Affect Soil Microbial Community Structure Research Articles

Karst Ecosystem: Moso Bamboo Intercropping Enhances Soil Fertility and Microbial Diversity in the Rhizosphere of Giant Lily (Cardiocrinum giganteum)

Intercropping affects soil microbial community structure significantly; however, the effects on understory medicinal plants in karst areas remain unclear. We investigated the effects of four intercropping systems (Moso bamboo, Chinese fir, bamboo-fir mixed forest, and forest gap) on the rhizosphere microbial communities of giant lily (Cardiocrinum giganteum), an economically important medicinal plant in China. We assessed the intercropping impact on rhizosphere microbial diversity, composition, and co-occurrence networks and identified key soil properties driving the changes. Bacterial and fungal diversity were assessed by 16S rRNA and ITS gene sequencing, respectively; soil physicochemical properties and enzyme activities were measured. Moso bamboo system had the highest fungal diversity, with relatively high bacterial diversity. It promoted a distinct microbial community structure with significant Actinobacteria and saprotrophic fungi enrichment. Soil organic carbon, total nitrogen, and available potassium were the most influential drivers of microbial community structure. Co-occurrence network analysis revealed that the microbial network in the Moso bamboo system was the most complex and highly interconnected, with a higher proportion of positive interactions and a greater number of keystone taxa. Thus, integrating Moso bamboo into intercropping systems can enhance soil fertility, microbial diversity, and ecological interactions in the giant lily rhizosphere in karst forests.

Adaptation strategies of soil microorganisms in resource changes and stoichiometric imbalances induced by secondary succession on the loess plateau

Sequestering farmland for secondary succession is an effective method of restoring ecosystem services to degraded farmland, but long-term secondary succession often alters ecosystem environments, resources, and substrate stoichiometry. Currently, it is not known how resource changes and stoichiometric imbalances due to secondary succession affect soil microbial community structure and function, hindering our understanding of the natural resilience for degraded ecosystems. Here, we assessed nutrient limitation elements, community structure, metabolic functions, co-occurrence network complexity, and community stability of soil microorganisms during secondary succession of abandoned farmlands on the Loess Plateau. Results showed that secondary succession significantly altered plant characteristics and soil properties, as well as causing stoichiometry imbalances in nutrient resources. Along the secondary succession chronosequence, microbial nutrient metabolism shifted from phosphorus (P) limitation to carbon (C) and nitrogen (N) co-limitation. Microbial diversity, eutrophic flora, plant growth-promoting bacteria, and metabolism functional groups increased significantly during the 20 years after the abandonment of the farmlands, but decreased significantly with long-term succession. However, oligotrophic flora and P-solubilizing bacteria became dominant after 30 years of secondary succession on abandoned farmlands. The topological features of microbial co-occurring networks, including nodes, degree, closeness, betweenness, and eigenvector complexity, natural connectivity, and community stability first increased and then decreased with secondary succession. Correlation and random forest analyses indicated that secondary succession-induced stoichiometry imbalances in C:N and N:P, as well as changes in soil organic C and lignin phenols, were the key factors influencing microbial community structure and function. Overall, these results enhance our understanding of the adaptation strategies of soil microbial communities in ecologically managed regions to changes in ecosystem resources and stoichiometric imbalances.

Control of inorganic and organic phosphorus molecules on microbial activity, and the stoichiometry of nutrient cycling in soils in an arid, agricultural ecosystem

Background The dynamics of carbon (C), nitrogen (N), and phosphorus (P) in soils determine their fertility and crop growth in agroecosystems. These dynamics depend on microbial metabolism, which in turn depends on nutrient availability. Farmers typically apply either mineral or organic fertilizers to increase the availability of nutrients in soils. Phosphorus, which usually limits plant growth, is one of the most applied nutrients. Our knowledge is limited regarding how different forms of P impact the ability of microbes in soils to produce the enzymes required to release nutrients, such as C, N and P from different substrates. Methods In this study, we used the arable layer of a calcareous soil obtained from an alfalfa cropland in Cuatro Cienegas, México, to perform an incubation experiment, where five different phosphate molecules were added as treatments substrates: three organic molecules (RNA, adenine monophosphate (AMP) and phytate) and two inorganic molecules (calcium phosphate and ammonium phosphate). Controls did not receive added phosphorus. We measured nutrient dynamics and soil microbial activity after 19 days of incubation. Results Different P molecules affected potential microbial C mineralization (CO2-C) and enzyme activities, specifically in the organic treatments. P remained immobilized in the microbial biomass (Pmic) regardless of the source of P, suggesting that soil microorganisms were limited by phosphorus. Higher mineralization rates in soil amended with organic P compounds depleted dissolved organic carbon and increased nitrification. The C:N:P stoichiometry of the microbial biomass implied a change in the microbial community which affected the carbon use efficiency (CUE), threshold elemental ratio (TER), and homeostasis. Conclusion Different organic and inorganic sources of P affect soil microbial community structure and metabolism. This modifies the dynamics of soil C, N and P. These results highlight the importance of considering the composition of organic matter and phosphate compounds used in agriculture since their impact on the microbial activity of the soil can also affect plant productivity.

Changes in the Soil Microbial Community Structure and Driving Factors during Post-Fire Recovery of the Larix gmelinii Rupr. Forest in Northern China

Fire is crucial for shaping northern forest ecosystems and can affect soil microbial community structure. However, there are few studies on the long-term effects of forest fire disturbance on soil microbial community diversity. In this study, we employed high-throughput sequencing of 16S rRNA and ITS1 to assess variations in the abundance of bacterial and fungal communities in dominant populations at 1, 6, and 11 years post-fire. Furthermore, a comprehensive analysis was conducted to examine the relationship between soil microenvironmental changes and soil microbial communities after fire disturbances, considering soil physicochemical properties, including bulk density, moisture content, pH, organic carbon, total nitrogen, ammonium nitrogen, nitrate nitrogen, available potassium, and available phosphorus. We found that fire significantly increased soil pH, NO3−-N, AP, and AK contents, in which the content of NO3−-N basically recovered to the pre-fire level at 11 years after fire. The soil SOC and TN contents decreased significantly 1 year after the fire. However, compared to the unfired site, the SOC content essentially recovered 11 years after the fire, while TN content was still significantly higher 11 years after fire. Furthermore, fire changed the diversity and richness of soil microbial communities to some extent. PCoA and NMDS analyses suggested that the bacterial community structures in soil samples from different burned areas with different recovery periods exhibited similarity. However, notable differences were observed in the fungal community structures between the 1-year and 6-year post-fire study sites when compared to the unburned control site. Bacterial communities predominantly comprised Proteobacteria, Actinobacteria, and Acidobacteria, while fungal communities were mainly dominated by Ascomycota and Basidiomycota. RDA confirmed the significant roles of SOC, TN, and NO3−-N in affecting the diversity of soil microbial communities. Therefore, our study not only enhances our understanding of the long-term effects of forest fire disturbances on soil properties and soil microbial community structure, but also provides insights for further utilizing and controlling carbon and nitrogen content to regulate soil microbial activity and accelerate the recovery process of burned areas.

Different no-till grain production systems with Urochloa spp. affect soil microbial community structure, biomass and activity in a tropical Ultisol

Different no-till grain production systems with Urochloa spp. affect soil microbial community structure, biomass and activity in a tropical Ultisol

Organic and conventional farming systems shape soil bacterial community composition in tropical arable farming

Soils present a limited resource for agricultural production and bear a vast diversity of organisms crucial for crop health and the provision of ecosystem services. There is growing evidence that agricultural practices affect soil microbial community structure and function but currently, there is a knowledge gap when it comes to tropical arable farming systems. In this study, we investigated the long-term impact of organic and conventional production systems on bacterial communities in two field trial located on a rhodic and humic nitisol in the Central Highlands of Kenya. The field sites operate on a full factorial design, testing farming systems (organic vs conventional) and input levels (high vs low). Including four field replication we assessed soil bacterial community structure via amplicon sequencing of the 16S rRNA gene and soils capacity for nitrification and nitrous oxide reduction via qPCR of functional genes (bacterial and archaeal amoA, nosZ) after 12 years of distinct management and before the start of the 5th three-year crop rotation period in 2019. The abundances of amoA bearing nitrifiers and nosZ bearing nitrous oxide reducers were enhanced in the high input organic production system on humic but not in rhodic nitisols. For both soil types, high input organic production system resulted in distinct bacterial community structure with enhanced bacterial richness compared to conventional and low input production systems. In rhodic and humic nitisols 160 and 84 OTUs were found to be indicative for organic production system at high input levels organic. Taxa associated with this system were identified as potential primary decomposers or symbionts related to plant nitrogen fixation, suggesting organic fertilization strategies such as manure composting as major driver for changes in soil bacterial community structure. This study reveals that organic production systems at high input levels on tropical nitisols translates to distinct soil bacterial communities with increased capacity for soil processes that are crucial for crop nutrient supply.

The effect of aboveground long-term low-dose ionizing radiation on soil microbial diversity and structure

Studies investigating the diversity and structure of soil microbial systems in response to ionizing radiation are scarce. In particular, effects of long-term low-dose radiation is rarely studied because of its unique conditions. In this study, an area in Chengdu, China, which has been irradiated by the radionuclide thorium-232 for more than 10 years was investigated. Four groups of samples with absorbed dose rates ranging from 192.906 ± 5.05 to 910.964 ± 41.09 nGy/h were collected to analyze the compositional and functional changes of the soil microbial systems in the region. The diversity and structure of the soil microbial systems were determined using high-throughput sequencing. Our results showed that long-term low-dose ionizing radiation had no significant effect on soil bacterial diversity, but had a great impact on fungal diversity. Long-term ionizing radiation strongly affected soil microbial community structure. Long-term low-dose ionizing radiation was shown to have a promoting effect on iron-oxidizing bacteria and ectomycorrhizal fungi and have an inhibiting effect on predatory or parasitic fungi, further affecting the soil C/N ratio. This study is of great reference significance for future research on the impact of long-term low-dose ionizing radiation on soil ecosystems.

Effect of Microwave Treatment at 2.45 GHz on Soil Physicochemical Properties and Bacterial Community Characteristics in Phaeozems of Northeast China

Microwave irradiation is a new means of non-toxic, residue-free, and green soil disinfection that prevents and controls soil diseases, insects, and weeds and helps to improve crop quality and yield. Soil microorganisms, as an important part of the ecosystem, are closely related to crop growth and health. To investigate the changes of soil physicochemical properties and microbial communities during microwave soil disinfection for different time periods, phaeozems from northeastern China were selected for microwave treatment at 3, 6, 9, and 12 min, and their physicochemical properties were measured after 30 days of incubation. The test soils (0–20 cm) after 30 days of incubation were used, and high-throughput sequencing was performed to detect changes in their soil microbial structure under different microwave time treatments. Microwave treatment had significant effects on soil pH, nitrate (NO3--N), ammonium (NH4+-N), and available phosphorus (AP) content. As shown by the Shannon, Chao, and Ace indices, microwave treatment at 3 min had the lowest effect on bacterial diversity compared to the control treatment (CK). Shannon index decreased by 9.92%, 24.56%, 34.37%, and 38.43% after 3, 6, 9, and 12 min microwave treatments, respectively; Chao index decreased by 7.69%, 18.13%, 32.21%, and 57.91%, respectively; Ace index decreased by 6.40%, 6.98%, 20.89%, and 52.07%, respectively. The relative abundance of beneficial soil microorganisms Micromonospora, Fictibacillus, Paenibacillus, and Bacillus (Firmicutes) increased significantly compared to CK. The results indicated that although the microwave treatment altered the soil microbial community, beneficial soil microorganisms showed faster recovery. In addition, pH, soil organic carbon (SOC), total nitrogen ratio (C/N), soil-available phosphorus (AP), and NO3--N were important factors affecting bacterial community diversity and composition following microwave treatment, and bacterial community composition was driven by soil chemical properties such as soil pH, SOC, C/N, and NO3--N. Microwave treatments at different time periods affected soil microbial community structure to different degrees, and soil bacteria of copiotrophic taxa (e.g., Firmicutes) were relatively higher than the control. Overall, microwave treatment from 3–6 min may be more suitable for soil disinfection. The study of the effect of microwave on soil physicochemical properties and bacterial microbial community not only provides some scientific reference for the rational application of microwave soil disinfection, but also has positive significance for soil-borne disease control and crop quality improvement.

Revealing the Effect of Saline Water Drip Irrigation on Soil Microorganisms in Cotton Fields Based on Metagenomics

Saline water irrigation has become an important means to alleviate the shortage of freshwater in arid areas. However, long-term saline water irrigation can cause soil salinity accumulation, affect soil microbial community structure, and then affect soil nutrient transformation. In this study, we used metagenomics to investigate the effects of long-term saline water drip irrigation on soil microbial community structure in a cotton field. In the experiment, the salinity of irrigation water (ECw) was set to two treatments:0.35 dS·m-1 and 8.04 dS·m-1 (denoted as FW and SW, respectively), and the nitrogen application rates were 0 kg·hm-2and 360 kg·hm-2 (denoted as N0 and N360, respectively). The results showed that saline water irrigation increased soil water content, salinity, organic carbon, and total nitrogen content and decreased soil pH and available potassium content. Nitrogen fertilizer application increased soil organic carbon, salinity, and total nitrogen content and decreased soil water content, pH, and available potassium content. The dominant bacterial phyla in each treatment were:Proteobacteria, Actinobacteria, Acidobacteria, Chloroflexi, and Gemmatimonadetes. Saline water irrigation significantly increased the relative abundances of Actinobacteria, Chloroflexi, Gemmatimonadetes, and Firmicutes but significantly decreased the relative abundances of Proteobacteria, Acidobacteria, Cyanobacteria, and Nitrospira. Nitrogen fertilizer application significantly increased the relative abundances of Chloroflexi and Nitrospira but significantly decreased the relative abundances of Acidobacteria, Gemmatimonadetes, Planctomycetes, Cyanobacteria, and Verrucomicrobia. LEfSe analysis showed that saline water irrigation had no significant effect on the number of potential biomarkers, and nitrogen fertilizer application decreased the number of potential biomarkers in soil microbial communities. The correlation network diagram showed that the 20 genera had different degrees of correlation, including 44 positive correlations and 48 negative correlations. The core species in the network diagram were Nocardioides, Streptomyces, Pyrinomonas, Candidatus_Solibacter, and Bradyrhizobium spp. Saline water irrigation increased the relative abundances of the denitrification genes nirK, nirS, nasB, and norC and decreased the relative abundances of the nitrification genes amoB, amoC, and nxrA, whereas nitrogen fertilizer application increased the relative abundances of the nitrification genes amoA, amoB, amoC, hao, and nxrA and decreased the relative abundances of the denitrifying genes narB, napA, nasA, and nosZ. Saline water irrigation could adversely affect soil physicochemical properties; SWC, EC1:5, and BD were the main driving factors affecting soil microbial community structure and function genes; and soil microorganisms adapted to soil salt stress by regulating species composition.

Effects of nitrogen deposition on soil enzymatic activity and soil microbial community in a Mediterranean holm oak forest

Ongoing increases in global levels of nitrogen (N) deposition are predicted to continue, causing important shifts in the structure and function of ecosystems worldwide. Soil microbes and enzymes are key components of biogeochemical cycles and ecosystem functioning, so understanding their response to N deposition is crucial. We studied the effects of N addition on the activities of five extracellular enzymes and microbial biomass and composition in a mesic Mediterranean holm oak forest characterized by moderate soil N- and P-limitation. Addition of N increased photosynthetic potential of higher plants, activities of P- and C-, but not N- related enzymes, and biomass of total microbes, bacteria and fungi, and decreased ratios of fungi:bacteria. Overall, N deposition increased general biological activity of the mesic Mediterranean forest, enhanced ecosystem investment in P mobilization and affected soil microbial community structure.

Litter, Root, and Mycorrhiza Input Affected Soil Microbial Community Structure in Schima superba Pure Forest in Subtropical China

During forest vegetation rehabilitation, changes in aboveground litter and underground root inputs affect soil microbial communities. Clarifying the effects of forest ecosystem carbon inputs on soil microbial community structure can provide a theoretical basis for the microbial driving mechanism of soil fertility evolution and ecosystem rehabilitation of vegetation rehabilitation in degraded red soil. Our research focuses on a Schima superba pure forest recovered from eroded and degraded red soil in a subtropical region. Five treatments were set as follows: control treatment (CT), mycorrhiza (M), root + mycorrhiza (RM), litter + root + mycorrhiza (LRM), and double litter + root + mycorrhiza (DLRM). We used Illumina HiSeq technology to study the effects of different organic carbon inputs on soil microbial community structure. The results showed that all organic carbon input treatments reduced the total population of soil bacteria by 55–79%; M, RM, and DLRM treatments increased the quantity of operational taxonomic units (OTUs) by 25–37%, ACE index by 25–34%, and Chao1 index by 28–39%. Acidobacteria, Proteobacteria, and Actinobacteria were the dominant bacteriophyta in the Schima superba pure forest soil. The relative abundance of Alphaproteobacteria decreased by 55% under LRM treatment, and Thermoleophilia increased by 81% under M treatment. The dominant fungal phyla were Basidiomycota and Ascomycota. RM, LRM, and DLRM treatments reduced the relative abundance of Sordariomycetes by 46–64% and increased the relative abundance of Mortierellomycetes by 251–615%. The order of effects of different organic carbon inputs on the bacterial community composition at the phylum level was LRM > RM > M > DLRM and that on the fungal community composition was DLRM > LRM and RM > M. Alphaproteobacteria, Thermoleophilia, Sordariomycetes, and Mortierellomycetes were the main microbial groups affected by changes in organic carbon inputs. Soil organic carbon and total nitrogen were the key factors affecting the change of Mortierellomycetes. The bacterial community mainly affected the activity of soil acid invertase, while the fungal community affected the activities of various enzymes, with positive or negative effects. We concluded that the organic carbon inputs changed the species and quantity of soil microorganisms in the Schima superba forest, and the influence of organic carbon input on the fungal community structure was greater than that of bacteria.

Phosphorus limitation induced by nitrogen addition changed soil microbial community structure in a subtropical Pinus taiwanensis forest.

Soil microorganisms play an important role in the biogeochemical cycles of terrestrial ecosystems. How-ever, it is still unclear how the amount and duration of nitrogen (N) addition affect soil microbial community structure and whether there is a correlation between the changes in microbial community structure and their nutrient limi-tation status. In this study, we conducted an N addition experiment in a subtropical Pinus taiwanensis forest to simulate N deposition with three treatments: control (CK, 0 kg N·hm-2·a-1), low N (LN, 40 kg N·hm-2·a-1), and high N (HN, 80 kg N·hm-2·a-1). Basic soil physicochemical properties, phospholipid fatty acids content, and carbon (C), N and phosphorus (P) acquisition enzyme activities were measured after one and three years of N addition. The relative nutrient limitation status of soil microorganisms was analyzed using ecological enzyme stoichiometry. The results showed that one-year N addition did not affect soil microbial community structure. Three-year LN treatment significantly increased the contents of Gram-positive bacteria (G+), Gram-negative bacteria (G-), actinomycetes (ACT), and total phospholipid fatty acids (TPLFA), whereas three-year HN treatment did not significantly affect soil microbial community, indicating that bacteria and ACT might be more sensitive to N addition. Nitrogen addition exacerbated soil C and P limitation. Phosphorus limitation was the optimal explanatory factor for the changes in soil microbial community structure. It suggested that P limitation induced by N addition might be more beneficial for the growth of certain oligotrophic bacteria (e.g. G+) and the microorganisms participating in the P cycling (e.g. ACT), with consequences on soil microbial community structure of subtropical Pinus taiwanensis forest.

Changes in Essential Soil Nutrients and Soil Disturbance Directly Affected Soil Microbial Community Structure – A Metagenomic Approach

Changes in Essential Soil Nutrients and Soil Disturbance Directly Affected Soil Microbial Community Structure – A Metagenomic Approach

Maize root exudate composition alters rhizosphere bacterial community to control hotspots of hydrolase activity in response to nitrogen supply

Improving nitrogen (N) acquisition by crops from soil is essential to reduce fertilization rates whilst maintaining yields. Plants can adapt their nutrient acquisition strategies according to N availability, which also affects soil microbial community structure, functions and activities and relies on the supply of carbon (C) for energy. We hypothesized that N deprivation would create hotspots of N- and C-acquiring hydrolase activities in maize rhizosphere through the effects of altered root exudation on the rhizosphere bacterial community. We grew maize under three N fertilization rates and combined soil zymography with the identification of rhizosphere microbial communities and non-targeted metabolic profiling of root exudates to explore enzyme hotspot formation. The rhizosphere extents of β-1,4-glucosidase (BG) and β-N-acetylglucosaminidase (NAG) activities decreased after N fertilization, narrowing by 48% and 39%, respectively, under typical field N application rates compared to zero application. Rhizosphere extents of enzyme activities were more sensitive to altered N supply than changes in the rates of enzyme activities: BG activity decreased by ∼10%, while NAG activity was unaffected. Decreases in the activities of both hydrolases and their rhizosphere extents caused by N addition correlated with reduced abundances of oligotrophs. The relative abundances of oligotrophic bacteria (e.g., Acidobacteria) decreased, while copiotrophs (e.g., Pseudomonadota and Patescibacteria) increased under the highest N application rate. Co-occurrence networks of the rhizosphere bacterial community revealed that functional units increased with BG activity, while an efficient and denser co-occurrence network supported expansion of its rhizosphere extent. The metabolic profiles of root exudates changed according to the N application rate, suggesting that their chemistry was regulated by the plant in response to N supply. The composition of root exudates and dissolved organic C and nitrate contents explained the largest variations in NAG hotspots in the rhizosphere. In summary, maize actively adjusts the composition of root exudates to increase interactions with rhizosphere bacteria, thereby stimulating hydrolase production and activities, and altering their rhizosphere extents to mobilize N and energy (C) in a larger soil volume, under conditions of N deficiency.

Straw amendment and soil tillage alter soil organic carbon chemical composition and are associated with microbial community structure

Soil organic carbon (SOC) accumulation and its components are influenced by agricultural practices, which are interfered by soil microorganisms. A field experiment was conducted to investigate how straw amendment and soil tillage influenced SOC fractions and chemical components, and their interrelations with microbial communities evaluated through phospholipid fatty acids (PLFAs) in Mollisols. Density fractionation and Fourier-transform Infrared Spectroscopy were combined to characterize OC properties, including free and occluded light fractions (fLFC, oLFC), heavy fraction (HFC), aliphatic-C and aromatic-C functional groups. Compared with control soil, straw amendment caused surface SOC increased by 6.7%–12.4% (P < 0.05). The dissolved OC, microbial biomass carbon (SMBC), fLFC, oLFC, aliphatic-C, and total PLFAs also increased after straw amendment. Whereas the aromatic-C proportions in bulk soil, fLFC, and oLFC decreased. The OC components and microbial properties didn't obviously change in soil with straw ash amendment. Straw amendment to the subsurface layer only increased subsurface SOC and OC fractions (P < 0.05). Principal component analysis revealed that soil microbial community structure changed with the amounts of straw amendment, soil tillage further underpinned the separation. The separation via PC1 was associated with labile OC components, including SMBC, fLFC, oLFC, and aliphatic-C pointing to soils with higher amounts of straw amendment, and with recalcitrant aromatic-C and HFC pointing to soils without straw or straw ash. Higher amounts of straw amendment plus soil tillage affected soil microbial community structure, and consequently influenced OC sequestration by altering labile OC fractions and components in Mollisols.

Effects of moso bamboo (Phyllostachys edulis) expansion on soil microbial community in evergreen broad-leaved forest

The special eco-physiological characteristics of moso bamboo (Phyllostachys edulis) facilitate their fast invasion in nature ecosystems. The widespread expansion of moso bamboo causes degradation of adjacent forest ecosystem and change of landscape, as well as soil properties and microbial community composition. However, how moso bamboo expansion affects soil microbial composition is far from fully understood. Herein, we selected four moso bamboo expansion transects with three forest types at the Anji Lingfeng temple forest farm, Zhejiang Province, including evergreen broadleaved forest (BLF), mixed P. edulis and broadleaved forest (MEF) and P. edulis forest (PEF). We examined the effects of moso bamboo expansion on soil properties and soil microbial phospholipid fatty acids (PLFAs). Our results showed that soil pH was higher in moso bamboo forest than in MEF and BLF by 0.37 and 0.32 unit. In contrast, soil organic carbon, ammonium, and nitrate contents significantly decreased. Biomass of soil microbial groups displayed a decreasing trend except arbuscular mycorrhizal fungi, and the microbial richness index (SR) and diversity index (H) decreased significantly. In summary, moso bamboo expansion affected soil nutrient and carbon inputs, which was an important factor affecting soil microbial community structure. Results of redundancy analysis showed that changes of soil organic carbon and ammonium content were the main factors driving soil microbial community.

Effects of long-term different fertilization patterns on soil nutrients and microbial community structure of tomato in a solar greenhouse.

The phospholipid fatty acid (PLFA) technique was used to investigate the effects of fertilization on soil characteristics and microbial community of tomato in a solar greenhouse in Shouguang, Shandong Province, China, based on a long-term (12-year) fertilization experiment. The experiment involved a control (CK) and five fertilization treatments, namely, traditional nitrogen application (CN), traditional nitrogen application+straw return (CNS), optimized nitrogen application (SN), optimized nitrogen application+straw return (SNS), and organic manure nitrogen application+straw return (MNS). Results showed that the contents of soil organic matter and avai-lable P and K under all fertilization treatments were significantly higher than that of CK, but no significant difference among fertilization treatments. The traditional nitrogen application (i.e., CN and CNS) significantly decreased soil pH. The reduction of nitrogen fertilizer (i.e., SN, SNS and MNS) did not affect soil pH. Compared with CK, no straw treatment (i.e., CN and SN) and MNS did not affect the content of soil available N, but nitrogen combined with straw returned (i.e., CNS and SNS) significantly increased soil available N content. The optimized N with straw return (i.e., SNS) treatment resulted in the highest soil available N. Compared with CK and treatments without straw (i.e., CN, SN), treatments with straw (i.e., MNS, CNS and SNS) substantially changed soil microbial community structure and increased the biomass of soil bacteria, fungi, actinomycetes, mycorrhizal fungi, and the total amount of PLFA. SNS treatment had the highest soil microbial diversity, the highest biomass of soil bacteria, fungi, and actinomycetes, the highest total amount of PLFA, the highest ratios of fungi/bacteria and monounsaturated fatty acids/saturated fatty acids (MONO/SAT), the two indicators for soil ecosystem stability. Further, it had the lowest ratios of iso/anteiso fatty acids (i/a) and gram-positive/gram-negative bacteria (G+/G-), the indicators for nutritional stress. Redundancy and correlation analysis revealed that soil organic matter was the main factor affecting soil microbial community structure, with a significant positive correlation with actinomycetes and gram-positive bacteria. In conclusion, straw returning combined with optimized nitrogen application (i.e., SNS, 8 t·hm-2 of wheat straw with N fertilizer reduced by 58.3%) could improve soil nutrient status, soil microbial biomass, soil microbial community structure, and soil ecological environment. It would be an effective measure for reducing fertilizer application and improving efficiency.

贺兰山东坡不同海拔典型植被带土壤微生物磷酸脂肪酸分析

PDF HTML阅读 XML下载 导出引用 引用提醒 贺兰山东坡不同海拔典型植被带土壤微生物磷酸脂肪酸分析 DOI: 10.5846/stxb202104130959 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 宁夏自然科学基金项目（2020AAC03102）；宁夏重点研发计划项目（2018BFG02015，2021BGF02005）；国家自然科学基金项目（31960359） Phospholipid fatty acid analysis of soil microbes in typical vegetation types at different elevation on the east slope of Helan Mountain Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:土壤微生物在维持干旱区森林生态系统功能稳定方面具有重要作用，但有关干旱区微生物群落结构及多样性沿海拔分布规律研究较少，采用磷酸脂肪酸（PLFA）法定量分析贺兰山自然保护区东坡不同海拔典型植被带（荒漠草原HM、蒙古扁桃MG、油松林YS、混交林HJ、青海云杉林QH）土壤微生物群落结构特征及多样性。结果表明，不同海拔植被带土壤中共检测出59种PLFA生物标记，YS土壤中生物标记的含量明显高于其他植被类型，5个植被带共有且含量较高的PLFA生物标记为16：0、18：1ω9c、18：1ω7c、10Me 16：0和18：2ω6c，特征微生物的含量在不同植被带土壤中分布不同，细菌分布数量最大，其次是真菌、放线菌，原生动物分布数量最小。聚类分析发现，不同植被带土壤PLFA生物标记可分成不同的类群，16：0、18：1ω9c和18：1ω7c基本在每个植被带都会单独聚为一类。对不同植被带所共有的PLFA生物标记绘制热图，发现不同的PLFA生物标记在不同植被带分布不同，YS植被带PLFA生物标记分布最高。不同植被带土壤微生物群落多样性显示，HJ土壤中微生物多样性指数大于其他植被类型，HM土壤中微生物多样性指数最小，说明土壤微生物多样性与植被多样性密切相关。主成分分析表明，与土壤微生物群落相关的2个主成分解释量为78.01%和8.80%，对第1主成分起主要作用的微生物类群有非特异性细菌、革兰氏阳性细菌、革兰氏阴性细菌、真菌、放线菌和原生动物等，对第2主成分起主要作用的微生物类群为厌氧细菌。土壤微生物与土壤因子相关性分析表明，土壤有机碳（SOC）、全氮（TN）与微生物类群及多样性指数正相关，pH、容重（BD）与微生物类群及多样性指数负相关，海拔引起土壤因子的改变是影响土壤微生物群落结构及多样性的重要因素。研究表明YS土壤中微生物含量最大，HJ土壤中微生物多样性最高，与山地生态系统中中部区域生物多样性高的其他研究结果相吻合，可为贺兰山自然保护区土壤微生物的研究及保护区的管理提供科学依据。 Abstract:Soil microorganisms play an important role for maintaining the functional stability of forest ecosystem in arid areas. However, distribution of soil microbial community structure and diversity along an elevation gradient remains poorly understood, especially in the arid areas. In this study, the phospholipid fatty acid analysis (PLFA) was used to examine variations in soil microbial community diversity along an elevational eastern slope in the Helan Mountain (Desert Steppe (HM), Amygdalus mongolica (Maxim) Ricker (MG), Pinus tabulaeformis forest (YS), Mixed forest (HJ), Picea crassifolia Kom forest(QH)). The results showed that, there existed 59 PLFAs which were significantly different in the soil samples from different vegetation types. The YS soil exhibited richer PLFAs distribution amount than the other vegetation types. The PLFAs biomarkers of five vegetation types with the highest contents were 16:0, 18:1ω9c, 18:1ω7c, 10Me 16:0 and 18:2ω6c, respectively. The amount of characteristic microorganisms was different in soil of different vegetation types, the bacteria had the richest distribution, followed by fungi, actinomycetes and protozoa. Cluster analysis showed that soil PLFAs could be divided into different groups in different vegetation types, 16:0, 18:1ω9c and 18:1ω7c could be divided into one group in different vegetation types. The heat map of the common PLFAs in different vegetation types was drawn. It was found that the distribution of different PLFAs was different in different vegetation types, and the distribution of PLFAs in YS vegetation was the highest. The diversity of soil microbial communities in different vegetation types showed that the microbial diversity index in HJ was higher than the other vegetation types, and the HM was the lowest, indicating that soil microbial diversity was closely related to vegetation diversity. Component analysis (PCA) identified 2 principal component factors in relation to microbial community diversity, explaining 78.01% and 8.80% of the variation, respectively. The microorganisms, which play a major role on first principal component, are nonspecific bacteria; Gram-positive bacteria and Gram-negative bacteria, fungi, actinomycetes and protozoa, which play a major role on second principal component, are anaerobic bacteria. Correlation analysis between soil microorganisms and soil factors showed that soil organic carbon (SOC) and total nitrogen (TN) were positively correlated with soil microbial groups and diversity index, while pH and bulk density (BD) were negatively correlated with microbial groups and diversity index. The change of soil factors caused by altitude was an important factor affecting soil microbial community structure and diversity. The results show that YS soil has the highest microbial content, and HJ soil has the highest microbial diversity, which accords with the theory of high biodiversity in the central region of mountain ecosystem, and can provide scientific basis for the study of soil microorganisms and the management of Helan Mountain Nature Reserve. 参考文献 相似文献 引证文献

人参种植对林地土壤细菌群落结构和代谢功能的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 人参种植对林地土壤细菌群落结构和代谢功能的影响 DOI: 10.5846/stxb201909201963 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（31670614） Effects of Ginseng cultivation on soil microbial community structure and metabolic functions in forest land Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:揭示人参种植对土壤微生物群落结构和代谢功能的影响，对防治人参连作障碍具有重要的理论意义。利用高通量测序技术研究了林地和由林地开垦耕种人参3a和4a后土壤微生物群落结构和代谢功能的变化。结果表明，变形菌门（Proteobacteria）、放线菌门（Actinobacteria）、酸杆菌门（Acidobacteria）、疣微菌门（Verrucomicrobia）、绿弯菌门（Chloroflexi）是林地和人参种植土壤微生物的主要优势类群。林地开垦种植人参后，土壤放线菌门和疣微菌门的相对丰度显著增加，土壤酸杆菌门的相对丰度显著降低；而土壤微生物多样性指数明显降低。除趋势对应分析（DCA）显示不同种植a限人参的土壤微生物群落结构存在明显差异。Tax4Fun功能预测表明，人参种植后土壤微生物的萜类化合物和聚酮类化合物代谢与信号转导功能的相对丰度显著降低，而膜转运功能的相对丰度增加。典范对应分析（CCA）和Partial Mantel Test分析表明，土壤速效钾、全钾含量和土壤pH值是影响土壤微生物群落结构的重要因子。因此，林地开垦种植人参对土壤微生物群落结构、多样性以及代谢功能产生了显著影响，土壤速效钾、全钾含量和pH值是影响土壤微生物群落结构的重要因素。 Abstract:The aim of this research is to reveal changes in soil microbial community structure and metabolic function in forested land after planting Panax ginseng. This study used high-throughput sequencing technology to analyze the soil microbial community structure and metabolic function of forested land and forested land cultivated with ginseng for 3 and 4 years. The results showed that Proteobacteria, Actinobacteria, Acidobacteria, Verrucomicrobia, and Chloroflexi were the dominant phyla. After ginseng was planted, the relative abundance of Actinomycetes and Verrucomicrobia significantly increased while the relative abundance of Acidobacteria significantly decreased. Overall soil bacteria diversity also significantly decreased. Detrended correspondence analysis (DCA) showed significant differences in soil bacteria community structure of ginseng across different cultivation years. The relative abundance of metabolism of terpenoids and polyketides and signal transduction significantly decreased, while the relative abundance of membrane transport significantly increased. Canonical correspondence analysis (CCA) and the Partial Mantel Test showed that potassium availability, total potassium content and soil pH were key factors affecting soil microbial community structure. The results show that soil microbial community structure, diversity and metabolic function changed significantly after planting ginseng in forested land. This work has important theoretical significance for the prevention and treatment of ginseng continuous cropping obstacles. 参考文献 相似文献 引证文献

Biochar inoculated with Pseudomonas putida improves grape (Vitis vinifera L.) fruit quality and alters bacterial diversity

Soil degradation is the major factor restricting agricultural and fruit industry development in Xinjiang. In the current study, biochar inoculated Pseudomonas putida Rs-198 were applied to soil to improve grape (Vitis vinifera L.) quality, soil quality and microbial community. Field experiments showed that the fruit weight, length and width in the inoculated biochar treatment increased by 7.6%, 3.8% and 3.8% when compared to that of control, respectively (P < 0.05). The soluble protein and hardness of grape treated with the inoculated biochar were increased by 28.6% and 10.8%, while the total acid was reduced by 15.8%. Physicochemical and biological properties such as electrical conductivity, alkali-hydrolyzed nitrogen, available phosphorus, available potassium, organic matter, urease activity, sucrase activity of soil which the inoculated biochar was added increased by 87.3%, 24.28%, 73.2%, 78.17%, 71.6%, 17.50%, and 82.11%, respectively. 16S rRNA sequencing results indicated that inoculated biochar application causes increased (P < 0.05) Gemmatimonadetes, Actinobacteria, Bacteroidetes and Planctomycetes, while Acidobacteria, Chloroflexi, Rokubacteria, Nitrospirae were reduced (P < 0.05). Redundancy analysis suggested that the inoculated biochar amendment significantly affected soil microbial community structure, critical environmental factors consisted of alkali-hydrolyzed nitrogen, available phosphorus, available potassium, urease activity, sucrase activity. In conclusion, the inoculated biochar has the ability to improve the quality of grape fruit, increase the nutrient content of the soil, and affect the bacterial community as a potential soil amendment agent.