Search Results (2,890)

Soil microorganisms play an important role in maintaining the functioning of terrestrial ecosystems. Soil microbial communities usually contain both abundant and rare microorganisms. However, in forest ecosystems, the differences in the functions and assembly processes of abundant and rare microbial taxa in soils between planted pure and mixed forests are currently unknown. In this study, four different forest types in the Zhongtiao Mountains were selected, and the diversity and assembly processes of abundant and rare microbial communities in their soils were quantitatively analyzed. The results show that there are differences in the diversity and assembly processes of abundant and rare microorganisms in the four forests. Significant differences in the α-diversity (Shannon index) of abundant bacteria (p = 0.019) and rare fungi (p = 0.049) were obtained in the four forests. The assembly of abundant bacterial and fungal communities in the four forest types was mainly influenced by stochastic processes, the assembly of rare bacterial communities was mainly influenced by deterministic processes, and the assembly of rare fungal communities was influenced by a combination of deterministic and stochastic processes. Planted mixed forests increase the relative contribution of deterministic processes in the assembly of rare fungal communities compared to planted pure forests. This study determined the relative contributions of deterministic and stochastic processes in the assembly of abundant and rare microbial communities among different forest types, providing a theoretical basis for forest management in mixed forests. Full article

Selenium (Se) is a natural detoxifier of the heavy metal mercury (Hg), and the interaction between Se and Hg has been widely investigated. However, the ecological response of Hg to Se in Hg-contaminated farmland requires further study, especially the relationship between Se–Hg interactions and soil abiotic and biological properties. Through a field experiment, the effects of different levels of exogenous Se (0, 0.50, 0.75, 1.00, and 2.00 mg kg⁻¹) on Hg and Se transport in maize, soil properties, enzyme activities, and the microbial community in Hg-contaminated farmland were systematically studied. The Se treatments significantly reduced the Hg concentration in maize roots, stems, leaves, and grains and significantly increased the Se concentration in maize tissues. Except for the 0.75 mg kg⁻¹ Se treatment which significantly increased electrical conductivity compared to the control, other Se treatments hadnon-significant effect on soil physicochemical properties (pH, conductivity, organic matter content, and cation exchange capacity) and oxidoreductase activities (catalase, peroxidase, and ascorbate peroxide). The activities of soil invertase, urease, and alkaline phosphatase increased significantly after Se application, and the highest enzyme activities were observed with a 0.50 mg kg⁻¹ Se treatment. The bacteria and fungi with the highest relative abundance in this study were Proteobacteria (>30.5%) and Ascomycota (>73.4%). The results of a redundancy analysis and predictions of the microbial community showed that there was a significant correlation between the soil nutrient cycle enzyme activity, microbial community composition, and microbial community function. Overall, exogenous Se application was found to be a viable strategy for mitigating the impact of Hg stress on ecosystems. Furthermore, the results provide new insights into the potential for the large-scale application of Se in the remediation of Hg-contaminated farmland. Full article

The plant microbiome plays a role in pathogen defense, but its role in different resistant varieties and ecological niches remains unclear. This study used 16S rRNA and ITS sequencing to investigate microbial communities and interactions in disease-resistant (PT) and susceptible (Bourbon) coffee varieties of five ecological niches: leaves, fruits, roots, rhizosphere soil, and non-rhizosphere soil. We found that the microbial communities differed significantly between the two varieties. The resistant variety was enriched in beneficial bacteria from the Actinobacteriota phylum and a stable, modular microbial network dominated by saprotrophic fungi. In contrast, the susceptible variety had a higher abundance of opportunistic pathogens and stress-indicator fungi, including Neurospora spp., which were more prominent in the rhizosphere and non-rhizosphere soils. These networks were fragile and dominated by pathotrophic fungi, reflecting ecological imbalance. Our findings show that plant disease resistance is influenced not only by host genetics but also by co-evolutionary interactions with the microbiome. These insights provide a foundation for developing targeted biocontrol strategies to manage plant-associated microbial communities. Full article

In order to precisely improve the quality of major tree species in northern China, near-natural differentiated management has been gradually introduced into forestry practice, aiming to optimize forest structure, enhance forest quality, and promote nutrient cycling and water conservation. As an essential element of forest ecosystems, soil microbes contribute to biodiversity preservation and nutrient turnover in soils. This study selected three typical forest types (Quercus acutissima forest, Pinus tabulaeformis forest, and Pinus tabulaeformis × Quercus mixed forest) that have been managed with target trees on Zhongtiao Mountain. Using 16S/ITS rRNA high-throughput sequencing, this study systematically assessed the influences of forest type and soil depth (0–60 cm) on the soil properties and microbial communities. The results showed that the fungal alpha diversity indices were the highest in Pinus tabulaeformis forest, which decreased with soil depth. Actinobacteriota exhibited the greatest relative abundance in mixed forest, whereas Ascomycota predominated in the Pinus tabulaeformis forest. The microbial co-occurrence network exhibited greater complexity compared to the pure forest. Microbial carbon and nitrogen cycling functions showed strong correlation with soil pH and nutrient levels. Symbiotrophs dominated the fungal community, and ectomycorrhizae were significantly abundant in mixed forests. pH is the dominant factor driving changes in microbial communities. In summary, the mixed forest improved soil nutrients, enhanced the complexity of microbial networks, and supported higher ectomycorrhizal abundance. These findings provide practical guidance for improving soil health and stability of forest ecosystems through near-natural management. Full article

The excessive use of conventional fertilizers has led to low nutrient-use efficiency and significant environmental challenges. To address these limitations, this study aimed to evaluate the effects of Fe₂O₃ and CuO nanoparticles (NPs) as potential nanofertilizers, on the soil chemical composition, nutrient fractionation, enzyme activity, and Lepidium sativum L. growth. The results of the study showed that Fe₂O₃-NPs improved nitrogen bioavailability and enhanced plant biomass, particularly at low to moderate doses. CuO-NPs, in contrast, reduced nitrogen and phosphorus mobility and showed phytotoxic effects at high concentrations. Enzyme activity was suppressed at high NP levels, likely due to oxidative stress. Nutrient fractionation revealed the increased immobilization of phosphorus and the moderate mobilization of potassium and copper, depending on NP type. Based on the results, Fe₂O₃-NPs show potential as a nanofertilizer for enhancing soil fertility and plant growth in sandy loam soils, whereas CuO-NPs require caution due to toxicity risks. Future research should focus on long-term environmental impact, optimal NP concentrations, and their interaction with soil microbial communities. Full article

Global agricultural intensification has exacerbated soil compaction and nitrogen (N) inefficiency, thereby threatening sustainable crop production. Sub-soiling, a tillage technique that fractures subsurface layers while preserving surface structure, offers potential solutions by modifying soil physical properties and enhancing microbial-mediated N cycling. This study investigated the effects of subsoiling depth (0, 20, and 40 cm) on soil microbial communities and N transformations in a semi-arid maize system in China. The results demonstrated that subsoiling to a depth of 40 cm (D2) significantly enhanced the retention of nitrate-N and ammonium-N, which correlated with improved soil porosity and microbial activity. High-throughput 16S rDNA sequencing revealed subsoiling depth-driven reorganization of microbial communities, with D2 increasing the abundance of Proteobacteria (+11%) and ammonia-oxidizing archaea (Nitrososphaeraceae, +19.9%) while suppressing denitrifiers (nosZ gene: −41.4%). Co-occurrence networks indicated greater complexity in microbial interactions under subsoiling, driven by altered aeration and carbon redistribution. Functional gene analysis highlighted a shift from denitrification to nitrification-mineralization coupling, with D2 boosting maize yield by 9.8%. These findings elucidate how subsoiling depth modulates microbiome assembly to enhance N retention, providing a mechanistic basis for optimizing tillage practices in semi-arid agroecosystems. Full article

Mulching and irrigation are key practices for improving cotton yield and soil conditions, especially in Xinjiang, China. This study investigated the combined effects of mulching width and irrigation depth on cotton growth and rhizosphere microorganisms. Two mulching widths—conventional (M1) and ultra-wide (M2)—and three irrigation depths, 0.8 ETc (W1), 1.0 ETc (W2), and 1.2 ETc (W3), were tested. The impacts on cotton growth, soil environment, and rhizosphere microbial communities were analyzed. Results showed that under the same irrigation depth, M2 significantly increased soil moisture and reduced salt accumulation. Soil temperature under M2 was higher than M1, with increases of 0.55 °C and 1.65 °C during the budding and flowering–boll stages. M2 also increased root length (3.52–10.72%) and root surface area (5.8–7.51%). The beneficial fungus Cladosporium was enriched, while the pathogen Fusarium was suppressed under M2. With the same mulching width, increasing irrigation improved soil moisture, reduced electrical conductivity, and decreased soil temperature. Root diameter and volume increased by 7.67–47% and 9.43–10.36%, respectively. Mulching width and irrigation depth significantly affected bacterial α-diversity. M2W3 showed the highest microbial richness and functional diversity. This study offers guidance for efficient cotton cultivation in southern Xinjiang. Full article

An attempt was made to understand the interactive consequences of subjecting a rhizospheric microbial community of xTriticocereale (Triticale) to higher CO₂ levels and soil nitrogen addition in the short term in a tropical agro-ecosystem. Open-top chambers (OTCs) were used to grow the test crops for a single season under ambient CO₂ (AC) and elevated CO₂ (EC) along with two variable N dosages: recommended (N₀: 0.053 g N/kg of soil) and high (N₂: 0.107 g of N/kg of soil) levels. Variations in the composition of microbial communities and abundances were investigated using phospholipid fatty acid analysis (PLFA). A significantly (p < 0.001) increased microbial biomass content (MB) was observed under EC compared to AC, while the addition of N had a minor effect. A decreased fungi/bacteria (F/B) ratio (~38%) was observed with high N application in the CO₂ enrichment treatment. Bacteria were more abundant, while fungal abundance decreased under N₂ and EC. Gram (+ve) bacteria used these conditions to thrive under N₂ and EC, while Gram (−ve) bacteria declined. No significant effects on actinomycetes were noticed in any of the treatments. However, eukaryotes acquired more benefits and flourished in response to EC. Varied responses were noted for the Shannon diversity index (H’) under EC. Overall, (i) bacteria (Gram-positive) and eukaryotes dominated under EC and high N addition, while fungi decreased, and (ii) EC and high levels of N addition did not affect actinomycetes. Short-term exposure under the given conditions was found to alter the rhizospheric microbial community. However, multiple season studies are needed to elucidate whether these short-term responses are transient or continuous. Full article

Desert ecosystems pose extreme challenges to plant survival. This study explores the adaptive strategies of two xerophytic halophytes, Alhagi sparsifolia and Nitraria roborowskii, in Xinjiang’s Ebinur Lake wetland, focusing on their plant–soil–microbe (PSM) coupling systems across desert gradients. Results revealed significant interspecific and gradient-dependent differences in plant functional traits: A. sparsifolia showed high growth plasticity with a fast-growth strategy, while N. roborowskii adopted a conservative strategy. Rhizosphere soil physicochemical properties and microbial community structure exhibited strong spatial heterogeneity and host specificity, with N. roborowskii having a more complex microbial network and A. sparsifolia showing higher modularity. Multivariate factor analysis elucidated couplings among plant traits, soil properties, enzymes, and microbes. The two species form distinct interaction systems adapted to desert saline–alkali stress, advancing the understanding of ecological adaptation and informing restoration. Full article

Using meta-analysis of 479 sites across Chinese forests from 136 publications, we quantified changes in soil microbial diversity across forest successional stages and compared patterns between plantation and natural secondary forests. Our systematic review included 136 publications (92 in Chinese, 44 in English), spanning tropical to cold temperate climate zones from 1995–2025. Microbial $\alpha$-diversity exhibited a significant U-shaped pattern across successional stages: early succession (0–15 years) and mature forests (>50 years) had higher Shannon diversity (4.56 ± 0.34 and 4.72 ± 0.41, respectively) than middle-aged forests (16–50 years, 4.18 ± 0.27; standardized mean difference = 0.54, 95% CI: 0.39–0.69, p < 0.01). Response patterns differed significantly among microbial groups (Q = 8.74, p = 0.013), with fungi showing the strongest successional responses (SMD = 0.61, 95% CI: 0.43–0.79), followed by bacteria (SMD = 0.49, 95% CI: 0.32–0.66) and actinomycetes (SMD = 0.42, 95% CI: 0.24–0.60). Natural secondary forests consistently supported higher microbial diversity than plantations (SMD = 0.42, 95% CI: 0.28–0.56), particularly for fungal communities (SMD = 0.47, 95% CI: 0.31–0.63). The climate zone significantly moderated diversity–succession relationships, with subtropical regions showing the largest changes ($\Delta$Shannon = 0.68 ± 0.07) compared to temperate ($\Delta$Shannon = 0.42 ± 0.05) and tropical regions ($\Delta$Shannon = 0.54 ± 0.06). Meta-analytic structural equation modeling revealed that soil organic carbon (path coefficient $\beta$ = 0.68, p < 0.001), total nitrogen ($\beta$ = 0.43, p < 0.001), and pH ($\beta$ = −0.35, p < 0.01) were key mediators connecting succession stage with microbial diversity. Despite substantial between-study heterogeneity (I² = 83.6%), a publication bias was not detected (Egger’s test, p = 0.347). These findings provide the first comprehensive quantification of microbial diversity patterns during forest succession in China, with important implications for forest management and ecological restoration strategies targeting microbial conservation. Full article

Peat soil is a significant global carbon storage pool, accounting for one-third of the global soil carbon pool. Its greenhouse gas emissions have a significant impact on climate change. Seasonal freeze–thaw cycles are common natural phenomena in high-latitude and high-altitude regions. They significantly affect the mineralization of soil organic carbon and greenhouse gas emissions by altering the physical structure, moisture conditions, and microbial communities of the soil. In this study, through the construction of an indoor simulation experiment of the typical freeze–thaw cycle models in spring and autumn in the Greater Xing‘an Range region of China and the Jinchuan peatland of Jilin Longwan National Nature Reserve, the physicochemical properties, greenhouse gas emission fluxes, microbial community structure characteristics, and key metabolic pathways of peat soils in permafrost and seasonally frozen ground areas were determined. The characteristics of greenhouse gas emissions and their influencing mechanisms for peat soil in northern regions under different freeze–thaw conditions were explored. The research found that the freeze–thaw cycle significantly changed the chemical properties of peat soil and significantly affected the emission rates of CO₂, CH₄, and N₂O. It also clarified the interaction relationship between soil’s physicochemical properties (such as dissolved organic carbon (DOC), dissolved organic nitrogen (DON), ammonium nitrogen (NH₄⁺), soil organic carbon (SOC), etc.) and the structure and metabolic function of microbial communities. It is of great significance for accurately assessing the role of peatlands in the global carbon cycle and formulating effective ecological protection and management strategies. Full article

Drought is a global issue that affects agricultural productivity and sustainable development. The application of Bacillus subtilis has significant potential in alleviating drought stress and increasing yield. However, it is not yet clear how Bacillus subtilis affects microbial populations, crop yield, and the biochemical characteristics of rhizosphere soil, as well as the interactions among these factors. In this study, cotton was used as the experimental crop, and different application rates of Bacillus subtilis (0 kg·ha⁻¹ and 45 kg·ha⁻¹ (B)) and drought stress levels (H represents conventional irrigation, 350 mm; L represents 80% of conventional irrigation, 280 mm) were set as three replicates per group. The changes in rhizosphere-soil-related variables, microbial community diversity, enzyme activity, and cotton yield were studied. Compared to the control, the available nitrogen content increased by 19.76–62.40%, and soil moisture increased by 2.48–7.72%. The activities of urease, sucrase, and alkaline phosphatase increased, malondialdehyde content decreased, the Soil Plant Analysis Development (SPAD) value increased, and cotton yield increased by 8.94–9.28%. According to the structural equation model, Bacillus subtilis can increase microbial community diversity and network complexity, improve soil nutrients and enzyme activity, and increase cotton yield. This study’s findings may offer a theoretical foundation for enhancing soil quality and raising agricultural yields in arid regions. Full article

Semi-natural grasslands are key biodiversity reservoirs in Mediterranean mountain ecosystems. Grazing pressure may significantly influence plant communities and soil conditions, with potential effects on ecosystem functioning. This study evaluated the impact of grazing intensity on floristic diversity, community structure, and soil physico-chemical and microbiological properties across eight grasslands in the Jbel Bouhachem massif (northern Morocco). Species richness, Shannon diversity, and floristic composition were assessed using PERMANOVA and NMDS ordination. Soil parameters and microbial groups were analyzed through laboratory measurements, with statistical comparisons based on Wilcoxon and t-tests. No significant differences were found in species richness or alpha diversity between grazing intensities, although floristic dispersion was higher under intensive grazing. Soil texture, potassium, iron, zinc, and electrical conductivity differed significantly between treatments. Among microbial groups, only yeasts and molds showed higher abundance under intensive grazing, while sulfite-reducing clostridia were exclusively detected in these plots. These results suggest that grazing intensity has a selective impact on soil properties and microbial communities, while plant diversity remains relatively stable. Full article

Continuous planting results in a higher occurrence rate of oriental melon Fusarium wilt caused by Fusarium oxysporum f. sp. melonis (FOM), and treatment with Trichoderma can considerably alleviate the incidence of disease. However, the tripartite interaction mechanisms among T. harzianum–melon–rhizosphere microorganisms remain poorly understood in current research. Pot experiments elucidate the growth-promoting, antagonistic, and rhizosphere-regulating effects of T. harzianum on oriental melon. The experiment consisted of two treatments: (1) water control (CK), and (2) T. harzianum inoculation (MM) with three repetitions per treatment. Illumina high-throughput sequencing was employed to analyze the microbial community and associated metabolic pathways. Additionally, a comprehensive correlation analysis clarified how T. harzianum-modulated physiological factors regulate soil microbial communities to enhance melon resistance to FOM. T. harzianum inoculation significantly promoted plant growth, decreased the incidence rate of Fusarium wilt by 41.85%, and increased rhizosphere nitrate-N, pH, EC, and soil enzyme activity (e.g., sucrose and alkaline phosphatase). Notably, T. harzianum inoculation altered the rhizosphere microbial community’s relative abundance and structure, with the most striking changes in the fungal community. Principal coordinate analysis showed this fungal restructuring accounted for 44.9% of total community variation (37% from PCo1, 7.9% from PCo2). Soil-borne pathogens (e.g., Fusarium, Verticillium, Phytophthora) decreased in relative abundance with the inoculation of T. harzianum. Meanwhile, the microbial community shifted from a “fungal-dominated” to “bacterial-dominated” state: fungal proportion decreased by 9.47% (from 23.95% in CK to 14.48% in MM), while bacterial proportion increased by 9.47% (from 76.05% in CK to 85.52% in MM). Microbial abundance shifts primarily impacted amino acid and cofactor biosynthesis metabolic pathways. The application of T. harzianum modified the soil environment, restructuring microbial communities through these changes, which in turn regulated microbial metabolic pathways, creating a soil environment conducive to melon growth and thereby enhancing oriental melon resistance to FOM, while mitigating the obstacles of continuous cropping. Full article

Soil organic matter (SOM) decomposition is a critical biogeochemical process that regulates the carbon cycle, nutrient availability, and agricultural sustainability of cropland systems. Recent progress in multi-omics and microbial network analyses has provided us with a better understanding of the decomposition process at different spatial and temporal scales. Climate factors, such as temperature and seasonal variations in moisture, play a critical role in microbial activity and enzyme kinetics, and their impacts are mediated by soil physical and chemical properties. Soil mineralogy, texture, and structure create different soil microenvironments, affecting the connectivity of microbial habitats, substrate availability, and protective mechanisms of organic matter. Moreover, different microbial groups (bacteria, fungi, and archaea) contribute differently to the decomposition of plant residues and SOM. Recent findings suggest the paramount importance of living microbial communities as well as necromass in forming soil organic carbon pools. Microbial functional traits such as carbon use efficiency, dormancy, and stress tolerance are essential drivers of decomposition in the soil. Furthermore, the role of microbial necromass, alongside live microbial communities, in the formation and stabilization of persistent SOM fractions is increasingly recognized. Based on this microbial perspective, feedback between local microbial processes and landscape-scale carbon dynamics illustrates the cross-scale interactions that drive agricultural productivity and regulate soil climate. Understanding these dynamics also highlights the potential for incorporating microbial functioning into sustainable agricultural management, which offers promising avenues for increasing carbon sequestration without jeopardizing soil nutrient cycling. This review explores current developments in intricate relationships between climate, soil characteristics, and microbial communities determining SOM decomposition, serving as a promising resource in organic fertilization and regenerative agriculture. Specifically, we examine how nutrient availability, pH, and oxygen levels critically influence these microbial contributions to SOM stability and turnover. Full article