Microbial responses to long-term warming differ across soil microenvironments.

Soil carbon loss is likely to increase due to climate warming, but microbiomes and microenvironments may dampen this effect. In a 30-year warming experiment, physical protection within soil aggregates affected the thermal responses of soil microbiomes and carbon dynamics. In this study, we combined metagenomic analysis with physical characterization of soil aggregates to explore mechanisms by which microbial communities respond to climate warming across different soil microenvironments. Long-term warming decreased the relative abundances of genes involved in degrading labile compounds (e.g. cellulose), but increased those genes involved in degrading recalcitrant compounds (e.g. lignin) across aggregate sizes. These changes were observed in most phyla of bacteria, especially for Acidobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, and Planctomycetes. Microbial community composition was considerably altered by warming, leading to declined diversity for bacteria and fungi but not for archaea. Microbial functional genes, diversity, and community composition differed between macroaggregates and microaggregates, indicating the essential role of physical protection in controlling microbial community dynamics. Our findings suggest that microbes have the capacity to employ various strategies to acclimate or adapt to climate change (e.g. warming, heat stress) by shifting functional gene abundances and community structures in varying microenvironments, as regulated by soil physical protection.

Positive buttress reduction in femoral neck fractures: a literature review.

BACKGROUND: Femoral neck fractures (FNFs) in young adults are usually caused by high-energy trauma, and their treatment remains a challenging issue for orthopedic surgeons. The quality of reduction is considered an important factor in improving the poor prognosis of patients with FNFs. In recent years, positive buttress closed reduction technique has received widespread attention in the treatment of FNFs. This comprehensive literature review is designed to encapsulate the impacts of both non-anatomic and anatomic reduction on the biomechanical stability, clinical outcomes, and postoperative complications in the management of FNFs, conjecture the efficacy of positively braced reduction techniques and provide a thorough summarization of the clinical outcomes. METHODS: In this literature review, we have examined all clinical and biomechanical studies related to the treatment of FNFs using non-anatomical reduction or positive and negative buttress reduction. PubMed, Web of Science, Google Scholar and Embase Library databases were searched systematically for studies published before September 1, 2023. Published literature on fracture reduction techniques for treating FNFs was reviewed. In addition, we evaluated the included literature using the MINORs tool. RESULTS: Although the "arch bridge" structure formed by the positive buttress reduction technique improved the support to the cortical bone and provided a more stable biomechanical structure, no significant differences were noted in the clinical efficacy and incidence of postoperative complications between the positive buttress reduction and anatomical reduction. CONCLUSION: Positive buttress reduction is an effective treatment method for young patients with FNFs. When facing difficult-to-reduce FNF, positive buttress reduction should be considered first, followed by anatomical reduction. However, negative buttress reduction should be avoided.

Novel Risk Factors for Cervical Facet Joint Degeneration in the Subaxial Cervical Spine: Correlation with Cervical Sagittal Alignment and Bone Mineral Density.

OBJECTIVE: The impact of cervical sagittal alignment on cervical facet joint degeneration (CFD) and the risk factors for CFD in patients with degenerative cervical myelopathy (DCM) were investigated in the current study. METHODS: A total of 250 surgical patients with DCM were recruited. The clinical data and radiographical characteristics, including CFD, cervical sagittal balance parameters, Hounsfield unit (HU) values, disc degeneration (DD), and modic change, were collected. The detailed correlation between these characteristics and CFD was analyzed. Characteristics, including CFD, were compared among the various cervical alignment types and different CFD groups. Finally, the risk factors for CFD were revealed via logistic regression. RESULTS: CFD was prevalent in DCM patients. Age, cervical sagittal vertical axis (cSVA), range of motion, T1 slope, thoracic inlet angle, DD, HU value, and modic change correlated with CFD segmentally and globally (P < 0.05). The lordosis and sigmoid types had a significantly higher CFD prevalence (P < 0.05). Furthermore, the average CFD threshold for the severe CFD group was 1.625 (area under the curve, 0.958). Additionally, 167 patients with average CFD <1.625 and 83 patients with CFD of ≥1.625 were classified into the mild CFD group and severe CFD group, respectively. Finally, multivariate analysis was performed, and age, cSVA, HU value, modic change, and DD were determined to be independent risk factors for CFD. CONCLUSIONS: The load distribution tends to shift to a more shear-like pattern in the sigmoid and kyphosis types and in those with a higher cSVA, thereby promoting CFD. Aging, cervical malalignment, low bone mineral density, DD, and modic change were revealed to result in high risks of CFD.

Influence of Tempering Temperature on Mechanical and Rotational Bending Fatigue Properties of 40CrNi2MoE Steel.

In order to examine the mechanical properties and rotational bending fatigue performance of 40CrNi2MoE steel subsequent to tempering at varying temperatures, the steel specimen was subjected to tempering within the range of 400~460 °C. SEM, EBSD, and TEM were used to analyze the microstructure as well as precipitates. The strain hardening law was studied using the modified Crussard-Jaoult method. Investigations were undertaken to reveal the rotational bending fatigue life with respect to the tempering temperature. The findings indicate that the strength and fatigue life of the examined steels exhibit a decline as the tempering temperature increases, with the primary factor affecting this trend being the alteration in dislocation density. No notable impact on the fatigue fracture morphology exerted by tempering temperature was found within the range of the experiment. The C-J model analysis reveals that the work-hardening behavior of the trial steels is influenced by dislocations and the second phase.

Glutamine suppresses senescence and promotes autophagy through glycolysis inhibition-mediated AMPKα lactylation in intervertebral disc degeneration.

Regulating metabolic disorders has become a promising focus in treating intervertebral disc degeneration (IDD). A few drugs regulating metabolism, such as atorvastatin, metformin, and melatonin, show positive effects in treating IDD. Glutamine participates in multiple metabolic processes, including glutaminolysis and glycolysis; however, its impact on IDD is unclear. The current study reveals that glutamine levels are decreased in severely degenerated human nucleus pulposus (NP) tissues and aging Sprague-Dawley (SD) rat nucleus pulposus tissues, while lactate accumulation and lactylation are increased. Supplementary glutamine suppresses glycolysis and reduces lactate production, which downregulates adenosine-5'-monophosphate-activated protein kinase α (AMPKα) lactylation and upregulates AMPKα phosphorylation. Moreover, glutamine treatment reduces NP cell senescence and enhances autophagy and matrix synthesis via inhibition of glycolysis and AMPK lactylation, and glycolysis inhibition suppresses lactylation. Our results indicate that glutamine could prevent IDD by glycolysis inhibition-decreased AMPKα lactylation, which promotes autophagy and suppresses NP cell senescence.

Experimental warming accelerates positive soil priming in a temperate grassland ecosystem.

Unravelling biosphere feedback mechanisms is crucial for predicting the impacts of global warming. Soil priming, an effect of fresh plant-derived carbon (C) on native soil organic carbon (SOC) decomposition, is a key feedback mechanism that could release large amounts of soil C into the atmosphere. However, the impacts of climate warming on soil priming remain elusive. Here, we show that experimental warming accelerates soil priming by 12.7% in a temperate grassland. Warming alters bacterial communities, with 38% of unique active phylotypes detected under warming. The functional genes essential for soil C decomposition are also stimulated, which could be linked to priming effects. We incorporate lab-derived information into an ecosystem model showing that model parameter uncertainty can be reduced by 32-37%. Model simulations from 2010 to 2016 indicate an increase in soil C decomposition under warming, with a 9.1% rise in priming-induced CO2 emissions. If our findings can be generalized to other ecosystems over an extended period of time, soil priming could play an important role in terrestrial C cycle feedbacks and climate change.

High performance solar-blind UV detector with Mg0.472Zn0.528O/Mg0.447Zn0.553O double layer structure on MgO substrate.

Mg0.472Zn0.528O/Mg0.447Zn0.553O double layer structure UV detectors are made on single structure MgO substrate by PLD method, and the effect of different thickness top MgZnO layer on the UV response characteristics of the detector are studied. Compared with the single layer MgZnO detector that made by Mg0.3Zn0.7O target, the Mg0.472Zn0.528O/Mg0.447Zn0.553O double layer detector with 30 nm top layer, shows much higher deep UV response (21.3 A W-1at 265 nm), much smaller dark current(66.9 pA) and much higher signal-to-noise ratio (2.8 × 105) at 25 V bias voltage. And the device also shows relative high response (23.1 A W-1) at 235 nm deep UV light at 25 V bias voltage, which is mainly attributed by the bottom MgZnO layer with higher Mg composition. When the top layer is 66.7 nm thick, the response of the Mg0.472Zn0.528O/Mg0.447Zn0.553O detector reached 228.8 A W-1at 255 nm under 25 V bias voltage, the signal-to-noise ratio of which is 10573 under 20 V bias voltage, and the near UV response of the device is also big because of more h-MgZnO in top MgZnO layer. When the top layer reached 90.2 nm, there are much more h-MgZnO in the top MgZnO layer, the peak response of the Mg0.472Zn0.528O/Mg0.447Zn0.553O detector is just 6.65 A W-1at 320 nm under 25 V bias voltage, the signal-to-noise ratio of which is 1248. The high Mg composition bottom MgZnO decrease the dark current of the Mg0.472Zn0.528O/Mg0.447Zn0.553O detector, both the 2DEG effect of the double layer structure and the amplify effect of the mix-phase MgZnO top layer, increased theIuvand deep UV response of the Mg0.472Zn0.528O/Mg0.447Zn0.553O detector. Therefore, the double layer Mg0.472Zn0.528O/Mg0.447Zn0.553O detector is more sensitive at faint deep UV light compared with previous reported MgZnO detectors, and the MgxZn1-xO/MgyZn1-yO detector shows similarIuvand signal-noise-ratio at faint deep UV light as high-temperature fabricated AlxGa1-xN/AlyGa1-yN detectors.

Effect of Aging Treatment on the Microstructure and Properties of 2.2 GPa Tungsten-Containing Maraging Steel.

Maraging steel is a prominent category of ultrahigh-strength steel (UHSS) characterized by excellent comprehensive properties, and it finds wide applications in manufacturing load-bearing structural components. In this study, a novel tungsten-containing maraging steel, C-250W, was designed. The effects of aging treatments on the mechanical properties, microstructure, precipitations, and reverted austenite of C-250W steel were investigated. The results revealed that the optimal combination of strength and toughness could be achieved through an aging treatment of C-250W steel carried out for 5 h at 480 °C after solution treatment at 1000 °C for 1 h. As the aging temperature increased, the proportion of dimples in the impact fracture gradually decreased while that of quasi-cleavage increased, leading to a reduction in Charpy impact energy. The boundary of martensitic lath decomposed gradually as the aging temperature increased, and it disappeared entirely at temperatures higher than 550 °C. Moreover, the aging process resulted in the formation of phases, including spherical Fe2M (M represents Mo, W) and thin strip-shaped Ni3N (N represents Mo, Ti) precipitates. These precipitates coarsened from 5 nm to 50-200 nm with increasing aging temperature. Additionally, the content of reverted austenite increased with the aging temperature. Within the temperature range of 400 °C to 500 °C for aging treatment, the content of film-shaped reverted austenite was approximately 3%, primarily distributed at the boundary of martensite lath. When the aging temperature exceeded 550 °C, the content of reverted austenite reached 20.2%, and its morphology changed from film-shaped to block-shaped, resulting in a decline in strength and toughness.

Effect of Cerium on Inclusion Modification in a Secondary-Hardening Steel.

Owing to the continuous increasing of steel strength, mechanical properties including toughness and fatigue performance are becoming increasingly sensitive to inclusions in ultra-high strength steel. Rare-earth treatment is considered as an effective method to reduce the harmful effects of inclusions, but is rarely applied in secondary-hardening steel. In the present study, different amounts of cerium were added in a secondary-hardening steel to investigate the modification effect of Ce on non-metallic inclusions in steel. The characteristics of inclusions were observed experimentally using SEM-EDS and the modification mechanism was analyzed based on thermodynamic calculations. The results indicated that the main inclusions in Ce-free steel are Mg-Al-O + MgS. Thermodynamic calculation indicated that MgAl2O4 is firstly formed in liquid steel and then successively transformed into MgO and MgS during cooling process. When the Ce content is 0.0030%, the typical inclusions in steel were individual Ce2O2S and MgO + Ce2O2S complex inclusions. When the Ce content was increased to 0.0071%, the typical inclusions in steel were individual Ce2O2S- and Mg-containing inclusions. Ce treatment modifies the angular magnesium aluminum spinel inclusions into spherical and ellipsoidal Ce-containing inclusions, thus reducing the harmful effect of inclusion on steel properties.

Soil glomalin-related protein affects aggregate N2O fluxes by modulating denitrifier communities in a fertilized soil.

Agricultural ecosystems contribute significantly to atmospheric emissions of soil nitrous oxide (N2O), which exacerbate environmental pollution and contribute to global warming. Glomalin-related soil protein (GRSP) stabilizes soil aggregates and enhances soil carbon and nitrogen storage in agricultural ecosystems. However, the underlying mechanisms and relative importance of GRSP on N2O fluxes within soil aggregate fraction remain largely unclear. We examined the GRSP content, denitrifying bacterial community composition, and potential N2O fluxes across three aggregate-size fractions (2000-250 µm, 250-53 µm, and <53 µm) under a long-term fertilization agricultural ecosystem, subjected to mineral fertilizer or manure and their combination. Our findings indicated that various fertilization treatments have no discernible impact on the size distribution of soil aggregates, paving the way to further research into the impact of soil aggregates on GRSP content, the denitrifying bacterial community composition, and potential N2O fluxes. GRSP content increased with the increase in soil aggregate size. Potential N2O fluxes (including gross N2O production and N2O reduction and net N2O production) among aggregates were highest in microaggregates (250-53 µm), followed by macroaggregates (2000-250 µm) and lowest in silt + clay (<53 µm) fractions. Potential N2O fluxes had a positive response to soil aggregate GRSP fractions. The non-metric multidimensional scaling analysis revealed that soil aggregate size could drive the denitrifying functional microbial community composition, and deterministic processes play more critical roles than stochasticity processes in driving denitrifying functional composition under soil aggregate fractions. Procrustes analysis revealed a significant correlation between denitrifying microbial community, soil aggregate GRSP fractions, and potential N2O fluxes. Our study suggests that soil aggregate GRSP fractions influence potential nitrous oxide fluxes by affecting denitrifying microbial functional composition within soil aggregate.

High-Performance Thin-Film Transistors with ZnO:H/ZnO Double Active Layers Fabricated at Room Temperature.

H doping can enhance the performance of ZnO thin-film transistors (TFTs) to a certain extent, and the design of double active layers is an effective way to further improve a device's performance. However, there are few studies on the combination of these two strategies. We fabricated TFTs with ZnO:H (4 nm)/ZnO (20 nm) double active layers by magnetron sputtering at room temperature, and studied the effect of the hydrogen flow ratio on the devices' performance. ZnO:H/ZnO-TFT has the best overall performance when H2/(Ar + H2) = 0.13% with a mobility of 12.10 cm2/Vs, an on/off current ratio of 2.32 × 107, a subthreshold swing of 0.67 V/Dec, and a threshold voltage of 1.68 V, which is significantly better than the performance of single active layer ZnO:H-TFTs. This exhibits that the transport mechanism of carriers in double active layer devices is more complicated. On one hand, increasing the hydrogen flow ratio can more effectively suppress the oxygen-related defect states, thus reducing the carrier scattering and increasing the carrier concentration. On the other hand, the energy band analysis shows that electrons accumulate at the interface of the ZnO layer close to the ZnO:H layer, providing an additional path for carrier transport. Our research exhibits that the combination of a simple hydrogen doping process and double active layer construction can achieve the fabrication of high-performance ZnO-based TFTs, and that the whole room temperature process also provides important reference value for the subsequent development of flexible devices.

A model-based quantitative analysis of efficacy and associated factors of platelet rich plasma treatment for osteoarthritis.

OBJECTIVE: While platelet rich plasma (PRP) has been extensively studied in treating osteoarthritis (OA), there has been an ongoing debate regarding the efficacy of PRP and the optimal subpopulation for PRP treatment remains unknown. The authors hereby aim to establish a pharmacodynamic model-based meta-analysis to quantitatively evaluate PRP efficacy, comparing with hyaluronic acid (HA) and identify relevant factors that significantly affect the efficacy of PRP treatment for OA. METHODS: The authors searched for PubMed and the Cochrane Library Central Register of Controlled Trials of PRP randomized controlled trials (RCTs) for the treatment of symptomatic or radiographic OA from the inception dates to 15 July 2022. Participants' clinical and demographic characteristics and efficacy data, defined as Western Ontario and McMaster Universities Osteoarthritis Index and visual analog scale pain scores at each time point were extracted. RESULTS: A total of 45 RCTs (3829 participants) involving 1805 participants injected with PRP were included in the analysis. PRP reached a peak efficacy at ~ 2-3 months after injection in patients with OA. Both conventional meta-analysis and pharmacodynamic maximal effect models showed that PRP was significantly more effective than HA for joint pain and function impairment (additional decrease of 1.1, 0.5, 4.3, and 1.1 scores compared to HA treatment at 12 months for Western Ontario and McMaster Universities Osteoarthritis Index pain, stiffness, function, and visual analog scale pain scores, respectively). Higher baseline symptom scores, older age (≥60 years), higher BMI (≥30), lower Kellgren-Lawrence grade (≤2) and shorter OA duration (<6 months) were significantly associated with greater efficacy of PRP treatment. CONCLUSION: These findings sugges t that PRP is a more effective treatment for OA than the more well-known HA treatment. The authors also determined the time when the PRP injection reaches peak efficacy and optimized the targeting subpopulation of OA. Further high-quality RCTs are required to confirm the optimal population of PRP in the treatment of OA.

Early monitoring of parasitism by Aphidiinae parasitoids on the grain aphid Sitobion miscanthi in wheat fields using DNA barcoding.

BACKGROUND: Sitobion miscanthi is a major wheat pest at the grain-filling stage found in China. Identifying parasitoid species and understanding parasitism rates are keys to controlling the aphids via natural enemies in the wheat field. RESULTS: In the present study, a method based on DNA barcoding for early determination of the community composition of Aphidiinae parasitoids and parasitism on the aphid was developed. The proposed method detected Aphidius gifuensis as the predominant parasite, with parasitism rates of 40.1 ± 2.8% in 2019 and 65.7 ± 3.7% in 2022, and found that the rate varied significantly among different wheat varieties. COI primers efficiently amplified the Aphidiinae parasitoids COI fragments and amplified the aphid COI fragments derived from parasitized (mummified) S. miscanthi. Thus, the COI barcode is not sufficiently specific to unambiguously detect immature parasitoids inside their S. miscanthi hosts. However, it can be used to detect the DNA extracted from mummified aphids. In contrast, the 16S and LWRh primers effectively amplified and identified the parasitoids in parasitized aphids. The 16S primer was reliable even in the early stages of parasitism (24 h) and for DNA samples stored at -20 °C for 5 days. The three barcodes from COI, 16S, and LWRh genes could not clearly distinguish a few certain Aphidiinae species owing to relatively low intraspecific and interspecific diversity. CONCLUSION: The morphological features remain indispensable when identifying Aphidiinae species. Nonetheless, the COI and 16S primers could be used in combination for monitoring the parasitism rates on S. miscanthi in wheat fields. © 2022 Society of Chemical Industry.

Placebo Response to Oral Administration in Osteoarthritis Clinical Trials and Its Associated Factors: A Model-Based Meta-analysis.

Importance: In osteoarthritis (OA) clinical trials, a placebo is often used as control. Therefore, a thorough understanding of the placebo response is important for guiding drug development in OA. Objective: To develop an oral placebo response model for OA. Data Sources: PubMed, EMBASE, and Cochrane Library databases were searched systematically from January 1, 1991, to July 2, 2022. Study Selection: Randomized double-blind placebo-controlled trials of patients with primary OA were included. The interventions and placebo were administered orally. A total of 3032 trials were identified; of these, 130 (4.3%) met the inclusion criteria. Data Extraction and Synthesis: Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, dosage form of the placebo, sample size, proportion of patients who previously used nonsteroidal anti-inflammatory drugs, publication year, intervention categories, Kellgren-Lawrence grades, proportion of White patients, duration of pain, funding source, and risk of bias were extracted. A model-based meta-analysis was used to evaluate the time course of the placebo response in OA treatment and estimate the influencing factors. For subgroup analyses, a meta-analysis with a random-effects model was used to summarize the typical values of the model parameters and their SEs. Main Outcomes and Measures: The primary end point was the time course of the oral placebo response on the WOMAC pain, stiffness, and function subscale scores. Results: The 130 trials selected for analysis included 12 673 participants (mean age, 59.9 years; 68.9% women). The baseline scores of WOMAC pain, stiffness, and function subscales were found to be significantly associated with the placebo response. The placebo response reached 90% of its maximum response between 5 and 7 weeks. The placebo responses on the WOMAC subscales were also associated with the sample size, proportion of patients who had previously used nonsteroidal anti-inflammatory drugs, intervention drugs, and publication year. Conclusions and Relevance: In this study, an oral placebo response model of OA was developed that may quantitatively describe the placebo response at different baseline levels of symptoms. The findings may provide valuable references for future clinical trial design and decision-making.

Reduction of microbial diversity in grassland soil is driven by long-term climate warming.

Anthropogenic climate change threatens ecosystem functioning. Soil biodiversity is essential for maintaining the health of terrestrial systems, but how climate change affects the richness and abundance of soil microbial communities remains unresolved. We examined the effects of warming, altered precipitation and annual biomass removal on grassland soil bacterial, fungal and protistan communities over 7 years to determine how these representative climate changes impact microbial biodiversity and ecosystem functioning. We show that experimental warming and the concomitant reductions in soil moisture play a predominant role in shaping microbial biodiversity by decreasing the richness of bacteria (9.6%), fungi (14.5%) and protists (7.5%). Our results also show positive associations between microbial biodiversity and ecosystem functional processes, such as gross primary productivity and microbial biomass. We conclude that the detrimental effects of biodiversity loss might be more severe in a warmer world.

Water-Processed Ultrathin Crystalline Indium-Boron-Oxide Channel for High-Performance Thin-Film Transistor Applications.

Thin-film transistors (TFTs) made of solution-processable transparent metal oxide semiconductors show great potential for use in emerging large-scale optoelectronics. However, current solution-processed metal oxide TFTs still suffer from relatively poor device performance, hindering their further advancement. In this work, we create a novel ultrathin crystalline indium-boron-oxide (In-B-O) channel layer for high-performance TFTs. We show that high-quality ultrathin (~10 nm) crystalline In-B-O with an atomically smooth nature (RMS: ~0.15 nm) could be grown from an aqueous solution via facile one-step spin-coating. The impacts of B doping on the physical, chemical and electrical properties of the In2O3 film are systematically investigated. The results show that B has large metal-oxide bond dissociation energy and high Lewis acid strength, which can suppress oxygen vacancy-/hydroxyl-related defects and alleviate dopant-induced carrier scattering, resulting in electrical performance improvement. The optimized In-B-O (10% B) TFTs based on SiO2/Si substrate demonstrate a mobility of ~8 cm2/(V s), an on/off current ratio of ~106 and a subthreshold swing of 0.86 V/dec. Furthermore, by introducing the water-processed high-K ZrO2 dielectric, the fully aqueous solution-grown In-B-O/ZrO2 TFTs exhibit excellent device performance, with a mobility of ~11 cm2/(V s), an on/off current of ~105, a subthreshold swing of 0.19 V/dec, a low operating voltage of 5 V and superior bias stress stability. Our research opens up new avenues for low-cost, large-area green oxide electronic devices with superior performance.

Aqueous Solution-Processed Nanometer-Thin Crystalline Indium Ytterbium Oxide Thin-Film Transistors.

We demonstrate the growth of ultra-thin (~5 nm) indium ytterbium oxide (In-Yb-O) thin film using a simple vacuum-free aqueous solution approach for the first time. The influences of Yb addition on the microstructural, chemical, optical, and electrical properties of In2O3 are well investigated. The analyses indicate that Yb dopant could suppress oxygen vacancy defects effectively owing to the lower standard electrode potential, lower electronegativity, and stronger metal-oxide bond strength than that of In. The optimized In-Yb-O thin-film transistors (TFTs) exhibit excellent electrical performance (mobility of 8 cm2/Vs and on/off ratio of ~108) and enhanced stability. The triumph of In-Yb-O TFTs is owing to the high quality In2O3 matrix, the remarkable suppressor of Yb, and the nanometer-thin and atomically smooth nature (RMS: ~0.26 nm) of channel layer. Therefore, the eco-friendly water-induced ultra-thin In-Yb-O channel provides an excellent opportunity for future large-scale and cost-effective electronic applications.

Crop rotation stage has a greater effect than fertilisation on soil microbiome assembly and enzymatic stoichiometry.

Agronomic practises, such as fertilisation and crop rotation, affect soil microbial communities and functions. However, limited information is available regarding the relative importance of fertilisation and crop rotation stages in determining the soil microbiome and assembly processes. In addition, insights into the connections between the soil microbiome and enzymatic stoichiometry are scarce. In this study, soil samples were collected from a wheat-rice rotation system that received mineral and organic fertiliser inputs for 6 years to investigate soil microbiome assembly, and the relationship between the soil microbiome and enzymatic stoichiometry. Our results revealed that the crop rotation stage strongly affected the soil microbial community structure, assembly, and enzymatic functions compared to that of the fertilisation regime. Enzymatic stoichiometry results and vector analysis implied that mineral and organic fertilisation could alleviate the microbial N limitation. However, no-manure fertilisation led to microbial P limitation during the wheat stage. The decreases in soil pH mainly drove microbial P limitation due to the acidification induced by the mineral fertilisers. Microbial N/P limitation correlated more strongly with the bacterial assembly than with fungal assembly. Moreover, co-occurrence network analysis showed that ecological relationships between microbial taxa and enzymes were more complex during the wheat stage than that during the rice stage. Microbial nodes linked to acid phosphomonoesterase correlated significantly with the soil pH. Our study highlights the distinct responses of the soil microbiome to fertilisation in different crop-rotation stages, and provides novel insights into connections between microbial assembly and enzymatic stoichiometry.

Bacterial rather than fungal diversity and community assembly drive soil multifunctionality in a subtropical forest ecosystem.

Microbial diversities are key drivers of soil multifunctionality in terrestrial ecosystems and are important for stability and productivity of ecosystems. However, the relationships among microbial diversity, community assembly and soil multifunctionality in forest ecosystems remained unclear. Here, soil samples were collected from a subtropical forest ecosystem, Lushan Mountain, China. High-throughput sequencing was employed to reveal the bacterial/fungal community assembly and biodiversity, as well as 10 enzyme activities were measured to assess soil multifunctionality. We found that soil multifunctionality was negatively regulated by bacterial and fungal alpha diversity, implying a higher potential functional redundancy in this forest soil. The null model indicated that deterministic processes (variable selection) and stochastic processes (dispersal limitation) govern bacterial and fungal phylogenetic turnover, respectively. Correlation analysis revealed that bacterial rather than fungal community assembly processes have a significant linkage to soil multifunctionality. These observations projected that soil variables could regulate multifunctionality by shaping the phylogenetic and taxonomic turnover of bacteria rather than fungi. In summary, our study highlighted that soil multifunctionality is mainly driven by bacterial diversity and community assembly processes while not fungal, presenting different views and knowledge of microbial diversity and community assembly processes in ecosystem functioning.