The Sanjiang Plain hosts the largest freshwater wetland in Northeastern China and plays a critical role in regional climate stability. However, climate change and human activities have degraded the wetland, forming a successional gradient from the original flooded wetland to dry shrub and forest vegetation with a lower ground water level. This degradation has altered soil microbial structure and functions, reducing ecological and socio-economic benefits. Along this successional gradient, we used Biolog-ECO plates combined with soil enzyme assays (catalase, urease, sucrase, and acid phosphatase) to assess the dynamics of microbial carbon metabolic activity, measured by average well color development (AWCD). The results showed a systematic decline in AWCD values with advancing succession, revealing a pronounced reduction in overall microbial metabolic activity during wetland degradation. This trend correlated with loss of soil moisture, organic carbon, and nitrogen nutrients. Microbial communities in early successional wetland stages (i.e., original natural wetland and wetland edge) preferred labile carbon sources (e.g., carbohydrates, amino acids), while forested stages favored relatively more structural (e.g., polymers, phenolic compounds). These findings indicate that vegetation succession regulates microbial carbon metabolism by modifying soil physicochemical properties, providing insights for wetland restoration.

The succession of plant communities and soil-driven mechanisms triggered by wetland degradation are central issues in global ecology. To investigate the effects of Deyeuxia purpurea wetland degradation on plant community characteristics and its key soil regulatory factors, this study selected D. purpurea wetlands with different degradation degrees in the Sanjiang Plain as research objects and analyzed the characteristics of plant communities, soils, and their relationships. The results indicated that wetland degradation was significantly associated with turnover in plant community composition, with hydrophytic species progressively replaced by mesophytic and xerophytic species. As degradation intensified, Simpson's diversity index, the Shannon-Wiener index, Pielou's evenness index, and Patrick's richness index all increased significantly. The non-degraded wetland exhibited significantly higher aboveground, belowground, and total biomass than the degraded wetlands. Aboveground and total biomass showed a significant negative correlation with the diversity index. Soil pH, water content (WC), total phosphorus (TP), dissolved organic nitrogen (DON), and ammonium nitrogen (NH4+-N) were key factors associated with changes in plant community diversity and biomass. Partial least squares path modeling (PLS-PM) and variance partitioning analysis (VPA) further quantified potential association pathways, showing that wetland degradation exerted both direct and indirect effects on key soil physicochemical factors and plant community characteristics. Specifically, wetland degradation was directly associated with decreases in soil pH, WC, and TP, while positively affecting soil dissolved organic nitrogen (DON) and plant diversity. It also indirectly influenced plant species composition and biomass through changes in soil pH, WC, DON, and TP. TP was negatively correlated with plant diversity and biomass, whereas ammonium nitrogen had a direct positive effect on species composition. Dissolved organic nitrogen directly negatively affected species composition. Overall, this study systematically elucidates plant community response patterns and the synergistic driving mechanisms of multiple soil factors during D. purpurea wetland degradation, providing an important scientific basis for wetland conservation and ecological restoration in the Sanjiang Plain.

Wetland reclamation is one of the most globally widespread land-use transformations and strongly affects belowground biogeochemical processes. Even so, we still do not fully understand how the soil micro-food webs re-organized and regulate ecosystem multifunctionality (EMF) following the conversion of wetland to paddy field and soybean field. A natural experimental system of the Sanjiang Plain was created in this study using natural wetland (NW) as well as paddy (PF) and soybean (SB) fields. Through the integration of high-throughput sequencing, energy-flow analysis, and structural equation modeling, we systematically examined community assembly, interaction networks, and functional dynamics across multiple trophic levels. The findings revealed that the bacterial and fungal communities in paddy fields were mostly driven by strong deterministic processes while in soybean fields stochastic processes were dominant. In contrast, paddy fields selected protistan communities mainly by stochastic processes; soybean fields underwent a transition to deterministic selection. The co-occurrence network of micro-food web in paddy fields shrank and was characterized by a marked increase in positive correlations (64.44%) while soybean fields showed a marked increase in negative correlations. In agricultural systems, the overall state of the micro-food web changed from the wetland “structured” state to a “enrichment-driven” state. The main drivers of ecosystem multifunctionality also changed, transitioning from an “endogenous carbon limitation” pattern in wetlands to an “exogenous nutrient-driven” mechanism in farmland. Several key taxa, including the bacterium Romboutsia and the nematode Pseudacrobeles, showed strong predictive power for ecosystem multifunctionality. Structural equation modeling further revealed that positive network cohesion, rather than species diversity, acts as the primary driver promoting EMF. Overall, this study reveals the key mechanisms underlying the coordinated evolution of belowground micro-food web structure and ecosystem multifunctionality during wetland reclamation from a multi-trophic interaction perspective, providing a new theoretical framework for understanding how land-use change regulates ecosystem multifunctionality.

Boreal forests play a crucial role in global carbon regulation but are increasingly exposed to logging and fire disturbances. However, how belowground microbial-dissolved organic matter (DOM) interactions shape EMF during post-disturbance recovery remains unclear. Using absolute quantitative high-throughput sequencing and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS), we investigated microbe–DOM coupling (co-occurrence) in post-logging and post-fire boreal forests. The study included eight treatments with three independent replicate plots per treatment, resulting in 24 plots in total. These treatments comprised four post-logging forests representing undisturbed control and 20–32 years of natural recovery after clear-cutting or selective cutting, and four wildfire treatments representing unburned reference and light, moderate, and severe fire after 21 years of post-fire recovery. Post-logging forests exhibited incomplete recovery of soil nutrients and enzyme activity, accompanied by a shift toward K-strategist microbial communities and reduced proportions of recalcitrant-like DOM compounds. In contrast, high-severity fire was associated with the accumulation of thermodynamically constrained, recalcitrant-like DOM pools within the PPL-extractable and negative-ion-detectable DOM fraction; here, recalcitrance is interpreted as an operational inference based on molecular indices rather than direct biodegradability measurements. Despite recovery in DOM α-diversity, the complexity of microbe-DOM coupling networks remained lower than in undisturbed forests. Threshold analysis further showed that EMF responses were disturbance-dependent, with lower coupling thresholds in post-logging forests but higher minimum threshold (Tmin) values for microbe-DOM interactions following fire. In post-logging forests, the minimum EMF thresholds for bacterial-DOM coupling were relatively low, including 0.25 for all bacteria, 0.42 for core bacteria, and 0.26 for satellite bacteria, whereas the threshold for all bacterial species-DOM coupling was higher in post-fire forests (Tmin = 0.71). Moreover, EMF drivers differed between disturbance types, being primarily associated with soil nutrients in post-logging forests and litter quality in post-fire forests. These findings suggest that logging and fire reshape boreal carbon turnover through coordinated shifts in microbial life-history strategies, DOM molecular composition, and interaction network structure.

Climate warming and human activities have led to widespread expansion of shrubs in many wetlands, altering the distribution patterns of native vegetation and disrupting C cycling. Although the effects of shrub expansion on soil microbial communities and methane (CH4) emissions have been extensively studied, the specific microbial-mediated pathways involved in methane cycling remain unexplored. The static chamber method was used to investigate the characteristics of CH4 emission flux changes under different levels of shrub expansion. Additionally, metagenomics technology was employed to assess the effects of different shrub expansion levels on soil microbial community composition, function, and diversity (bacteria and fungi), as well as the methane metabolic pathways mediated by these communities. Shrub expansion in wetlands was categorized into four classes based on shrub coverage. We found that methane flux decreased significantly with increasing shrub expansion, with cumulative emissions under extensive expansion conditions being only 28 % of those under no expansion conditions. The peak emissions on August 15 under no expansion conditions were 2-3 times higher than those in shrub-expanded plots. The partial least squares path model (PLS-PM, GOF = 0.731) indicated that shrub expansion enhanced soil physicochemical properties (beta = 0.865), which inhibited methanogenic genes (beta = -0.617) and activated methane oxidation pathways (total effect beta = 0.728). Methane-oxidizing genes contributed the most to CH4 reduction, accounting for 72.4 % of the pathway effect. This was primarily manifested as inhibition of key genes involved in the acetate pathway for methane production (comB and hdrA) and upregulation of methane-oxidizing-related genes (mmoB and DAK). Shrub expansion significantly increased soil ammonium nitrogen content while reducing soil moisture content. Although bacterial alpha diversity remained unchanged, the fungal Chao1 index significantly increased. Additionally, MI and HI treatments significantly altered bacterial community structure, while fungal communities remained relatively stable. The relative abundance of Verrucomicrobia initially increased with shrub expansion but decreased at higher levels, while Ascomycota, Basidiomycota, and Mucoromycota showed significant increases. The study suggests that the reduction in CH4 emissions caused by shrub expansion is primarily regulated by a synergistic pathway involving the combined effects of soil physicochemical properties and oxidative microbial genes. Furthermore, bacterial communities are more sensitive to shrub expansion than fungal communities. These results highlight the complex interactions between aboveground vegetation dynamics, soil microbial communities, greenhouse gas fluxes, and environmental factors. However, this CH4 reduction likely reflects hydrological degradation and wetland desiccation, which may increase CO2 emissions from oxidized peat and compromise long-term carbon sequestration, underscoring the need to prevent shrub encroachment for wetland conservation.

Cold-temperate forest ecosystems in northeastern China have experienced significant changes due to long-term anthropogenic disturbances. To elucidate how different natural forest stands influence the structure, function, and assembly processes of soil microbial communities, we performed 16S rRNA and ITS amplicon sequencing (n = 3 plots per stand) across three natural stands in Northeast China: a 10-year-old natural poplar forest (A1), a 20-year-old natural larch mixed forest (A2), and a 40-year-old natural spruce-pine mixed forest (A3). The results demonstrated that significant variations in aboveground vegetation were accompanied by significant differences in soil physicochemical properties. Specifically, soil organic carbon (SOC) and total nitrogen (TN) were significantly lower in A1 compared to the coniferous stands (p < 0.05). While alpha-diversity remained stable across stands (p > 0.05), beta-diversity revealed distinct community structures (PERMANOVA, p < 0.05). Neutral Community Model (NCM) analyses indicated a shift in bacterial assembly from a stronger stochastic influence in A1 (R-2 = 0.431) to a more prominent deterministic influence in A3 (R-2 = 0.188). Because stand age and canopy composition co-vary in our sampling design, we cannot fully disentangle their individual contributions. This comparative observational study reveals distinct soil microbial community structures across the three natural forest types. The transition across forest stands was associated with shifts in dominant microbial taxa and a tendency toward stronger deterministic assembly processes in coniferous stands. These patterns are consistent with differences in litter quality and soil physicochemical properties, providing observational evidence that may inform sustainable management of cold-temperate forests.

Soil cadmium (Cd) contamination is a persistent global threat due to its high mobility and bioaccumulation. While biochar is a common remediation tool, empirical results remain inconsistent. This global hierarchical meta-analysis synthesized 5437 observations from 239 studies to quantify biochar's efficacy in reducing soil Cd and identify key regulatory drivers. The study confirms that biochar application significantly reduces soil Cd levels, though results vary by context. Feedstock type and pyrolysis temperature emerged as primary regulators. Specifically, biochars derived from wood, organic waste, and lignocellulosic materials were most effective. Interestingly, the response exhibited a non-linear pattern, with both low and high pyrolysis temperatures outperforming intermediate ranges. The model further identified 605.85 t ha-1 as a statistical inflection point for soil Cd response, beyond which the marginal reduction effect weakened; however, this threshold far exceeds conventional field application rates and should therefore be interpreted only as an upper-bound statistical feature of the model fit. Random forest modeling identified the application rate, pyrolysis temperature, soil texture, and study type as the dominant factors controlling Cd reduction. Among soil properties, increases in cation exchange capacity (CEC) and soil organic carbon (SOC) were the most significant contributors to variability. Interaction analyses further revealed that while manure-derived biochar might increase soil Cd in controlled laboratory settings, it effectively inhibits Cd in fine-textured soils. These findings provide quantitative evidence for understanding the context-dependent performance of biochar in Cd-contaminated soils. By identifying drivers and nonlinear patterns, this study informs cautious site-specific biochar application strategies.

Soil bacterial communities play a central role in biogeochemical cycles, yet their responses to land use change and soil depth in Albic soils remain poorly understood, despite the unique physicochemical characteristics of the soil type in cold regions. To address this knowledge gap, we investigated bacterial community diversity, composition, and assembly processes across five land-use types: Uncultivated land (CK), Corn-Soybean rotation for 10 years (CS), Corn-Soybean rotation for 20 years (CI), Rice continuous cropping (RC), and Forest land (FL) at two soil depths (0-20 cm and 20-40 cm) using high-throughput Illumina MiSeq sequencing. Land use, depth, and their interaction significantly influenced soil chemical properties and bacterial community patterns. Bacterial alpha-diversity was consistently higher in FL and CK than in RC in the surface layer, with FL maintaining the highest diversity in the subsoil. beta-diversity analysis showed clear separation of bacterial communities among land use types and depths, particularly between RC and the other systems. Dominant genera included Sphingomonas, Bryobacter, and Candidatus_Solibacter, with variations across depths and land uses. Co-occurrence networks revealed higher topological complexity under FL in the surface layer and stronger positive correlations under CS in the subsoil. Community assembly was primarily deterministic in surface soils and stochastic in subsoils. Soil depth and land use exerted both direct and indirect effects on bacterial diversity and stability, as revealed by correlation and structural equation modeling. Overall, this study demonstrates that land-use type and soil depth jointly structure bacterial communities in Albic soils, advancing understanding of microbial ecological processes in this ecologically fragile and underexplored soil system and offering insights for soil health management and sustainable agriculture.

To investigate the response of soil microbial communities to reduce chemical fertilization supplementation with organic fertilizer in Acanthopanax senticosus cultivation, we analyzed the diversity, composition, and structure of soil microbiota by using high-throughput sequencing technology. The results showed that reducing chemical fertilizer application significantly increased soil microbial richness (ACE and Chao1 indices), which was positively correlated with soil total nitrogen (TN) content. At the phylum level, the relative abundance of Cyanobacteria decreased at T2 (reduction of 20% for fertilizer application) but increased at T4 (reduction of 60% for fertilization application), exhibiting an opposite trend to Bacteroidetes. At the genus level, the relative abundance of Paucibacter was significantly higher in T4 than in other treatments, while Nitrospira reached its peak under T3 treatment. For fungal communities, the richness index showed a non-linear response, initially decreasing and then increasing, which was positively correlated with the soil available potassium (AK) content. At the phylum level, reduced fertilizer application significantly reduced the relative abundance of Ascomycota compared to conventional fertilization. At the genus level, the relative abundance of Fusarium was significantly lower in the T4 treatment than in the other treatments. Redundancy analysis (RDA) revealed that the total organic carbon (TOC), TN, and AK were the key environmental factors affecting the soil microbial community. This study demonstrated that partial substitution of chemical fertilizers with organic amendments can improve soil physicochemical properties and enhance microbial diversity, providing a scientific basis for developing sustainable fertilization strategies for Acanthopanax senticosus cultivation.

The cold temperate forest ecosystem is a crucial ecological zone in China, significantly impacted by human activities. To understand the impact of restoration on soil microbial communities following disturbance, this study employed high-throughput sequencing technology to systematically examine the assembly patterns and processes of soil microbial communities under two restoration modes (nature restoration (NR) and artificial restoration (AR)) in this forest ecosystem. The results indicated that the concentrations of total nitrogen (TN), alkaline hydrolysable nitrogen (AN), dissolved organic carbon (DOC) and soil organic carbon (SOC) were significantly higher in soils under natural restoration compared to artificial restoration. The α-diversity of soil bacteria remained unchanged, while soil fungal α-diversity changed significantly across different restoration modes. Furthermore, different restoration modes significantly alter the β-diversity of soil microbial (bacterial and fungal) communities. The relative abundance of soil microbial (bacterial and fungal) changed significantly across different forest restoration strategies, i.e., the relative abundance of Pajaroellobacter increased in natural restoration compared to that in natural forest; similarly, both Podila and Russula showed higher relative abundances in natural restoration than those in natural forest. Furthermore, analysis of variance for differences between groups shows that Incoybe plays a crucial role in artificial restoration. Community assembly analyses indicated that that soil microbial (bacterial and fungal) communities were primarily driven by deterministic processes in both restoration models. In short, our study improves our comprehension of how soil microbial communities respond to different restoration methods in temperate forest ecosystems, providing valuable insights for their sustainable management.

Soil microorganisms are crucial in global biogeochemical cycles, impacting ecosystems' energy flows and material cycling. This study, via high-throughput sequencing in four forests-the original Larix gmelinii (Rupr.) Kuzen. forest (LG), the conifer-broad-leaved mixed Pinus sylvestris var. mongolica Litv. forest (PS), the original pure Betula platyphylla Sukaczev forest (BP), and the original pure Populus L. forest (PL) in Shuanghe National Nature Reserve, Daxing'anling mountains-explored soil microbial community structures and diversities. The results indicated that the BP and PL forests had the lowest soil bacterial ACE and Chao1 indices, and the original pure birch forest's Shannon index was higher than that of the poplar forest. The soil's fungal Chao1 index of the birch forest was higher than that of the larch forests. Bradyrhizobium and Roseiarcus were the dominant soil bacterial genera; the dominant soil fungal genera were Podila, Russula, and Sebacina. RDA and mantel analyses indicated that soil microbial community structures varied across forest types mainly because of the effective phosphorous and pH levels, soil's total nitrogen level, and available phosphorus level. This study offers a scientific foundation for cold-temperate-forest ecosystem management regarding soil microbial diversity and community structural changes in different forest types.

In this study, we investigated the changes in the communities of arbuscular mycorrhizal fungi (AMF) and their driving factors across eight vegetation succession stages in the Sanjiang Plain, Northeast China, original natural wetland (NW), wetland edge (EW), shrub-invaded wetland (IW), shrub-dominated wetland (DW), young-Betula forest (YB), mature-Betula forest (MB), Populus and Betula mixed forest (PB), and conifer forest (CF), using Illumina MiSeq sequencing. As this research has revealed, significant differences exist in soil physicochemical indicators, including moisture content (MC), pH, soil organic carbon (SOC), total nitrogen (TN), available nitrogen (AN), total phosphorus (TP), and available phosphorus (AP). As vegetation succession progresses, the diversity and structure of AMF communities also undergo changes, with the Simpson diversity index being highest in coniferous forests (CF) and the Abundance-based Coverage Estimator (ACE) and Chao1 indices being elevated in shrub-dominated wetlands (PB). Non-metric multidimensional scaling (NMDS) analysis reveals distinct differences in AMF communities across various succession stages. Furthermore, stacked bar charts indicate that the genus Glomus dominates in most wetland and forest succession stages but is nearly absent in CF, where it is replaced by the genus Paraglomus. Canonical correspondence analysis (CCA) demonstrates that SOC has a more significant impact on AMF communities during the EW stage of succession, while AP and TP exert greater influence during the CF stage as well as the MB and YB stages. AN, on the other hand, plays a more prominent role in shaping AMF communities during the IW and NW stages. PICRUSt2 predictions reveal that enzymes such as alcohol dehydrogenase and L-aminoadipate-semialdehyde dehydrogenase are most abundant in YB, whereas pathways like 4-amino-2-methyl-5-diphosphomethylpyrimidine biosynthesis are most enriched in IW. These findings uncover the close interplay between soil physicochemical properties and AMF community dynamics, aiming to deepen our understanding of the relationships among soil physicochemical properties, AMF community changes, and succession dynamics in wetland and forest ecosystems.

Purpose: China has recently witnessed a significant rise in nitrogen (N) deposition associated with human activities, especially in temperate regions. Although much research has been conducted on aboveground biodiversity, the effects of long-term N deposition on the composition, function and variety of the soil microbiota (especially across seasons) have received less attention. Methods: We investigated the effects of varying levels of nitrogen deposition on the composition, function and diversity of soil microbiota (bacteria and fungi) in temperate natural wetlands in summer and winter using Illumina sequencing. N deposition are categorized into low N addition (LN: 40 kg N/ha yr-1) and high N addition (HN: 80 kg N/ha yr-1). Results: In both summer and winter, N deposition had a significant effect on bacterial alpha diversity. In contrast, fungal alpha diversity exhibited no significant change in either of the two seasons. Additionally, the diversity of the soil microbiota exhibited higher sensitivity to N deposition in winter compared to summer. During the summer months, nitrogen deposition significantly altered the relative abundance of bacterial phyla such as Acidobacteria, Myxococcota, Verrucomicrobia and Actinobacteria. In winter, bacterial phyla in the surface soil exhibited distinct changes in their relative abundance. Relative abundance of Epsilonbacteraeota was highest in plots without added nitrogen, whereas the N-treated plots exhibited the lowest abundances. In addition, the relative abundance of Ascomycota was significantly increased by the addition of N, whereas Mortierellomycota exhibited a significant decrease, with Basidiomycota exhibiting no significant effect. The results from the structural equation model (SEM) revealed that soil organic carbon (SOC) and total nitrogen (TN) exerted a significant influence on the composition of both bacterial and fungal communities in the soil, regardless of the season. Specifically, in the summer season, SOC and TN account for 87 % of the variation observed in bacterial diversity and 83 % of the variation in fungal diversity. Likewise, during the winter season, these factors explain 91 % of the changes in bacterial diversity and 88 % of the changes in fungal diversity. Conclusion: Our research findings have unveiled that bacterial communities display a heightened sensitivity to nitrogen (N) deposition compared to their fungal counterparts. This discovery emphasizes the crucial need to concurrently evaluate the responses of the soil microbiome to global changes across various seasons, highlighting the intricate interplay between microbial dynamics and environmental factors.

Soil microorganisms play a crucial role in maintaining soil functionality and ecological balance by participating in key processes such as organic matter decomposition, nutrient cycling, soil structure formation, and plant health support. High-throughput sequencing was utilized in this study to systematically investigate the influence of different crop types, maize (Zea mays), soybean (Glycine max), and Eleutherococcus senticosus, on the communities and assembly mechanisms of soil microorganisms in a cold-temperate agroecosystem. The results reveal that cultivation practices led to significant differences in soil chemical properties compared to fallow land (CK). Total carbon (TC), total nitrogen (TN), and available nitrogen (AN) were significantly lower in CK than in cultivated soils, with the highest values observed in maize treatments among all crop types (p < 0.05). Furthermore, the alpha diversity of bacteria in the maize and soybean treatments was significantly higher than that in CK, while there was no significant difference between the Eleutherococcus senticosus treatment and CK. However, no significant differences were observed in the ACE and Chao1 indices of the soil fungal communities across the four crop types. Beta diversity of bacterial and fungal communities exhibited significant variations under different crop cultivation practices. Specifically, compared with CK, the relative abundance of Sphingomonas, which contributes to the degradation of complex organic compounds, and Gemmatimonas, which plays a role in nitrogen cycling, significantly increased, whereas the relative abundance of Clavaria, a genus capable of decomposing recalcitrant lignin and cellulose, decreased. Analysis of community assemblies revealed that both bacterial and fungal communities were predominantly influenced by deterministic processes across all crop types. This finding provides a scientific basis for maintaining soil fertility in a targeted manner, precisely protecting crop health and optimizing agricultural management efficiently, thereby supporting sustainable agricultural practices. In conclusion, by examining microbial diversity and community dynamics across different crops, along with the underlying environmental factors, this study aims to enhance our understanding of plant–microbe interactions and provide insights for sustainable agricultural practices in cold-temperate regions.

Marsh wetland degradation and shrub expansion, driven by human activities and climate change, can impact carbon, nitrogen, and sulfur cycles by soil microorganisms. There is a paucity of systematic and in-depth research on the impact of shrub expansion in temperate wetlands on soil element cycles, which is a pressing scientific issue that demands resolution. This study used metagenomic sequencing and soil analysis methods to investigate the impact of shrub expansion in the Sanjiang Plain wetlands on carbon, nitrogen, and sulfur cycles in temperate wetland soils, as well as on functional microbial communities. Shrub expansion significantly altered soil carbon, nitrogen, and sulfur cycle processes and the composition (β diversity) of associated functional microbial communities, despite minimal changes in overall α diversity. Significant shifts occurred in the abundance of cycle pathways and related functional genes. Ammonia nitrogen, moisture, and total phosphorus were identified as the primary factors influencing these cycles and the functional microbial communities. Changes in the abundance of specific cycling pathways following shrub expansion are key drivers of functional community structure transformation. These changes may significantly reduce the long-term carbon sequestration potential of wetlands and affect regional climate feedback by altering greenhouse gas fluxes. The findings provide a theoretical basis for managing shrub expansion and assessing wetland function.

Land-use change, including deforestation and reforestation, has driven significant alterations in soil properties, phosphorus (P) dynamics, and microbial communities. Reforestation might alleviate the disturbance of forest-tocropland conversion. This study investigates the effects of converting natural forests (NF) to croplands (CP) and subsequent reforestation into cultivated forests (CF) on soil P fractions, and 18 P-cycling functional genes. The results showed that deforestation was associated with reductions in soil total nitrogen (TN), total organic carbon (TOC), pH, and microbial biomass phosphorus (MBP), along with a 37.5 % increase in available phosphorus (AP) pools. Reforestation decreased total P to levels comparable to those in NF. Additionally, CF exhibited lower concentrations of moderately labile (NaOH-Po and -Pi) and stable P pools (concentrated HCl-Pi and -Po), which may reflect enhanced biological P utilization or a gradual depletion of recalcitrant P reserves due to ongoing ecosystem recovery. Pi content was consistently 2-3 times higher than Po, with NF maintaining this ratio through greater Po conservation and stable P pools. Land-use change disrupted this balance, as reflected by shifts in Pcycling gene abundance. Deforestation was associated with higher abundances of genes related to inorganic P solubilization and organic P mineralization, whereas reforestation was associated with reductions in these genes to levels comparable to those observed in NF. For instance, PhoB and phoU showed higher abundances in CP with higher P availability. Ugp and phnCDE responsible for P uptake and organic P mineralization, which correlated with organic P content (NaOH-Po and concentrated HCl-Po). Utilizing a 40-year land-use chronosequence, this study uniquely captures the legacy effects on soil P cycling and microbial function by integrating metagenomic sequencing with phosphorus fractionation to offer a holistic view of nutrient cycling under land-use changes. The study highlights the importance of land management practices in maintaining P cycling and microbial community functions, with implications for potential improvements in reforestation strategies and nutrient management.

China has experienced a notorious increase in nitrogen (N) deposition as a result of anthropogenic activities, particularly in temperate areas. While aboveground biodiversity has been extensively studied, the impact of long-term N deposition on the diversity, composition, and function of the soil microbiome remains largely unexplored. In this study, we evaluated alterations in the diversity, composition, and function of soil bacterial and fungal communities in response to varying levels of N deposition (LN = low N addition, 40 kg N ha −1 yr −1 ; HN = high N addition, 80 kg N ha −1 yr −1 ) using Illumina MiSeq sequencing technology in a temperate natural wetland. N deposition had no discernible impact on bacterial α diversity, whereas fungal α diversity exhibited a significant decrease in response to high N addition only. Additionally, N deposition led to a notable increase in the relative abundance of the bacterial phylum Patescibacteria but a decrease in Latescibacteria. The relative abundance of Epsilonbacteraeota was highest in the unamended plots and lowest in the low N addition plots. Furthermore, N addition significantly increased the relative abundance of Ascomycota while decreasing that of Mortierellomycota, with no significant effect observed on Basidiomycota. Structural equation modeling (SEM) indicated that soil organic carbon (SOC), and total and available N were the two primary drivers shaping bacterial and fungal communities. Our study demonstrated that bacterial communities were less responsive to N addition compared to fungal communities, emphasizing the significance of simultaneously evaluating the soil microbiome in response to global changes.

Soil microbiota are significantly influenced by their microenvironments. Therefore, to understand the impacts of various land use patterns on the diversity and composition of soil bacterial communities, this study focused on three typical land use types—NF (natural forest), AF (artificial forests), and FL (farmland)—in the Heilongjiang Central Station Black-billed Capercaillie National Nature Reserve, located in the southwestern part of Heihe City, Heilongjiang Province, China. Using high-throughput sequencing of the 16S rRNA gene, we examined the soil bacterial community structures in these different land use types and explored their correlation with soil environmental factors. The following were our main observations: (1) Significant variations in soil chemical properties among different land use patterns were observed. In artificial forests, total nitrogen (TN), alkali hydrolyzed nitrogen (AN), total phosphorus (TP), and available phosphorus (AP) were higher compared to farmland and significantly higher than those in natural forests. Furthermore, the organic carbon content (SOC) in natural forests was higher than in artificial forests and significantly higher than in farmland. (2) Comparative analysis using the Shannon and Simpson indices revealed that bacterial community diversity was higher in artificial forests than in natural forests, which was significantly higher than in farmland. (3) The effect of different land use types on soil bacterial community structure was not significant. The three land types were dominated by Proteobacteria, Acidobacteria, and Actinobacteria. Proteobacteria exhibited a higher relative abundance in farmland and artificial forests compared to natural forests, whereas Actinobacteria exhibited the lowest relative abundance in natural forests. (4) Redundancy analysis (RDA) revealed that SOC, TN, AN, and AP were key environmental factors influencing the microbial communities of soil. Collectively, our findings demonstrated that land use practices can significantly alter soil nutrient levels, thereby influencing the structure of bacterial communities.

Nitrogen cycling in terrestrial ecosystems is critical for biodiversity, vegetation productivity and biogeochemical cycling. However, little is known about the response of functional nitrogen cycle genes to global change factors in soils under different land uses. Here, we conducted a multiple hierarchical mixed effects meta-analyses of global change factors (GCFs) including warming (W+), mean altered precipitation (MAP+/-), elevated carbon dioxide concentrations (eCO2), and nitrogen addition (N+), using 2706 observations extracted from 200 peer-reviewed publications. The results showed that GCFs had significant and different effects on soil microbial communities under different types of land use. Under different land use types, such as Wetland, Tundra, Grassland, Forest, Desert and Agriculture, the richness and diversity of soil microbial communities will change accordingly due to differences in vegetation cover, soil management practices and environmental conditions. Notably, soil bacterial

It is widely known that antibiotics can affect the structure and function of soil microbial communities, but the specific degree of impact and controlled factors on different indicators remain inconclusive. We conducted a multiple hierarchical mixed effects meta-analysis on 2564 observations that were extracted from 60 publications, to comprehensively assess the impact of antibiotics on soil microbiota. The results showed that antibiotics had significant negative effects on soil microbial biomass, α-diversity and soil enzyme activity. Under neutral initial soil, when soil was derived from agricultural land or had a fine-textured, the negative impacts of antibiotics on soil microbial community were exacerbated. Both single and mixed additions of antibiotics had significant inhibitory effects on soil microbial enzyme activities. The Random Forest model predicted the following key moderators involved in the effects of antibiotics on the soil microbiome, and antibiotics type, soil texture were key moderators on the severity of soil microbial biomass changes. Soil texture, temperature and single or combined application constitute of antibiotics were the main drivers of effects on soil enzyme activities. The reported results can be helpful to assess the ecological risk of antibiotics in a soil environment and provides a scientific basis for the rational of antibiotics use in the soil environment.