Search Results (549)

To explore the effects of legume intercropping on soil nitrogen (N) and phosphorus (P) cycling processes in mulberry plantations during the winter fallow period, three treatments were set up: control (no intercropping, CK), single-legume intercropping (T1: Medicago polymorpha), and mixed-legume intercropping (T2: Medicago polymorpha + Astragalus sinicus). The variations in soil available nutrients, enzyme activities, microbial community structure, and functional gene abundances were investigated, with a focus on the influence of spatial heterogeneity (middle of inter-row as position A, and mulberry-adjacent as position B). Compared with CK, both T1 and T2 significantly altered soil microbial community composition and enhanced β-diversity (R² = 0.747, p < 0.001), and these effects were more pronounced at position A. For soil N cycling, T1 and T2 reduced available N content especially at position B; however, T2 significantly increased urease activity, while T1 decreased urease activity at position A. Both treatments elevated the abundances of N-cycling functional genes (e.g., glnA, ureC, nifD) and symbiotic nitrogen-fixing rhizobia, with T1 increasing Bradyrhizobium and T2 increasing Sinorhizobium. For soil P cycling, T1 and T2 enhanced phosphatase activity to promote organic P conversion; T1 strengthened the entire P metabolic chain by upregulating multiple P-related functional genes, while T2 specifically increased the abundance of the organic P transport gene ugpb. Structural equation modeling showed that soil microbial Shannon diversity promoted the relative abundances of N-cycling and P-cycling functional genes, and cascading pathways among nutrient-cycling genes and enzyme activities governed soil available N and P. The distinct effects of T1 and T2 highlight the importance of optimizing intercropping patterns, and spatial heterogeneity should be considered in agronomic effect evaluation. Leguminous green manure intercropping should be encouraged in mulberry plantations to boost soil nutrient-cycling processes driven by microorganisms. Full article

Soil microorganisms are essential for nutrient cycling, plant productivity, and soil health, yet the relative importance of land-use and soil depth in shaping agricultural microbiomes remains poorly understood. This study investigated soil microbial communities across uncultivated land, alfalfa fields, crop systems (feed corn and sweet corn), and orchard systems (walnut and quince) in the Hajdúnánás region of Hungary using shotgun metagenomic sequencing and soil physicochemical analyses. Microbial alpha diversity showed limited variation among land-use systems but declined significantly with soil depth in both bacterial (Kruskal–Wallis, p = 0.00054) and fungal (p = 0.00051) communities. Beta diversity analyses identified soil depth as the primary driver of microbial community composition in both bacterial (R² = 0.305, p = 0.001) and fungal (R² = 0.277, p = 0.001) communities. In contrast, land-use significantly influenced only fungal community composition (R² = 0.250, p = 0.005). Fungal alpha diversity showed significant negative relationships with soil pH and CaCO₃, whereas bacterial diversity exhibited only weak correlations. Crop soils contained the highest numbers of unique bacterial and fungal taxa. Functional analyses revealed significant differences in nutrient cycling, plant-growth-related, decomposition, and environmental adaptation functions among land-use systems. In crop soils, topsoil communities were enriched in oxidative stress-related pathways involved in reactive oxygen species detoxification (ROS), redox homeostasis, and stress regulation, whereas subsoil communities showed a greater representation of antioxidant metabolite production functions. Co-occurrence network analyses indicated greater connectivity in perennial systems, particularly alfalfa soils. Analyses of bacterial and fungal species with reported phytopathogenic potential identified stable cores of phytopathogenic species across agricultural systems, with soil pH emerging as the strongest environmental factor associated with the abundance of phytopathogenic species. Overall, soil depth was the primary driver of bacterial and fungal community assembly, whereas land-use primarily shaped fungal community composition and influenced ecological functions, microbial interaction networks, and the distribution of phytopathogenic species. Full article

Moss-dominated biological soil crusts are associated with carbon and nitrogen cycling in dryland and alpine sandy ecosystems, but functional differentiation among closely related moss species and their mixed assemblages remains unclear. We used shotgun metagenomic sequencing to compare below-crust soil associated with Didymodon constrictus (Mitt.) K. Saito (D. constrictus) crusts (mossC), ferrugineus (Schimp. ex Besch.) M.O. Hill (D. ferrugineus) crusts (mossF), and visually co-dominated mixed crusts (mossM) in the Gonghe Basin on the northeastern Qinghai–Tibet Plateau. Fifteen spatially separated quadrats per category were pooled into three composite biological replicates (effective n = 3). KEGG, CAZy, and targeted carbon- and nitrogen-cycling annotations showed category-associated differences in relative gene representation. MossC had greater mean representation of glycoside hydrolases and several complex-carbon-processing functions, mossF had greater representation of nitrogen-assimilation and acetate-related functions, and mossM had greater representation of selected carbon-degradation, nitrogen-mineralization, and dissimilatory-nitrate-reduction functions. The full RDA model explained 58.4% of functional variation (adjusted R² = 0.334; exact permutation p = 0.028340), with single-variable associations retained for total carbon and soil water content. Genus-level taxonomic dissimilarity correlated with KEGG, CAZy, carbon-cycling, and nitrogen-cycling dissimilarities after FDR correction. MossM showed both positive and negative descriptive deviations from the approximate unweighted midpoint of mossC and mossF, but no inferential test was applied to these deviations. The small number of composite replicates, visually estimated moss proportions, edaphic confounding, and absence of activity measurements limit causal and confirmatory interpretation. Full article

Heavy metal/loid (HM) pollution of soils, primarily as a consequence of mining and ore-processing activities, poses significant risks to ecosystems and human health. Soil microbial communities play essential roles in maintaining key ecosystem functions, including nutrient cycling, carbon sequestration, and soil stability. The purpose of this study was to characterize the taxonomic composition and diversity of bacterial communities and evaluate their functional adaptation to heavy metal stress in soils affected by long-term gold–copper mining activities in Bulgaria. Ten soil samples representing a Cu pollution gradient (53–860 mg kg⁻¹) were categorized into five pollution classes. High-throughput sequencing of 16S rRNA gene amplicons revealed the dominance of the phyla Pseudomonadota (mean relative abundance 32%), Acidobacteriota (22%), and Actinomycetota (16%). At the class level, Alphaproteobacteria (18%), Terriglobia (16%), and Gammaproteobacteria (14%) were the most abundant taxa, indicating their adaptation to long-term heavy metal contamination. The genus Z2-YC6860 exhibited significant tolerance to Cu, whereas Bradyrhizobium_503372 was negatively associated with As and Zn concentrations. Functional predictions suggested enrichment of key pathways related to heavy metal resistance, including efflux systems and detoxification. The study design spans a broad Cu pollution gradient across river-associated and industrially impacted sites, providing an ecologically relevant framework for evaluating microbial responses to long-term metal stress. Full article

Rhizosphere microorganisms play critical roles in biogeochemical processes including carbon cycling; however, their linkages to carbon-cycling functions under distinct mine restoration approaches remain unclear. In this study, we compared natural and artificial vegetation restoration via metagenomic sequencing to characterize rhizosphere microbial communities and carbon-cycling functional genes. Artificial restoration (AR) decreased soil electrical conductivity (EC) and salt content (SC) while increasing total phosphorus and available phosphorus by 12.33% and 16.44%, respectively. AR also elevated the relative abundances of genes responsible for degrading aromatic compounds, lignin and starch, along with genes participating in carbon-fixation pathways. Taxa of the Actinomycetia, Chloroflexi, and Solirubrobacterales served as the primary contributors to genes encoding 2-isopropylmalate synthase, α-glucosidase, malate synthase, and α-mannosidase, as well as carbon-fixation-related genes, including aconitate hydratase (ACO), methylmalonyl-CoA mutase subunit (E5.4.99.2A), pyruvate orthophosphate dikinase (ppdK), and phosphoenolpyruvate carboxylase (ppc). Moreover, the relative abundances of carbon-fixation genes exhibited significant positive correlations with EC, SC, nitrate nitrogen (NO₃⁻-N) and ammonium nitrogen (NH₄⁺-N). Overall, microorganisms in AR soils hold relatively high genetic potential for carbon sequestration and decomposition. Such rhizosphere carbon-cycling functions are jointly shaped by restoration strategies and vegetation community composition, and our findings offer key theoretical support for mine ecological restoration. Full article

Cool-climate maize fields are characterized by low soil temperatures, strong seasonal hydrothermal fluctuations, and peat-influenced soil profiles, which may lead to patterns of nitrogen (N) cycling distinct from those in conventional agricultural soils. During maize growth, soils from three depths were characterized using physicochemical measurements, N-transformation and enzyme-activity assays, metagenomic sequencing, Mantel tests, variation partitioning analysis, and partial least squares path modeling (PLS-PM). Soil environmental factors varied significantly over time and with depth; soil organic matter (SOM) and total nitrogen (TN) increased with depth, while ammonium nitrogen (NH₄⁺-N) predominated early and nitrate nitrogen (NO₃⁻-N) predominated during the middle and late growth stages. The nitrogen fixation rate (NFR), nitrification rate (NitR), and denitrification rate (DNR) all peaked in August and showed a spatial pattern characterized by nitrogen fixation in the deepest layer and denitrification in the upper and middle layers. Bacterial communities varied less spatiotemporally than fungal communities. The genes nifK, hao, nirS/nirK, NR, nrfC, and hzsA/hzsC were identified as key nitrogen-cycling functional genes. Mantel tests and PLS-PM further characterized these relationships, with PLS-PM showing that soil physicochemical properties were positively associated with bacterial community composition (β = 0.87, p < 0.01), which, in turn, was negatively associated with N-cycling functional genes (β = −0.97, p < 0.001). Together, these pathways were associated with variation in N-cycling processes. Overall, this study advances an integrated understanding of N-cycling patterns and their potential controls in cool-climate maize fields and provides a scientific basis for optimizing N management strategies. Full article

Iron oxides are crucial to soil organic carbon (SOC) sequestration in wetland ecosystems. Whether vegetation drives soil microorganisms to regulate iron–carbon interactions and influence SOC sequestration capacity remains controversial. Thus, this study investigated iron–carbon coupling processes and their microbial drivers in the Caohai alpine freshwater closed wetland, Guizhou Province, China. Using metagenomic sequencing and physicochemical analyses, we compared vegetated areas (Phragmites australis and Scirpus tabernaemontani) with bare flats (BF). Levels of SOC, microbial necromass carbon (MNC), and plant-derived carbon (PC) in vegetated soils were significantly higher than those in BF (p < 0.05). In all study regions, the PC/SOC ratio (PA: 27.89 ± 3.59 %; ST: 24.58 ±1.86 %; BF: 24 ±2.82 %) exceeded the MNC/SOC ratio (PA: 15.58 ± 0.94 %; ST: 15.95 ± 0.73 %; BF: 13.06 ±1.30 %). The PC/SOC and MNC/SOC ratios were higher in vegetated areas than in BF areas. Compared with BF, vegetation enhanced wetland SOC stability and promoted carbon sequestration. Iron-bound organic carbon $\left({\mathrm{Fe}}_{\mathrm{d}}–\mathrm{OC}\right)$ content was substantially greater in vegetated soils (PA:0.34 ± 0.08 g/kg; ST:1.07 ± 0.58 g/kg) than in BF (0.14 ± 0.08 g/kg) (p < 0.05). Based on the ${\mathrm{Fe}}_{\mathrm{d}}–\mathrm{OC}$/${\mathrm{Fe}}_{\mathrm{d}}$ ratio (PA: 22.87 ± 14.00 %; ST: 23.00 ± 13.90%; BF: 5.36 ± 3.40 %), ${\mathrm{Fe}}_{\mathrm{d}}–\mathrm{OC}$ associations in vegetated soils were dominated by stable coprecipitation, whereas unstable adsorption prevailed in BF. In all study regions, the abundances of iron-reducing bacteria (FeRB) and iron-oxidizing bacteria (FeOB) peaked in BF. Several FeRB genera, including Thiobacillus, Intrasporangium, Gallionella, and Nocardioides, were significantly and positively correlated with ${\mathrm{Fe}}_{\mathrm{d}}$ (p < 0.05). Conversely, Geobacter and Nitrospira exhibited significant negative correlations with ${\mathrm{Fe}}_{\mathrm{d}}–\mathrm{OC}$ and PC (p < 0.05). The FeOB genera—Thioalkalivibrio, Thiohalobacter, and Pseudomonas—were negatively correlated with ${\mathrm{Fe}}_{\mathrm{d}}$. Vegetation presence appears to influence microbial metabolic potentials through the provision of rhizodeposits and the modulation of rhizosphere conditions, thereby affecting ${\mathrm{Fe}}_{\mathrm{d}}–\mathrm{OC}$ associations and contributing to SOC sequestration in wetland soils to some extent. These findings provide critical insights into plant–microbe–mineral interactions and a scientific framework for predicting carbon sink dynamics in wetland ecosystems. Full article

Continuous monoculture in poplar plantations often leads to declining soil nutrient availability and productivity. Phosphorus (P), in particular, frequently becomes a key limiting factor due to its high fixability and low chemical availability in the soil. Understory vegetation, however, may promote soil P cycling and enhance P availability by regulating the community structure and decomposition activity of soil microorganisms. In this study, a seven-year field experiment was conducted in degraded poplar plantations using a randomized complete block design to investigate the effects of four understory vegetation treatments—understory removal (UR), planting of a nitrogen-fixing species Sesbania cannabina in understory (PN), retention of a single dominant understory species Echinochloa crus-galli (RS), and retention of diverse understory vegetation (RD)—on soil P fractions and availability, and to elucidate the microbial mechanisms driving P cycling using a metagenomic approach. The results showed that, compared with UR, all understory retention treatments significantly increased soil labile P fractions, improved microbial community structure, and enhanced the abundance of P cycling-related functional genes and associated enzyme activities. Specifically, PN enriched the bacterial phylum Chloroflexi, thereby strengthening its role in P cycling, and increased the abundance of key functional genes such as ppa and phnH. These changes led to higher activities of acid phosphatase, phosphodiesterase, and phytase, ultimately improving soil P availability. In contrast, through the input of litter with greater diversity and higher biomass, RD enriched microbial communities dominated by Proteobacteria. This treatment increased the abundance of P cycling-related genes (e.g., phnW, purK, phnP, ugpQ) and associated enzyme activities, thereby enhancing soil P mobilization. Both the introduction of nitrogen-fixing species and the increase in understory species richness promoted soil P cycling and enhanced P availability, albeit through distinct mechanisms. Planting of nitrogen-fixing species enriched specific microbial taxa and functional genes, whereas increasing understory species richness boosts P cycling by increasing bacterial species richness and functional gene abundance. Both enhancing species richness and planting nitrogen-fixing species in the understory effectively improved soil P availability and supported the sustainable management of degraded poplar plantations. Among these approaches, retaining diverse understory vegetation is more cost-effective and contributes to biodiversity conservation, making it a recommended management strategy. Full article

Brassicaceae-based bio-disinfestation is a promising non-chemical option to manage lettuce Fusarium wilt caused by Fusarium oxysporum f. sp. lactucae (FOLac), but evidence integrating pathogen suppression, residue chemistry, and soil microbiome response remains limited. We conducted a greenhouse mesocosm assay with naturally infested soil to compare biofumigation (uncovered soil) and biosolarization (plastic-covered soil for 40 days) using five Brassicaceae residues (Brassica carinata, B. juncea, B. napus, Sinapis alba and Raphanus sativus) applied at two field-equivalent doses. Biosolarization created a distinct disinfestation environment, increasing soil temperature by an average of 2.74 °C and shifting oxidation–reduction potential toward reducing conditions. This strategy consistently reduced culturable Fusarium populations, F. oxysporum-assigned colony-forming units (CFU) and lettuce wilt severity compared with uncovered biofumigation. The strongest disease suppression was observed under plastic-covered conditions, including the soil-only control, indicating that the covered microenvironment was a major driver of suppressiveness, while Brassicaceae residues modulated the magnitude and consistency of the response. Glucosinolate profiling revealed contrasting residue chemistries among species, providing a biochemical context for interpreting species-dependent effects. Shotgun metagenomics further showed that biosolarization and biofumigation produced distinct genus-level microbial community structures, with significant effects of strategy, timepoint and their interaction, and higher Shannon diversity under biosolarization. Overall, the integration of disease severity, culture-based inoculum quantification, physicochemical indicators, residue chemistry and metagenomics supports Brassicaceae-based biosolarization as a promising pre-plant approach for suppressing FOLac wilt in naturally infested soils, with the plastic-covered disinfestation environment emerging as the main driver of suppression and Brassicaceae residues modulating the response. Full article

Soybean root rot caused by Fusarium oxysporum is an important soil-borne disease that affects soybean growth and disrupts rhizosphere microbial communities. However, how rhizosphere microbiomes respond to different levels of disease severity remains poorly understood. In this study, a five-level root rot severity gradient (F0–F4) was established using a carrier-matched inoculation design, and changes in soybean growth, rhizosphere soil properties, enzyme activities, microbial community composition, and functional potential were investigated using shotgun metagenomic sequencing. Increasing disease severity reduced soybean growth, with leaf area decreasing from 312.98 cm² in F0 to 32.45 cm² in F4. Root rot progression altered rhizosphere microbial communities, with fungal communities showing stronger responses than bacterial communities. The bacterial Chao1 richness index increased by 34.6% in F4 compared with F0, whereas fungal Shannon diversity decreased by 46.7%. Taxonomic analysis revealed clear shifts in microbial community composition, with Fusarium becoming strongly enriched under diseased conditions, increasing from 16.9% in F0 to maximum relative abundance of 68.8% in F2 and remaining highly abundant at 61.5% in F4, while Trichoderma decreased from 7.3% to 2.2% and Rhizophagus declined from 38.1% to nearly undetectable levels. Metagenomic functional profiling revealed disease-associated changes in microbial functional potential, particularly in pathways related to metabolism, membrane transport, signal transduction, and secondary metabolite biosynthesis. In addition, soil physicochemical properties and enzyme activities varied across the disease severity gradient, indicating changes in the rhizosphere environment during disease development. Overall, soybean root rot progression was associated with coordinated changes in plant performance, soil biochemical characteristics, microbial community structure, and functional potential, with fungal communities exhibiting stronger responses to disease-associated disturbance than bacterial communities. Full article

Soil microbiomes are essential for nutrient cycling, plant health, stress resilience, and sustainable agriculture. Recent advances in high-throughput sequencing, multi-omics technologies, systems biology, and artificial intelligence (AI) have transformed our understanding of plant–microbiome interactions and enabled the development of innovative microbiome engineering strategies. This review provides a comprehensive overview of the mechanisms governing plant-associated soil microbiome assembly, microbial community functions, plant–microbe communication, and microbiome-mediated stress resistance in agricultural ecosystems. Current approaches to plant-associated soil microbiome manipulation and engineering, including microbial inoculants, synthetic microbial communities (SynComs), microbiome transplantation, rhizosphere steering, and synthetic biology-based interventions, are critically examined. The review further discusses the growing role of metagenomics, metabolomics, metatranscriptomics, machine learning (ML), and precision agriculture technologies in improving microbiome characterization, prediction, and management. Particular attention is given to the application of microbiome-based solutions for sustainable crop production, nutrient management, biological control, climate-smart agriculture, and ecosystem restoration. Despite significant progress, challenges related to field-scale variability, colonization stability, biosafety, regulatory frameworks, and data integration continue to limit large-scale implementation. Future advances in precision microbiome engineering are expected to combine ecological principles, multi-omics technologies, AI, and synthetic biology to develop predictive and resilient microbiome-based solutions for sustainable and climate-resilient agriculture. Full article

Hypersaline soils are poly-extreme terrestrial habitats characterized by high salinity, in some cases heavy-metal contamination, temperature fluctuations, and nutrient limitation. These conditions impose strong selective pressures, and many prokaryotic inhabitants still remain uncultured. Here, we conducted an extensive culturomics study of 549 isolates from the hypersaline soils of the Odiel Saltmarshes Natural Area (Southwest Spain) and compared the results with previously generated shotgun metagenomic datasets from the same environment in order to evaluate taxonomic composition, functional potential, and ecological representativeness. Cultivation across media containing 7.5%, 15%, and 25% (w/v) total salts yielded microorganisms belonging to three major phyla: Pseudomonadota, Bacillota (Bacteria) and Halobacteriota (Archaea). At the genus level, bacterial isolates were dominated by Marinobacter, Halomonas, and Aquibacillus at 7.5% (w/v) salinity, whereas extremely halophilic archaea, including Halorubrum, Halogeometricum, and Haloarcula, were predominantly recovered from media containing 25% (w/v) salts. Among the isolates, 57 strains displayed identity values < 98.65% for 16S rRNA gene sequence comparison, suggesting their putative status as new taxa. Comparison with metagenomic datasets showed that culture-dependent approaches successfully recovered the dominant haloarchaeal groups but missed some abundant bacterial phyla, such as Gemmatimonadota. Conversely, culturomics enabled the isolation of unknown species from the rare biosphere, including representatives of the novel genus Terrihalobacillus, which are typically detected at low abundance in metagenomic datasets. Together, these results demonstrate the complementarity of culturomics and metagenomics and provide an insight into the microbial communities inhabiting the hypersaline soils of the Odiel Saltmarshes. Full article

To explore the effects of different fertilization regimes on physicochemical properties and microbial ecology of greenhouse soil, we set five treatments with original soil (BS) as the control: chemical fertilizer alone (GF), high/low-rate mushroom residue combined with chemical fertilizer (MH, ML), and high/low-rate organic fertilizer combined with chemical fertilizer (OH, OL). Metagenomic sequencing and bioinformatic analyses were adopted to characterize soil nutrients, microbial communities, and C-N-P-S metabolic functions. All treatments increased soil nutrients. MH had the highest organic matter, total nitrogen, nitrate nitrogen, and available phosphorus, while GF contained the most available potassium and ammonium nitrogen. Bacteria dominated the soil microbiota, with Pseudomonadota and Pseudomonas as keystone taxa. Mushroom residue amendments improved microbial richness and diversity. By improving soil physicochemical properties, the combined application of organic fertilizer with chemical fertilizer and mushroom residue with chemical fertilizer both enriched some beneficial microorganisms. Chemical fertilizer alone enhanced anaerobic metabolism, which was reversed by high-rate mushroom residue. Available phosphorus, available potassium, and ammonium nitrogen were key environmental factors driving the differentiation of microbial communities and their functions. Overall, mushroom residue combined with chemical fertilizer is effective for greenhouse soil improvement, with proper dosage and tillage recommended. Full article

Soil mulching influences soil organic carbon (SOC) dynamics and microbial communities, yet the functional potential linking these factors remains unclear. This two-year field study compared biodegradable liquid film (BLF, C:N = 26:1, 161 kg C·ha⁻¹) and grapevine branch mulch (GBM, C:N = 51:1, 2790 kg C·ha⁻¹) applied in-row in a vineyard, with clean tillage as control. The Vitis vinifera cv. Meili was used as the test material, SOC fractions were determined and metagenomic sequencing was performed. The results showed that GBM had the highest SOC content and significantly increased the levels of total organic carbon, all five labile fractions, and the three recalcitrant fractions. BLF significantly increased the levels of recalcitrant fractions, while its effect on labile fractions varied by year. Metagenomic analysis revealed that the two mulching treatments significantly influenced the abundances of Acidobacteria, Verrucomicrobia, and Bacteroidetes. Redundancy analysis identified soil moisture, pH, SOC, and total nitrogen as key drivers of community structure. Mulching downregulated carbon fixation and methane metabolism genes but upregulated carbohydrate metabolism pathways, including O-glycan biosynthesis, which correlated positively with SOC. Glycosyl transferases were the dominant carbohydrate-active enzymes across all treatments. These results demonstrate that GBM and BLF differentially affect SOC fractions and microbial functional traits, providing empirical evidence for mulch selection in vineyard carbon management. Full article

Despite extensive research on biochar’s effects on soil properties, the molecular mechanisms linking carbon-cycling functional genes to soil organic carbon dynamics under biochar application remain poorly understood. This study evaluated the effects of corn stalk biochar applied at different rates (0, 300, 600, and 900 kg/hm²) on soil physicochemical properties, microbial community structure, carbon cycling genes, and soybean (HeiNong551) growth in Northeast China’s black soil region. Metagenomic analysis and metabolic pathway analysis were also conducted. Biochar application significantly improved soil fertility by increasing pH, moisture content, and various SOC fractions, while modulating the activities of key soil enzymes, including β-glucosidase, alkaline phosphatase, cellulase, and polyphenol oxidase. Metagenomic analysis revealed that biochar substantially enhanced soil microbial richness and diversity, with significant enrichment of beneficial bacterial genera, including Nocardioides and Sphingomicrobium. Functional gene analysis demonstrated that biochar promoted soil carbon cycling by increasing the abundance of Glycosyltransferases, Glycoside Hydrolases, and Auxiliary Activities, while decreasing the abundance of Carbohydrate-Binding Modules, Carbohydrate Esterases, and Polysaccharide Lyases. Analysis of 22 key carbon cycling pathway genes indicated that biochar enhanced carbon fixation via the reductive tricarboxylic acid cycle (korA gene) and promoted the degradation of easily mineralizable SOC components, while suppressing stable carbon degradation pathways. Full article