Impact of Vegetation Restoration on Soil Fungal Community Structure in Karst Rocky Desertification Areas

In this paper,managed forest(MF)and natural forest(NF)in the Huajiang Demonstration Zone of Guanling,Guizhou were selected as research objects,and cropland(CL)was taken as control.High-throughput sequencing technology was used to study the characteristics of fungal community composition and species diversity in the surface(0-10 cm)soil of each restoration measure,in order to reveal the dominant soil fungal groups and fungal community composition in karst rocky desertification areas,which was conducive to a more comprehensive understanding of the soil conditions of different vegetation restoration measures.Research has shown that vegetation restoration significantly affected the diversity of soil fungal community,with significant increases in Sob index,Ace index,and Chao index.The vegetation restoration has significantly changed the composition of fungal community.The dominant fungi in the CL topsoil are Sordariomycetes(62.28%),Dothideomycetes(12.34%),and Eurotiomycetes(9.12%);the dominant fungi in the MF soil are Sordariomycetes(45.05%),Dothideomycetes(14.74%),and Mortierellomycetes(10.40%);the dominant fungi in the NF soil are unclassified fungal community(26.38%),Sordariomycetes(19.78%),and Agaricomycetes(13.82%).Vegetation restoration has changed the key fungal groups in the soil.Sordariomycetes,Fusarium,and Setophoma are the key dominant fungal groups in CL soil;Dioszegia is key dominant fungal group in MF soil;c_unclassified_k_Fungi,p_unclassified_k_Fungi,o_unclassified_k_Fungi,f_unclassified_k_Fungi,g_unclassified_k_Fungi,Teichospora,and Diaporthe are key dominant fungal groups in NF soil.

Fungal community structure analysis of peanut pod rot in soil in Hebei Province,China

In recent years,peanut yield and quality are more seriously affected by pod rot disease in China.However,managing this disease has proven challenging due to the wide host range of its pathogens.In this study,four soil samples were collected from fields with pod rot disease in Hebei Province,and 454 pyrosequencing was used to analyze the fungal communities structure within them.All 38490 ITS high-quality sequences were grouped into 1203 operational taxonomic units,the fungal community diversity of four soil samples was evaluated and compared using Shannon index and Simpson index.The results showed that members of Ascomycota were dominant,followed by Basidiomycota.According to the BLAST results at the species level,Guehomyces had the highest abundance,accounting for about 7.27%,followed by Alternaria,Fusarium,and Davidiella.The relative abundance of Fusarium oxysporum isolated from rotting peanuts in soil with peanut rot was higher than that in the control,indicating that Fusarium oxysporum might be one of the main pathogenic fungus of peanut rot in this area.This study delved into the broader fungal community associated with peanut pod rot,providing a theoretical foundation for preventing and treating this disease in agriculture.

Effects of Consecutively Monocultured Rehmannia glutinosa L.on Diversity of Fungal Community in Rhizospheric Soil

Continuous monoculture problems, or replanting diseases, are one of the key factors affecting productivity and quality of Chinese medicinal plants. The underlying mechanism is still being explored. Most of the studies on continuous monoculture ofRehmannia glutinosa L. are focused on plant nutritional physiology, root exudate, and its autotoxieity. However, the changes in the diversity of microflora in the rhizosphere mediated by the continuous monoculture pattern have been remained unknown. In this study, terminal restriction fragment length polymorphism （T-RFLP） technique was used for fingerprinting fungal diversity in the rhizosphere soil sampled from the fields ofR. glutinosa monocultured for 1 and 2 yr. The results showed that the structure of fungal community in consecutively moncultured rhizosphere soil was different from that in control soil （no cropping soil）, and varied with the consecutive monoeulture years （1 and 2 yr）. The comprehensive evaluation index （D） of fungal community estimated by principal component analysis of fragment number, peak area, Shannon-Weiner index, and Margalef index was higher in 1 yr monoculture soil than that in 2 yr monoculture soil, suggesting that consecutive monoculture of R. glutinosa could be a causative agent to decrease the diversity of fungal community in the rhizosphere soil.

Response of soil fungal community to long-term chromium contamination

To further study the fungal community in heavy metal contaminated ecosystems,soil samples were collected from an abandoned chromium(Cr)factory,and fungal community was analyzed by Illumina sequencing of Internal Transcribed Spacer(ITS)amplicons.The results showed that Cr contamination changed the composition and structure of soil fungal community,but didn’t change the diversity.Fungus showed various responses to Cr contamination.LEfSe analysis revealed that the biomarker changed a lot in the Cr-contaminated samples in comparison with that in the control samples.The changes in fungal community may be caused by the direct toxic effects on fungi by high concentration of Cr and the significant change in soil properties resulting from Cr contamination.Among all the Cr fractions,organic matter-bound Cr and exchangeable Cr showed significant effects on the fungal community and organic matter also showed a significant effect on soil fungal community.

A comprehensive analysis of the response of the fungal community structure to long-term continuous cropping in three typical upland crops

Certain agricultural management practices are known to affect the soil microbial community structure;however,knowledge of the response of the fungal community structure to the long-term continuous cropping and rotation of soybean,maize and wheat in the same agroecosystem is limited.We assessed the fungal abundance,composition and diversity among soybean rotation,maize rotation and wheat rotation systems and among long-term continuous cropping systems of soybean,maize and wheat as the effect of crop types on fungal community structure.We compared these fungal parameters of same crop between long-term crop rotation and continuous cropping systems as the effect of cropping systems on fungal community structure.The fungal abundance and composition were measured by quantitative real-time PCR and Illumina MiSeq sequencing.The results revealed that long-term continuous soybean cropping increased the soil fungal abundance compared with soybean rotation,and the fungal abundance was decreased in long-term continuous maize cropping compared with maize rotation.The long-term continuous soybean cropping also exhibited increased soil fungal diversity.The variation in the fungal community structure among the three crops was greater than that between long-term continuous cropping and rotation cropping.Mortierella,Guehomyces and Alternaria were the most important contributors to the dissimilarity of the fungal communities between the continuous cropping and rotation cropping of soybean,maize and wheat.There were 11 potential pathogen and 11 potential biocontrol fungi identified,and the relative abundance of most of the potential pathogenic fungi increased during the long-term continuous cropping of all three crops.The relative abundance of most biocontrol fungi increased in long-term continuous soybean cropping but decreased in long-term continuous maize and wheat cropping.Our results indicate that the response of the soil fungal community structure to long-term continuous cropping varies based upon crop types.

Soil Cellulase Activity and Fungal Community Responses to Wetland Degradation in the Zoige Plateau, China

Four soil types(peat, marsh, meadow, and sandy) in the Zoige Plateau of China are associated with the severity of wetland degradation. The effects of wetland degradation on the structure and abundance of fungal communities and cellulase activity were assessed in these 4 soil types at 3 depths using DGGE(Denatured Gradient Gel Electrophoresis), q PCR(Quantitative Real-time PCR),and 3,5-dinitrosalicylic acid assays. Cellulase activity and abundance of the fungal community declined in parallel to the level of wetland degradation(from least to most disturbed). DGGE analysis indicated a major shift in composition of fungal communities among the4 soil types consistent with the level of degradation.Water content(WC), organic carbon(OC), total nitrogen(TN), total phosphorus(TP), available nitrogen(AN), and available phosphorus(AP) were strongly correlated with cellulase activity and the structure and abundance of the fungal community.The results indicate that soil physicochemical properties(WC, OC, TN, TP, AN, and AP), cellulase activity, and diversity and abundance of fungal communities are sensitive indicators of the relative level of wetland degradation. WC was the major factorinvolved in Zoige wetland degradation and lower WC levels contributed to declines in the abundance and diversity of the fungal community and reduction in cellulase activity.

Promoting the Growth of Pinus sylvestris var.mongolica Seedlings and Improving Rhizosphere Fungal Community Structure through Interaction between Trichoderma and Ectomycorrhizal Fungi

In this study,pot experiments were conducted on the seedlings of Pinus sylvestris var.mongolica to study the influence of Trichoderma(Trichoderma harzianum E15)and Ectomycorrhizal fungi(Suillus luteus N94)on the growth of these seedlings.In particular,the effects of these fungi on the fungal community structure in the rhizosphere soil of the seedlings were investigated.Inoculation with Trichoderma harzianum E15 and Suillus luteus N94 significantly(P<0.05)promoted the growth of the Pinus sylvestris seedlings.The non-metric multidimensional scaling(NMDS)results indicated a significant difference(P<0.05)between the fungal community structures in the rhizosphere soil of the annual and biennial seedlings.In the rhizosphere soil of annual seedlings,the main fungi were Ascomycota,Basidiomycota,Zygomycota.Ascomycota,Basidiomycota,Mortierellomycota,and p-unclassified-k-Fungi were the main fungi in the rhizosphere soil of biennial seedlings.The dominant genus in the rhizosphere soil and a key factor promoting the growth of the annual and the biennial seedlings was Trichoderma,Suillus,respectively.Both of them were negatively correlated with the relative abundance of microbial flora in the symbiotic environment.Trichoderma had a significant promoting effect on the conversion of total phosphorus,total nitrogen,ammonium nitrogen,nitrate nitrogen,and the organic matter in the rhizosphere soil of the seedlings,while Suillus significantly promoted the conversion of organic matter and total phosphorus.

Analysis of the Fungal Community in Apple Replanted Soil Around Bohai Gulf

Apple replant disease(ARD) is a frequently occurring plant disease in replanted orchards around Bohai Gulf, which causes growth inhibition and even death of plants. The aim of this study was to investigate the etiology of ARD around Bohai Gulf. In this study, the primary growth inhibition of apple seedlings was evaluated in ten replanted soils, sampled around Bohai Gulf. A fungal clone library was used to identify changes in the structure and composition of the soil fungal community. The results revealed that the Simpson diversity indices of Laizhou and Pulandian orchards were higher than others, presenting severe ARD. Ascomycota dominated around Bohai Gulf at the phyla level. Fusarium and Saccharomyces were abundant in all replanted soils. In addition, correlations between the relative abundance of fungal genera in soils and the severity of ARD were analyzed. The results showed that Fusarium was correlated positively with the severity of ARD, but Mortierella was negatively correlated. Furthermore, the quantitative PCR of Fusarium oxysporum, which was regarded as a factor of ARD, was performed. Overall, this study demonstrated that ARD was strongly associated with an unbalanced microbial ecosystem with more pathogenic fungi, while Fusarium in the apple replanted soil was the key factor for ARD around Bohai Gulf.

Characteristics of fungal community structure during the decomposition of mixed foliage litter from Pinus massoniana and broadleaved tree species in southwestern China

Aims The conifer litter is fairly recalcitrant and nutrient poor,and broadleaved litter promotes coniferous litter decomposition by increasing degradable nutrients and promoting microbial metabolism.Mixing Pinus massoniana litter and three broadleaved litters may increase the diversity and abundance of fungal decomposers compared with those in P.massoniana litter and vary depending on the number and proportion of broadleaved species included.Methods We analysed the composition and diversity of fungal communities during mixed litter decomposition in southwestern China with 35 treatments(P.massoniana,Toona sinensis,Cinnamomum camphora and Sassafras tzumu litter)using Illumina high-throughput sequencing.Important Findings The mixed litters increased fungal diversity and richness compared with those in the single-species litter,except in the following treatments:P.massoniana litter accounting for 70%-80%in the P.massoniana+T.sinensis,P.massoniana+S.tzumu+T.sinensis and P.massoniana+S.tzumu+C.camphora combinations,and P.massoniana+S.tzumu+C.camphora+T.sinensis combination with small proportion of T.sinensis litter.The diversity and richness of the 7:1:2 combination of P.massoniana+C.camphora+T.sinensis were significantly higher than those in the other treatments.Ascomycota and Basidiomycota were the dominant phyla,and Aspergillus was the most abundant genus.The decomposition of litters from one needleleaf and one broadleaved species(6:4)and one needleleaf species and two broadleaved species(broadleaved litter accounting for 30%-40%)exhibited synergistic interactions throughout the decomposition process,and the relative abundance of fungi that decompose refractory substances increased.The P.massoniana+C.camphora+T.sinensis combination and a 30%-40%broadleaf litter proportion increased fungal diversity and accelerated the decomposition of recalcitrant coniferous litter.Therefore,C.camphora and T.sinensis are a potential candidate species for mixed planting with P.massoniana.

Grazing greatly reduces the temporal stability of soil cellulolytic fungal community in a steppe on the Tibetan Plateau

Excessive livestock grazing degrades grasslands ecosystem stability and sustainability by reducing soil organic matter and plant productivity. However, the effects of grazing on soil cellulolytic fungi, an important indicator of the degradation process for soil organic matter,remain less well understood. Using T-RFLP and sequencing methods, we investigated the effects of grazing on the temporal changes of cellulolytic fungal abundance and community structure in dry steppe soils during the growing months from May to September, on the Tibetan Plateau using T-RFLP and sequencing methods. The results demonstrated that the abundance of soil cellulolytic fungi under grazing treatment changed significantly from month to month, and was positively correlated with dissolved organic carbon(DOC) and soil temperature, but negatively correlated with soil p H. Contrastingly, cellulolytic fungal abundance did not change within the fencing treatment(ungrazed conditions). Cellulolytic fungal community structure changed significantly in the growing months in grazed soils,but did not change in fenced soils. Grazing played a key role in determining the community structure of soil cellulolytic fungi by explaining 8.1% of the variation, while p H and DOC explained 4.1% and 4.0%, respectively. Phylogenetically, the cellulolytic fungi were primarily affiliated with Ascomycota(69.65% in relative abundance) and Basidiomycota(30.35%).Therefore, grazing substantially reduced the stability of soil cellulolytic fungal abundance and community structure, as compared with the fencing treatment. Our finding provides a new insight into the responses of organic matter-decomposing microbes for grassland managements.

Soil Fungal Diversity and Community Composition in Response to Continuous Sweet Potato Cropping Practices

Soil fungi are extremely important for maintaining soil health and plant production in agricultural systems.Currently,the effect of continuous cropping of sweet potato on soil fungal communities and physiochemical parameters has not been well documented.In the present study,four sweet potato fields consecutively monocultured for 1,2,3,and 4 years were selected to investigate the effect of monoculture on soil fungal communities through Illumina MiSeq sequencing.Continuous cropping of sweet potatoes dramatically altered the fungal community composition,whereas fungal diversity was almost unchanged.Ascomycota and Basidiomycota were the most abundant phyla in all soil samples,accounting for 32.59%and 21.14%of the average relative abundance,respectively.The abundance of some potential pathogens,such as Ascobolus spp,specifically Ascobolus stercorarius,and some unknown fungi increased significantly as the sweet potato monoculture period increased,and their presence were highly positively correlated with disease incidence.In contrast,Basidiomycota,Bullera,Fusarium and Trichocladium most likely play roles as antagonists of sweet potato disease development,as their relative abundance decreased significantly over time and were negatively correlated with disease incidence.Redundancy and correlation analyses revealed that soil pH and organic carbon content were the most important factors driving these changes.Our findings provided a dynamic overview of the fungal community and presented a clear scope for screening beneficial fungi and pathogens of sweet potato.

Soil bacterial and fungal community successions under the stress of chlorpyrifos application and molecular characterization of chlorpyrifos-degrading isolates using ERIC-PCR

Chlorpyrifos is a widely used insecticide in recent years,and it will produce adverse effects on soil when applied on crops or mixed with soil.In this study,nested polymerase chain reaction（PCR） and denaturing gradient gel electrophoresis（DGGE） were combined to explore the bacterial and fungal community successions in soil treated with 5 and 20 mg/kg of chlorpyrifos.Furthermore,isolates capable of efficiently decomposing chlorpyrifos were molecular-typed using enterobacterial repetitive intergenic consensus-PCR（ERIC-PCR）.Under the experimental conditions,degradation of chlorpyrifos in soil was interpreted with the first-order kinetics,and the half-lives of chlorpyrifos at 5 and 20 mg/kg doses were calculated to be 8.25 and 8.29 d,respectively.DGGE fingerprint and principal component analysis（PCA） indicated that the composition of the fungal community was obviously changed with the chlorpyrifos treatment,and that samples of chlorpyrifos treatment were significantly separated from those of the control from the beginning to the end.While for the bacterial community,chlorpyrifos-treated soil samples were apparently different in the first 30 d and recovered to a similar level of the control up until 60 d,and the distance in the PCA between the chlorpyrifos-treated samples and the control was getting shorter through time and was finally clustered into one group.Together,our results demonstrated that the application of chlorpyrifos could affect the fungal community structure in a quick and lasting way,while only affecting the bacterial community in a temporary way.Finally,nine typical ERIC types of chlorpyrifos-degrading isolates were screened.

Changes in soil fungal community on SOC and POM accumulation under different straw return modes in dryland farming

We conducted a 2.5-year field experiment to test the effects of straw incorporated evenly into the soil(EIS)on soil fungal community,SOC chemical composition,and particulate organic matter fractions via comparing with no straw returning(CK),straw mulching(SM),straw plowed into the soil(SP),and identified the linkages between soil fungal community as well as organic C accumulation and POM formation.Our results showed that EIS treatment significantly increased the concentrations of SOC and the proportion of carbohydrate C,di-O-alkyl C,and O-alkyl C in SOC structure,increased the mass proportion and OC contents of MA(c)POM and mM-POM in the upper 40 cm of soil.Meanwhile,EIS treatment increased the relative abundance of Ascomycota,Zygomycota,Chytridiomycota,and Dothideomycetes in 0-20 cm depths,and also had the highest relative abundance of Glomeromycetes and Dothideomycetes in the 20-40 cm soil.Also,our study suggests that straw return enhanced the relative abundances of fungi involved in the carbon cycle and sequestration,including Zygomycota,Chytridiomycota,and Glomeromycota,and Ascomycota.The shifts in fungal community structure can accelerate organic C accumulation and the formation of soil particulate organic matter,especially in EIS treatment.

Significant changes in arbuscular mycorrhizal community and soil physicochemical properties during the saline-alkali grassland vegetation succession

Arbuscular mycorrhizal(AM)fungi are widely distributed in various habitats,and the community composition varies in response to the changing environmental conditions.To explore the response of community composition to the succession of saline-alkali land,soil samples were collected from three succession stages of Songnen saline-alkali grassland.Subsequently,the soil characteristics were determined and the AM fungi in soil samples were analyzed by high-throughput sequencing.Then,the response relationship between community composition and soil characteristics was studied by Canonical correlation and Pearson analyses.The soil properties improved with the succession of saline-alkali grassland.There was no significant difference in alpha diversity between the first and second succession stage(Suaeda glauca and Puccinellia tenuiflora,respectively),and the microbial community had a dense association network at the third stage(Leymus chinensis);in addition,each succession stage had significantly enriched amplicon sequence variants(ASVs)and functional pathways.All the soil properties except cellulase activity had significant effects on community composition.Furthermore,the pH,organic carbon,organic matter,and sucrase activity significantly correlated with alpha diversity indices.These results provide a theoretical basis for realizing the significant changes in AM fungal community and soil properties during the saline-alkali grassland vegetation succession.

Effect of Environmental Factors on Rock-inhabiting Fungal Communities from Brazilian Soapstone Samples

The present study aims to evaluate the environmental effect on fungal community composition associated with biodeterioration occurring in stones （soapstone） at two distinct locations in Minas Gerais State, Brazil： Congonhas city and Sanctuary of Cara^a. Four collections of fungal communities over one year were obtained from both research sites from the soapstone block surfaces exposed for over two decades. The molecular diversity profile of the fungal community at the two localities was obtained by DGGE （Denaturing Gradient Gel Electrophoresis）, and the genomes of the most representative population were sequenced. DGGE showed the formation of two clusters with filamentous fungal communities. Sequencing of the most representative bands revealed the presence of fungi associated with the biodeterioration of soapstone. In addition, many of the identified species were associated with photobionts that could generate lichens, indicating that environmental characteristics affect the occurrence of filamentous fungi, which leads to biodeterioration of stones. Authors＇ study focused on an environmental variation of an extreme habitat for fungi associated with soapstone in the state of Minas Gerais, Brazil and identified the presence of interesting rock-inhabiting fungal communities including species related to lichens, which can accelerate the deterioration of stones by the production of organic acids.

Soil pH and dissolved organic carbon shape microbial communities in wetlands with two different vegetation types in Changdu area,Tibet

Soil microorganisms play pivotal roles in element biogeochemical cycling and ecological functions in wetland ecosystem,which may affect global climate change.Variations in biotic and abiotic factors are known to affect soil microbial diversity,community structure and the corresponding functions.However,the relative importance of these biotic and abiotic factors on wetland soil microbial diversity and community structure on the QinghaiTibet Plateau remains poorly understood.In this study,we explored soil bacterial and fungal diversity and composition of five wetlands under two vegetation types(herbs vs Hippophae thibetana)in Changdu area,Tibet,through Illumina high throughput sequencing analysis of 16S rRNA for bacteria and internal transcribed spacer(ITS)for fungi.Results showed that soil bacterial alpha diversity was higher in H.thibetana dominated wetlands and was significantly and positively correlated with soil pH.No difference was detected in the soil fungal alpha diversity among samples and between vegetation types.The dominant soil bacterial phyla were Proteobacteria,Actinobacteria,Acidobacteria,and Firmicutes.While Ascomycota,Basidiomycota and Mucoromycota were the dominant fungal phyla.Soil bacterial and fungal community structures were significantly distinct by vegetation types.In addition,redundancy analysis indicated that soil pH was the key factor shaping soil bacterial community structure.Nevertheless,soil p H showed no effect on fungal community.Instead,soil dissolved organic carbon was the major factor contributing to soil fungal community structure.This study emphasized that wetland soil microbial communities were distinct by vegetation types and the driving factors of microbial beta diversity between bacterial and fungal community were also different in wetlands in Changdu area.

Effects of Tillage Depth on Nutrients and Microbial Communities in Tobacco-Planting Soil

The implementation of appropriate tillage practices is of great significance for agricultural production. However, the effects of different tillage depths on soil nutrients content and microbial communities in tobacco-planting soils are still lacking systematic research. In this study, three different tillage depths of 15 cm (T1), 20 cm (T2), and 30 cm (T3) were set up for field experiments in Liupanshui, Guizhou Province, to explore the effects of tillage depth on tobacco-planting soil nutrients and bacterial and fungal communities based on 16S rRNA and ITS sequencing and figure out the key factors affecting soil microbial communities. The results showed that T2 and T3 increased the contents of organic matter, total nitrogen, total phosphorus, available phosphorus, and available potassium in tobacco-planting soil, and increased the diversity of bacterial communities compared with T1. There was no significant difference in the structure of bacterial and fungal communities in different tillage depth treatments, but some dominant genera were significantly enriched in T2 and T3. Desulfobacter, Setophoma, Humicola, and Acremonium were significantly enriched in T2. Chthonomonas and Fusarium were significantly enriched in T3. These genera favor the decomposition of organic matter and the cycling of nutrients, and control soil pests and diseases. Redundancy analysis indicated that TP and AK were the key factors influencing the dominant genera of bacteria and fungi. This study provides a scientific basis for the selection of soil tillage depth for tobacco production in this region.

Rubber-based agroforestry systems modify the soil fungal composition and function in Southwest China

Rubber-based agroforestry systems have been recognized as a practical and sustainable solution to promote the development of agriculture and the environment.However,interactions between fungal communities and these systems are still not sufficiently investigated.In this study,we compared the abundance,diversity,and community composition of soil fungi in four treatments,including rubber monoculture and three rubber-based agroforestry treatments involving intercropping with Camellia sinensis,Coffea liberica,and Theobroma cacao.The results revealed that the community composition exhibited significant variation between the four different treatments,while the overall soilα-diversity was relatively stable across all treatments.Soil pH and soil organic carbon were significantly related to the structure of the fungal community.In particular,the complexity of the functional fungal network increased in response to agroforestry treatments,promoting beneficial fungi and suppressing certain plant pathogens.These results suggest that rubber-based agroforestry systems can promote the health of soil microbial community composition,and therefore provide an effective approach to enhancing soil quality.

Spore production in the solid-state fermentation of stevia residue by Trichoderma guizhouense and its effects on corn growth

Trichoderma is an important and widely used plant growth-promoting fungus(PGPF).In this study,stevia residue amended with amino acids hydrolyzed from animal carcasses was used for the production of Trichoderma guizhouense NJAU 4742 by solid-state fermentation,and then its potential to promote corn plant growth was evaluated in combination with chemical fertilizer(CF)or organic fertilizer(OF).The highest spore number of 7×10^(9) CFU g^(–1) fresh weight was obtained under the following optimal parameters:material ratio of 50%(stevia residue:rice bran=1:1),pH value of 3.0(amended with 6.67%amino acids),initial moisture content of 60%,inoculum size of 10%,material thickness of 3 cm and an incubation time of 4 days.The aboveground corn plant biomass obtained with T.guizhouense applied alone and with CF treatments were slightly higher than those of no fertilizer control and CF treatments,respectively.However,T.guizhouense applied with OF significantly(P<0.05)increased aboveground biomass compared to OF and yielded the highest aboveground biomass among all the treatments.Moreover,T.guizhouense applications primarily influenced the fungal bulk soil community composition,among which three OTUs(OTU_(2) and OTU_(9) classified as Chaetomium,and OTU_(4)classified as Trichoderma)were stimulated in both bulk and rhizosphere soil.Notably,a specific OTU_(3)(Phymatotrichopsis)was only stimulated by T.guizhouense applied with OF,possibly leading to high soil productivity.These results show that it is feasible to employ stevia residue in the eco-friendly fermentation of T.guizhouense,which is strongly suggested for enhancing OF applications.

Different mechanisms underlying divergent responses of autotrophic and heterotrophic respiration to long-term throughfall reduction in a warm-temperate oak forest

Background:There are many studies on disentangling the responses of autotrophic(AR)and heterotrophic(HR)respiration components of soil respiration(SR)to long-term drought,but few studies have focused on the mechanisms underlying its responses.Methods:To explore the impact of prolonged drought on AR and HR,we conducted the 2-year measurements on soil CO_(2) effluxes in the 7th and 8th year of manipulated throughfall reduction(TFR)in a warm-temperate oak forest.Results:Our results showed long-term TFR decreased HR,which was positively related to bacterial richness.More importantly,some bacterial taxa such as Novosphingobium and norank Acidimicrobiia,and fungal Leptobacillium were identified as major drivers of HR.In contrast,long-term TFR increased AR due to the increased fine root biomass and production.The increased AR accompanied by decreased HR appeared to counteract each other,and subsequently resulted in the unchanged SR under the TFR.Conclusions:Our study shows that HR and AR respond in the opposite directions to long-term TFR.Soil microorganisms and fine roots account for the respective mechanisms underlying the divergent responses of HR and AR to long-term TFR.This highlights the contrasting responses of AR and HR to prolonged drought should be taken into account when predicting soil CO_(2) effluxes under future droughts.