Soil aggregates are essential to the long-term sequestration of soil organic carbon (SOC) in coastal wetlands. Coastal wetlands in China have undergone profound transformation by the invasion of Spartina alterniflora and subsequent aquaculture reclamation, but the effects on soil aggregates remain unclear. This study examined the distribution of soil aggregate size, stability and organic carbon content across 21 coastal wetlands in China that had undergone a similar transformation, from native mudflats (MFs) to S. alterniflora marshes (SAs), and subsequent conversion to aquaculture ponds (APs). The results showed that silt+clay was the dominant fraction of soil aggregates (78.7%–83.1%), followed by micro-aggregates (12.8%–13.9%) and macroaggregates (4.1%–6.6%). Transition from MFs to SAs led to an increase in macroaggregate and microaggregate contents and the aggregate stability index (MWD, MGD and DR_0.25), but a reduction in silt+clay content. Subsequent conversion of SAs to APs led to a reduction in macroaggregate content and aggregate stability index, and an increase in silt+clay and microaggregate contents. Change from MFs to SAs increased SOC by 69.6% in the silt+clay fraction, 29.4% in the microaggregate fraction, and 22.4% in the macroaggregate fraction. Conversely, converting SAs to APs decreased SOC content by 11.4% in the silt+clay fraction and 16.3% in the macroaggregate fractions, but an 8.5% increase in the microaggregate fraction. The results underscore the crucial role of soil aggregate formation in sequestration and storage of SOC under varying land cover change scenarios.

Partitioning of soil organic matter for particulate organic carbon (POC) and mineral-associated organic carbon (MAOC) is essential to understand carbon (C) storage under climate change, given their distinct properties and response to warming. The mechanisms underlying warming-induced changes in C pools in black soils (Mollisols) remain unknown, owing to the stability of C pools and the complexity of their associated microbial communities. This study elucidates POC and MAOC contents and their microbial controls in black soils along a mean annual temperature (MAT) gradient from 0.6 to 7.3 °C. The POC content (3.3–17 g kg⁻¹) increased with MAT, while MAOC content (33–60 g kg⁻¹) decreased, indicating accelerated C turnover with warming. Higher MAT shifted the bacterial communities from K- to r-strategies, aligning with increased POC content. The dominance of r-strategists facilitated rapid utilization and mineralization of organic compounds (e.g., mainly with low C/N ratio), reducing MAOC and increasing POC through sustained plant residue inputs. This shift towards r-strategists also corresponded with increased abundance of saprotrophic fungi and stronger bacteria–saprotrophic fungi associations. Warming in colder regions may release available organic matter that saprotrophic fungi preferentially utilize over plant residues to minimize energy expenditure, decreasing POC decomposition. Our findings suggest that integrating microbial r-/K-strategies help to elucidate these mechanisms and simplify the interpretation of temperature effects on the dynamics of two main functional pools of soil organic matter.

The functional traits of soil fauna are closely related to ecosystem functions. The gut microbiota, which can reflect environmental changes, may be associated with functional traits. Therefore, in this study, collembolan (Entomobrya proxima) was used to clarify the linkage response of specific gut taxa and traits under long-term urea exposure. A small amount of urea had positive effects on functional traits of E. proxima. Chao1 and Shannon indices of gut bacteria conditionally rare or abundant taxa (CRAT) gradually decreased under low and medium fertilizer, while increased under high fertilizer. Shannon index of abundant taxa (AT) showed a similar trend to that of CRAT except that the value of Shannon index was higher at high fertilizer than that of medium treatments. The structure and community assembly of CRAT changed significantly, and with the increase of urea addition amount, the dominant mechanism of community assembly changed from a deterministic process to a stochastic process. The niche width of AT and CRAT decreased. Relative abundance of some genera in AT and CRAT was closely related to functional traits. In conclusion, CRAT was more sensitive to urea than AT, had the potential to characterize functional traits of E. proxima, which will provide a basis for predicting the changes of soil animal traits and functions under the change of agricultural fertilizer strategy in the future.

Soil microbial alpha diversity is essential for driving ecosystem functions and processes. However, little is known about the beta-diversity affect community functions. Here, we combine distinct community inocula using the dilution-to-extinction approach with two wheat genotypes to study the effect of microbial diversity loss on rhizosphere community assembly processes, which are related to beta-diversity (between-habitat diversity), and the consequences for ecosystem functions within greenhouse experiment. Compared with alpha-diversity, the bacterial and fungal community beta-diversity are stronger predictors of ecosystem functions (organic matter degradation, phosphorus supply capacity and nitrogen supply capacity), plant genotypes regulated the relationship between microbial diversity and ecosystem functions, with ecosystem functions being significant link to microbial diversity under different wheat genotypes. Loss of microbial diversity decreased the abundance of Bacterial_ASV6 (Burkholderia) and increased Fungal_11 (Altemaria) within the restored rhizosphere soil. Null modeling analysis showed that the deterministic assembly processes are dominant in bacterial community and fungal high-diversity (alpha-diversity) community, associating with the change of specialized functions (organic matter degradation, phosphorus supply capacity and nitrogen supply capacity) that are correlated with microbial diversity and specific microbial taxa. In addition, these two species were key role for regulating to the network cohesion. Overall, our study pointed out that the regulation of community assembly by microbial diversity loss limits the development of soil ecological functions and weakens the stability of rhizosphere microbial network, highlighting the potential regulatory effect of microbial taxa distribution on microbial community stability and changes of specific ecological functions.

Hurricanes cause significant damage to tropical forests; however, little is known of their effects on decomposition and decomposer communities. This study demonstrated that canopy debris deposited during Hurricane Otto stimulated sequential changes in soil carbon (C) and nitrogen (N) components, and decomposer microbial communities over 5 years. The initial response phase occurred within 2 years post-hurricane and appeared associated with decomposition of the labile canopy debris, suggested by: increased DNA sequences (MPS) of the Acidobacterial community (as common decomposers of labile plant material), decreases in total organic C (TOC), increased biomass C, respiration, and {\text{NH}}_{\text{4}}^{+}, conversion of organic C in biomass, and decreased MPS of complex organic C decomposing (CCDec) Fungal community. After 3 years post-hurricane, the later response phase appeared associated with decomposition of the more stable components of the canopy debris, suggested by: increased MPS of the Fungal CCDec community, TOC, stabilized Respiration, decreased Biomass C, the return to pre-hurricane levels of the conversion of organic C to biomass, and decreased MPS of Acidobacterial community. These changes in the microbial community compositions resulted in progressive decomposition of the hurricane-deposited canopy material within 5 years, resulting several potential indicators of different stages of decomposition and soil recovery post-disturbance.

A comprehensive understanding of microbial biogeography is essential to elucidate the mechanisms that regulate microbial diversity and facilitate ecosystem functioning. Here, we present a standardised approach for microbial biogeography research, using the ‘6W principles’ of ‘Who’, ‘What’, ‘Where’, ‘When’, ‘Why’, and ‘How’, to provide a paradigmatic framework for its study. The ‘6W principle’ we developed aimed to address the six fundamental questions in microbial biogeographical researches, including the taxonomic and functional identity, abundance and diversity, distribution patterns, movement or evolutionary trajectory, driving factors, and future changes of microbial communities. Some key corresponding actions were suggested to promote the microbial biogeographical research such as constructing high-resolution taxonomic and functional annotation databases, developing absolute-quantitative high-throughput sequencing, increasing sampling coverage, establishing multidimensional time-series monitoring, developing unified theoretical frameworks and advanced biogeographical modelling approaches, and establishing long-term global networking experiments. We call on the community to jointly enrich the connotation and coverage of the 6W principle, in order to promote the further development and exploitation of microbial biogeography in the context of ongoing global change.

The metabolic complexity of microorganisms can be simplified by classifying them into r-strategists and K-strategists. However, their associations with plant growth during drought remain largely unclear. Herein, we used the ribosomal RNA gene operon (rrn) copy number to characterize bacterial life-history strategies, with increased rrn copy numbers suggesting a shift from K- to r-strategies. We generated a series of bacterial communities with increased rrn copy numbers in rhizosphere. Drought decreased rhizosphere bacterial rrn copy numbers, rather than in root, indicating a prevalence of K-strategies during drought stress in rhizosphere. The rrn copy numbers of rhizosphere communities were negatively related to wheat growth during drought, while no significant associations were observed in control treatment. Rhizosphere bacterial communities with higher rrn copy numbers exhibited less community dissimilarity and tended to be more stable. Moreover, the abundance of most predicted functions decreased with rrn copy numbers in drought-stressed rhizosphere. Co-occurrence network analysis indicated that increased rrn copy numbers in rhizosphere community improved the proportion of negative to positive cohesion, implying more stable networks. Our findings bring up innovative knowledge about the relationships between microbial life-history strategies, communities and plant growth, and highlights the importance of plant-microorganism interactions for plant growth during stress.

In the Argentine Puna, a particular type of wetlands called vegas are considered unique, as they are the main biodiversity hotspots in this arid high-elevation environment. Also, they provide essential ecosystem services. Despite their ecological significance, these ecosystems remain poorly studied. Particularly soil mesofauna, which play critical roles in nutrient cycling and organic matter dynamics, remain to be explored. We investigated the composition, abundance, and richness of taxa and feeding guilds of soil mesofauna communities across 10 vegas. These wetlands were distributed along an environmental gradient, in an elevation range of 3323–4748 m a.s.l., where we analysed soil properties and plant communities. We collected a total of 5239 invertebrates, from which Acari was the most abundant group, followed by Collembola. Regarding feeding guilds, detritivores and predators dominated soil mesofauna communities. Variability in taxa abundance and richness was strongly influenced by local soil properties, such as organic matter, carbon-to-nitrogen ratio, and phosphorus content, as well as plant community attributes, particularly cushion plant cover. However, no soil or vegetation variables explained the differences in taxa identity across vegas. These findings highlight the critical role of local heterogeneity in shaping soil mesofauna communities and provide the first insights into these understudied ecosystems.

Soil microbiomes play a crucial role in ecosystem functioning, yet knowledge about region-specific bacterial taxa across diverse soil types, particularly at a continental scale, remains uncertain. This study employs 16S rRNA sequencing to analyze 141 soil samples collected along a 1400 km transect in New South Wales, Australia, revealing distinct bacterial communities adapted to the varying climatic and soil conditions from east to west. The transect is characterised by three unique pedo-climatic zones: >900 mm mean annual precipitation in the eastern region, 900300 mm in the central region, and <300 mm in the western region. These variations in climate and soil properties, particularly soil pH, organic carbon, and precipitation, significantly influence bacterial diversity and composition. We identified regionally enriched taxa, including Verrucomicrobia in the eastern, Chloroflexi in the central, and Gemmatimonadetes in the western, demonstrating the adaptation of microbial communities to local environmental conditions. Additionally, our findings show that increasing land use intensity, particularly in agricultural areas, correlates with higher Actinobacteria abundance and leads to more homogenised and interconnected microbial networks. This study provides new insights into the biogeography of soil bacteria in Australia, highlighting the importance of local environmental factors in shaping microbial community structure and offering valuable information for ecological and agricultural management strategies.

Common bean root rot becomes serious in continuous cropping fields with over-application of chemical fertilizer. Through the standard field fertilization, the disease might be alleviated. This study aimed to investigate the impacts of standard field fertilization practices on bean root rot severity and rhizosphere microbial community shifts under continuous cropping. From 2018 to 2021, beans were monocultured for eight cycles in field soil in the greenhouse at an average interval of 4 months. Root rot severity was assessed at each cycle, and rhizosphere microbial communities were analyzed at 1^st, 5^th, and 7^th cycles using high-throughput sequencing approach. Bean root rot severity was found to keep increasing until the 5^th cycle and decreased sharply at the 7^th cycle. Corresponding to the disease aggravation and suppression, Fusarium exhibited the highest abundance at the 1^st cycle, followed by Plectosphaerella at the 5^th cycle, and Dactylonectria at the 7^th cycle. Pseudomonas showed the highest abundance in the rhizosphere soils at the 1^st and 7^th cropping cycles. Correlation analysis indicated that the soil microbes were closely related to disease severity as well as soil nitrogen and phosphorus contents. These findings suggest that continuous cropping of bean with standard field fertilization practices could create suppressive soil with reduced disease severity. This study revealed the microecological immune mechanism of continuous cropping of bean against root rot and provided cost-effective and highly efficient techniques for sustainable farming.

The increasing global demand for timber and forest products has triggered the widespread conversion of subtropical forests into secondary forests and plantations. Soil fauna, the active angel in material cycling, are sensitive to changes in food resources and soil environments. However, the impact of forest conversion on soil fauna abundance and diversity remains insufficiently understood. To address this, we conducted seasonal soil fauna sampling in a subtropical region of China during July and November 2022, as well as January and March 2023. The sampling covered secondary forests, Castanopsis carlesii (broadleaved) plantations, and Cunninghamia lanceolata (fir) plantations, with natural forests serving as the control. We assessed soil fauna diversity including taxonomic and functional composition, along with soil physicochemical properties. Overall, forest conversion led to a decline in soil fauna abundance and biodiversity, with litter quality and soil moisture emerging as primary drivers according to Post hoc Least Significant Difference tests. Macrofauna demonstrated higher sensitivity to forest conversion than meso- and microfauna, with their abundance decreasing by 10% in secondary forests, 18% in broadleaved plantations, and 27% in fir plantations. Moreover, the number of predator and saprophage groups declined more significantly when natural forests were converted into fir plantations (by 24% and 15%, respectively) than into broadleaved plantations (by 16% and 10%, respectively). Additionally, soil fauna showed more sensitive responses to forest conversion in spring and summer, especially in the case of the conversion into fir plantations. Our findings underscore the negative impacts of forest conversion on soil fauna biodiversity, particularly the reduction in predators and saprophages, which may disrupt the food web and increase ecosystem vulnerability to pests and diseases, thereby indicating potential risks to the stability of forest ecosystems.

Organic fertilization may influence soil carbon−iron (C-Fe) cycling and enhance phosphorus (P) availability, yet the direct connection between soil organic matter molecules and iron-reducing processes in long-term fertilized paddy soils remains underexplored. In this study, we conducted a microcosm experiment using paddy soils treated with six distinct fertilization regimes involving varying P and organic matter inputs up to five years. We assessed P activation under reflooding conditions, evaluated Fe reduction, and characterized dissolved organic matter (DOM) at the molecular level using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), alongside profiling soil microbial community composition via high-throughput sequencing. Our findings revealed that after 25 days of reflooding, soil Olsen-P content increased by an average of 73% compared to its initial state, showing a strong correlation with the Fe reduction process. Specifically, treatments involving pig manure application exhibited higher Fe reduction rates and enhanced P activation, highlighting the role of organic matter in facilitating Fe reduction. Examination of Fe-reducing microorganisms revealed that their relative abundance was decoupled from Fe reduction and P release rates, potentially due to limitations of lower soil organic matter content. Further analysis of DOM composition and network structures suggested that high-molecular-weight DOM, particularly lignin, acted as key resources for Fe-reducing microbes, thereby driving Fe reduction and promoting P release. Overall, our study highlights the crucial role of soil DOM in enabling microbial-driven Fe reduction and enhancing P availability, providing insights valuable for sustainable agricultural practices.

The formation and stabilization of soil organic carbon (OC) are key to building resilient soil structures and maintaining biogeochemical functions. As the main component of soil organic matter (OM), the portion of stabilized soil OC is influenced by both inherent properties of OM and physical and chemical characteristics of soil. In a perspective study by Angst et al. (2023), particulate organic matter (POM) was highlighted as a factor that enhances OC sequestration under conditions where mineral-associated OM is saturated. The study primarily proposes increasing OC sequestration by enhancing POM inputs while overlooking pathways that improve the soil’s capacity for OC stabilization, particularly through the multifaceted role of reactive minerals. We suggest that efforts should focus on both increasing OM inputs and enhancing reactive minerals to promote OC stabilization through both POM occlusion in soil aggregates and new mineral-associated OM formation. Furthermore, future strategies should consider the overlooked organo-mineral dynamics and the multiple roles of reactive minerals in governing soil OM biochemical properties and persistence. Only through a systematic consideration of OM inputs and soil mineral characteristics can practical and effective strategies be developed to enhance soil OC sequestration.

Anaerobic ammonium ({\text{NH}}_{\text{4}}^{+}) oxidation is one of the key processes in nitrogen cycling. After the canonical pathway for it using {\text{NO}}_{\text{2}}^{-} as the electron acceptor was first discovered, novel pathways for it using Fe³⁺, Mn⁴⁺, {\text{SO}}_{\text{4}}^{\text{2}-}, or {\text{AsO}}_{\text{4}}^{\text{3}-}, as electron acceptors have recently been confirmed. Nitrous oxide (N₂O) is a strong oxidant, and there is currently no report on whether it can act as an electron acceptor to couple with anaerobic ammonium oxidation in natural habitats. From a thermodynamic perspective, the potential anaerobic ammonium oxidation driven by N₂O reduction generates much higher free energy than the canonical anaerobic ammonium oxidation driven by {\text{NO}}_{\text{2}}^{-} reduction, indicating that it is more likely to occur spontaneously. Some specific habitats such as ammonium-rich wastewater, with low levels of active organic carbon and high concentration of N₂O may be favorable for N₂O-mediated anaerobic ammonium oxidation. The extracellular electron transfer between symbiotic bacteria may be an important way of electron transfer in this coupling process. By using enrichment culture combined with ¹⁵N labeling technique, oxidation rate, electron transfer pathway, and metagenome (and transcriptome) information of this coupling process could be powerfully investigated. The study could expanding our understanding of transformation process in nitrogen biogeochemical cycle.

The application of cattle manure may significantly burden the reservoir of antibiotic resistance genes (ARGs) in agricultural soils, necessitating careful consideration. A 3-year field experiment was conducted to investigate the distribution characteristics of ARGs and bacterial communities in soil with different levels of cattle manure application, encompassing five distinct amounts of cattle manure: Control (0 t hm⁻²), M1 (35.28 t hm⁻²), M2 (68.62 t hm⁻²), M3 (102.87 t hm⁻²), and M4 (137.23 t hm⁻²). Applying varying rates of cattle manure slightly increased the abundance of tetracycline and sulfonamide resistance genes in vegetable fields, posing a potential risk of soil contamination with these genes. As the amount of cattle manure fertilization increased, soil bacterial 16S rRNA gene abundance gradually increased, however, the Shannon index and OTUs did not differ significantly among varying rates of cattle manure fertilization. PCoA plot based on Bray−Curtis revealed that soil bacterial community structure significantly differed between cattle manure treatments and Control. No significant difference was found for physicochemical indicators among various cattle manure treatments. In addition, the intI1 gene was significantly and positively correlated with sul1, sul2, and tetL genes, indicating that the intI1 played a crucial role in the proliferation of certain ARGs. These findings enhance our understanding of the impacts of varying rates of cattle manure fertilization on the prevalence of ARGs in vegetable fields, and assist in developing effective strategies to mitigate their spread.

Direct comparison of the difference in biomass between live and sterilized soils may result in deviations in biological plant-soil feedback (B-PSF) due to changes induced by sterilization in bulk soil microorganisms, soil structure, and nutrient availability. The sterilization-induced deviation (sterilization-effect, SS_c) to often-used method B-PSF_ou was corrected by adding a parallel experiment without conditioning by any plants (B-PSF_c). Plant-soil feedback experiments were conducted for two plants with contrasting in root traits and rhizosphere microbial community to test the reliability of the method (Kalidium foliatum and Reaumuria songaric). The specific root length (SRL), root tissue density (RTD) and of R. songarica was higher compared to that of K. foliatum, but the root diameter (RAD) of it was significantly lower than that of K. foliatum. The plasticity of root traits of K. foliatum was stronger than that of R. songarica. The B-PSF_ou of K. foliatum was four times negative than B-PSF_c, whereas there was no statistically significant difference of B-PSF_ou and B-PSF_c for R. songarica. The correlation between B-PSF_c and the relative abundance of pathogens and EcMF was found to be stronger compared to B-PSF_ou. We proposed method corrects the deviation in B-PSF. The variation of deviation between species may be related to root traits.

Invasions of exotic plant species pose a serious threat to local biodiversity and ecosystem functioning, with their effects on soil persisting even after removal. In a mesocosm experiment, we investigated the impact of two alien species, Conyza bonariensis (annual) and Solanum elaeagnifolium (perennial) on soil bacterial community after one year of growth (conditioning sampling), and their legacy effects on the bacterial community developed during the subsequent growth of a native grass species, Cichorium intybus (legacy sampling). We assessed the effects of these species by analysing soil enzymatic activity, bacterial community biomass and structure, β-diversity and the co-occurrence patterns of microbial members. Plant identity did not affect enzymatic activity, bacterial biomass and community composition. The communities across all treatments were dominated by the phylum Firmicutes particularly the Bacillus genus. The heterogeneity in the composition of bacterial communities between treatments (β-diversity) was higher at conditioning compared to legacy sampling while the niche width of the bacterial members expanded after C. intybus growth. β-diversity in soils with S. elaeagnifolium legacy was mainly driven by stochastic processes such as ecological or genetic drift while in soils with C. bonarienzis legacy, deterministic processes like environmental filtering played a dominant role. Regulation of microbial co-occurrence patterns was nearly equally influenced by stochastic and deterministic processes. However, the legacy effects of the invaders significantly impacted the robustness of bacterial networks to further disturbance, with the networks in C. bonarienzis exhibiting enhanced robustness. Our results suggest divergent management strategies for these two species: precautionary containment for S. elaeagnifolium vs. direct intervention for C. bonariensis.

Despite extensive research, fungal diversity along elevation gradients remains difficult to generalize. In this study we examined soil fungal diversity and network stability on two snow mountains in the Hengduan Mountain Range of China and identified distinct biodiversity patterns. On Meili Snow Mountain, fungal ASV richness declined significantly with altitude, with MAT identified as the primary driver. On Baima Snow Mountain, richness exhibited a hump-shaped pattern, with TN as the key influencing factor. Regression analysis and structural equation modelling revealed that elevation indirectly influenced fungal richness by affecting climate, vegetation, and soil properties. Despite similar climatic conditions, elevational patterns of fungal communities on the two mountains are driven by distinct local factors: Fungal communities on Meili Snow Mountain are mainly driven by NDVI, whereas those on Baima Snow Mountain are mainly shaped by soil fertility. Co-occurrence network analysis further indicates that fungal network complexity on Meili Snow Mountain increases with altitude, while fungal network stability follows a U-shaped distribution driven by species interactions and environmental filtering. In contrast, on Baima Snow Mountain, fungal network complexity peaks at mid-altitudes and stability shows no significant correlation with altitude, suggesting strong niche adaptability. These findings highlight the complex effects of elevation on fungal diversity and networks, providing new insights into biodiversity in mountain ecosystem and guidance for ecosystem management under climate change.

Soil nematodes regulate belowground ecological processes, yet their community composition and energy structure responses to Chinese herbal medicine planting are largely unknown. Here, four Euphorbiaceae plants—Phyllanthus emblica, Excoecaria acerifolia, Baccaurea ramiflora, and Aporosa yunnanensis—were selected and cultivated in the Xishuangbanna Tropical Botanical Garden. After two years of cultivation, we assessed soil physicochemical properties, plant traits, microbial diversity, nematode diversity and community composition, and nematode energy flux. Our results revealed that the cultivation of these four medicinal plants significantly reduced soil nematode abundance and diversity and altered the community composition. Total nematode abundance was positively correlated with soil pH, aboveground biomass, and microbial richness, but negatively correlated with soil moisture, soil total phosphorus, and leaf thickness. Additionally, the energy flux within the soil nematode food web decreased by 40%−71% after the cultivation of medicinal plants, which was attributed to the reduction in nematode diversity and abundance. Our findings suggest that the cultivation of medicinal plants can influence soil resource availability and alter soil nematode communities, with diverse nematode species playing a key role in energy transfer within the belowground ecosystem.

Phytoavailability of phosphorus (P) is limited in most soil orders due to insoluble precipitates formation in the rhizosphere with ions of calcium, iron, and aluminum. Therefore, biochar has been adopted as an eco-friendly soil amendment to unlock soil P reserves and modulate P dynamics in soil–biota–plant system. However, this hotspot area of research has not been critically reviewed up to now. This review delves into the specific mechanisms responsible for improving P phytoavailability in the charosphere, either directly by its inherent P content or indirectly via modulating soil physicochemical characteristics that would solubilize the legacy P. Data of this review were extracted from recent publications to evaluate the beneficial effects of biochar on mechanisms responsible for modulating P phytoavailability in the charosphere. Data analysis illustrated that inherent P content in biochar is a feedstock– and pyrolysis temperature–dependent, in which bones feedstock and the high pyrolysis temperature (>600 °C) could produce the highest P concentration (124216 and 31160 mg kg^–1, respectively). Biochar showed pivotal roles in stimulating the colonization of microorganisms mediating P phytoavailability involved in organic P mineralization and legacy P solubilization. The high functionality of biochar also showed a beneficial effect in minimizing the vulnerability of P losses through surface runoff and percolation into groundwater. These modulating effects of biochar were responsible for maximizing P use efficiency (PUE) relative to the unamended soils (43.36% vs. 20.26%). %Average values of PUE varied widely according to biochar’s feedstock (29.1%–38.5%), pyrolysis temperature (9.4–60.1) and application rate (29.9%–88.1%). Nonetheless, this data showed contradictory results with obvious significant effects under lab investigations and only minimal effects under field-scale experimentations.

Plant roots and microorganisms are integral to the phosphorus (P) transformation process in forest soils. However, the specific mechanisms by which they affect soil P availability under long-term nitrogen (N) addition remain elusive. Therefore, a long-term N addition experiment was conducted in a temperate forest in China. After 11-year N addition, measurements focused on P fractions, soil microbial biomass (SMB), microbial community (PLFAs), phosphatase activity, fine root biomass (FRB), and fine root biomass P (FRBP). The results demonstrated that N addition significantly decreased Resin-P and total extractable organic P (Po), while having no significant effect on total extractable inorganic P (Pi). Moreover, a strong positive correlation was observed between Resin-P and total extractable Po, suggesting that under N addition, organic P serves as the primary source of soluble P. This implies that continuous N deposition may exhaust the potential P source stored as organic P in forest soils. N addition also led to a reduction in SMB and FRB. Notably, microbial biomass P and FRBP were positively correlated with Resin-P and total extractable Po, indicating that the decrease in SMB and FRB is the main contributor to the decline in soluble P and organic P. Additionally, N addition significantly reduced phosphatase activity, suggesting an inhibition of the organic P hydrolysis process. In conclusion, N addition decreases P input into the soil by reducing SMB and FRB, and inhibits the transformation of different P forms by lowering enzyme activity. Consequently, soil organic P and soluble P decline, further intensifying P limitation.

Moss crusts play a vital function in the phosphorus (P) cycle in arid regions. Global climate change and anthropogenic disturbances have led to differing levels of mortality in desert mosses. However, the effects of moss mortality on soil P fractions across different soil depths are still unclear. This study compared and analyzed the soil P fractions and P cycle-related enzyme activities across different soil depths between living and moss mortality crusts in the Gurbantunggut Desert. The results demonstrated that moss mortality have significantly increased the contents of resin-P and NaHCO-Pi (inorganic phosphorus) across all soil depths, and NaOH-Po contents in 5–20 cm soil. Conversely, the contents of NaHCO-Po and residual-P in 0–2 cm and 5–20 cm soil depths were decreased with the moss mortality. Compared with living moss crusts, moss mortality have enhanced the contents of available P (5%–54%) across all soil depths, and moderately available P (17%–39%) in 0–10 cm. Meanwhile, the contents of non-available P (15%–16%) in 5–20 cm and total Pi (13%–15%) were decreased. The results of variance decomposition indicated that, the key factors for soil available P after moss mortality shifted from the interaction between biological and abiotic factors (30.09%) to abiotic factors (37.24%). SEM also revealed that moss mortality affected the soil available P contents by influencing the soil pH and S-ALP activity. In summary, moss mortality could enhance soil P availability and alleviate P limitation. This will contribute to understanding the soil P cycle and management of degraded desert ecosystems.₃₃

Earthworm gut microbiome can significantly influence soil microbial community and functions. However, how earthworms affect the abundant, intermediate, and rare soil bacterial taxa and subsequently regulate soil multifunctionality remains poorly understood. In this study, we investigated bacteria composition and functional gene traits with and without earthworm addition in low-nutrient soil. Our results show that earthworm addition enhanced soil multifunctionality, including organic carbon, nitrogen, and phosphorus mineralization. Compared to other groups, abundant taxa in earthworm-treated soil exhibited higher 16S rRNA operon copy numbers, copiotroph/oligotroph ratios, niche width, and network efficiency, suggesting a greater competitive capacity for resource acquisition. We identified a core set of persistent abundant taxa genera (11 genera) in earthworm-treated soil, which persisted throughout the incubation period, and were notably dominant among abundant taxa in the earthworm gut (67.1%−79.2%). Furthermore, structural equation modeling revealed that gut-associated abundant taxa strongly influenced the composition of soil abundant taxa and persistent core abundant taxa genera, which in turn increased soil r-strategists and enhanced multifunctionality. Overall, our findings provide new insights into the ecological strategies of different soil taxa in response to earthworm addition and highlight the role of earthworm gut microbiome in adapting to nutrient-poor environments.

Many termite species create conspicuous, aboveground soil nest mounds. Once the resident termite colony disappears, the mound structure gradually disintegrates. The now empty mound, which is rich in nutrients, and stable in microclimate, potentially provides an important microhabitat for a different range of species. However, the communities in unoccupied termite mounds remain poorly explored, and the relative importance of these mounds in anthropogenically modified habitats is completely unknown. Here we quantify the invertebrate communities in unoccupied mounds of the soil-feeding termites Dicuspiditermes spp. in primary and logged lowland tropical rain forest in Malaysian Borneo and compare them to communities found in control soil. We also quantify the introgression of plant roots into the mounds. We found the unoccupied mounds support a range of invertebrate groups, with ants (Formicidae) having the highest abundances of any group across both habitats. Mounds supported significantly higher abundances of invertebrates overall in both primary forest (nine times more) and logged forest (five times more). However, the number of invertebrate taxa did not differ between mounds and control soils. Plant root mass was higher in control soils than in unoccupied mounds, possibly due to dominance of fine roots in the latter microhabitat. Using previous estimates of mound densities, we estimate that unoccupied Dicuspiditermes spp. mounds support >340000 invertebrate individuals in primary forest and >17000 individuals in logged forest per hectare. Our results indicate that unoccupied mounds are an important, although ephemeral, microhabitat for a range of invertebrate groups, in both pristine and anthropogenically disturbed habitats.

The root microdomain represents a “hot spot” where microorganisms play a pivotal role in driving ecological processes and interact intimately with the host plants. In this study, we investigated 11 indica and 4 japonica rice varieties as test crops and analyzed the structural and functional characteristics of the microbial communities in the rhizosphere, rhizoplane and root endosphere ofindica and japonica rice using high-throughput sequencing technology. Our findings reveal that, during the assembly process within the root microdomain, community diversity gradually decreases, while the filtering effect of the rice root intensifies from the rhizosphere to the root endosphere. Gammaproteobacteria tended to be recruited by both indica and japonica rice, while Clostridia and Betaproteobacteria were specifically recruited by japonica rice to colonize the rhizoplane and root endosphere. In contrast, Bacteroidia were depleted in the root microdomain of both indica and japonica rice, whereas Deltaproteobacteria and Nitrospira were specifically depleted in the root microdomain of indica rice. Compared to japonica rice, the bacteria enriched in the root microdomain of indica rice were primarily affiliated with Bacillales, Pseudomonadales, and Nitrospirales. Moreover, the indica rice had a lower number of instances of co-occurrence (edge/node ratio), network density and degree, while displayed a higher number of modularity, among-module connectivities, average path length and closeness centrality compared with japonica rice. These findings provide detailed insights into the assembly process of the microbiome in the root microdomain of different rice cultivars, as well as host genotype-regulated changes in microbial communities.

Paddy soil is frequently flooded, which leads to anaerobic decomposition of soil organic matter (SOM) to produce CO₂ and CH₄. Currently, there is limited research about the impact of nanoparticles on anaerobic SOM decomposition and CH₄ production in paddy soil. This study investigates the effects of iron oxide nanoparticles (Fe₃O₄ NPs) and multi-walled carbon nanotubes (MWCNTs) on anaerobic SOM decomposition in two paddy soils. The findings showed that addition of nanoparticles (Fe₃O₄ NPs: 0.08% and 0.3%; MWCNTs: 0.05% and 0.2%) reduced methane production by 7.48%−31.72% in Guiyang soil and 3.32%−31.24% in Fuyang soil, with decrease in SOM decomposition of 32.19%−47.87% and 19.60%−33.09%, respectively. However, the CH₄/TIC (total inorganic carbon) ratio was elevated (by 3.17% to 61.92%) after nanoparticles amendment, suggested that TIC production was more significantly suppressed than CH₄. The Prolixibacteraceae, which usually involve in organic macromolecule decomposition, decreased in relative abundance with inhibition of CH₄ production by nanoparticles in both soils, suggesting their sensitivity to nanoparticles. In contrast, the relative abundances of many microbial populations increased with the intensified inhibition of soil mineralization by nanoparticles in both soils. Especially, Sedimentibacter and Melioribacterae increased with inhibition of CH₄ by nanoparticles, and Clostridiaceae, Minicystis as well as Rhodomicrobium increased with the CH₄/TIC ratio in both soils, probably because they might provide substrates for methanogens. These results suggested that nanoparticles not only inhibit the decomposition of SOM but also change the fate of decomposed carbon through modulating microbial populations, leading to a substantial increase in the proportion of CH₄ produced from SOM decomposition.

Litter decomposition drives grassland biogeochemical cycles, yet the distinct roles of leaf and root litter identity, richness, and functional traits in regulating soil microbial diversity and decomposition remain poorly resolved. Using a 120-day mesocosm experiment with leaf and root litter of the dominant species in Inner Mongolia grassland, we assessed how litter type (leaf vs. root), richness (1, 2, 4 species), and identity (root or leaf litter of 4 dominant species) modulate microbial diversity and soil carbon (C) and nitrogen (N) release. We found that litter type and identity more strongly influenced microbial biomass than species richness, and root litter supported higher bacterial alpha diversity but lower microbial biomass and fungal beta diversity compared to leaf litter. Root litter identity primarily affected the overall beta diversity patterns of both bacterial and fungal communities, while greater leaf litter richness significantly suppressed soil C release. Mechanistically, root litter identity associated with the resource-conservative strategy directly controlled soil C release and indirectly regulated N retention via bacterial beta diversity. Conversely, leaf litter type characterized by the resource-acquisitive strategy primarily affected soil C release by altering microbial alpha diversity, and could also enhance N release by directly increasing soil microbial biomass. Our results underscore the significant influence of litter type, identity, and richness on soil microbial diversity and C and N release, supporting the strategic use of litter identity to modulate C and N release and the enhancement of C sequestration through increased leaf litter richness in grassland restoration efforts.