NO 3 - was the prominent driving factor on fungal diversity in the A. georgei forests.

Effects of Oxathiapiprolin on the Structure, Diversity and Function of Soil Fungal Community.

Pesticides can affect non-target microorganisms in the soil and are directly related to soil microecological health and environmental safety. Oxathiapiprolin is a piperidinyl thiazole isoxazoline fungicide that shows excellent control effect against oomycete fungal diseases, including late blight, downy mildew, root rot, stem rot, and blight. Though it can exist stably in the soil for a long time, its effects on soil microbial structure and diversity are not well investigated. In the present study, the effects of oxathiapiprolin on the abundance and diversity of soil fungal communities in typical farmland were studied. The results show that the abundance and diversity of soil fungi were increased by oxathiapiprolin treatment with differences not significant on the 30th day. Oxathiapiprolin was found to change the structure of soil fungal communities, among which Ascomycota and Mortierellomycota were the most affected. Undefined saprophytic fungi increased in the treatment groups, and the colonization of saprophytic fungi can act as a major contributor to the function of soil microbial communities. This study lays a solid foundation regarding environmental behavior with the use of oxathiapiprolin in soil and details its scientific and rational use.