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Soil acidification due to the long-term application of nitrogenous fertilizers and the consequent impact on crop growth have been frequently reported. The effects of acidification on soil humus, charge, and microbial communities need to be studied. In this experiment, fertilizer drenching was used to simulate the effects of multiple years of fertilizer application on the black soil. The results showed that 25 years of soil acidification treatment resulted in a decrease of 8.97% in the content of stable humus and led to a decrease of 58% and 51.18% in the humic acid (HA) content and degree of humification (PQ) value in stable humus, respectively. In addition, soil acidification leads to a significant decrease in total negative charge (CEC8.2) and variable negative charge (CECv), with both decreasing by 63.28% and 88.67%, respectively, at 25 years. Acidification treatments affected both soil microbial community abundance and diversity, with a significant decrease in Acidobacteriota and Gemmatimonadota abundance and an increase in Bacteroidia abundance and Acidobacteriota abundance at 25 years. [ABSTRACT FROM AUTHOR]

Scrub root systems play a crucial role in preventing soil erosion and nutrient loss. However, the effects of the root system configuration on soil nutrient dynamics and microbial changes at various evolutionary stages remain poorly understood. In this study, we investigated the relationship between soil physical and chemical properties and the diversity of bacteria and fungi throughout the evolutionary stages of the scrub root systems. This was achieved through a combination of whole-root excavation and root tracing techniques. The results indicated that root diameter was the main factor contributing to the continuous increase in carbon (C): phosphorus (P) and nitrogen (N): P ratios as the scrub sand pile developed. The soil organic carbon (SOC), total soil nitrogen (TN), and total soil phosphorus (TP) contents in the soil in the four evolutionary stages were the highest during the developmental stage, but the change in TP content was not statistically significant (P > 0.05). Partial least squares path modeling and redundancy analysis (RDA) indicated that root system stoichiometric C and N contents were positively correlated with microbial diversity (R² = 0.85). There was no correlation between the evolutionary stage and soil nutrient TN, whereas soil nutrient TN was negatively correlated with microbial diversity (R² = −0.92). These findings elucidate the relationship between the evolutionary stage of root chemical measurement characteristics, soil elements and microorganisms, and their subsequent effects on root elemental composition and microbial diversity. This study enhances the current understanding of plant–soil interactions in desert steppe ecosystems. [ABSTRACT FROM AUTHOR]

Background: Nanofertilisers can enhance the efficiency of nutrient utilization in crop production. Nevertheless, it is unclear how soil microbial and enzyme activities are affected by the application of nanofertilisers to wheat inter‐root soil. Aims: The study aims to investigate the influences of nanocarbon (NC) and nano‐calcium carbonate (NCC) on soil enzyme activities and microbial community in the open field setting. Methods: The effects of nanofertilisers on soil wheat rhizosphere soil were studied through the evaluation of soil microbial quantity, enzyme activity, and microbial diversity. Results: The findings revealed that the combined utilization of nanofertilizers and compound fertilizers (CF) led to an augmentation in the diversity of the soil microbial community. When comparing the effects of 100% composite nanofertilizers (100% CF + 50% NC + 50% NCC) with the control (CK) (100% CF), it was observed that the activities of urease (EC 3.5.1.5), catalase (EC 1.11.1.6), alkaline phosphatase (EC 3.1.3.1), sucrase (EC.3.2.1.26), as well as the number of fungi, actinomycetes, and bacteria, increased by 22.4%, 7.7%, 17.8%, 9.3%, 35.9%, 27.7%, and 26.0%, respectively. Similarly, the employment of 70% composite nanofertilizers (70% CF + 35% NC + 35% NCC) also resulted in an enhancement of these aforementioned indicators. The magnitude of increase over the 100% CF was 19.0%, 6.6%, 13.6%, 6.2%, 26.8%, 21.3%, and 23.5%, respectively. Notably, there was no significant difference observed between 100% CF + 50% NC + 50 % NCC and 70% CF + 35% NC + 35% NCC within the 0–35 d after anthesis. Furthermore, both 100% CF + 50% NC + 50% NCC and 70% CF + 35% NC + 35% NCC contributed to an improvement in the species uniformity and operational taxonomic unit abundance of wheat rhizosphere microorganisms, while also increasing the abundance of Proteobacteria and Actinobacteria compared to the CK. The relative abundance of Bacteroidetes and Actinobacteria was found to be elevated in the nanomaterials‐treated groups, both at 0–7 d and 14–21 d after anthesis, and positively correlated with soil enzyme activities and soil microbial populations. Conclusions: These results indicate that the application of composite nanofertilizers can enhance the soil microenvironment in wheat fields, particularly under reduced fertilization conditions. [ABSTRACT FROM AUTHOR]

Introduction: Grazer exclosure is widely regarded as an effective measure for restoring degraded grasslands, having positive effects on soil microbial diversity. The Intergovernmental Panel on Climate Change (IPCC) predicts that global surface temperatures will increase by 1.5-4.5°C by the end of the 21st century, which may affect restoration practices for degraded grasslands. This inevitability highlights the urgent need to study the effect of temperature on grassland soil microbial communities, given their critical ecological functions. Methods: Here, we assessed the effects of heavy grazing (control), grazer exclosure, and grazer exclosure plus warming by 1.5°C on soil microbial community diversity and network properties as well as their relationships to soil physicochemical properties. Results and discussion: Our results showed that grazer closure increased soil microbial richness relative to heavy grazing controls. Specifically, bacterial richness increased by 7.9%, fungal richness increased by 20.2%, and the number of fungal network nodes and edges increased without altering network complexity and stability. By contrast, grazer exclosure plus warming decreased bacterial richness by 9.2% and network complexity by 12.4% compared to heavy grazing controls, while increasing fungal network complexity by 25.8%. Grazer exclosure without warming increased soil ammonium nitrogen content, while warming increased soil nitrate nitrogen content. Soil pH and organic carbon were not affected by either exclosure strategy, but nitrate nitrogen was the dominant soil factor explaining changes in bacterial communities. Conclusion: Our findings show that grazer exclosure increases soil microbial diversity which are effective soil restoration measures for degraded desert steppe, but this effect is weakened under warming conditions. Thus, global climate change should be considered when formulating restoration measures for degraded grasslands. [ABSTRACT FROM AUTHOR]

Legumes enhance pasture health and soil productivity by fixing atmospheric nitrogen and boosting soil microbiota. We investigated the effects of tropical pasture legumes, including butterfly pea (Clitoria ternatea), seca stylo (Stylosanthes scabra), desmanthus (Desmanthus virgatus), lablab (Lablab purpureus), and Wynn cassia (Chamaecrista rotundifolia), on the soil microbial community and buffel grass (Cenchrus ciliaris) gene expression. Additionally, we explored the impact of a phytogenic bioactive product (PHY) in the coculture system. A pot trial using soil enriched with cow paunch compost included four treatments: monoculture of buffel grass and five legume species with and without PHY supplementation and coculture of buffel grass with each legume species with and without PHY supplementation. Actinobacteriota and Firmicutes were the dominant bacterial phyla. Regardless of PHY application, the coculture of buffel grass with legumes positively influenced microbial composition and diversity. Transcriptomic analysis revealed significant gene expression changes in buffel grass shoots and roots, with each legume uniquely affecting nitrogen metabolism. Lablab and Wynn cassia exhibited similarities in modulating metabolic processes, butterfly pea contributed to mycotoxin detoxification, and desmanthus balanced cell death and growth. Seca stylo enhanced root cell growth and regeneration. These findings offer insights for optimizing legume–grass coculture systems, enhancing soil activity and promoting sustainable agriculture. [ABSTRACT FROM AUTHOR]

Despite conservation tillage being a promising strategy to mitigate soil degradation, the intricate role of microbial communities in shaping soil quality over long‐term tillage remains poorly understood. The study aimed to investigate the microbial mechanisms governing the soil quality index (SQI) and maize yield under different tillage practices spanning 13 years, including no‐till without straw retention (NT0), no‐till with straw retention (NTSR), plough tillage with straw retention (PTSR), and rotary tillage with straw retention (RTSR). The findings revealed that NTSR improved the SQI index by 22.4% and 11.3% higher than PTSR and RTSR, respectively, within the 0–10 cm soil layer. This improvement was correlated with an increase in maize yield (R2 = 0.39, p < 0.05). PERMANOVA analysis confirmed that both soil depth and tillage practices significantly impacted the composition of microbial communities (p < 0.05). Furthermore, conservation tillage, compared to PTSR and RTSR, increased the abundance of arbuscular mycorrhizal symbiosis by 78.6%–460.3% but decreased the saprophytic fungal abundance by 27.5%–28.3%. Soil quality was notably influenced by the interaction between bacterial and fungal communities. The presence of bacterial‐dominated Module 2 was associated with decreased soil quality in the 0–10 cm soil depth (r = −0.47, p < 0.01). This study emphasizes the pivotal role of microbial diversity and dominant taxa in driving soil quality after long‐term conservation tillage practices. Understanding these mechanisms is crucial for establishing farmland management to achieve agricultural and ecological sustainability in the face of climate change and soil degradation challenges. [ABSTRACT FROM AUTHOR]

Morels (Morchella spp.) are a kind of rare and precious edible fungus and have been successfully cultivated in many places. Currently, the widespread cultivation of morels poses a significant challenge owing to their demanding environmental requirements. Soil properties and the soil microbiome are thought to play pivotal roles in morel growth. However, it remains unknown what factors exert a decisive influence on morel growth. In this study, soils with different morel yields were studied in nine sites from four locations. The basic soil physical and chemical properties were measured. In addition, the soil microbiome was analyzed using high-throughput metagenomic sequencing. We found that soil pH, nitrogen, carbon and conductivity were key indicators for the impact on microbial communities in soil for cultivating morels. Among these, nitrate was more positively associated with morel yield. The soil microbial diversity was more abundant in the soil with a high morel yield. Moreover, certain unknown archaea might be unfavorable to morel growth. The microbes that perform incomplete denitrification (no step of N2O reduction to N2) and nitrogen fixation were positively and negatively correlated with morel growth, respectively. In summary, morels prefer to live in nutrient-rich soils with a variety of microbes and are supported by nitrate and microbiome components involved in denitrification. The findings elucidate a pivotal mechanism in eliciting morel fructification and provide valuable insights for guiding production practices. [ABSTRACT FROM AUTHOR]

Soils are the largest reservoir of microplastics (MPs) on earth. Since MPs can remain in soils for a very long time, their effects are magnified. In this study, different concentrations of polyethylene (PE) MPs derived from commercial resins (0%, 1%, 7%, and 14%, represented as MP_0, MP_1, MP_7, and MP_14) were added to soils to assess the changes in the soils' chemical properties, enzyme activities, and bacterial communities during a 70-day incubation period. The results show that PE MP treatments with low concentrations differed from other treatments in terms of exchangeable Ca and Mg, whereas at high concentrations, the pH and availability of phosphate ions differed. Fluorescein diacetate (FDA), acid phosphatase (ACP), and N-acetyl-β-d-glucosaminidase (NAG) enzyme activities exhibited a dose-related trend with the addition of the PE MPs; however, the average FDA and ACP activities were significantly affected only by MP_14. Changes in the microbial communities were observed at both the phylum and family levels with all PE MP treatments. It was revealed that even a low dosage of PE MPs in soils can affect the functional microbes, and a greater impact is observed on those that can survive in polluted environments with limited resources. [ABSTRACT FROM AUTHOR]

Over the past three decades, yellow poplar (Liriodendron tulipifera) has been widely employed in reforestation efforts across the country. This study delves into the potential influence of yellow poplar afforestation on the indigenous soil microbial demography within the original native stand. By scrutinizing microbial populations, a comprehensive understanding is sought. Utilizing pyrosequencing, a total of 92,300 sequencing reads were acquired from soil samples collected at seven distinct sites, each with two replicates. The comprehensive analysis unveiled the presence of 15 phyla, 158 families, 307 genera, and 439 distinct species. Notably, proteobacteria dominated at the phylum level, constituting 50% of the microbial presence, succeeded by acidobacteria (18%) and verrucomicrobia (10.7%). Remarkably, no significant disparities were observed in the microbial community composition across the yellow poplar, mixed, and pitch pine stands, spanning the phylum, family, and genus levels. Particularly noteworthy was the challenge of distinguishing between the microbial compositions of the mixed tree stand and the yellow poplar stand. Remarkably high-rank correlation coefficients underscored the striking similarity in microbe abundance between these two stands, indicating minimal variation in their microbial composition. The beta diversity index revealed parity between the microbial communities of the yellow poplar and mixed tree stands. However, a discernable contrast emerged in the soil microorganism composition of the pitch pine stand.

Fertilization significantly influences soil quality and its sustainable use in urban garden maintenance. The widespread application of inorganic fertilizers has raised ecological concerns due to their potential environmental impacts. Organic fertilizers, while beneficial, often have slow effects and are costly. Biofertilizers, with their eco-friendly nature and low carbon footprint, are gaining attention for their multifaceted role in supporting plant growth. Despite the focus on fruit trees, vegetables, and medicinal plants, ornamental plants have been understudied. This study aims to evaluate the efficacy of a novel microbial fertilizer, 'natural soil biotin', on Rhododendron plants, specifically the Azalea hybrid 'Carnation'. The study employed a comparative approach to assess the impact of different fertilization strategies on soil properties, microbial diversity, enzyme activity, plant morphology, and physiological parameters. The application of 'natural soil biotin' was compared with the use of inorganic and organic fertilizers. The combined application of 'natural soil biotin' was found to effectively enhance soil properties and mitigate the impact of other fertilizers on soil pH. It also improved the relative abundance of beneficial microbial groups such as Proteobacteria, Ascomycota, and Basidiomycota. Furthermore, the mixed application significantly increased the activities of urease and sucrase in Rhododendron plants, which promoted their growth, development, and stress resistance. The results indicate that the mixed application of 'natural soil biotin' with inorganic and organic fertilizers not only improved the soil quality but also enhanced the efficiency of fertilizer utilization. This approach led to increased economic and environmental benefits in Rhododendron cultivation. The findings contribute to the foundation for soil improvement and ecological restoration, suggesting that 'natural soil biotin' could be a promising alternative or supplement to traditional fertilization methods in sustainable landscape architecture. [ABSTRACT FROM AUTHOR]

Introduction: Panax notoginseng, a medicinal herb in China, is attacked by several pathogens during its cultivation. Dazomet (DZ) is a soil fumigant that is effective in controlling soil-borne pathogens, but its long-term effects on P. notoginseng growth and soil properties are unknown. Methods: We conducted field experiments over two consecutive years to assess the impact of three concentrations of DZ fumigation (35 kg/666.7 m2, 40 kg/666.7 m2, and 45 kg/666.7 m2) on soil physicochemical properties, microbial diversity, and P. notoginseng growth. Correlation analyses were performed between microbial community changes and soil properties, and functional predictions for soil microorganisms were conducted. Results: DZ fumigation increased total nitrogen, total phosphorus, total potassium, available phosphorus, available potassium, and ammonia nitrogen levels in the soil. DZ fumigation promoted the nutrient accumulation and improvement of agronomic traits of P. notoginseng, resulted in a 2.83-3.81X yield increase, with the highest total saponin content increasing by 24.06%. And the 40 kg/666.7 m2 treatment had the most favorable impact on P. notoginseng growth and saponin accumulation. After DZ fumigation, there was a decrease in the relative abundance of pathogenic fungi such as Fusarium, Plectosphaerella, and Ilyonectria, while beneficial bacteria such as Ramlibacter, Burkholderia, and Rhodanobacteria increased. The effects of fumigation on soil microorganisms and soil physicochemical properties persisted for 18 months post-fumigation. DZ fumigation enhanced the relative abundance of bacteria involved in the biosynthesis of secondary metabolites and arbuscular mycorrhizal fungi, reduced the relative abundance of plant-animal pathogenic fungi, reduced the occurrence of soil-borne diseases. Conclusion: In conclusion, DZ fumigation enhanced soil physicochemical properties, increased the proportion of beneficial bacteria in the soil, and rebalanced soil microorganism populations, consequently improving the growth environment of P. notoginseng and enhancing its growth, yield, and quality. This study offers a theoretical foundation for DZ fumigation as a potential solution to the continuous cropping issue in perennial medicinal plants such as P. notoginseng. [ABSTRACT FROM AUTHOR]

Although studies have explored how soil microbial diversity and soil multifunctionality respond to land‐use change at local scales, they have rarely been explored at larger scales and across different climatic and soil environmental conditions. By sampling 40 paired sites of land‐use change from natural forests to agricultural lands (including croplands and orchards) along the middle and lower Yangtze River, combined with a global meta‐analysis, we investigated the effects of land‐use change and climate on the alpha and beta diversity of soil bacterial and fungal functional groups (FGs) and their associated soil multifunctionality at a regional scale. Our results showed that land‐use change strongly changed the diversity of soil bacterial and fungal FGs and decreased multifunctionality, which was supported by our meta‐analysis at a global scale. Direct effects of land‐use change and climate and their interaction, together with changes in soil environmental variables, were the main determinants of the land‐use change‐induced changes in the diversity of soil bacterial or fungal FGs. The land‐use change‐induced decrease in multifunctionality was mainly associated with the direct effect of forest conversion, soil fertility and diversity of fungal FGs. Furthermore, climate also regulated the effects of land‐use change on multifunctionality by affecting soil fertility and fungal FGs diversity along the Yangtze River. Synthesis and applications. Taken together, our findings highlight the important effects of land‐use change, climate and their interactions on microbial diversity and multifunctionality and suggest that effective land‐use management and climate change mitigation strategies should be adopted to protect biodiversity and ecosystem function in the Yangtze River Basin. [ABSTRACT FROM AUTHOR]

Interest in improving plant nitrogen use efficiency (NUE) in conjunction with reduced usage of nitrogen (N) fertilizers in forestry management is growing. Although biochar amendment is widely applied to increase soil nutrient availability and NUE, the mechanism underlying their positive effects remains little understood. We treated the economically important eucalypt species with biochar (BC), N-enriched fertilizer with 15N isotope labeling (NF), and biochar plus 15N-labeled fertilizer (NFB). Moreover, we determined plant N absorption and soil N availability, soil bacterial community composition and its putative keystone taxa, and plant NUE and competition index under different treatments. Our results indicated that NF and NFB significantly increased plant atom % 15N in both eucalypt stem, root, and foliar, as well as the competition index of eucalypt to forbs for acquiring N. NF and BC increased the network complexity of keystone taxa by shifting putative keystone taxa, including phylum Proteobacteria, Chloroflexi, Actinobacteria, Acidobacteria, and Firmicutes. Piecewise structural equation modeling indicated that variations in plant performance were best directly and positively predicted by soil Proteobacteria. This study highlights the importance of interactive effects between biochar and N fertilizer on plant performance mediated by soil microbial community. The change in soil putative keystone taxa has the potential to be a suitable predictor for plant performance in terms of biochar. Our findings may provide important implications for improving fertilization and afforestation management. [ABSTRACT FROM AUTHOR]

Lactarius hatsudake Tanaka is a mycorrhizal edible mushroom with an appealing taste and rich nutrition. It is also a significant food and has medicinal value. In this study, the plantation of L. hatsudake during the harvest period was taken as the research object, and this article explores which bacteria in the soil contribute to the production and growth of L. hatsudake. The soil of the control (CK) and the soil of the mushroom-producing area [including the soil of the base of the mushroom (JT) and the mycorrhizal root soil (JG)] was collected in the plantation. The three sites' bacterial community structure and soil diversity were analyzed using high-throughput sequencing technology, and a molecular ecological network was built. Soil bacteria in the L. hatsudake plantation had 28 tribes, 74 classes, 161 orders, 264 families, 498 genera, and 546 species. The dominant phyla were Proteobacteria and Acidobacteria, and the dominant genera were Burkholderia_Caballeronia_Paraburkholderia, Acidothermus, Bradyrhizobium, Candidatus_Xiphinematobacter, and Granulicella. The α-diversity of soil bacteria in JT was significantly lower than that in JG and CK, and the β-diversity in JT samples was significantly different from that in JG and CK samples. The size and complexity of the constructed network were smaller in JT samples than in JG and CK samples, and the stability was higher in JT samples than in JG and CK samples. The positive correlation between species in JT samples was dominant. The potential mycorrhizal helper bacteria (MHB) species of L. hatsudake was determined using correlation and differential group analysis. The results support future research on mycorrhizal synthesis, plantation management, and the function of microorganisms in the soil rhizosphere of L. hatsudake. [ABSTRACT FROM AUTHOR]

Sustainable crop production systems should promote large and diverse soil microbial communities to enhance biological soil processes rather than depend solely on chemical interventions that include pesticide applications. Crop rotation increases above-ground temporal diversity which, relative to monoculture, usually increases soil microbial diversity. But comparisons between short and long crop rotations that also include pesticide effects are rare. A 5-yr (2013-2017) field study was conducted to investigate crop rotation and fungicide effects on the soil microbiome and activity. There were nine rotations, with or without fungicide applications, that included four 2-yr rotations (wheat preceded by canola, barley, pea, or flax), four 3-yr rotations where barley or canola were added to the 2-yr rotations, and one rotation where canola and wheat were stacked (canola-canola-wheat-wheat). In 2017, soil microbial biomass, composition, diversity and enzyme activities were measured in the rhizosphere of the final wheat crop in each rotation. Fungicides reduced fungal richness (the number of different fungal taxa) in the wheat rhizosphere (e.g., Chao1 indices of 64.0 vs. 79.9) especially in 2-yr rotations, but rotation length/type and the crops that preceded wheat had different effects on different taxa. Two of the three most predominant prokaryotic phyla, Proteobacteriota and Actinobacteriota, responded differently to rotation length: 3-yr rotations enriched the former (27.4% vs. 20.1% relative abundances), but 2-yr rotations enriched the latter (19.9% vs. 28.3% relative abundances). Relative to oilseed crops preceding the sampled wheat, a field pea preceding crop enriched Actinobacteriota (31.7% vs. 24.8% relative abundances) and the most abundant fungal class, Sordariomycetes (39.1% vs. 22.1% relative abundances), in addition to increasing microbial biomass carbon (MBC) and arylsulphatase activity by 33% and 57%, respectively. Correlations of the relative abundances of fungal or prokaryotic genera with β-glucosidase and arylsulphatase activities were similar (both positive or negative), but they were the opposite of correlations with acid phosphomonoesterase, suggesting a close link between C and S cycling. Besides the nutrient cycling implications of these soil microbial characteristics, there is need to study their biological disease control significance.

Abstract Yerba mate (Ilex paraguariensis) represents a culture of economic, social, and ecological importance for the cultivation regions. Due to the chemical, physical, and biological variations that occur in the different soils where yerba mate is economically exploited, the symbiotic associations with arbuscular mycorrhizal fungi (AMF) guarantee the plant's ability to absorb nutrients. The purpose of this study was to identify and quantify the occurrence of arbuscular mycorrhizal fungi in different environments of yerba mate cultivation. The research was performed in four areas located in the rural area of the municipality of Seberi/RS: Environment with production of yerba mate in the conventional system, silvopastoral system, organic system, and native forest. The normality of residuals and homogeneity of variances assumptions were verified using the Lilliefors and Chi-square tests and the averages compared by the Tukey's test at 5% probability of error. In addition to calculations of diversity, equivalent species, and evenness indices. The presence of AMF spores showed a direct relationship with the phosphorus (P) availability in each treatment, with a count reduction in the organic system, with P content lower than 3 mg kg-1 of soil. The species with the highest predominance were the Acaulosporaceae (Acaulospora colombiana, A. delicata, and A. tuberculata), followed by the Glomaceae (Glomus ambisporum and Glomus pansihalos) in the conventional and silvopastoral systems. The silvopastoral and conventional systems showed the highest levels of Shannon-Weaver diversity (H') and Pielou's evenness, demonstrating greater diversity and consequently greater richness and uniformity.

Biodiversity is widely recognized as a crucial factor in driving ecosystem functioning. However, the processes that sustain forest ecosystem multifunctionality (EMF) through plant and soil microbial diversity are not yet fully understood. Here, we assessed eight ecosystem functions in a mixed temperate forest using averaging and weighted threshold methods to examine the associations between EMF and diversity across environmental gradients. The findings indicated that structural attributes serve as the optimal predictor of EMF. Both complementarity and selection effects had minor impacts on EMF, while the jack-of-all-trades effect drove the relationship between plant diversity and EMF. EMF was positively correlated with soil fungal diversity but negatively correlated with soil bacterial diversity. Soil microbial diversity influenced forest EMF by regulating the trade-offs between different functions. Additionally, we noted that forests situated on steep slopes may experience limitations in terms of multifunctionality, while nutrient-rich soils had a facilitative effect. This study underscores the significance of taking into account both aboveground and belowground diversity to improve forest functions. Within a certain range, more complex and diverse stand structures are effective strategies for sustainable forest management.

The TRIAD approach is widely used as a scientific methodology available to deal with site-specific contamination scenarios. In this study, a soil environmental risk assessments (SERA) of ten industrial sites in China was conducted by ranking risks across multiple sites based on the TRIAD method, and attempted to provide an alternative method for risk ranking, the VIKOR method, when reference screening values for assessing individual indicators are unavailable. The VIKOR method was developed to address ranking and selection problems in multi-criteria decision-making, particularly in complex decision environments. The present assessments analyzed 33 chemical analysis indicators, 14 ecotoxicological indicators, and 5 ecological indicators related to soil microbial diversity, subsequently compared and discuss the differences in risk ranking results obtained using the two methods. The results of the TRIAD approach showed that six sites (including F, G, E, B, J and I) were ranked high in the risk order, which were in the moderate-risk range (Integrated risk value, 0.5–0.75). While the results of the VIKOR method showed that four sites (including F, G, H, and E) were ranked high in the risk order, followed by another four sites (including D, A, B, and C). Although there were differences in the assessment results, both methods consistently identified three sites (including F, G, and E) with relatively higher risks. The results indicated that when the TRIAD method is not applicable in special cases, the VIKOR comprehensive evaluation can be used to infer the relative ecological risk of the assessed site.

Soil salinization is a global constraint that significantly hampers agricultural production, with cotton being an important cash crop that is not immune to its detrimental effects. The rhizosphere microbiome plays a critical role in plant health and growth, which assists plants in resisting adverse abiotic stresses including soil salinization. This study explores the impact of soil salinization on cotton, including its effects on growth, yield, soil physical and chemical properties, as well as soil bacterial community structures. The results of β-diversity analysis showed that there were significant differences in bacterial communities in salinealkali soil at different growth stages of cotton. Besides, the more severity of soil salinization, the more abundance of Proteobacteria, Bacteroidota enriched in rhizosphere bacterial composition where the abundance of Acidobacteriota exhibited the opposite trend. And the co-occurrence network analysis showed that soil salinization affected the complexity of soil bacterial co-occurrence network. These findings provide valuable insights into the mechanisms by which soil salinization affects soil microorganisms in cotton rhizosphere soil and offer guidance for improving soil salinization using beneficial microorganisms. [ABSTRACT FROM AUTHOR]

This study analyzed the impact of leachate from a temporary landfill on soil microbial diversity in Tingo María, Huánuco region, Peru. Three treatments were used: untreated soil (S), addition of stream water (T0), leachate (T1), and leachate treated by coagulation and flocculation (T2), with 828.5 ml/week added in three weekly doses. Soil samples were collected from the Reserved Forest of the Universidad Nacional Agraria de la Selva. Twenty-one randomly distributed soil samples were taken and homogenized for analysis. Soil quality parameters measured included sand, clay, silt, texture, pH, organic matter, nitrogen, phosphorus and potassium. As for microorganisms, viable aerobes, lactobacilli, actinomycetes, fungi, nitrogen-fixing bacteria, and Escherichia coli were quantified using specific culture and counting methods for each of them. To evaluate the impact of the leachate on microbial diversity, equity indices (Shannon and inverse Simpson), dominance indices (complementary Simpson and Berger Parker) and the percentage composition of each microorganism per treatment were used. An ANOVA was performed to estimate differences in microbial diversity, with a Tukey test at a significance level of α = 0.05. The study showed that leachates affect soil microbial diversity, reducing equity and increasing the dominance of certain species such as E. coli. They also alter physicochemical parameters, decreasing organic matter and nitrogen but increasing other elements such as phosphorus and potassium. This could have implications for soil health and functionality. [ABSTRACT FROM AUTHOR]

Halophyte-based remediation emerges as a novel strategy for ameliorating saline soils, offering a sustainable alternative to conventional leaching methods. While bioremediation is recognized for its ability to energize soil fertility and structure, the complex interplays among plant traits, soil functions, and soil microbial diversity remain greatly unknown. Here, we conducted a 5-year field experiment involving the continuous cultivation of the annual halophyte Suaeda salsa in saline soils to explore soil microbial diversity and their relationships with plant traits and soil functions. Our findings demonstrate that a decline in soil salinity corresponded with increases in the biomass and seed yield of S. salsa, which sustained a consistent seed oil content of approximately 22% across various salinity levels. Significantly, prolonged cultivation of halophytes substantially augmented soil microbial diversity, particularly from the third year of cultivation. Moreover, we identified positive associations between soil multifunctionality, seed yield, and taxonomic richness within a pivotal microbial network module. Soils enriched with taxa from this module showed enhanced multifunctionality and greater seed yields, correlating with the presence of functional genes implicated in nitrogen fixation and nitrification. Genomic analysis suggests that these taxa have elevated gene copy numbers of crucial functional genes related to nutrient cycling. Overall, our study emphasizes that the continuous cultivation of S. salsa enhances soil microbial diversity and recovers soil multifunctionality, expanding the understanding of plant-soil-microbe feedback in bioremediation. IMPORTANCE The restoration of saline soils utilizing euhalophytes offers a viable alternative to conventional irrigation techniques for salt abatement and soil quality enhancement. The ongoing cultivation of the annual Suaeda salsa and its associated plant traits, soil microbial diversity, and functionalities are, however, largely underexplored. Our investigation sheds light on these dynamics, revealing that cultivation of S. salsa sustains robust plant productivity while fostering soil microbial diversity and multifunctionality. Notably, the links between enhanced soil multifunctionality, increased seed yield, and network-dependent taxa were found, emphasizing the importance of key microbial taxa linked with functional genes vital to nitrogen fixation and nitri fication. These findings introduce a novel understanding of the role of soil microbes in bioremediation and advance our knowledge of the ecological processes that are vital for the rehabilitation of saline environments. [ABSTRACT FROM AUTHOR]

Introduction: Modern agriculture emphasizes the design of cropping systems using ecological function and production services to achieve sustainability. The functional characteristics of plants (grasses vs. legumes) affect changes in soil microbial communities that drive agroecosystem services. Information on the relationship between legume-grass mixtures and soil microorganisms in different ecological zones guides decision-making toward eco-friendly and sustainable forage production. However, it is still poorly understood how cropping patterns affect soil microbial diversity in alpine grasslands and whether this effect varies with altitude. Methods: To fill this gap in knowledge, we conducted a field study to investigate the effects of growing oats (Avena sativa L.), forage peas (Pisum sativum L.), common cornflower (Vicia sativa L.), and fava beans (Vicia faba L.) in monocultures and mixtures on the soil microbial communities in three ecological zones of the high alpine zone. Results: We found that the fungal and bacterial community structure differed among the cropping patterns, particularly the community structure of the legume mixed cropping pattern was very different from that of monocropped oats. In all ecological zones, mixed cropping significantly (p < 0.05) increased the a-diversity of the soil bacteria and fungi compared to oat monoculture. The a-diversity of the soil bacteria tended to increase with increasing elevation (MY [2,513m] < HZ [2,661m] < GN [3,203m]), while the opposite was true for fungi (except for the Chao1 index in HZ, which was the lowest). Mixed cropping increased the abundance of soil fungi and bacteria across ecological zones, particularly the relative abundances of Nitrospira, Nitrososphaera, Phytophthora, and Acari. Factors affecting the bacterial community structure included the cropping pattern, the ecological zone, water content, nitrate-nitrogen, nitrate reductase, and soil capacity, whereas factors affecting fungal community structure included the cropping pattern, the ecological zone, water content, pH, microbial biomass nitrogen, and catalase. Discussion: Our study highlights the variation in soil microbial communities among different in alpine ecological regions and their resilience to cropping systems. Our results also underscore that mixed legume planting is a sustainable and effective forage management practice for the Tibetan Plateau. [ABSTRACT FROM AUTHOR]

Mixing with different broadleaf trees into the monocultures of Cunninghamia lanceolata is widely adopted as an efficient transformation of the pure C. lanceolata forest. However, it is unclear how native broad-leaved trees influence the belowground ecological environment of the pure C. lanceolata culture plantation in nutrient-poor soil of South China. Herein, we aimed to investigate how a long-time mixing with native broadleaf trees shape soil microbial community of the pure C. lanceolata forest across different soil depth (0-20cm and 20-40cm) and to clarify relationships between the modified soil microbial community and those affected soil chemical properties. Using high-throughput sequencing technology, microbial compositions from the mixed C. lanceolata-broadleaf forest and the pure C. lanceolata forest were analyzed. Network analysis was utilized to investigate correlations among microorganisms, and network robustness was assessed by calculating network natural connectivity. Results demonstrated that the content of soil microbial biomass carbon and nitrogen, total phosphorus and pH in mixed forest stand were significantly higher than those in pure forest stand, except for available phosphorus in topsoil (0-20cm). Simultaneously, the mixed C. lanceolata-broadleaf forest has a more homogeneous bacterial and fungal communities across different soil depth compared with the pure C. lanceolata forest, wherein the mixed forest recruited more diverse bacterial community in subsoil (20-40cm) and reduced the diversity of fungal community in topsoil. Meanwhile, the mixed forest showed higher bacterial community stability while the pure forest showed higher fungal community stability. Moreover, bacterial communities showed significant correlations with various soil chemical indicators, whereas fungal communities exhibited correlations with only TP and pH. Therefore, the mixed C. lanceolata-broadleaf forest rely on their recruiting bacterial community to enhance and maintain the higher nutrient status of soil while the pure C. lanceolata forest rely on some specific fungi to satisfy their phosphorus requirement for survive strategy. [ABSTRACT FROM AUTHOR]

Soil extracellular enzymes play an important role in regulating nitrogen (N) mineralization processes in paddy fields. Therefore, in this work, we determine the influence of a long-term fertilizer regime on rhizosphere soil N fertilization rates, soil enzymes, soil microbial community (bacterial ureolytic community (ureC), bacterial chitinolytic community (chiA)) under the double-cropping rice field in southern of China. The field experiment included the following fertilizer regimes: inorganic fertilizer alone (IF), rice straw and inorganic fertilizer (RF), 30% organic manure and 70% inorganic fertilizer (OM), without any fertilizer input as a control (CK). The results showed that rhizosphere soil N transformation rates in the paddy fields with OM and RF treatments were increased, compared with IF and CK treatments. Soil urease, β-glucosaminidase and arginase activities were significantly increased under OM and RF treatments. This result indicated that functional gene abundances of sub, npr and chiA were significantly greater under RF and OM treatments compared to IF and CK treatments. Soil bacterial ureolytic and chitinolytic communities were significantly changed by the different fertilization strategies. The practice of applying rice straw and organic manure seems beneficial for increasing rhizosphere soil N mineralization rates and microbial community diversity in the double-cropping rice fields. [ABSTRACT FROM AUTHOR]

Background. In a context of long-term highly intensive grazing in grassland ecosystems, a better understanding of how quickly belowground biodiversity responds to grazing is required, especially for soil microbial diversity. Methods. In this study, we conducted a grazing experiment which included the CK (no grazing with a fenced enclosure undisturbed by livestock), light and heavy grazing treatments in a desert steppe in Inner Mongolia, China. Microbial diversity and soil chemical properties (i.e., pH value, organic carbon, inorganic nitrogen (IN, NH+4 -N and NO-3-N), total carbon, nitrogen, phosphorus, and available phosphorus content) both in rhizosphere and non-rhizosphere soils were analyzed to explore the responses of microbial diversity to grazing intensity and the underlying mechanisms. Results. The results showed that heavy grazing only deceased bacterial diversity in the non-rhizosphere soil, but had no any significant effects on fungal diversity regardless of rhizosphere or non-rhizosphere soils. Bacterial diversity in the rhizosphere soil was higher than that of non-rhizosphere soil only in the heavy grazing treatment. Also, heavy grazing significantly increased soil pH value but deceased NH4+-N and available phosphorus in the non-rhizosphere soil. Spearman correlation analysis showed that soil pH value was significantly negatively correlated with the bacterial diversity in the non-rhizosphere soil. Combined, our results suggest that heavy grazing decreased soil bacterial diversity in the non-rhizosphere soil by increasing soil pH value, which may be due to the accumulation of dung and urine from livestock. Our results highlight that soil pH value may be the main factor driving soil microbial diversity in grazing ecosystems, and these results can provide scientific basis for grassland management and ecological restoration in arid and semi-arid area. [ABSTRACT FROM AUTHOR]

Purpose: Biochar has been proven to mitigate the detrimental impacts on the high use of nitrogen (N) fertilizer on vegetable yield by influencing the microbial community, but the impacts on the microbial pathway of biochar remain unclear. Methods: A pot experiment of pakchoi was conducted with eight treatments, including normal level (100 mg N kg−1: N1) and high level (200 mg N kg−1: N2) of N fertilizer treatments, as well as four biochar levels (0%: B0, 0.5% w/w: B05, 1% w/w: B1, and 2% w/w: B2) to determine its practical effects. Results: High nitrogen fertilizer significantly reduced pakchoi yield. Biochar increased the pakchoi yield by 13.46–55.76% at N1 and 53.3–75.56% at N2, but the effect of the application of biochar on pakchoi yield rates was not significant. The bacterial and fungal diversity was significantly increased by biochar but was decreased by high N in vegetable soil. Soil bacterial communities were dominated by Proteobacteria, Actinobacteriota, Gemmatimonadota, Acidobacteriota, and Chloroflexi, while soil fungal communities were dominated by Ascomycota, Chytridiomycota, Mortierellomycota, and Basidiomycota. Biochar and nitrogen fertilizer all changed the bacterial and fungal community composition. Conclusions: Biochar enhanced the pakchoi yield through regulated bacterial communities, but the regulatory pathways vary under different N levels. It enhanced the prevalence of beneficial species involved in disease suppression and supported the soil organic matter degradation, thereby resulting in increased vegetable yield at N1. It increased the abundance of eutrophic species, which were related to the available nutrients in the soil and its retention capacity to improve the yield at N2. It was noteworthy that biochar could increase the risk of vegetable yield reduction by reduction of nutrient cycling phylum and enhancement of soil-borne plant pathogens at a higher nitrogen level. [ABSTRACT FROM AUTHOR]

Soil structure is important for plant growth and ecosystem functioning, and provides habitat for a wide range of soil biota. So far, very few studies directly compared the effects of three main farming practices (conventional, organic and conservation agriculture) on soil structure and soil physical properties. Here, we collected undisturbed soil cores from the FArming System and Tillage long-term field experiment (FAST) near Zurich (Switzerland). This trial compares the effects of conventional tillage, conventional no-tillage, organic tillage and non-inversion reduced tillage under organic farming since 2009. We assessed 28 soil chemical and physical properties and related them to root and microbial biomass as well as to the diversity of bacteria and fungi. Tillage decreased bulk density (−14 %) and penetration resistance (−40 %) compared to no/reduce-tillage, potentially promoting a facilitative environment for plant root growth. Water holding capacity varied among systems, being the lowest in conventional tillage and highest (+10 %) in organic reduced tillage. We observed that microbial biomass and rhizosphere microbial diversity was positively associated with water holding capacity and the occurrence of mesopores. The presence of mesopores could provide additional niche space for microbes possibly explaining its positive effect on microbial diversity. Soil microbial biomass and rhizosphere microbial diversity were higher in plots subjected to soil conservation practices, indicating that tillage has a detrimental effect on soil microbes. Our work demonstrates that organic, conventional and conservation agriculture create contrasting soil physical environments. This work highlights the trade-off between creating a facilitative environment for root growth by tillage and maintaining complex and diverse soil microhabitats for microbes under conservation agriculture.

Legumes enhance pasture health and soil productivity by fixing atmospheric nitrogen and boosting soil microbiota. We investigated the effects of tropical pasture legumes, including butterfly pea (Clitoria ternatea), seca stylo (Stylosanthes scabra), desmanthus (Desmanthus virgatus), lablab (Lablab purpureus), and Wynn cassia (Chamaecrista rotundifolia), on the soil microbial community and buffel grass (Cenchrus ciliaris) gene expression. Additionally, we explored the impact of a phytogenic bioactive product (PHY) in the coculture system. A pot trial using soil enriched with cow paunch compost included four treatments: monoculture of buffel grass and five legume species with and without PHY supplementation and coculture of buffel grass with each legume species with and without PHY supplementation. Actinobacteriota and Firmicutes were the dominant bacterial phyla. Regardless of PHY application, the coculture of buffel grass with legumes positively influenced microbial composition and diversity. Transcriptomic analysis revealed significant gene expression changes in buffel grass shoots and roots, with each legume uniquely affecting nitrogen metabolism. Lablab and Wynn cassia exhibited similarities in modulating metabolic processes, butterfly pea contributed to mycotoxin detoxification, and desmanthus balanced cell death and growth. Seca stylo enhanced root cell growth and regeneration. These findings offer insights for optimizing legume–grass coculture systems, enhancing soil activity and promoting sustainable agriculture.

Covering about 30% of the global total land area, desert ecosystems have been influenced by warming and nitrogen deposition. However, it remains unclear how desert ecosystems respond to warming and nitrogen deposition. Therefore, we conducted a greenhouse experiment to examine the impacts of N addition and warming on the plant–soil system of Neotrinia splendens, the dominant plant in the desert ecosystem in Northern China. Our findings revealed that low-N dose (N1) and high-N dose additions (N2) increased the biomass by 22.83% and 54.23%, respectively; meanwhile, moderate warming (T2) and severe warming (T3) decreased the biomass by 39.07% and 45.47%, respectively. N addition did not significantly affect the C:N:P stoichiometry in the plant–soil system. T2 and T3 decreased the leaf N content by 17.50% and 16.20%, respectively, and decreased the leaf P content by 10.61% and 45.29%, respectively. This resulted in the plant C:N ratio, C:P ratio, and N:P ratio increasing with warming. Furthermore, warming or N addition not only decreased soil microbial diversity, but also inhibited microbial genera associated with nutrient cycling, such as that of Tumebacillus spp., Bacillus spp., and Mortierella spp.; it additionally influenced important bacterial functions, such as nitrate reduction and ureolysis. Moreover, warming and N addition induced P limitation in the plant–soil system by inhibiting soil microorganisms, such as Mortierella spp. and Bacillus spp., which are associated with P transformation; this was also brought about by increasing the effects of leaf P content on leaf N:P. In conclusion, our results showed that warming and N addition had significant effects on the C:N:P stoichiometry of the plant–soil system through microbial mediation and led to P limitation in the system, regardless of how they affected biomass. Soil microorganisms could mediate the impacts of environmental changes on the plant–soil system. Our findings may provide valuable insights for adjusting vegetation restoration strategies in desert ecosystems under environmental changes. [ABSTRACT FROM AUTHOR]

Currently, there is a noticeable scarcity of applications that harness composite microbial inoculants to stimulate straw decomposition, nitrogen fixation, and crop growth. This study addresses this gap by selecting and coculturing three bacterial strains to create a composite microbial inoculant named HY-1. This innovative inoculant exhibits multifunctional capabilities, including nitrogen fixation, straw decomposition, and crop growth promotion. Furthermore, we aimed to explore its impact on soil microbial communities. The results showed that the optimal preparation conditions for the compound microbial inoculant HY-1 were 28.5 ± 0.6 °C, pH = 7.34 ± 0.40, and bacteriophage ratio 1:2:1 (Microbacterium: Streptomyces fasciatus: Bacillus amyloliquefaciens). Compared to single strains, the combination exhibited higher levels of cellulose-degrading and nitrogen-fixing enzyme activity, increased the straw degradation rate by 37.91% within 180 days, and significantly promoted the growth of corn seedlings. Under the condition of straw return, the compound bio-fungicide HY-1 effectively improved the soil microbial diversity. At that time, the soil had the highest number of unique bacterial operational taxonomic units (166), and the abundance of Proteobacteria in the soil increased by 7.24%, while that of Acidobacteriota decreased by 2.27%. The biosynthetic function of the cell wall/membrane/periplasm and the metabolic function of transporting inorganic ions were significantly enhanced. In this study, we discovered that employing coculturing techniques to produce the composite microbial inoculant HY-1 and applying it in the field effectively compensates for the limitations of single-strain inoculants, which often exhibit fewer functions and less pronounced effects. This approach demonstrates significant potential for enhancing the quality of agricultural soils. [ABSTRACT FROM AUTHOR]

Soil physicochemical properties affect crop growth and yield. The addition of fertilizers can improve the soil quality during crop cultivation, leading to increased agricultural production. Organic fertilizers may be produced by composting straw that would otherwise be discarded as agricultural waste, with potential implications for sustainable agricultural development. However, the mechanism underlying the effects of straw compost on crop growth is unknown. In this study, a microbial agent suitable for straw decomposition in cold regions was used for a large-scale biological fermentation. Organic compost was obtained after the decomposition of straw. The straw compost was mixed with soil in different proportions and then used to cultivate Songjing 2 rice plants. The addition of straw compost significantly increased the growth and yield of the rice plants and enhanced various physiological indices. Moreover, the straw compost treatment significantly improved soil physicochemical properties (e.g., pH, enzyme activity, nutrient composition, and microbial diversity) and optimized the soil conditions for crop growth. In addition, the application of straw compost influenced the expression of genes in rice metabolic pathways as well as pathways mediating secondary metabolite synthesis and plant hormone signal transduction. The study data reflect the potential applicability of low-temperature straw fermentation technology for maximizing crop production. [ABSTRACT FROM AUTHOR]

Cigar tobacco, an economically important cash crop, holds a substantial role within the fiscal framework of the national economy. This crop, however, is characterized by a marked vulnerability to pathogenic bacteria, culminating in consequential financial loss throughout its cultivation phase. Plant growth-promoting rhizobacteria (PGPR), a salient class of advantageous bacterial flora, are recognized for their ability to enhance plant growth, inhibit deleterious pathogens, and synthesize compounds that either have a direct impact on plant morphogenesis or activate otherwise ineffectual soil components. Through these mechanisms, PGPR augments the soil's nutritional profile, making it more receptive to plant uptake, thus stimulating vegetative growth. The Bacillus subtilis microbial fertilizer, the prime exemplar of PGPR, demonstrates not only a pathogen-suppressive effect but also an induction of the plant's innate disease resistance mechanism. This bolsters the plant's resilience to disease fosters a probiotic milieu within the soil, and catalyzes the formation of agglomerate structures, all of which contribute to enhanced soil fertility and moisture retention, increased soil friability, and the facilitation of root expansion. In this study, a controlled pot experiment was conducted to elucidate the mechanism through which inter-root probiotics rehabilitate the soil's ecosystem and foster crop growth in cigar tobacco seedlings afflicted with root black rot bacteria. Four treatments were instituted, including CK: a blank control (no microbial application); A: probiotic only (Bacillus subtilis microbial fertilizer); B: both pathogenic and probiotic (the Bacillus subtilis microbial fertilizer together with root black rot pathogen); C: pathogenic only (the root black rot pathogen). Our empirical findings delineate that the presence of pathogenic bacteria deteriorates the soil environment, thereby constraining the transmutation of soil nutrients and their subsequent assimilation by plants. This severely impedes the vegetative development of cigar plants. By contrast, the application of a PGPR microbial fertilizer modified the soil microbial community structure, exhibiting an antagonistic interaction with the indigenous pathogenic bacterial species. Relative to the CK treatment, the application of the Bacillus subtilis microbial fertilizer was found to invigorate the catalytic conversion of soil enzymes, incrementing the peroxidase, acid phosphatase, urease, and sucrase activity by 12.98%, 19.55%, 13.57%, and 17.91%, respectively. Meanwhile, it was observed to ameliorate the soil's physicochemical attributes, enhancing the available content of nitrogen, phosphorus, and potassium by 4.52%, 6.52%, and 15.14%, respectively, along with the augmentation of soil organic matter content by 17.33%. The fortification of soil physicochemical properties and the enrichment of soil fertility, as a result of the PGPR microbial fertilizer application, translated into a robust 57.23% enhancement of root vigor and a 60.47% extension of the root length of cigar tobacco seedlings. These soil amendments subsequently fueled an uptick in the growth parameters of cigar plants, including increases in plant height, stem girth, leaf count, maximal leaf dimensions, and both the fresh and dry weight of cigar tobacco. [ABSTRACT FROM AUTHOR]

The world is facing a hidden hunger crisis, where millions of people are suffering from nutritional deficiencies despite having access to food. While much research has focused on the quality and quantity of food, recent studies have shown that soil microbial diversity may also play a crucial role in human nutrition. Soil microbes interact with plants in complex ways, influencing the absorption of nutrients and producing compounds that are essential for human health. However, factors such as intensive agriculture, climate change, and soil pollution can lead to a decline in soil microbial diversity, which may contribute to the rise of hidden hunger. In this paper, we explore the link between soil microbial diversity and nutritional deficiencies, examining the latest research on the topic and discussing potential solutions to this pressing global issue. Our findings suggest that promoting soil health and biodiversity could be a key strategy for addressing hidden hunger and improving global nutrition. [ABSTRACT FROM AUTHOR]

Defoliation, often induced by herbivores, and soil microbiomes are recognized as key drivers of plant diversity and productivity in grasslands. However, lack of experiments simultaneously manipulating defoliation and soil microbial diversity has constrained our understanding of how these two factors interactively influence both above‐ground and below‐ground net primary productivity (ANPP and BNPP).We employed a soil filtering approach to create the gradient of soil microbial diversity and removal of above‐ground biomass by clipping to simulate defoliation effect from herbivores. Our goal was to investigate how soil microbial diversity affected both ANPP and BNPP under the stress of defoliation.We found that defoliation and soil microbial diversity loss decreased the ANPP and BNPP of the plant community, and Medicago falcata (legume) was more responsive to these treatments than Leymus chinensis (grass) and Artemisia frigida (forb). ANPP was positively correlated with soil microbial richness only when plants suffered defoliation. By contrast, BNPP showed a closer relationship with soil fungal richness than bacteria, and defoliation enhanced this relationship. The structural equation model (SEM) showed that defoliation indirectly regulated ANPP by affecting plant P content, while soil bacterial diversity loss decreased the ANPP through altering plant P and fungal diversity loss directly decreased BNPP. The LEfSe and linear regression analysis revealed that the biomarkers of bacteria (e.g. Actinobacteria, Xanthobacteraceae) and fungi (e.g. Ascomycota, Glomerales) significantly contributed to the variation of ANPP and BNPP under defoliation treatment respectively. Defoliation enhanced phosphorus acquisition by soil microorganisms, further strengthening the microbial regulation of plant productivity.Overall, we provide novel insights on how defoliation enhances the positive effects of soil microbial diversity on above‐ and below‐ground net primary productivity. Our findings highlight that soil microorganisms associated with phosphorus cycling are mobilized to play a more active role in promoting productivity after defoliation. It may provide a new perspective on how to better utilize the role of soil microorganisms in grazed or managed grasslands. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Vegetation blanket restoration of mine soils provides a diverse environment for soil microbes, but the effects of vegetation blanket cover on soil physicochemical properties, microbial structure, and diversity are not well understood, particularly in arid areas. In this study, high‐throughput sequencing was used to examine the microbial community at Dafeng Mine, the Helan Mountains, Ningxia, China. Soil microbial communities were analyzed with four different materials: 100% straw, 50% straw–50% coconut, and 100% coconut vegetation blanket types, and a bare ground control (CK). The results showed that the contents of soil total nitrogen (TN), available potassium (AP), urease, and catalase were significantly increased in different types of vegetation blankets. High‐throughput sequencing showed that the straw vegetation blanket increased bacterial diversity, while the coconut vegetation blanket increased fungal diversity. The main influencing factors of the dominant bacterial phylum were total nitrogen, catalase, urease, protease, soil water content (WC), soil organic carbon (SOC), and electrical conductivity (EC). The main influencing factor of the dominant fungal phylum was soil water content. These results show that compared with straw vegetation blankets, coconut, and straw–coconut vegetation blanket mulches are more likely to improve soil physicochemical properties, increase the diversity and abundance of soil microorganisms and improve the structural composition of the community, thus improving the soil environment in dryland mining areas. However, further research is needed as to which is the more significant environmental improvement, coconut or straw–coconut vegetation blankets. [ABSTRACT FROM AUTHOR]

Global warming may exacerbate cropland soil drought, affect microbial systems, and decrease grain yield. However, the compensatory effects of supplementary irrigation on winter wheat yield and soil microbial communities under increased temperatures have not been fully studied. Here, a three-year field experiment was conducted, to verify the effects of warming treatments (WS: winter and spring warming; FF: flowering and filling period warming) and irrigation (W0: conventional irrigation; W1: supplemental irrigation) on crop-soil systems during the winter wheat growth stages. The results demonstrated that warming measures have significant negative effects on the net assimilation rate of flag leaves and yield formation, which led to a reduction of wheat yield by 14–40%. However, increasing irrigation can compensate for a yield of 9.7–15%. In addition, warming increases the soil temperature and decreases the soil water content, resulting in decreased soil microbial diversity. The effect size (β) = −0.23 to −0.53 for index of phylogenetic diversity (PD) under warming, while β= 0.16 under increased irrigation. The SEM model further showed that supplementary irrigation during anthesis to filling can improve the soil environment and extend the validity of photosynthetic to increase production, which was an important mitigation measure to adapt to the warming climate in wheat production.

Despite being cultivated with annual crops, marginal agricultural lands are usually more suitable for grasses, trees, or other perennial vegetation with persistent roots that are better adapted to unfavorable growth conditions. Replacing crops with perennial grassland vegetation (i.e., grassland restoration) on such marginal land can also contribute to realizing positive agroecological outcomes. However, while agroecological principles can guide multiple pathways and management practices, little work has explored the role of marginal agricultural land restoration in soil-based agroecological outcomes. Here we analyzed how soil properties linked with achieving three positive agroecological outcomes (enhanced soil health, higher recycling, and input reduction) are affected by marginal-land restoration and the plant traits of the established vegetation. To do this, we focused on changes in three indicators of these agroecological outcomes: active soil C (soil health), diversity of soil bacterial communities (recycling), and nutrient acquisition via total root biomass (input reduction) measured in three plant-cover types (forest, cropland, restored grassland) in 13 farms distributed in an agricultural landscape in southern Ontario, Canada. Active C and root biomass were highest in forests, intermediate in grasslands and lowest in croplands, while there were no differences in terms of soil bacterial diversity, indicating that restoring land can help achieve some positive agroecological outcomes. Using path analysis, we also found that two plant traits, leaf mass per area (LMA) and leaf dry matter content (LDMC), were key in mediating the link between grassland restoration and agroecological outcomes. Specifically, grassland restoration helped improve indicators of soil health and input reduction via the promotion of vegetation with conservative traits (high LMA and LDMC). Our analytical approach enabled the assessment of the agroecological outcomes after implementing restoration practices, while identifying the most important mechanistic paths mediated by plant traits.

Morels (Morchella spp.) are a kind of rare and precious edible fungus and have been successfully cultivated in many places. Currently, the widespread cultivation of morels poses a significant challenge owing to their demanding environmental requirements. Soil properties and the soil microbiome are thought to play pivotal roles in morel growth. However, it remains unknown what factors exert a decisive influence on morel growth. In this study, soils with different morel yields were studied in nine sites from four locations. The basic soil physical and chemical properties were measured. In addition, the soil microbiome was analyzed using high-throughput metagenomic sequencing. We found that soil pH, nitrogen, carbon and conductivity were key indicators for the impact on microbial communities in soil for cultivating morels. Among these, nitrate was more positively associated with morel yield. The soil microbial diversity was more abundant in the soil with a high morel yield. Moreover, certain unknown archaea might be unfavorable to morel growth. The microbes that perform incomplete denitrification (no step of N2O reduction to N2) and nitrogen fixation were positively and negatively correlated with morel growth, respectively. In summary, morels prefer to live in nutrient-rich soils with a variety of microbes and are supported by nitrate and microbiome components involved in denitrification. The findings elucidate a pivotal mechanism in eliciting morel fructification and provide valuable insights for guiding production practices.

Lactarius hatsudake Tanaka is a mycorrhizal edible mushroom with an appealing taste and rich nutrition. It is also a significant food and has medicinal value. In this study, the plantation of L. hatsudake during the harvest period was taken as the research object, and this article explores which bacteria in the soil contribute to the production and growth of L. hatsudake. The soil of the control (CK) and the soil of the mushroom-producing area [including the soil of the base of the mushroom (JT) and the mycorrhizal root soil (JG)] was collected in the plantation. The three sites’ bacterial community structure and soil diversity were analyzed using high-throughput sequencing technology, and a molecular ecological network was built. Soil bacteria in the L. hatsudake plantation had 28 tribes, 74 classes, 161 orders, 264 families, 498 genera, and 546 species. The dominant phyla were Proteobacteria and Acidobacteria, and the dominant genera were Burkholderia_Caballeronia_Paraburkholderia, Acidothermus, Bradyrhizobium, Candidatus_Xiphinematobacter, and Granulicella. The α-diversity of soil bacteria in JT was significantly lower than that in JG and CK, and the β-diversity in JT samples was significantly different from that in JG and CK samples. The size and complexity of the constructed network were smaller in JT samples than in JG and CK samples, and the stability was higher in JT samples than in JG and CK samples. The positive correlation between species in JT samples was dominant. The potential mycorrhizal helper bacteria (MHB) species of L. hatsudake was determined using correlation and differential group analysis. The results support future research on mycorrhizal synthesis, plantation management, and the function of microorganisms in the soil rhizosphere of L. hatsudake.

Soil microbes mediate soil organic carbon (SOC) storage by affecting microbial residue carbon (C) in terrestrial ecosystems, a main source of SOC. However, how microbial residue C accumulation changes during the conversion of subtropical primary forest to plantations and the role of soil microbial community structure in regulating these changes remain unclear. Here, effects of conversion from forest on microbial residue C accumulation in three plantations, including tea (Camellia sinensis var. assamica), walnut (Juglans regia), and macadamia (Macadamia integrifolia). We assessed amino sugars content and the relative importance of soil microbial community structure, soil fertility, and aboveground biomass in four forest types in southwest Yunnan province, China. Our results show that total microbial residue C accounted for 27.8 % of SOC on average across all forest types, and fungal residue C contributed more to SOC than bacterial residue C across different forest types. Conversion from primary forest decreased fungal, bacterial, and total microbial residue C content in all plantation types except tea. Microbial residue C contents was significantly lower in the macadamia plantation than in the primary forest and the tea plantation. Fungal and total microbial residue C content increased with increasing soil microbial community composition, soil fungal abundance, and soil fertility. Soil fertility regulated fungal, bacterial, and total microbial residue C accumulation, which was major determinant of microbial residue C via its influence on soil fungal and bacterial abundance. Overall, we found that soil fungal abundance contributed more to microbial residue C accumulation than change in soil microbial community composition. We also found that soil bacterial abundance was negatively correlated with fungal and microbial residue C, while soil fungal abundance was positively related to microbial residue C accumulation. Ascomycota was most important phylum regulating microbial residue C. These findings suggest that soil fungal and bacterial abundance and soil fertility are the principal regulators of microbial residue C accumulation during the conversion from primary forest to different plantations.

Soil salinization is a serious environmental problem that affects agricultural productivity and sustainability worldwide. Organic amendments have been considered a practical approach for reclaiming salt-affected soils. In addition to improving soil physical and chemical properties, organic amendments have been found to promote the build-up of new halotolerant bacterial species and microbial diversity, which plays a critical role in maintaining soil health, carbon dynamics, crop productivity, and ecosystem functioning. Many reported studies have indicated the development of soil microbial diversity in organic amendments amended soil. But they have reported only the development of microbial diversity and their identification. This review article provides a comprehensive summary of the current knowledge on the use of different organic amendments for the reclamation of salt-affected soils, focusing on their effects on soil properties, microbial processes and species, development of soil microbial diversity, and microbial processes to tolerate salinity levels and their strategies to cope with it. It also discusses the factors affecting the microbial species developments, adaptation and survival, and carbon dynamics. This review is based on the concept of whether addition of specific organic amendment can promote specific halotolerant microbe species, and if it is, then which amendment is responsible for each microbial species' development and factors responsible for their survival in saline environments. [ABSTRACT FROM AUTHOR]

The application of organic materials contributes to the sustainable development of agriculture. Increased manure inputs have a fundamental effect on the composition and dynamics of soil organic carbon (SOC). In this study, we conducted a 10-year field experiment in Changchun, Jilin, Northeast China, to investigate the effects of manure addition on soil organic carbon components and soil microorganisms. Specifically, we established four treatments: (i) chemical fertilizer or no addition of manure (CK), (ii) pig manure with chemical fertilizer (ZF), (iii) cow manure with chemical fertilizer (NF), and (iv) chicken manure with chemical fertilizer (JF). The results showed that the JF treatment significantly increased the soil organic carbon (SOC), dissolved organic carbon (DOC), and readily oxidized organic carbon (ROC) content by 20.36%, 105.9%, and 61.32%, respectively, relative to CK. The microbial biomass carbon (MBC) content in JF, ZF, and NF treatments were significantly higher than that of CK, which increased by 107.24%, 116.45%, and 96.71%, respectively. The particulate organic carbon (POC) content in NF and JF treatments differed significantly, increasing by 25.61% and 19.01%, respectively, relative to CK. Redundancy analysis showed that continuous manure application had a positive effect on soil microbial community diversity and abundance, which was favorable for the accumulation of soil carbon. We also found that soil fungi were more sensitive than bacteria to changes in soil carbon composition following manure application. In conclusion, adding different organic materials can better support biodiversity conservation and realize ecosystem services of surface carbon storage and soil conservation. Our results reveal the importance of microbial fixation in soil carbon dynamics according to the different distribution of active organic carbon pools, which will help enhance our understanding of the carbon cycle. [ABSTRACT FROM AUTHOR]

Introduction: Plant diversity and soil microbial diversity are important driving factors in sustaining ecosystem multifunctionality (EMF) in terrestrial ecosystems. However, little is known about the relative importance of plant diversity, soil microbial diversity, and soil microbial network complexity to EMF in tropical rainforests. Methods: This study took the tropical rainforest in Xishuangbanna, Yunnan Province, China as the research object, and quantified various ecosystem functions such as soil organic carbon stock, soil nutrient cycling, biomass production, and water regulation in the tropical rainforest to explore the relationship and effect of plant diversity, soil microbial diversity, soil microbial network complexity and EMF. Results: Our results exhibited that EMF decreased with increasing liana species richness, soil fungal diversity, and soil fungal network complexity, which followed a trend of initially increasing and then decreasing with soil bacterial diversity while increasing with soil bacterial network complexity. Soil microbial diversity and plant diversity primarily affected soil nutrient cycling. Additionally, liana species richness had a significant negative effect on soil organic carbon stocks. The random forest model suggested that liana species richness, soil bacterial network complexity, and soil fungal network complexity indicated more relative importance in sustaining EMF. The structural equation model revealed that soil bacterial network complexity and tree species richness displayed the significantly positive effects on EMF, while liana species richness significantly affected EMF via negative pathway. We also observed that soil microbial diversity indirectly affected EMF through soil microbial network complexity. Soil bulk density had a significant and negative effect on liana species richness, thus indirectly influencing EMF. Simultaneously, we further found that liana species richness was the main indicator of sustaining EMF in a tropical rainforest, while soil bacterial diversity was the primary driving factor. Discussion: Our findings provide new insight into the relationship between biodiversity and EMF in a tropical rainforest ecosystem and the relative contribution of plant and soil microibal diversity to ecosystem function with increasing global climate change. [ABSTRACT FROM AUTHOR]

Superior yields of super hybrid rice have demonstrably contributed to contemporary food security. Despite this, the extent to which intensive nitrogen fertilizer requirements of such crops have impacted on soil health and microbial communities primarily remains unchartered territory, evoking questions of sustainability. Here, we examine how four management treatments (zero fertilizer, CK; farm practice, FP; high-yield and high-efficiency, HYHE; and super-high-yield management, SHY) influenced the grain yields, soil biodiversity and community strata underpinning soil health of an elite super hybrid rice variety (Y-liangyou 900). We show that SHY treatments increased yields, altered soil physicochemical properties, and fostered greater biodiversity and soil bacteria and fungi abundance, while FP, HYHE and SHY treatments transformed community bacteria and fungi strata. Environmental regulators of bacterial and fungal communities differed widely, with bacterial communities most closely associated with soil organic carbon (SOC) and NH4+-N, and with fungal communities more related to available phosphorus. We show that alpha diversity of bacteria and fungi and community composition of fungi were positively correlated with yield, but bacterial community composition was negatively correlated with yield. Our work clearly exemplifies the nexus between appropriate farm and landscape management in enabling soil health and driving consistently high yields, of which both are required for sustainable food security. [ABSTRACT FROM AUTHOR]

Diversity of the soil microbial community is an important factor affecting its stability against disturbance. However, the impact of the decline in soil microbial diversity on the stability of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) is not known, particularly considering the repeated soil nutrient disturbances occurring in modern agricultural systems. Here, we conducted a microcosm experiment and modified the soil microbial diversity using the dilution-to-extinction approach to determine the stability and population dynamics of AOB and AOA communities with repeated nitrogen (N) fertilizer application. Our results demonstrated that the AOB community became more abundant and stable against repeated disturbances by N in the treatments with the highest microbial diversity. In contrast, the abundance of AOA decreased following repeated N fertilizer application, regardless of the microbial diversity. Notably, during the initial application phase, AOA displayed a potential for increased abundance in treatments with high soil microbial diversity. These findings highlight that the soil microbial diversity controls the stability of ammonia oxidizers during short-interval repeated N disturbances.