The trade‐offs in plant root traits significantly influence the adaptation and community dynamics in heterogeneous habitats. However, the role of inter‐ and intraspecific root trait variation in the adaptation of pioneer plants in stressed mine tailings is poorly understood. We assessed root morphological and chemical traits of 16 dominant species from unexploited forest sites adjacent to rare earth elements (REEs) mine tailings, and three pioneer species ( Miscanthus sinensis , Dicranopteris linearis and Pinus massoniana ) across a gradient of soil stress—including REEs toxicity, nutrient deficiency and compaction—from forest to REEs tailings. In the two‐dimensional root economics space (RES), the contents of cellulose, hemicellulose and silicon were coaxial with the collaboration gradients (‘do‐it‐yourself’–‘outsourcing’) and inversely related to fine root diameter. Meanwhile, root REEs content aligned with conservation gradients (‘fast’–‘slow’), indicating a slow strategy. Interspecific variations did not show a distinct strategy preference for pioneer species compared with non‐pioneer plants. However, notable intraspecific variations were observed, particularly in stress‐related traits, such as root N content, C:N ratio and REEs content, which exceeded interspecific variations. All three pioneer species exhibited a shift towards ‘slow’ strategies, while P. massoniana also transitioned towards ‘do‐it‐yourself’ strategies, driven by increased soil bulk density, elevated bioavailable REEs content, and reduced soil carbon and nutrient levels in the tailings. Synthesis and applications . Our findings highlight the pivotal role of root chemical traits and intraspecific plasticity in facilitating the adaptation of pioneer plants to extreme REE tailing environments. The observed shifts towards stress‐tolerant ‘slow’ strategies and ‘do‐it‐yourself’ nutrient acquisition provide a trait‐based framework for advancing phytoremediation in the ecological restoration of degraded mine tailings, such as informing plant species selection.

Carbon inputs from crop residues regulate soil organic carbon (SOC) dynamics, but how microbial diversity loss modulates residue-induced priming across residue qualities remains unclear. We utilized a soil dilution approach to manipulate microbial diversity and quantified the cumulative priming effect (CPE) over 90 days following the addition of 13C-labeled high C:N maize and low C:N soybean residues. Reduced diversity significantly decreased CPE with maize (p < 0.05) but increased CPE with soybean (p < 0.05) across decomposition stages. These contrasting responses were linked to shifts in mineral N availability and carbohydrate-active enzyme (CAZyme) genes in the early and later stages. During early decomposition, maize residue intensified N limitation, and diversity loss was associated with reduced N-hydrolase activity, diminishing CPE (from 19.7 to 8.9 mg C g−1 SOC). In contrast, soybean residue sustained mineral N, and lower diversity heightened the ratio of negative to positive links, increasing CPE (from 11.3 to 15.6 mg C g−1 SOC). In the later stage, reduced diversity significantly decreased (p < 0.05) the relative abundance of cellulose- and glucan- (fungal-derived) degrading genes with maize straw, accumulated fungal necromass C, corresponding to lower CPE (from 43.6 to 28.7 mg C g−1 SOC). In contrast, soybean residue significantly increased (p < 0.05) the relative abundance of peptidoglycan-degrading (bacterial-derived) genes, reduced bacterial necromass C, consistent with higher CPE (from 35.2 to 41.2 mg C g−1 SOC). These findings reveal residue-specific mechanisms by which microbial richness and composition regulate CPE through enzymatic and necromass pathways.

In rainfed agroecosystems with limited water resources, ridge-furrow plastic film mulching (RFPM) combined with microbial inoculation has shown great potential for enhancing grain yield and water use efficiency (WUE). However, how RFPM reshapes the soil microenvironment to promote the recruitment of beneficial taxa by microbial inoculants and how these interactions vary across maize developmental stages remain poorly understood. Here, we integrated 16S rRNA gene amplicon sequencing and shotgun metagenomics, and field validation to elucidate the microbial mechanisms underlying improved water and nitrogen use efficiency in maize under two cultivation practices, flat planting (FP) and RFPM, combined with the co-inoculation of Rhizophagus irregularis and Bacillus velezensis (FP-AB and RFPM-AB). Compared with the other three treatments, the RFPM-AB treatment increased soil water content (SWC), bacterial diversity, and the enrichment of Klebsiella and Pseudomonas in both the rhizosphere and endosphere at the silking stage (VT), and enhanced the proportion of macroaggregates (250–1000 μm) at the physiological maturity stage (R6). It also enhanced WUE, nitrogen use efficiency (NUE), and grain yield. Compared with the R6 stage, the VT stage was more responsive, showing lower α-diversity, greater network complexity, broader niche breadth, higher abundances of functional genes associated with nitrogen (N) and phosphorus (P) cycling. At the VT stage, RFPM-AB treatment particularly enhanced the abundances of genes involved in anammox, N fixation and ABC transporter in the rhizosphere. The RFPM-AB treatment enriched the rhizosphere with Klebsiella and Pseudomonas, which are linked to nitrogen fixation (nifH, nifD, nifK), nitrification (amoB), and nitrite reduction (nirB). Strain-level characterization and pot inoculation assays confirmed that Klebsiella sp. YCMR11 and Pseudomonas sp. MR464 possessed diverse plant growth-promoting traits, and field inoculation experiments demonstrated that these strains increased maize grain yield by up to 25.92% relative to uninoculated controls. Collectively, RFPM combined with co-inoculation of R. irregularis and B. velezensis improves soil water content, promotes stage-specific enrichment of rhizosphere taxa and enhances the abundance of genes involved in N cycling, thereby improving maize WUE, NUE, and grain yield under semiarid conditions. This integrated strategy offers a mechanistic foundation for sustainable crop production in water-limited agroecosystems.

Soil organic carbon is well known to shape microbial communities. However, the mechanisms by which carbon source quality filters diazotroph assemblages in agroecosystems remain poorly understood. We incubated two contrasting agricultural soils with ten distinct carbon substrates to investigate whether carbon quality functions as a dominant, trait-based filter for diazotroph assembly. Carbon type accounted for a larger proportion of the variation in diazotroph community structure than either soil type or incubation time. Across both soils, carbon amendments induced convergent shifts in key soil properties, including dissolved organic carbon, pH, inorganic nitrogen and available phosphorus, as well as diazotroph community trajectories. High-quality carbon inputs (glucose, sucrose and citric acid) reduced diazotroph diversity and shifted communities toward r-strategist dominance. In contrast, low-quality substrates (oxalic acid, cellulose, lignin and crop residues) maintained higher diversity and favored K-strategists. Amino acids exerted a unique dual effect, maintaining diversity by simultaneously alleviating both carbon and nitrogen limitations. Azotobacter consistently emerged as the predominant r-strategist taxon, showing strong competitive dominance under labile carbon enrichment. These findings demonstrate that carbon quality functions as a primary trait-based filter, regulating the trade-off between diazotroph growth rate and community diversity. This framework helps predict how diverse organic amendments, from simple sugars to complex residues, restructure diazotroph communities in agricultural soils.

Environmental disturbances often drive the mixing of previously isolated microbial communities, a process termed coalescence, which reshapes community structure and interactions. While coalescence is recognized as a major driver of microbial diversity and ecosystem functioning, the specific metabolic mechanisms that stabilize coexistence remain poorly understood. In this study, we established controlled soil microcosms with single-source (derived from individual sites) and mixed-source inocula (coalesced from multiple sites) and utilized an integrated approach of metagenomics, genome-scale metabolic modeling, and vitamin supplementation to investigate the mechanisms that sustain diversity during coalescence. Coalescence increased α‑diversity but reduced β‑diversity, with most taxa originating from their single-source communities. At the genomic level, coalescence increased both metagenome-assembled genome (MAG) richness and functional trait breadth, with Bacteroidota and Pseudomonadota remaining the dominant lineages across all treatments. Coalesced communities exhibited extensive chimeric associations (newly formed associations), which were accompanied by enhanced metabolic complementarity and more frequent positive interactions among dominant MAGs affiliated with Bacteroidota and Pseudomonadota. We identified thiamine metabolism as a key mechanism stabilizing this co-dominance. Genomically streamlined Pseudomonadota prototrophs harbored the complete thiamine biosynthesis pathway, while most Bacteroidota MAGs (82%) were thiamine auxotrophs, forming the genetic basis for potential thiamine cross-feeding interactions that may alleviate widespread thiamine auxotrophy. The relative abundance of thiamine biosynthesis genes positively correlated with the abundance of cellulose and lignin derivative degradation genes (e.g., biphenyl, phenylacetate, and protocatechuic acid). In parallel, coalesced communities exhibited significantly higher soil respiration rates, indicating enhanced carbon mineralization potential. Exogenous thiamine supplementation further supported this mechanism by increasing community richness across dilution gradients. Together, our results indicate that vitamin-mediated metabolic dependencies support microbial coexistence during microbial community coalescence and are positively associated with enhanced soil carbon mineralization, with implications for understanding soil carbon processing under global change.

Freeze-thaw cycles (FTCs) facilitate the mobilization of colloid-bound cadmium (Cd) in mid- to high-latitude soils, thereby increasing the environmental risks of Cd. However, the contribution of different soil aggregate size fractions to colloidal Cd mobilization remains poorly understood, which hinders the development of targeted remediation strategies. Using asymmetric flow field-flow fractionation and 111Cd isotope tracing, this study demonstrated that 83-89% of colloidal Cd released during FTCs was bound to 100 nm-1 μm organo-clinochlore composite colloids, with 64.1%, 33.2%, and 2.7% of this Cd fraction originating from macroaggregates, microaggregates, and the fine fraction, respectively. Microcomputed tomography showed that macroaggregates contained more abundant and larger pores and pore throats, with pore-throat numbers 6.8 and 41.5 times higher than those in microaggregates and the fine fraction, respectively. Such porous structures enable freezable water inside macroaggregates to freeze readily during FTCs, whereas fine fractions mainly store bound water with depressed freezing points that barely freeze. This stark discrepancy renders macroaggregates susceptible to FTC-induced disruption and further amplifies colloidal Cd release. These findings highlight that limiting colloidal Cd release from macroaggregates is critical for reducing Cd environmental risk and stabilizing Cd in cold-region soils, particularly during the FTC period.

The productivity and sustainability of legume crops are highly dependent on their tripartite symbiotic system with rhizobia and arbuscular mycorrhizal fungi (AMF), a system currently facing significant pressure from long-term excessive nitrogen (N) fertilization. However, how long-term N input and host niche selection jointly regulate the structure and function of this tripartite symbiotic system remains poorly understood. Using a soybean pot experiment with soils collected in 2022 from a 24-year field experiment (winter wheat-summer maize rotation, receiving annual urea at 0, 200, 400, 600 kg N ha-1 year-1 since 1998), we systematically elucidated these mechanisms. The results demonstrate that host niche selection is the dominant driver structuring the core symbiotic network. This manifests as a progressive, stringent homogeneous selection for rhizobia from soil to nodules, and as dispersal limitation for AMF, imposed by strong physical filtration at the root epidermis. Long-term N input nonlinearly disrupted this host-dominated framework. Specifically, excessive N fertilization shifted rhizobial community assembly from deterministic to stochastic dominance, weakened their cross-kingdom synergy with AMF, and triggered a transition in the systemic N-cycling pathway. This transition moved from an efficient, low-loss internal symbiotic N-fixation mode to a high-loss-risk external N metabolism mode. This functional trade-off ultimately compromised the system's nutrient accumulation and retention capacity, offering a mechanistic explanation for how excessive N fertilization drives agroecosystems from symbiosis-dependence to fertilizer-dependence. These findings demonstrate that optimizing N management sustains nutrient retention and productivity by preserving the host-shaped symbiotic network, offering a reference for reducing fertilizer dependence and improving the sustainability of legume production.

Cadmium (Cd) contamination poses a serious problem in wheat fields. Although wheat is predominantly cultivated in neutral-alkaline soils, where Cd bioavailability is conventionally considered low, soil colloids constitute a dynamic Cd reservoir capable of releasing Cd2+ for wheat adsorption. Argosol colloids (North China Plain) caused 1.6-fold higher Cd bioaccumulation in wheat than Aridosol colloids (Loess Plateau), despite having 2.1-fold less colloidal Cd and similar pH (∼9.0). Analysis revealed mineral-organic colloids >50 nm enhance Cd bioavailability via two pathways: disaggregation-released <1 kDa soluble Cd and 1 kDa to 50 nm colloidal Cd. Crucially, pedogenic calcite prevalent in Aridosol colloids suppresses Cd2+ release, explaining their lower bioavailability despite the higher colloidal Cd content. This demonstrates that colloidal Cd significantly contributes to Cd uptake in alkaline wheat soils, and its bioavailability is fundamentally constrained by region-specific, pedogenically derived mineral compositions like calcite.

To evaluate the actual effects of different ecological restoration technologies on high and steep rock slopes in the dry-hot valley area, we compared three typical slope ecological restoration techniques, vegetation concrete (VC), soilless spraying (SPF), and vegetation trough (VS) on the high and steep rock slope of Baihetan Hydropower Station. We conducted a one-year monitoring of soil physical and chemical indicators and vegetation characteristics from January to December 2022, and calculated the ecological restoration index (ERI) using the minimum dataset method, which were used to comprehensively evaluate the ecological restoration effects of each technique. The results showed that: 1) During the maintenance monitoring period, soil physical characteristics (bulk density, porosity, moisture content), soil organic matter, and nutrient (total nitrogen, total phosphorus, available phosphorus) contents of the three remediation techniques showed a fluctuating trend with seasons. Plant characteristics (plant height, plant diameter, vegetation coverage coefficient, aboveground biomass) increased from 3.6-9.3 cm, 0.98-2.16 mm, 0.12-0.61, and 42.80-163.56 g·m-2 to 11.5-14.7 cm, 2.85-4.05 mm, 0.68-0.98, and 368.00-421.12 g·m-2, respectively, while cation exchange capacity increased from 6.13-13.94 cmol·kg-1 to 13.94-20.42 cmol·kg-1. Soil pH decreased from 7.56-8.05 to 7.17-7.51. VC was generally superior to SPF and VS in enhancing soil structure and plant growth. 2) The minimum dataset consisted of plant height, available phosphorus, vegetation coverage, bulk density, and total nitrogen, which were significantly positively correlated with the entire dataset (R2=0.733) and could effectively replace the entire dataset for ecological restoration evaluation. 3) The restoration process of slopes presented a restoration path of "soil matrix construction plant growth and reproduction". The contribution rate of soil ERI of the three restoration techniques in spring was 66.3%-70.5%, that in summer was 43.7%-58.4%, with the contribution rate of vegetation to ERI being 41.6%-56.3%. The contribution rate of vegetation to ERI in autumn and winter exceeded that of soil, ranging from 54.7% to 64.1% and 55.6% to 61.0%, respectively. 4) The annual average ERI values of three typical slope ecological restoration techniques were ranked as VC (0.576)>SPF (0.549)>VS (0.452), and the final values showed the same trend (0.676>0.639>0.538), indicating that VC had the best ecological restoration effect.

This study explores the soil biodiversity and distribution of earthworms in Yunnan Province. Employing a quadrat survey method, the province was divided into six climate types, among which four representative land-use types (arable land, wasteland, grassland, and garden) were selected for sampling of earthworms and soil. In total, 1984 earthworm individuals were gathered from 148 plots, representing 27 species occurrences across four families, with Moniligastridae being dominant. The present study emphasized that different land use modes can affect the distribution of earthworm communities; there are differences in soil physical and chemical properties under different land use types; therefore, various land use modes can further affect the density and biomass of earthworms by influencing soil physical and chemical properties. Soil properties such as SOM, TN, TK, and OP significantly affect earthworm communities. For example, SOM had a significant positive correlation with earthworm density in Wasteland and Arable land and a significant positive correlation with earthworm biomass in Grassland and Garden; in addition, soil temperature and TK content had a significant negative correlation with earthworm density in Garden. This study provides data support for understanding earthworm species diversity and its spatial distribution characteristics in Yunnan Province. It gives a scientific basis for further discussion of the influence of land use on soil fauna conservation and its ecological functions.

Plant and rhizosphere soil samples of the rare earth element (REE) hyperaccumulator plant Dicranopteris linearis were collected across tropical and subtropical China to elucidate how rhizosphere microbiota drive soil REE solubilization and accumulation in this species. The results show that this facultative REE hyperaccumulator species grows under severe phosphorus deficiency conditions, with soil available phosphorus concentrations ∼2 mg kg-1 and a leaf nitrogen-to-phosphorus ratio >20. The core rhizosphere microbiota comprise 111 OTUs (occupancy >95%, relative abundance >0.1%), with community structure primarily correlated with soil phosphorus availability, rather than with geographical location or climatic variables. Foliar phosphorus and REE concentrations are positively associated with soil total phosphorus concentrations and glucose dehydrogenase (GCD) gene abundance─a key biomarker of microbial phosphate solubilization activity─but exhibit no significant association with soil available phosphorus or soil extractable REE concentrations. Combined 16S rRNA sequencing and metagenomic analyses further reveal abundant phosphate-solubilizing microbes within the core microbiome. These results show that REE mineral weathering in the rhizosphere soil and subsequent accumulation in D. linearis are side effects of phosphate solubilization promoted by the rhizosphere microbiome under phosphorus deficiency conditions.

Biochar- and hydrochar-amended organic fertilizers are widely used to enhance saline–alkali soil fertility and crop production. However, their effects on ammonia (NH3) volatilization from saline–alkali soils remain unclear. Here, we conducted a pot experiment to investigate the impacts of organic fertilizer (OF), and of that with biochar (BC-OF) and hydrochar (HC-OF) amendments at a rate of 15% on crop production, on soil fertility and NH3 loss in saline–alkali soil with rice–wheat rotation, using chemical fertilizer alone as the control (CK). Compared with CK, OF, BC-OF, and HC-OF increased the rice and wheat yields. In particular, HC-OF harvested a significant 16.6% more grain yield than OF (p < 0.05). Organic fertilizer amendments exerted a general mitigating effect on the NH3 volatilization during different observations after nitrogen (N) fertilization. Correspondingly, they reduced total NH3 volatilization during the rice season compared to CK. Compared with CK, HC-OF significantly reduced NH3 emissions by 61.6% during the wheat season and 28.3% annually (p < 0.05). Moreover, HC-OF treatment reduced total NH3 volatilization in the wheat season by 55.8% and 64.7% compared to OF and BC-OF, respectively. Compared with CK, HC-OF treatment significantly reduced soil pH, while both the BC-OF and HC-OF treatments increased soil total N and ammonium N contents, even surpassing those in the OF treatment. However, no significant differences were observed among treatments in soil electrical conductivity, nitrate, available phosphorus and potassium, as well as organic matter content. In conclusion, HC-OF is more suitable for enhancing crop yield and reducing soil N loss in saline–alkali soils.

The process of anthropogenic pedogenesis has necessarily become an important aspect of the study of today’s soils. The sustainable reclamation or remediation of soils degraded by industrial or mining activities is currently of great interest worldwide. In this field, the study of thin soil sections can provide relevant answers, particularly to questions concerning the evolution of these soils under the impact of reclamation practices. Here, we describe an experiment to reclaim former rare earth element mining sites in China using organic soil amendments and plantations of a local fiber plant, Boehmeria nivea. Two years after the start of the experiment, a study of soil structure, considered as an indicator of soil biofunctioning, was carried out on the different plots, supplemented by monitoring of physico-chemical properties. Morphological (light microscopy) and analytical (SEM-EDX, µ-XRF) characterization of thin sections allowed us to pinpoint some pedological processes as aggregation with particular reference to the contribution of biological factors and mineral species, highlighting the impact of the practices implemented. Using a soil micromorphology approach enabled us to track the rapid evolution of the early stages of pedogenesis of these Technosols and to provide insight into the potential for reclamation of these mined sites in the future.

Soil acidification poses a significant challenge to soil health worldwide, and biochar emerges as a promising remedy. Nonetheless, a comprehensive evaluation of the impact of biochar on soil pH change is lacking, leaving considerable uncertainty regarding its efficacy across different environmental and management contexts. Here, we conducted a meta-analysis of 232 global studies to elucidate the impact of biochar on soil pH and identify key variables influencing its effectiveness. Our findings revealed that biochar application significantly increased soil pH by an average of 5.59

Understanding priority effects is crucial for predicting and managing microbial community dynamics to maintain ecosystem sustainability. However, the impact of bacterial interactions within microbial communities on the strength of priority effects remains unknown. To address this, we applied a community coalescence approach to soil communities and manipulated the order, ratio, and timing of community arrival. Our results showed that community coalescence reduced alpha diversity compared with the controls. Early-arriving communities tended to lose fewer amplicon sequence variants (ASVs) than late-arriving communities during community coalescence. Priority effects were detected using non-metric multidimensional scaling (NMDS), which also showed that the strength of the priority effects was influenced by both dispersal timing and inoculation ratio. Longer dispersal intervals and higher inoculation ratios enhanced the strength of priority effects, especially when inoculation ratios were unequal. Notably, abundant populations were significantly shaped by the interaction between dispersal timing and inoculation ratio (p = 0.001), with variance explained (R2 = 0.12) nearly two times higher than that of rare populations (R2 = 0.07). Moreover, transitions from abundant to rare taxa also facilitated the emergence of new species within rare populations. Network analysis revealed that abundant populations exhibited more pronounced changes in network complexity and in the ratio of negative to positive edges with dispersal intervals increased. Finally, our study revealed that the relative abundances of core taxa (Cyclo-bacterium, Salinarimonas, and Rhodothermaceae) were significantly positively correlated with both the strength of priority effects (R2 = 0.74, 0.55, and 0.49, respectively) and the ratio of negative to positive edges (R2 = 0.71, 0.47, and 0.18, respectively). These findings highlight the regulatory role of core species within abundant populations in shaping microbial priority effects and provide a conceptual basis for future efforts to manipulate soil microbial assembly processes for ecosystem management.

The impact of varying antibiotic residue levels on antibiotic resistance gene (ARG) removal during composting is still unclear. This study investigated the impact of different residue levels of tilmicosin (TIM), a common veterinary macrolide antibiotic, on ARG removal during pig manure composting. Three groups were used: the CK group (no TIM), the L group (246.49 ± 22.83 mg/kg TIM), and the H group (529.99 ± 16.15 mg/kg TIM). Composting removed most targeted macrolide resistance genes (MRGs) like ereA, ermC, and ermF (>90% removal), and reduced ermB, ermX, ermQ, acrA, acrB, and mefA (30–70% removal). However, ermA increased in abundance. TIM altered compost community structure, driving succession through a deterministic process. At low doses, TIM reduced MRG–bacteria co-occurrence, with horizontal gene transfer via intI1 being the main cause of ermA rebound. In conclusion, composting reduces many MRG levels in pig manure, but the persistence and rebound of genes like ermA reveal the complex interactions between composting conditions and microbial gene transfer.