Climate warming is exacerbating soil drought and precipitation events, as well as different land use types lead varying nutrient inputs, driving substantial shifts in microbial communities that may influence soil respiration. Microbial thermal compensation mechanisms serve as critical biological regulators, alleviating the warming-induced enhancement of soil respiration. However, the effects of soil moisture and land use types on the thermal responses of microbial respiration remain insufficiently understood and constrained. Here, we collected soil from four distinct sites, each comprising both farmland and forest, and conducted indoor experiments to simulate drought and rewetting events. We then assayed the thermal responses of microbial respiration rates at 40% and 60% of soil water holding capacity (WHC) in the first moisture incubation experiment, and at a consistent moisture level (60% WHC) in the subsequent recovery moisture experiment. Our results showed that low soil moisture suppressed the thermal compensatory response while enhancing respiration in both soil types after drought and rewetting. In the incubation experiment, the respiratory response of soil microbes to warming was stronger in farmland ecosystems than in forest ecosystems. Notably, farmland soils under prior low moisture stress exhibited a high thermal compensatory response of microbial respiration after rewetting–opposite to forest soils. Overall, our findings suggested that climate warming-induced drought might weaken the thermal compensatory response of microbial respiration in both farmland and forest soils, with this effect persisting after rewetting. By improving estimates of projected soil carbon losses to the atmosphere via respiration, our work contributes to more accurate predictive modelling of carbon dynamics in farmland and forest soils under climate warming.

Straw management significantly influences soil microbial dynamics, shaping biodiversity and resistance in agroecosystems. This study investigated how distinct straw management practices affect bacterial communities and their ecological interactions in bulk soil and the sugarcane rhizosphere. The study was conducted in an Oxisol using a split-plot design with two straw management treatments (burnt and unburnt) and two soil compartments (bulk soil and rhizosphere). Bacterial communities were characterized using 16S rRNA gene sequencing, followed by analyses of diversity, co-occurrence networks, and niche occupancy. The rhizosphere consistently exhibited higher bacterial richness and diversity, regardless of straw management. Burnt straw reduced the relative abundance of Actinobacteriota (~52%) and Firmicutes (~53%) but increased Proteobacteria (~65%) in bulk soil, whereas the rhizosphere bacterial community remained stable. Network analysis revealed higher connectivity and modularity in the rhizosphere, while burnt straw increased negative correlations and reduced microbial complexity in bulk soil. Niche occupancy analysis showed a higher proportion of specialist taxa in the rhizosphere, particularly under burnt straw. Overall, the sugarcane rhizosphere exhibited high microbial resistance to straw burning. These findings highlight the importance of sustainable straw management for preserving soil biodiversity and maintaining ecological stability in tropical cropping systems.

Soil microbial heterotrophic respiration (HR), a crucial carbon flux to the atmosphere, is closely related to microbial community traits. However, community level microbial traits associated with such process remain understudied across forest biomes. Here, we accessed microbial traits influence on HR across a forest climatic gradient in China. We found that microbial HR showed distinct differentiation along an environmental gradient, which were highest in temperate forest Maoer mountain (1067.95 mg C kg^‒1) and lowest in tropical forest Xishuangbanna (178.83 mg C kg^‒1). At the community level, microbial HR was tightly related to microbial biomass and composition, and genomic traits. Notably, the HR was positively correlated with guanine-cytosine base pair content, but negatively correlated to the average 16S rRNA copy number and the average genome size of microbes (P < 0.05). Moreover, among the forests, soil organic carbon and alkyl-C/O-alkyl-C ratio were the crucial variables in explaining HR, which attributed to their effects on microbial composition and genomic traits. Overall, microbial genomic traits at the community level play an important role in understanding HR. Our findings elucidate new evidence on the mechanisms driving soil carbon fluxes and enhance predictions of soil carbon responses to future climatic change.

Soil organic carbon (SOC) reflects soil quality and affects ecosystem productivity and the capacity for carbon sequestration. Grazing regimes modulate the status of SOC in grasslands, but their impacts on SOC distribution among soil aggregates are not entirely clear. In this study, the effects of grazing with different intensities and no-grazing with varied enclosure durations were investigated. Increasing grazing intensity enhanced the proportion of 150‒53 μm aggregates, while reducing larger aggregates. After 5 years of enclosure, the distribution of soil aggregates in heavily degraded grassland recovered to resemble that in light-grazed grassland. Heavy grazing decreased SOC concentration in the 10–20 cm layer, and SOC concentration in different aggregate sizes decreased with increasing grazing intensity. Differences in SOC stocks among management measures were mainly reflected in the 10–20 cm soil layer, with heavy grazing significantly reducing SOC stocks. SOC stocks were lowest in 2000–250 μm and 250–150 μm aggregates and highest in <20 μm aggregates. Moderate grazing enhanced SOC stocks in <20 μm aggregates. In the 10–20 cm soil layer, 10 years of enclosure significantly decreased SOC stocks in 2000–250 μm, 250–150 μm and <20 μm aggregates compared to 5 years of enclosure. It indicated that grazing regimes affected grassland carbon sequestration and its distribution in soil aggregates, and moderate grazing had a better positive effect on carbon sequestration. This study provides novel insights into the patterns underlying changes in soil organic carbon from soil aggregates perspective.

To understand large-scale drivers of soil nitrification and community-specific N₂O yield in forest ecosystems, we collected five forest soils along a climatic gradient in China, differing in soil pH (4.07‒6.44) and atmospheric N deposition. We conducted oxic soil slurry incubations with inhibitors to infer potential nitrification rates and N₂O yields for ammonia oxidizing bacteria (AOB), ammonia oxidizing archaea (AOA) and heterotrophic nitrification. The largest nitrification potential and N₂O accumulation rate were observed in the temperate, circum-neutral soil. (Sub)tropical soils with low pH had relatively small nitrification rates with an increased contribution of AOA and heterotrophic nitrification to ammonia oxidation and N₂O production. The smallest nitrification potential with largest apparent N₂O yield (6.97%) was found in the most acidic subtropical forest soil, which also had the highest atmospheric N deposition. Ammonia oxidation kinetics showed nitrite (NO₂^‒) accumulation, suggesting inhibition of nitrite oxidizing bacteria (NOB) which together with chemical conversion of nitrification intermediates can explain the high apparent N₂O yield of this soil. NO₂^‒ and NO₃^‒ production did not balance NH₄⁺ consumption by autotrophic nitrification, strongly suggesting that acidic soils with high N deposition in subtropical China are a hotspot for nitrification-driven gaseous N loss, a substantial share of which emits as N₂O. These findings highlight the need to incorporate N saturation status and microbial community dynamics into global models of forest N cycling and to refine N management strategies in regions experiencing high atmospheric N deposition.

Morphological identification of soil oribatid mites is constrained by taxonomic complexity and reliance on specialized expertise, limiting its practical applicability and hindering the efficiency of soil mesofaunal diversity assessments. Despite advances in deep learning-based automated classification, key process factors influencing model performance remain underexplored. This study aimed to establish a generalized convolutional neural network (CNN)-based framework for rapid, accurate identification of nine co-distributed oribatid mite species from subtropical forests (Tianmu and Guan Mountains, China). We systematically evaluated the effects of CNN architectures (AlexNet, VGG16, ResNet50, ResNet101, DenseNet), image resolutions (32×32 to 224×224 pixels), background colors (eight RGB treatments), and habitat origins on classification performance using a balanced dataset (118 images per species per habitat). DenseNet achieved the highest accuracy (99.32%) at 224×224 pixels with white backgrounds (RGB 255,255,255) and successfully distinguished habitat origins (accuracy: 92.45%–100%). A standardized workflow for image acquisition, dataset construction, and model optimization was proposed. This work bridges computer vision and soil zoology, advances Soil Animal Informatics, and offers a scalable solution for large-scale soil mesofauna biodiversity monitoring in the big data era.

Nanobubble-oxygenated drip irrigation (NODI) mitigates the dual stress of high salinity and hypoxia on crop growth in salinized soils. However, while the responses of bacterial communities to NODI have been documented, the regulatory mechanisms on soil fungal community assembly and root–fungal interactions remain unclear. This knowledge gap hinders a comprehensive understanding of NODIʼs role in enhancing crop productivity. To address this, we employed a dual-factor experiment combining irrigation amount (deficit: I_0.8, full: I₁, excess: I_1.2) and dissolved oxygen concentration (DO: 5, 15, 30 mg L⁻¹). This study aimed to investigate the effects of NODI on fungal communities and root systems in mildly salinized tomato soil, thereby elucidating the mechanisms of water-oxygen coupling in regulating crop growth through root–fungal interactions. The results indicated: (1) High dissolved oxygen (DO₃₀) significantly reduced soil electrical conductivity (EC) (by 34.87% and 34.09% compared to DO₅ and DO₁₅, respectively; P ⩽ 0.05), enhanced modularity and keystone taxa abundance in fungal co-occurrence networks, and increased the relative abundance of saprotrophic functions (e.g., Dung Saprotroph–Undefined Saprotroph), endophytic functions (e.g., Endophyte), and the proportion of homogeneous selection indeterministic assembly; (2) Different DO-I combinations led to significant variations in therelative abundance of fungal phyla (Ascomycota, Basidiomycota, Olpidiomycota, Rozellomycota, Zoopagomycota) and five functional guilds (P ⩽ 0.05); (3) Root architecture (tips, forks, etc.) and EC jointly drove fungal community variation. Root tips exhibited a significant positive correlation with the relative abundance of arbuscular mycorrhizal fungi. The structural equation modeling (SEM) revealed that Forks indirectly affected yield by modulating Basidiomycota abundance (r=0.51), while saprotrophs (Dung Saprotroph–Undefined Saprotroph) directly promoted yield under low EC (<35 mS cm⁻¹) (r= 0.54); (4) The optimal treatment DO₃₀I_1.2 (30 mg L⁻¹ DO and 20% excess irrigation) minimized root-zone EC (32.40 mS cm⁻¹) and achieved peak tomato yield (210.90 kg plot⁻¹) and lycopene content (56.92 μg g⁻¹). In conclusion, NODI optimizes the rhizosphere microenvironment through water-oxygen coupling, activates saprotrophic functions, and strengthens root-fungal symbiotic networks, thereby enhancing tomato yield and quality in salinized soils. DO₃₀I_1.2 is recommended as the optimal application mode.

Sea-level rise is salinizing estuarine wetlands, yet its impact on Fe-bound organic carbon (Fe-OC) persistence remains unclear. Here, we analyzed topsoil (0–10 cm) and subsoil (40–50 cm) samples from paired Phragmites australis-dominated saltwater and freshwater marshes at six Chinese estuaries spanning 18° of latitude, to determine how saltwater intrusion modulates Fe-OC sequestration and soil organic carbon (OC) degradation. Freshwater marshes stored 18.7% of OC as Fe-OC, significantly more than 16.3% in saltwater marshes. The Fe-OC pool declined markedly with soil depth. Salinity stress can reduce the pools of OC and Fe-OC by suppressing plant biomass accumulation. Concurrently, higher salinity stimulates soil hydrolase activity and enhances potential Fe(III)-reduction rates (FeRRs). Both Fe-oxidizing bacteria (FeOB) and Fe-reducing bacteria (FeRB) were more enriched in freshwater marshes than in saltwater marshes. Structural equation modelling revealed that salinity and soil depth negatively influenced the Fe-OC pool by shifting OC composition and by enhancing enzyme activity. The abundances of poorly crystalline Fe (Feo) and root Fe(III) plaque were the strongest predictors of the Fe-OC pool in coastal marshes. Thus, saltwater intrusion destabilizes Fe-OC, so evaluations of OC stabilization in estuarine marshes must explicitly include Fe-OC dynamics under salinization.

The widespread environmental persistence of nanoplastics (NPs) poses critical threats to aquatic ecosystems, yet their impacts on sediment bacterial communities and ecosystem functionality remain poorly characterized. Through a 180 days microcosm experiment integrating 16S rRNA sequencing and structural equation modeling (SEM), we investigated the ecological effects of NPs (polyethylene, PE, and polypropylene, PP) on sediment bacterial communities. PE significantly increased sediment bacterial richness (Chao1 index: 555±36.57 vs. CK: 546.33±52.48), whereas large-particle/high-concentration PP exhibited the lowest diversity. Proteobacteria (30%‒40%) and Actinobacteriota (15%‒18%) dominated community composition across treatments. At the genus level, NPs type significantly restructured dominant taxa composition. Moreover, PE amendments significantly increased total organic carbon (TOC; +9.4%) and nitrate retention (NO₃^‒-N; +21.4%), whereas PP reduced TOC (‒10.3%), total phosphorus (TP; ‒46.3%), and available phosphorus (AP; ‒36.6%). Enzymatic analyses demonstrated polymer-dependent effects: PE inhibited urease activity by 45.7% relative to controls, whereas PP stimulated nitrate reductase activity by 316.3%, indicating distinct metabolic adaptations. Functional profiling predicted NP-induced enrichment of nitrogen fixation, methylotrophy, and chemoheterotrophy pathways. Notably, PP treatments selectively enriched genetic traits associated with stress tolerance and virulence potential. Structural equation modeling elucidated cascading interdependencies among microbial diversity, sediment geochemistry, enzymatic profiles, and functional gene dynamics. Our results demonstrate that polymer type is a stronger driver of microbial functional shifts than particle size in wetland sediments, emphasizing the need for tailored mitigation strategies to protect wetland ecosystem integrity from plastic pollution.

Nitrogen (N) fertiliser form is a key regulator of soil microbial processes, yet its role in shaping soil extracellular enzyme and as a stoichiometric indicator remains unclear. We conducted a two-year field experiment (2023‒2024) in a tropical perennial durian orchard in Hainan, China, to examine how contrasting N forms influence soil biochemical properties and microbial nutrient acquisition strategies. Six fertilisation regimes were tested, namely control (CK), urea (URT), ammonium sulfate (AMT), calcium nitrate (NT), slow-release N (SRT) and bio-organic fertiliser (BFT). The bio-organic and slow-release N treatments significantly supplemented organic carbon in soils (50%‒113%), cation exchange capacity (26%‒134%), and microbial biomass C and N (22%‒206%), and maintained a relatively constant β-glucosidase (β-G): urease: alkaline phosphatase (ALP) ratio (coordinated nutrient acquisition) by the microbes. Synthetic N fertilisers particularly the nitrate-based and ammonium-based ones, in contrast, altered the stoichiometry of enzymes and deactivated enzyme phosphatase and reinforced phosphorus inhibition, which was followed by a successively growing decline in soil carbon retention. The enzyme-substrate relations (e.g., β-G-SOC, r = 0.76; p < 0.01) were improved under BFT and SRT, but not synthetic N inputs. Multivariate findings indicated that there was segregation in the first year of treatment and partial convergence in the second year, which is a sign in microbial acclimation to the continuous nutrient feeds. Combined, these findings show that N form modulates the patterns of microbial allocation and nutrient fixation systems in tropical soils, and that ecoenzymatic stoichiometry provides a sensitive biochemical quantification of fertilisation responses of soil functional processes.

The mucus-associated microbiome of soil fauna plays a critical role in host health and ecosystem functioning, but the information of mucus microbiota remains largely unexplored. Here, this study investigated bacterial communities of four soil fauna species (earthworm Eisenia fetida, Metaphire guillelmi; snails Cathaica fasciola, Lissachatina fulica) after 28 days of standardized cultivation. A diverse bacterial community was identified in the mucus of earthworms and snails, dominated by Proteobacteria (53.2%), followed by Bacteroidetes (15.2%), and Actinobacteria (11.9%) at the phylum level. Compared to the surrounding soil, the mucus harbors distinct bacterial communities with lower bacterial diversity. 0.5% of amplicon sequence variants (ASVs) were shared among the mucus, gut, and soil samples, with L. fulica harboring the most unique ASVs (1896). Furthermore, co-occurrence network analysis suggested predominantly positive bacterial interactions, indicating potential cooperative relationships within the host-associated community. Our study indicates that soil fauna mucus environment serves as a bacterial filter, and its community composition is shaped by host habits. These findings advance our understanding of mucus-associated microbes of soil fauna.

Salinity represents a major abiotic constraint limiting plant productivity in natural ecosystems. A key characte-ristic of saline soils is their inherent spatial heterogeneity in salt distribution, yet current understanding of plant responses to salinity primarily derives from homogeneous exposurescenarios, with limited data availableon root zone adaptation mechanisms under heterogeneous salinity conditions. To address this knowledge gap, we employed a split-root experimental system to systematically compare cucumber responses to heterogeneous versus homogeneous salinity at equivalent total salt concentrations. Our findings demonstrate that cucumber roots exhibited pronounced compensatory growth in low-salinity compartments, concomitant with enhanced osmotic adjustment capacity in high-salinity root zones. This differential adaptation resulted in significantly improved growth performance (P<0.05) and photosynthetic efficiency under heterogeneous salinity compared to homogeneous treatment. Moreover, rhizosphere microbiome analysis revealed enrichment of halotolerant rhizosphere microbiota (e.g., Rhizobiaceae, Xanthomonadaceae) under heterogeneous conditions. Metabolomic profiling identified significant accumulation of osmolytes (proline) and organic acids (e.g., citrate) in high-salinity root sectors, showing strong positive correlations with beneficial bacterial populations. In conclusion, through compensatory growth responses and modulation of rhizosphere microbial communities, the cucumber plants effectively alleviated the detrimental effects of heterogeneous salinity stress by optimizing water and resource allocation at the whole-plant level.

Manipulating rhizosphere microbial community assembly through rhizosphere effects is vital for plants to combat soil-borne pathogen infection. However, little is known regarding both the shifts in the rhizosphere effects of plants on soil microbial community assemblage after being infected by a soil-borne pathogen and how the changes impact the associations between rhizosphere microbiota and pathogens. In this study, the impact of the infection of Verticillium dahliae on cotton rhizosphere bacterial community assemblage and the ability of rhizosphere bacteria to suppress V. dahliae was explored. The results showed that diseased plants exerted greater rhizosphere effects and selectivity on soil bacterial community than healthy plants, leading to a 21.75% decline in the richness of rhizosphere bacteria. However, the content of dissolved organic carbon in the rhizosphere of diseased plant was 114.10% higher than that of heathy plants. The rhizosphere microbiota of diseased cotton plants exhibited a higher antagonism against V. dahliae than healthy plants, which was associated with the enrichment of antagonistic bacteria against V. dahliae, primarily Enterobacter spp. These results revealed that enhancing rhizosphere effects on soil microbiota and shaping a rhizosphere microbiota with high antagonism against V. dahliae is an important strategy for cotton to respond to V. dahliae infection.

Long-term continuous peanut monoculture has led to soil degradation, increased soil-borne diseases, and reduced crop productivity in the dryland Ultisols of southern China. The application of green manure has shown promising results in improving soil ecological functions; however, limited information is available regarding the most appropriate green manure type for dryland Ultisols. This study aimed to comprehensively evaluate the effects of three green manure crops (hairy vetch, ryegrass, and radish) on agricultural ecosystems. Soil fertility and peanut yield were assessed using conventional experimental methods, whereas fungal community structure was analyzed using high-throughput sequencing. Green manure application maintained higher soil nutrient levels. The radish treatment reduced soil bulk density and significantly increased peanut yield. Green manure application significantly increased fungal abundance, with the highest abundance observed under the radish treatment. Peanut yield was significantly positively correlated with fungal abundance. In addition, green manure application increased the complexity of the soil fungal network. The diversity and relative abundance of plant saprotrophs increased under hairy vetch and radish treatments, with the highest values observed under the radish treatment. Conversely, radish treatment significantly reduced the diversity and relative abundance of plant pathogens. Overall, peanut–radish rotation appears to be an appropriate agricultural practice for maintaining soil fertility, optimizing soil fungal communities, and improving crop yield in dryland Ultisols. These findings provide a theoretical basis for the deve-lopment of sustainable agricultural practices in Ultisols.

Ficus tikoua Bur., a perennial creeping fig of both medicinal and ecological importance, demonstrates notable adaptability across heterogeneous soil conditions; however, the physiological and genetic bases of its photosynthetic plasticity remain inadequately characterized. In this study, we evaluated leaf morphology, gas-exchange parameters, chlorophyll fluorescence indices, photosynthetic pigment concentrations, and light-response characteristics in eight naturally occurring populations from contrasting soil habitats in Guiyang, Guizhou Province, and concurrently conducted complete chloroplast genome sequencing for all samples. Phenotypic analyses revealed substantial variation in photosynthetic performance, which demonstrated a strong correlation with edaphic factors such as soil pH, organic matter content, and the availability of macronutrients. Notably, individuals inhabiting nutrient-deficient substrates exhibited reduced chlorophyll content and diminished photosynthetic capacity. Furthermore, our findings suggest that mature leaves integrate broader soil conditions, whereas developing leaves serve as sensitive bio-indicators of specific nutrient stressors. Comparative synteny analysis of chloroplast genomes indicated an overall conserved genomic architecture with no evidence of large-scale structural rearrangements, while phylogenomic reconstruction resolved the eight accessions into two well-supported clades that corresponded to provenance: one comprising the six wild accessions (A‒F) and the other containing the two cultivated varieties (G and H). Collectively, these results indicate that both soil environment and chloroplast genetic variation contribute to the modulation of photosynthetic traits in F. tikoua, thereby providing a genomic and physiological framework that may inform targeted breeding and conservation strategies.

Soil pollution is a defining feature of the Anthropocene. Industrial emissions, intensive agriculture, and waste mismanagement have loaded soils with heavy metals, legacy organics, microplastics, and other novel entities at levels that threaten biodiversity, food security, and human health. Meanwhile, climate change and land-use intensification alter soil temperature and moisture, creating complex multi-stressor conditions that conventional controlled single-variable tests rarely capture. 1) We argue that soil food webs spanning microbes, microfauna, mesofauna, and macrofauna constitute core living infrastructure for remediation and ecological risk assessment. 2) Building on recent advances, we synthesize evidence that cross-trophic interactions regulate the fate of organic pollutants, metals, and emerging contaminants, and that chemical stressors together with climate-driven shifts in temperature and moisture can reshape food-web structure, energy channels, and stability. 3) We outline how food web metrics and bioindicators can be operationalized to guide remediation design and ecological risk assessment. We propose that diverse, functionally redundant, and well-connected food webs provide resilience that buffers contaminant pulses while sustaining nutrient cycling. Realizing this potential requires trait-based multitrophic research aided by omics, synthetic biology, network analysis, and big data modeling to embed food web principles into nature-based remediation and governance.

Livestock grazing strongly influences soil microbial diversity in grasslands, yet the role of dung deposition, particularly differences among livestock species, remains poorly understood. Here, we investigated how cattle and sheep dung influence soil microbial diversity using a field experiment in a temperate meadow steppe combined with a microcosm experiment separating nutrient and microbial effects. Results showed that both cattle and sheep dung deposition significantly increased soil fungal diversity but not bacterial diversity in the first year after dung deposition, with no effect detected in the second year. Cattle dung increased fungal diversity most strongly directly beneath dung pads (0 cm), with the stimulatory effect declining with increasing distance (15 and 30 cm). In contrast, sheep dung produced a relatively uniform response with no significant differences among distances. Structural equation modelling showed that cattle dung had a direct positive effect on fungal diversity, whereas sheep dung influenced fungal diversity mainly through indirect soil pathways. Consistent with this pattern, the microcosm experiment demonstrated that only fresh cattle dung containing live microbiota, but not sterilized dung, increased fungal diversity, indicating that the direct effect of cattle dung is attributable to dung-associated microbiota. Overall, livestock dung functions as both a nutrient hotspot and a microbial inoculum, regulating fungal diversity through biotic and abiotic pathways. Dung inputs generate a short-term microbial and nutrient pulse rather than a persistent driver of soil microbial diversity. Our study provides new insights into how grazing livestock shape belowground biodiversity and nutrient cycling in grassland ecosystems.

Amazonian Dark Earths (ADE) are fertile anthropogenic soils rich in organic matter and microbial diversity, offering potential for restoring degraded tropical soils. We tested the combined effects of ADE (2% w/w) and Urochloa brizantha conditioned soil (CS 20%) on soil microbial communities and early growth of four tree species (Cecropia pachystachya, Schizolobium amazonicum, Handroanthus avellanedae, Acacia mangium) in a pasture-degraded Oxisol. Plant performance, soil enzyme activity, prokaryotic community structure (16S rRNA sequencing), predicted functions, and co-occurrence networks were evaluated. Neither ADE nor U. brizantha, alone or combined, significantly improved tree growth or microbial alpha diversity (p < 0.05). However, the combination CS+ADE shifted microbial composition, reducing by 3-fold the abundance of several aerobic Gram-positive taxa (Actinophytocola, Lysinibacillus, Rubrobacter) and nitrogen-fixers (Herbaspirillum). Network analyses showed treatment-specific connectivity changes, especially in Cecropia and Acacia, where CS+ADE increased both positive and negative microbial associations. Functional prediction and enzyme assays revealed a largely stable functional core, except for a 70% decline in β-glucosidase activity in Acacia under CS+ADE, indicating altered carbon cycling. Overall, while microbial networks responded strongly, limited ADE input and the stability of native microbiota constrained plant and functional benefits, underscoring the importance of application strategies in restoration.

This study evaluated the spatial distribution and drivers of soil organic carbon (SOC), microbial biomass carbon (MBC), readily oxidizable carbon (ROC), non-labile organic carbon (NLOC), and the carbon pool management index (CPMI) in the 0–40 cm soil layer across forest, shrubland, and grassland on the southern slope of the Qilian Mountains. Results showed that forest soils had the highest SOC and MBC, while grassland soils had the lowest. ROC was significantly higher in shrubland, and grasslands had a higher proportion of NLOC. Forest soils also exhibited higher carbon pool activity (A), carbon activity index (AI), and CPMI, whereas grasslands had significantly lower values. Correlation analysis revealed significant positive relationships between SOC, NLOC, and MBC with soil water content (SWC), total nitrogen (TN), available nitrogen (AN), available phosphorus (AP), and enzyme activities (alkaline phosphatase, PHO; β-glucosidase, BG). ROC and CPMI were mainly influenced by electrical conductivity (EC), SWC, TN, AN, and total phosphorus (TP). Redundancy analysis (RDA) explained 96.02% and 89.8% of the variation in carbon components and CPMI, respectively. Monte Carlo tests identified TN, AP, and SWC as key drivers of carbon components, and SWC, EC, AN, and AP as major factors shaping CPMI. The study suggests that vegetation type strongly regulates soil carbon dynamics in high-altitude regions, with forests promoting greater carbon accumulation and activity, while grasslands exhibit higher stability.

Changes in the use of land have a profound effect on the nitrogen cycle (N-cycle) in terrestrial ecosystems. Related research in fragile ecological environments needs to be promoted in the context of increasing human activities. In this study, four soil types were sampled in the Qaidam Basin (northeastern Qinghai-Tibet Plateau), ordered by increasing management intensity as follows: grassland (GL), irrigated land (IL), orchard land (OL) and facility agricultural land (FAL). Our results indicate that: Intensive management reduces spatial differentiation of N-cycling microbial communities (P < 0.05), while soil salinity dominated the spatial differentiation in this taxa; From GL to FAL, the abundance of nitrogen fixation (nifK: 0.08‰‒1.48‰, nifD: 0.07‰‒1.79‰, nifH: 0.04‰-1.11‰) and nitrification function genes decreased significantly (p < 0.05), while the abundance of ammonification (aomA:1.13‰‒0.28‰, aomB: 2.20‰‒0.98‰, aomC: 2.76‰‒0.76‰) genes increased significantly (P < 0.05); Meanwhile, the complexity of the nitrogen cycle microbial co-occurrence network decreased from GL to FAL (average degree 0.17‒17.03), and halophilic microorganisms (Halophiles) was replaced by abundant biosphere with the turnover process. In summary, in the Qaidam Basin, different land use types regulate salinity rather than nutrients, shaping the spatial pattern of N-cycling microbial communities and thereby dominating the transformation of Halophiles niches.

Soil microbial communities represent high-resolution environmental fingerprints with considerable potential for forensic microbial geolocation. However, spatiotemporal variation patterns, carrier substrate effects, and interannual dynamics of soil microbes in urban environments remain poorly understood. Here, we conducted a 393-day systematic survey encompassing 16 sampling time points at six representative sites across three major Chinese cities (Beijing, Nanjing, and Guangzhou). By comparing bacterial communities associated with in situ soil, tool soil, and shoe-sole soil, we assessed the forensic geolocation potential of different soil carriers. Spatial factors explained a substantially greater proportion ofvariation in soil bacterial community composition (13.4%) than temporal factors (2.3%). Community similarity exhibited a distance–decay relationship that was more than 28 times (R²) stronger along geographic distance than along temporal distance, with significant but weak temporal distance–decay detected only when absolute time intervals were considered. Bacterial communities associated with tool soil closely resembled those of in situ soil and retained a comparable spatial distance–decay pattern. In addition, community composition showed no significant cyclical recurrence at interannual scales, as seasonal fluctuations far exceeded interannual variation. Collectively, these results demonstrate that urban soil bacterial communities maintain strong and stable spatial differentiation that is largely independent of interannual cyclicity. Importantly, tool soil effectively preserves the spatial microbial signature of in situ soil, indicating that it constitutes a more reliable forensic carrier than shoe-sole soil. Our findings provide a robust ecological foundation for the application of microbial evidence in forensic geolocation.

Soil nematodes are critical bioindicators of ecosystem responses to environmental change, yet their spatial patterns across geographic gradients in alpine grasslands of the Qinghai-Tibetan Plateau (QTP) are not well characterized. We examined the taxonomic composition, diversity, trophic structure, and ecological traits of soil nematodes along longitudinal, latitudinal, and altitudinal gradients on the eastern QTP. From 2019 to 2021, 90 sampling sites were investigated across these gradients. Taxonomic composition varied markedly, and total nematode abundance and all trophic groups showed unimodal longitudinal patterns, decreased with latitude and increased with altitude. Taxonomic richness and Shannon index also exhibited unimodal longitudinal patterns and significant latitudinal decreases, but no clear altitudinal trend. Trophic structure also varied, with bacterivore relative abundance increased longitudinally and latitudinally, whereas predator-omnivore decreased longitudinally. With increasing altitude, the relative abundances of bacterivores and fungivores decreased, while herbivores increased and dominated at 3500 m. Ecological indices displayed contrasting spatial patterns, with cp2 peaking at 101°E and cp3-5 showing opposite longitudinal trends, and their latitudinal patterns converging near 30°N. Mean annual precipitation, temperature, and aboveground biomass were the primary drivers of nematode distributions. These results reveal complex geographical patterns of soil nematode communities in eastern QTP alpine grasslands and indicate 101°E, 30°N and 3500 m as key ecological transition zones. This highlights the joint influence of longitude, latitude, and altitude on nematode community assembly. Environmental tolerance thresholds may further shape these spatial patterns, influencing climate responses and ecosystem functions such as carbon cycling and nutrient mineralization.

Soil ecosystems are shaped by complex interactions between their biological communities, environmental conditions and physicochemical properties. However, higher-trophic soil fauna is often neglected in soil risk assessments. This study utilized environmental DNA (eDNA) barcoding to describe arthropod and nematode communities from 445 agricultural sites in north-east China. We analyzed these community profiles in combination with key soil physicochemical variables to predict agricultural soil quality, degradation and health indices using machine learning models. Arthropod community composition consistently outperformed that of nematodes in predicting individual soil variables (e.g., pH, total carbon, soil organic carbon, total nitrogen), generating stronger correlations. Predictions of soil degradation and health indices also showed higher accuracy when based on arthropod communities. Notably, keystone arthropod taxa (e.g., Diptera, Araneae and Coleoptera) explained over two-thirds of the predictive power achieved by the full community models, indicating their potential to underpin accurate soil quality assessments. Our study demonstrates the potential value of keystone arthropods as bioindicators and provides a foundation for developing biologically-informed soil health frameworks for sustainable land management.

Microbes drive global nitrogen cycling, yet the extent to which taxonomic identity is associated with functional potential across bacterial diversity remains poorly quantified. Using 73472 representative bacterial genomes, we develop a quantitative framework integrating Information Gain analysis, functional classification, and molecular evolutionary analysis across six nitrogen cycling pathways and five taxonomic ranks. Association strength increases monotonically from phylum to genus level across all six pathways, with genus-level associations ranging from 39.5% (ANRA) to 67.5% (DNRA) among pathways with substantial prevalence (NIT excluded due to its extremely low global prevalence of 0.3%, which mathematically amplifies normalized IG values). Hierarchical clustering identifies four class-level functional archetypes—Functionally Inactive, Functionally Moderate, N-Retention Dominant, and Nitrification Specialist—among 77 bacterial classes, largely stable across genome source environments. At genus level, 1281 genera resolve into five ecological strategies spanning from single-direction specialists to genera maintaining both nitrogen retention and loss capacities. Molecular evolutionary analysis of 13 genes reveals that sequence conservation operates partially independently of pathway-level functional associations, generating four systematic decoupling patterns: congruent conservation for NF (nifH), under-conservation for DNRA (nrfA), over-conservation for DNN (napA), and gene-specific heterogeneity within DNF (nirS versus nirK). This framework establishes quantitative baselines that enable probabilistic inference of nitrogen cycling capabilities from taxonomic composition, with applications in amplicon-based community analysis, targeted cultivation, and biogeochemical modeling.