Abstract:Soil health is an important prerequisite to ensuring food security and maintain the services and functions of terrestrial ecosystems. Soil microorganisms play a key role in regulating nutrient circulation, enhancing rhizosphere immunity, and preventing environmental pollution. Rational development and application of microbial resources is an important means to protect soil health and exert soil functions in the future. However, the heterogeneity and complexity of soil ecosystems limit the identification and utilization of microbial functions. Currently, the development of synthetic biology provides new ways and ideas for using microorganisms to promote soil health. By fully exploiting the metabolic diversity, functional stability, environmental adaptability of microbial communities, and rationally constructing synthetic communities, technical support can be provided for the ecological restoration of soil damaged by environmental pollution or degraded in quality due to agricultural use. This review summarizes the approaches, tools, and application scenarios for constructing synthetic communities and explores their mechanisms in remediating contaminated soils, enhancing soil fertility, and promoting plant resistance to soil-borne diseases and abiotic stresses. Furthermore, future research directions are proposed, including the construction of synthetic community repositories, the development of synthetic biology tools, and the application of artificial intelligence for screening synthetic communities. These strategies are of great significance for achieving precise construction and directional utilization of synthetic communities in a specific range to improve soil health and ensure sustainable use of soil.

Abstract:Soil pollution risk control and remediation is the key to the safe use of constructed land. The effectiveness of this work is influenced by both technological development and environmental management, and the systematic and coherent linkage of supervision is crucial. National and local governments have made diverse attempts at the collaborative supervision of soil environments within constructed land. Utilizing local legislation, regulatory documents, and technical standards, these strategies have progressively honed and standardized the allocation of departmental responsibilities, process supervision, and access management, leading to effectively controlling the environmental risks of contaminated sites. Despite these advancements, there is a clear need for further bolstering the all-encompassing and interconnected nature of coordinated supervision. This thesis, based on the analysis of the natural attributes, socio-economic attributes, and soil remediation particularities of constructed land, systematically reviews the current status and typical issues of constructed land soil pollution risk control and remediation, and provides suggestions on optimization of collaborative supervision. Overall, within the framework of the national institutional system, local governments have focused on refining the scope of supervision, formulating implementation details, and strengthening supervision and implementation to meet national requirements, without imposing additional demands. In addition, the text analyzes issues such as unclear scope of joint supervision, insufficient planning considerations, shallow integration of land transfer, and inadequate integration of land plot information. It advances a suite of recommendations for enhancing the coordinated supervision framework, including clarifying supervisory scopes, alignment of land planning with soil remediation endeavors, specification of land transfer procedures, embracing a unified national land spatial "one map" strategy, and strengthening of oversight through a multiplicity of approaches. Future investigative trajectories may delve into the realms of precision regulation, pivot to green and low-carbon remediation methodologies, and digital transformation of soil pollution oversight, all aimed at significantly elevating the collective impact of coordinated supervision. This study offers valuable insights for enhancing the integrated regulatory framework for soil risk control and remediation on constructed land, thereby ensuring the safe and effective use of such land.

Abstract:【Objective】 Soil erosion resistance reflects the vulnerability or sensitivity of soil to erosion, which is a critical parameter utilized for soil erosion prediction and is of significant importance for predicting regional soil erosion and adjusting land use patterns. Nevertheless, the potential effect as well as their driving mechanism of vegetation types on soil erosion resistance is still scarce in the purple soil of the Three Gorges Reservoir Area. Therefore, this study aimed to explore the potential effect of vegetation types on soil erosion resistance and decipher the influencing mechanisms of purple soil in the Three Gorges Reservoir area. 【Method】 Based on a full field investigation in the Qinling watershed of Zhongxian Country in the Three Gorges Reservoir area, seven typical vegetation types of the coniferous forest of Cupressus funebris Endl. (CF) and Pinus massoniana Lamb. (PM), broadleaf forest of Eucalyptus spp. (E), Citrus reticulata Blanco. (CR), shrub(S), grassland(G) and maize(M) were selected. Combined with the field sampling and indoor analysis, difference analysis, correlation analysis, redundancy analysis and path analysis, the differences as well as the main influencing factors of soil erosion resistance between different vegetation types were comprehensively analyzed. 【Result】 The comprehensive soil erosion resistance index(CSRI) varied from 0.05 to 0.72 between different vegetation types, among which maize had the minimum CSRI, then followed by CR, G, E, PM, S and CF. Moreover, CSRI varied significantly between different vegetation types with the CSRI of SL and CR being significantly lower than that of other vegetation types. Compared to M, CSRI of CR, G, E, PM, S, and CF increased by 210%, 407%, 779%, 816%, 1095% and 1217%, respectively. Differences in CSRI between different vegetation types was closely related to near-surface soil properties and vegetation characteristics. Correlation analysis indicated that CSRI was significantly positively correlated with organic matter content, water-stable aggregates content, total porosity, clay content, litter weight of the semi-decomposed layer, and root mass density, whereas significantly negatively correlated with bulk density (p<0.05). The results of redundancy analysis showed that water-stable aggregates, clay, and organic matter contents were the main factors controlling the differences in CSRI between different vegetation types, which could explain 64% of the total differences. However, the influencing mechanism of vegetation types on CSRI in purple soil was different from most previous studies carried out in other regions. Influenced by the formation process of purple soil, variation in CSRI between different vegetation types was dominantly controlled by clay content via its direct effect and indirect effect through increasing organic matter and water-stable aggregates contents. 【Conclusion】 Sloping land and orchard land are still the potential areas of soil erosion in the Three Georges Reservoir area since it has the minimum CSRI. Cupressus funebris Endl land can be promoted as soil and water conservation species in the reservoir area. The relevant research results can provide a scientific basis for the adjustment of land use structure and the selection of tree species for soil and water conservation, to realize the green and sustainable development of the Three Georges Reservoir area.

Abstract:【Objective】 Under the influence of extreme rainstorms, the slope of a dump site(a typical artificial re-plastic landform) is prone to geological disasters such as landslides and debris flow. This has resulted in soil erosion and vegetation restoration difficulties in the nearby mining areas. Therefore, to understand this phenomenon, this study focuses on the soil of an open-pit coal mine as the research object. 【Method】 The soil erosion process on the slope of the dump site was studied using an artificial simulated rainfall test. Runoff and sediment samples were collected when the slope of the dump site began to produce runoff after rainfall. Data on the flow velocity, flow width, flow depth, runoff, sediment content, etc., were collected once every 3 min. The runoff and sediment samples were collected and the volume was measured with a graduated measuring cup. Then, the cups were allowed to stand, and when the upper liquid was static and precipitated, the liquid was removed, and the erosion was measured by drying method (105 ℃). Furthermore, Reynolds number, runoff shear force, runoff power, and soil erosion rate were calculated from the collected data. Based on the data analysis of different rainfall intensities (50, 75, 100 mm·h^-1) and vegetation coverage (0%, 40%, and 70%), the change characteristics of slope denudation rate with water flow generation time and the quantitative relationship between soil denudation rate and hydrodynamic parameters were explored. 【Result】 (1) The soil erosion rate increased with the increase of rainfall intensity, and decreased with the increase of vegetation coverage. The contribution rates of the two factors to the soil erosion rate were 50% and 36%, respectively. (2) Under the three rainfall intensifies, the total sediment yield of 70% vegetation coverage decreased significantly by 18%~27% and 84%~87% compared with 0% (P < 0.05), respectively. Compared with 50 mm·h^-1, the total sediment yield of 100 mm·h^-1 was significantly increased by 1940~2530 mL and 66.92~386.14 g, respectively (P < 0.05). (3) At 0%, 40%, and 70% vegetation coverage, soil denudation rate showed a significant power function relationship with Reynolds number, runoff shear force, and runoff power(P < 0.01) while the hydrodynamic parameters showed a significant linear positive correlation (P < 0.01). In terms of goodness of fit, the vegetation coverage of different hydraulic parameters was 70% > 40% > 0%. The fitting effect between soil denudation rate and runoff power was the most significant, and the determining coefficient R² was 0.894, followed by runoff shear force. 【Conclusion】 Rainfall intensity is the main factor affecting soil erosion rate and with an increase in rainfall intensity, the rate of soil erosion also increases. The increase in vegetation cover led to a decrease in soil erosion rate. Under 70% vegetation coverage, the regression relationship between runoff power and soil erosion rate was most significant, and this parameter was the best hydraulic index to describe runoff erosion of the mine dump slope.

Abstract:【Objective】 This study aimed to investigate the impact of different vegetation restoration types on soil pore characteristics in Benggang areas. 【Method】 Surface soil samples were collected from four vegetation-restored lands(artificial arbor, artificial forest, artificial shrubland, and artificial grassland) in the Benggang erosion area and an unplanted site was selected as the control (eroded land). The pore characteristics of the aggregates (3~5 mm) were visualized and quantified using X-ray microcomputed tomography (μCT) at a voxel resolution of 5.91 μm. Following the imaging, we measured various physical soil hierarchies, including bulk density, aggregate size distribution, and mechanical composition across multiple scales. 【Result】 The results indicated that vegetation restoration significantly improved the formation and stability of soil aggregates, leading to notable changes in aggregate pore characteristics and characterized by high anisotropy and fractal dimension. This suggests that different vegetation types not only influence the physical properties of the soil but also enhance its ability to retain water and nutrients, thereby contributing to overall soil structure. The aggregate pore size distribution varied among the different revegetated sites, reflecting the influence of specific environmental conditions and management practices associated with each type of vegetation. The Soil Structure Index (SSI) was used to assess the overall quality of soil structure. The findings revealed that, except for artificial grassland, the SSI values were consistently higher for all vegetation-restored lands compared to the eroded land. The ranking of SSI values followed artificial arbor (0.66) > artificial forest (0.60) > artificial shrubland (0.48) > eroded land (0.31) > artificial grassland (0.25). This hierarchy underscores the significant benefits of arboreal woodlands, particularly citrus orchards, in enhancing soil structure and stability. 【Conclusion】 Overall, the results of this study underscore the critical role of vegetation restoration in promoting ecological recovery and improving soil quality in the Benggang erosion areas of South China. By demonstrating the positive impacts of different vegetation types on soil aggregate pore characteristics, this research provides valuable insights for land management and ecological restoration efforts. Future studies could expand on these findings by exploring the long-term effects of various restoration practices on soil health and erosion control, thereby contributing to more effective strategies for sustainable land use and environmental conservation.

Abstract:【Objective】 Estimating the spatial-temporal changes of farmland soil organic carbon density(SOCD) provides a scientific basis for food security and double-carbon strategy. 【Method】 In this study, a total of 371, 976 polygonal patches and 57, 254 sampling sites were used to establish 1: 10, 000 databases. The raster dataset of soil organic matter content was interpolated using the simple kriging method combining with ancillary variables of terrain information, which was an optimal interpolation established in the earlier study based on the idea of “ideal interpolation method + efficient auxiliary variables”. Then, the SOM content was assigned to each polygonal patch of the farmland map with the help of the spatial analyst tools of ArcGIS v. 10.8 software. Eventually, the SOCD was calculated. Moreover, the gravity center migration model was employed to quantify the regional differences in farmland SOCD changes in Fujian Province from 1982 to 2018. The regions mentioned above referred to different administrative regions of nine cities, soil types of nine soil groups, three land use types of paddy fields, dry-land, and irrigated land, and two climatic zones such as the middle subtropics and south subtropics of Fujian. Also, these nine cities were divided into the southeastern coastal cities and northwest inland cities of Fujian. 【Result】 The farmland soils in different regions had dual functions of carbon source and sink in the past 40 years. Viewed from the area ratio of farmland soil carbon source and sink, the carbon sequestration capacity or loss intensity of most farmland was concentrated in the range of 0~1 kg·m^-2, regardless of administrative regions, soil types, land use types, or climatic zones. Specifically, the farmland SOCDs in the southeastern coastal cities of Fujian were 2.37~2.65 kg·m^-2 and 2.23~2.83 kg·m^-2 in 1982 and 2018, respectively, which were much lower than those of northwest inland cities(2.92~3.24 kg·m^-2 and 2.99~3.30 kg·m^-2). It was also found that Putian was the only city to experience a decline in SOCD, with a carbon source effect of 0.31 kg·m^-2. In terms of soil types and land use patterns, paddy soils and paddy fields were the most important carbon sink, with SOCD increased by 0.10 kg·m^-2, while coastal solonchaks, aeolian soils, and dry-land contributed as a carbon source, with SOCD decreased by 0.23 kg·m^-2, 0.22 kg·m^-2 and 0.03 kg·m^-2, respectively. When it came to climatic zones, the farmland soil in the middle subtropics of Fujian increased from 3.02 kg·m^-2(1982)to 3.16 kg·m^-2(2018) in SOCD, with higher SOCD level and carbon sequestration efficiency than those of south subtropics. 【Conclusion】 The farmland soil organic carbon pool changes varied greatly with regions in Fujian Province from 1982 to 2018. These changes might have been mainly influenced by a combination of intrinsic soil factors and external factors such as human disturbance. Thus, our work suggests that in formulating policies for farmland carbon sequestration management in Fujian in the years to come, priority should be given to the SOCD level in different regions and their change differences.

Abstract:【Objective】 Soil dissolved organic matter(DOM) plays an important role in the biogeochemical processes in wetland ecosystems. This study aimed to uncover the total quantity, components, and source features of DOM in the river-lake confluence area of Hongze Lake. 【Method】 The spectral characteristics of DOM in soil covered by lake-sedge, reed, poplar, and willow in the river-lake confluence area of Hongze Lake were studied using UV-visible absorption spectroscopy and the three-dimensional fluorescence spectroscopy method. 【Result】 The results showed that the DOM content of soil covered by different vegetation was in the order of reed wetlands, lake-sedge wetlands, poplar forests, and willow forests. Additionally, soil within 40 cm of reed wetlands contained a dissolved organic carbon level of 193.2 mg·kg^-1. The soil DOM values of A₂₅₀/A₃₆₅, SUVA₂₅₄, SUVA₂₆₀, and S_R ranged from 3.7 to 4.5, 1.3 to 1.8, 0.86 to 1.8, and 3.6 to 4.9, respectively. Moreover, the molecular weight, aromaticity, and hydrophobicity of lake-sedge wetlands soil were significantly higher than those of other soils. As revealed, DOM's molecular weight, aromaticity, and hydrophobicity decreased in the 20~40 cm soil layer as opposed to the 0~20 cm soil layer. As shown by EEM-PARAFAC, four fluorescence components, terrestrial humic acid-like, marine humic acid-like, fulvic acid-like, and protein-like, have been recognized. Humic acid-like substances were found in all soil layers, with 55.1% to 70.1% being the majority, but the 20~40 cm soil layer saw a rise in protein-like substances, especially in reed wetlands soil. The FI, BIX, and HIX indices of DOM varied depending on the vegetation, with a range of 1.3 to 1.5, 0.47 to 0.72, and 1.7 to 7.4, respectively. The soil DOM properties were greatly influenced by the coverage of different vegetation. Also, terrestrial humic acid-like substances were the dominant soil DOM in the river-lake confluence area of Hongze Lake, with a lesser level of self-obtained and a higher degree of humification. 【Conclusion】 In summary, the research results revealed the differences in total DOM content and spectral characteristics of soils with different vegetation cover in the river-lake confluence area of Hongze Lake. It further provides a scientific basis for understanding DOM environmental behavior in the river-lake confluence area, thus, strengthening carbon sequestration efficiency in key areas and enhancing habitat protection.

Abstract:【Objective】 In the past few decades, soil potassium has received less attention than nitrogen and phosphorus, despite that potassium loss in farmland is a common issue due to large crop demand and the relatively small application amount. Soluble potassium resources are relatively unabundant in China. The low self-sufficiency rate and high reliance on imports led to the high cost of potassium fertilizers. Due to the importance of potassium in crop production and the cost and environmental consequences of applying potassium fertilizer, it is worth paying attention to mineral potassium in future agricultural production. It has been found that there is a unique potassium release mechanisms of layered silicate potassium-rich minerals in paddy soils. However, there is currently a lack of systematic research on the changes and influencing factors of different potassium transformation thresholds during the formation of paddy soils, which greatly limits the establishment and development of potassium transformation models for these soils. 【Method】 This study selected “potassium-rich’ purple paddy soil and “potassium-poor” red paddy soil, and investigated the evolution characteristics and influencing factors of different potassium transformation thresholds during their formation through time series analysis. The aim was to provide theoretical support for reducing the dependence on soluble potassium fertilizers in rice fields. 【Result】 For "potassium-rich" purple paddy soil, traditional rice cultivation in the early stages(within 0-20 years)significantly reduced the total amount of water-soluble potassium and exchangeable potassium in the plow layer(about a 28% decrease). After this period, the transformation thresholds between water-soluble potassium and exchangeable potassium, and between exchangeable potassium and non-exchangeable potassium, remained relatively stable, with thresholds stabilizing between 61±4 and 106±9 mg·kg^-1, respectively. For “potassium-poor” red paddy soil, the total amount of water-soluble potassium and exchangeable potassium also decreased significantly in the early stages of rice cultivation(within 0-100 years), reaching very low levels(about a 30% decrease). Subsequently, the transformation thresholds between water-soluble potassium and exchangeable potassium, and between exchangeable potassium and non-exchangeable potassium, stabilized, with thresholds remaining between 32±4 and 64±4 mg·kg^-1, respectively. 【Conclusion】 During the formation of paddy soils, the potassium forms and transformation thresholds in these soils are closely related to the potassium-rich minerals in clay and silt particles. The potassium release mechanisms of layered silicate potassium-rich minerals can remain stable over a long period during the formation of “potassium-rich” paddy soils. For red paddy soils, especially those with over 200 years of rice cultivation, it is necessary to increase potassium fertilizer input in a sustainable and potassium-balanced manner to avoid negative potassium balance in the fields. There is great potential in using gravel-rich layered silicate potassium minerals as an alternative to traditional potassium fertilizers in paddy fields.

Abstract:【Objective】 The spatial distribution of soil is consistent with the changes in bioclimatic conditions, with the soil mineral and organic composition also showing certain zonal changes. Consequently, the evolution of soil minerals accompanies the changes in soil surface properties. However, it remains unclear how these changes will vary among soil particles of different sizes. The goal of this study was to research the surface properties of soil particles with different diameters of 0-500, 500-1 000, 1 000-2 000, and > 2 000 nm in the latitudinal zonal soils and reveal the zonal changes of soil particle surface properties in different particle diameter ranges. 【Method】 The surface electrochemical properties(specific surface area, surface charge amount, charge density) of soil particles were determined by the combined determination method, the organic matter of soil particles was determined by the potassium dichromate method, the mineral composition of soil particles was determined by X-ray diffractometer. 【Result】 It was found that: (1) < 2 000 nm soil particles played a major role in the contribution of soil organic matter, secondary minerals, specific surface area, and surface charge while < 500 nm soil particles were the largest contributors to the soil specific surface area and surface charge. (2) With the decrease of latitude, the content of 0-500 nm particles gradually increased, the content of secondary minerals increased, the content of organic matter decreased, and the soil surface charge and specific surface area showed decreasing trends. (3) The soil-specific surface area and surface charge in the high latitude area increased linearly with the increase of the content of organic matter and montmorillonite, and the influence of montmorillonite content was greater than that of organic matter content. There was no obvious linear relationship between the specific surface area and surface charge with the increase of illite content. Also, the soil-specific surface area and surface charge increased linearly with the increase of organic matter content in the low latitude area while there was no obvious linear relationship between the specific surface area and surface charge with the increase of illite or kaolinite content. 【Conclusion】 The soil specific surface area and surface charge at high latitudes were mainly affected by the contents of montmorillonite and organic matter, while the soil specific surface area and surface charge at low latitudes were mainly affected by the content of illite and organic matter.

Abstract:【Objective】 The sedimentation characteristics of soil colloids are intricately linked to soil fertility and erosion resistance, with the critical coagulation concentration serving as a pivotal parameter for evaluating particle aggregation and dispersion. The rapid and accurate determination of this critical coagulation concentration holds significant importance in assessing soil quality. 【Method】 This study evaluated the critical coagulation concentrations of three types of particles: —montmorillonite, humic acid, and brown earth colloids, —by observing the trend in zeta potential variation on their surfaces. Through piecewise linear fitting, the feasibility of determining the critical coagulation concentration using the zeta potential method was verified in conjunction with dynamic laser light scattering. 【Result】 The findings reveal that: (1) The absolute value of zeta potential in each system decreased with increasing electrolyte concentration. This decline was rapid in the relatively low electrolyte concentration range but slowed down in the higher concentration range. (2) The critical coagulation concentration of montmorillonite and brown earth colloids on the charged surface in potassium and calcium ion systems, determined through piecewise fitting with electrolyte concentration changes, aligned with measurements from dynamic laser light scattering. (3) However, there was a significant difference between the critical coagulation concentration measured by the zeta potential and dynamic laser light scattering methods for humic acid colloid with variable charged surface in potassium and calcium systems. 【Conclusion】 For montmorillonite and brown earth colloidal particles with constant charged surfaces, the zeta potential method could be used to rapidly and accurately determine their critical coagulation concentrations. This method boasted simplicity, required minimal sample volume, and offered high efficiency. Conversely, for humic acid colloidal particles with variable charged surfaces, the zeta potential method failed to accurately assess the critical coagulation concentration.

Abstract:【Objective】 Acidic soil is not conducive to the formation of water-stable macroaggregates, which in turn affects the level of soil fertility and the normal growth of crops. Research suggests that the application of organic fertilizer is an important way to improve acidic soils, however, the effect of organic fertilizers on the formation processes of acidic soil aggregates remains not clear. Also, there is a lack of evaluation and comparison between different types of organic fertilizers. 【Method】 The rare earth oxide tracer method was used to test different organic fertilizers with equal carbon content on purple and red soil for 56 days. Four treatments were set up (no organic fertilizer control as CK; ordinary organic fertilizer as OF; biochar organic fertilizer as BC; and bio-organic fertilize as BO) and used to determine the stability of soil aggregates, the content of organic carbon in each fraction of aggregates, soil respiration, and the turnover path and rate of aggregates. 【Results】 The results showed that compared with the CK, the addition of organic fertilizer effectively reduced the amount of aggregate fragmentation, promoted the turnover and formation of large aggregates (>0.25 mm), and increased the average weight diameter (MWD) of soil aggregates. The BO treatment had the best effect on improving the stability of soil aggregates, which could be increased by 53.5%~103.35%. Adding organic fertilizer promoted the formation of the 0.25 mm aggregates and by calculating the turnover rate of soil aggregates, it was found that the addition of organic fertilizer reduced the turnover rate of large aggregates and increased the turnover rate of small aggregates (<0.25 mm). It is worth noting that in purple soil, the turnover rate of small aggregates was higher than that of large aggregates, while in red soil, the opposite trend was observed. Also, the addition of organic fertilizer promoted soil respiration and significantly increased the content of organic carbon in individual fractions (P<0.05). The total organic carbon content of different treatments was BC>BO>OF>CK, which increased by 14.50%~27.78% in purple soil and only increased by 6.40%~9.82% in red soil. 【Conclusion】 In general, the application of organic fertilizer can effectively reduce the fragmentation process of aggregates, promote the turnover of small aggregates to large aggregates, and improve the stability of aggregates. The application of bio-organic fertilizer was more conducive to improving the level of soil water-stable macroaggregate structure, increasing soil stability, and improving soil structure.

Abstract:【Objective】 Existing literature has predominantly concentrated on the influence of microbial activity on soil organic nitrogen mineralization. However, the role of abiotic processes, particularly the non-biological mineralization of organic nitrogen facilitated by typical manganese oxides, has received little attention. 【Method】 This study employed nsutite(γ-MnO₂) as the experimental mineral and soybean-derived peptone as a representative of soil organic nitrogen to investigate the effect of abiotic nitrogen mineralization mediated by γ-MnO₂ under a near-neutral environment and elucidated the reaction mechanism. Three experimental systems were designed: a peptone system(0.25 g·L^-1), a γ-MnO₂ system(1.0 g·L^-1), and a mixed system comprising both peptone(0.25 g·L^-1) and γ-MnO₂(0.25~2.0 g·L^-1). 【Result】 The results indicated that under pH 7.0 and in an air atmosphere, γ-MnO₂ could facilitate the mineralization of peptone nitrogen, producing inorganic nitrogen. The mineralization rate of peptone(0.25 g·L^-1) initially increased and then tended to stabilize with increasing initial γ-MnO₂ concentrations(0.0-2.0 g·L^-1). In this process, Mn(IV) and Mn(III) present in γ-MnO₂, along with reactive oxygen species(ROS) generated on the mineral surface, served as the principal oxidizing agents facilitating the mineralization of peptone into inorganic nitrogen. 【Conclusion】 This study is anticipated to advance the understanding of organic nitrogen mineralization mechanisms in farmland soils and to enhance the comprehension of nitrogen cycling processes within agricultural ecosystems.

Abstract:【Objective】 Enchytraeus crypticus is a model species widely used in toxicology studies and soil environmental risk assessments. It is known for its low sensitivity to polycyclic aromatic hydrocarbons (PAHs) which are prevalent soil contaminants. However, there remains a lack of toxicokinetic research on this species. This study selected phenanthrene as a representative PAH to investigate its toxicokinetics on E. crypticus under different exposure concentrations. 【Method】 Laboratory experiments were conducted to study the toxicokinetics of phenanthrene on E. crypticus at three concentrations: 20, 40, and 80 mg·kg^-1. Phenanthrene uptake and elimination were monitored over time. Toxicokinetic modeling was used to calculate the uptake rate constant, elimination rate constant, and bioaccumulation factor(BAF). A comprehensive model was also fitted to assess the overall phenanthrene dynamics. 【Result】 The results indicated that phenanthrene rapidly accumulated in E. crypticus during the initial exposure phase and reached steady-state concentrations of 47.83±11.69, 106.8±15.52, and 364.1±51.11 mg·kg^-1 at exposure levels of 20, 40, and 80 mg·kg^-1, respectively. During the elimination phase, phenanthrene was eliminated at a decreasing rate over time. The uptake rate constants increased significantly with exposure concentration, while the elimination rate constants declined, resulting in elevated BAF values at higher concentrations. E. crypticus exhibited high tolerance and bioaccumulation potential for phenanthrene, with prolonged retention at high exposure levels, posing potential risks to soil ecosystems. 【Conclusion】 The study concludes that the concentration-dependent toxicokinetics of phenanthrene, particularly differences in uptake, accumulation, and elimination, could result in varied soil environmental risk assessments. These findings underscore the need for careful consideration of such concentration-dependent dynamics in PAH risk evaluations. Furthermore, low-sensitivity species like E. crypticus should receive special attention in environmental risk assessments to ensure accurate evaluations of PAH-related risks.

Abstract:【Objective】 In recent years, the enrichment of soil-borne pathogens and antibiotic resistance genes(ARGs)has led to biological co-contamination of soil, posing a serious threat to agricultural product safety and human health. 【Method】 To investigate the synergistic remediation effect of reductive soil disinfestation(RSD) on soil biological co-contamination, intensive farmland soils(black soil, red soil and fluvo-aquic soil) with co-contamination of Ralstonia solanacearum, ARGs, and mobile genetic elements(MGEs) were selected. RSD was applied with 1% ethanol(ET), alfalfa meal(AL, C/N: 21.2), and molasses(MO, C/N: 12.6), alongside controls of maximum water holding treatment(FCK) and untreated soil(CK). Real-time PCR was used to analyze the changes of R. solanacearum, major ARGs and MGEs before and after treatment, and the reduction rate of relative abundance was used to measure the mitigation effect of RSD treatment on soil biological co-contamination. 【Result】 The results showed that RSD could effectively reduce a variety of ARGs and MGEs, among which AL and MO treatment could decrease the relative abundance of aadA7, aadA21, tet36, sul1, and IS6100 genes in black soil, with a reduction rate of 28.4%-49.9%. After ET treatment, the relative abundance of aadA7, msrE, tetG, tetM, tet36, intl1, IS6100, and IS26 genes in fluvo-aquic soil decreased significantly, and the reduction rate reached 56.2%-81.6%. Additionally, RSD efficiently reduced the relative abundance of R. solanacearum in soil, and the decrease in red soil and fluvo-aquic soil was 88.0%-92.3% and 76.1%-94.2%, respectively. Correlation analysis showed that there was a certain coupling relationship between the relative abundance of R. solanacearum and ARGs and MGEs. In fluvo-aquic soil, the relative abundance of R. solanacearum was significantly and positively correlated with the relative abundances of most ARGs(aadA7, msrE, tetG, tetM, and tet36) and MGEs(intl1, IS6100, and IS26) genes, indicating that RSD treatment had a good synergistic reduction effect on the biological co-contamination in fluvo-aquic soil. Furthermore, there were considerable differences in the correlation results between the relative abundance of R. solanacearum, ARGs, and MGEs and soil physicochemical properties in different soil types. This indicates that the effectiveness of RSD treatment in remedying soil biological co-contamination varies depending on soil physicochemical properties. 【Conclusion】 RSD can synergistically reduce soil biological co-contamination caused by the superposition of soil R. solanacearum, ARGs, and MGEs, but its reduction effect is affected by soil and organic material types.

Abstract:【Objective】 This study aims to systematically characterize the evolutionary dynamics of modified nanoscale zero valent iron (M-nZVI) in the field of environmental remediation, identify critical technological trends and knowledge gaps in this field. 【Method】 Utilizing bibliometric analysis on data from the Web of Science Core Collection(1994-2024), this study quantitatively mapped the international collaboration networks, research priorities, and frontiers related to M-nZVI. 【Results】 The findings reveal that: (1) Global collaboration in environmental remediation using M-nZVI exhibits robust interconnectedness. China leads in academic output, contributing 49.02% of total. However, its relatively lower ranking in average citation frequency per paper, suggests the need for enhanced research translation efficiency. Trend analysis indicates that research activity in this domain may transition from rapid growth to gradual decline, constrained by uncertainties in environmental risk and techno-economic limitations. (2) At the technological development level, mainstream techniques include sulfurization, magnesium hydroxide encapsulation, various loading methods, and coupled modification approaches. Application research predominantly targets contaminant removal in soil and groundwater systems, such as hexavalent chromium and trichloroethylene. Nevertheless, studies on the toxicological effects of M-nZVI are still quite limited. 【Conclusion】 Future research should focus on establishing a three-pronged framework integrating "technology development-mechanistic elucidation-risk assessment." This includes advancing surface functionalization techniques to create eco-friendly, cost-effective, and high-performance modified materials; clarifying synergistic removal mechanisms for emerging contaminants (e.g., perfluorinated compounds, endocrine disruptors) and complex pollutant mixtures; setting up ecological risk prediction models and migration-transformation simulations based on life cycle assessment; and developing microbial-coupled remediation systems along with integrated equipment solutions.

Abstract:【Objective】 Clarifying the soil nutrient status of peanut production regions in China is crucial for guiding the scientific fertilization practices in peanut cultivation and promoting high yield and high nutrient use efficiency. 【Method】 In 2022, 1 020 soil samples were collected from major peanut production regions in China, and the soil organic matter (SOM), total nitrogen (TN), available N(AN), available phosphorus (AP), available potassium (AK) and pH status were evaluated. The variation characteristics of soil nutrients in peanut planting soils were also analyzed by different ridge planting methods, yield levels, soil types and soil textures. 【Result】 The results showed that the average SOM, TN and AN contents in the peanut-producing regions were 15.15 g·kg^-1, 1.01 g·kg^-1 and 104.49 mg·kg^-1, respectively. Also, 78.62%, 60.49% and 43.72% of the sampling points for SOM, TN and AN were deficient, mainly concentrated in the Northeast, Northwest, and Huang-Huai-Hai peanut production regions, such as Liaoning, Hebei, Henan, and Xinjiang provinces. The average soil AP content was 39.76 mg·kg^-1, with only 13.14% of the sample points in the P deficiency level, mainly distributed in the south and the Yangtze River basin, in areas such as Sichuan and Yunnan provinces. The average soil AK content was 126.71 mg·kg^-1 and 38.62% of the sample points were deficient in K and mainly distributed in Hebei and Guangdong province in the Huang-Huai-Hai and southern peanut production regions. In addition, the soil nutrient status was affected by the tillage practices, planting modes, and yield levels, with the soil AN and AP contents in ridge cropping significantly increased by 6.04% and 31.72% compared with those of flat cropping. The result also revealed that SOM, AN, AP, and TN contents in summer peanut were significantly increased by 24.33%, 67.37%, 25.85%, and 14.87% (respectively) compared with those of spring peanut and intercropped peanuts with wheat. The soil pH, AN, and AP contents of high-yield plots were respectively increased by 5.48%, 6.33%, and 26.24% compared with those of low-yield plots. There were also differences in soil nutrient characteristics among different soil types. For instance the SOM content(16.08 g·kg^-1) of all soil types was generally low, with the lowest in the wind-sand soil (11.5 g·kg^-1) while the soil AN content of the wind-sand soil (79.2 mg·kg^-1), brown soil (75.33 mg·kg^-1), grey calcareous soil (84.29 mg·kg^-1), and tidal soil (84.88 mg·kg^-1) was deficient. The AP content(39.43 mg·kg^-1) of all soil types was relatively abundant and highest in the lime concretion black soil (70.31 mg·kg^-1) whereas AK content was deficient in the latosols (78.78 mg·kg^-1). 【Conclusion】 There are significant differences in soil nutrients in different peanut-producing regions in China. The deficiencies of SOM, TN, and AN mainly occurred in wind-sand soil, tidal soil and brown soil in the northeast, northwest China, and Huang-Huai-Hai peanut production regions. Also deficiencies in AK mainly occurred in the peanut areas of southern brick-red soil. It was recommend strict control of the input of P fertilizer and increase the application of N and K fertilizers in soils with N and K deficiencies in peanut production regions of China.

Abstract:【Objective】 Converting agricultural straw into biochar and then returning it to the field has received widespread attention at home and abroad as a potential pathway for soil improvement and carbon sequestration and emission reduction in the southern acidic red soil area. 【Method】 Relying on soil column experiments of rice-wheat paddy-upland rotation and millet-wheat upland-upland rotation established in June 2011, the changes in the quantity and chemical composition of organic carbon in paddy soils (QP and TP) and upland soils (QU and TU) developed from Quaternary red clay and Tertiary red sandstone soils under long-term straw biochar application(BC0, 0 t·hm^-2 per season; BC11.3, 11.3 t·hm^-2 per season) were analyzed. We used ¹³C solid-state NMR to clarify the differences in carbon sequestration effect of biochar application on different acidic red soils. 【Result】 The results showed that: (1) soil texture, land use type, and their interaction significantly affected soil organic carbon density under biochar treatment. Compared with BC0, under the same land use pattern, the increase in soil organic carbon density from 0-20cm was higher in partial clayey soils (QP, 25.22 kg·m^-2; QU, 8.07 kg·m^-2) than sandy soils (TP, 8.67 kg·m^-2; TU, 7.58 kg·m^-2), and higher in paddy soils than upland soils after 11 years of BC11.3 treatment. (2) Under the same land use pattern, there was no significant difference in the contents of each functional group of soil organic carbon with different textures. The change in the utilization pattern of paddy and upland significantly affected soil organic carbon stability. The proportions of alkyl carbon and o-alkyl carbon in paddy soil were higher than those in dryland soil, and the proportion of aromatic carbon was lower than that in upland soil. Also, the stability of retained organic carbon in upland soil was higher. 【Conclusion】 We observed that the organic carbon sequestration potential of partial clay soil is higher than that of sandy soil after long-term straw carbonization and returning to the field in the acidic red soil area of South China, but there was no difference in long-term stability. Organic carbon sequestration in paddy soils was greater than in upland, but the stability of soil organic carbon was lower than in upland soils.

Abstract:【Objective】 Microbial necromass carbon plays a significant role in the global carbon cycle and is a key contributor to soil organic carbon. Its importance stems from its stability, which is crucial for carbon protection and long-term carbon storage in soils. Within microbial necromass carbon, fungal necromass carbon (FNC) and bacterial necromass carbon (BNC) are two main components, and research has shown that FNC is more stable than BNC. Therefore, a higher proportion of FNC relative to BNC, expressed as the FNC/BNC ratio, is often considered indicative of greater microbial necromass carbon stability. However, despite the recognition of this relationship, the global distribution patterns of microbial necromass carbon stability and the factors influencing these patterns remain unclear due to a lack of large-scale observational data. Addressing this gap is essential for advancing our understanding of the mechanisms behind soil carbon cycling and protection. 【Method】 To address these uncertainties, this study employs a combination of meta-analysis and machine learning techniques to analyze microbial necromass carbon stability on a global scale. Meta-analysis allows for the synthesis of findings from multiple studies to produce more robust conclusions, while machine learning enables the identification of complex patterns in large datasets. Together, these methods offer a powerful approach to uncovering the spatial distribution of microbial necromass carbon stability and its driving factors. The study specifically examines the relationship between FNC/BNC ratios and various environmental variables, including soil nutrient levels (such as soil organic carbon, total nitrogen, and total phosphorus) and climatic factors (such as annual mean temperature and evaporation). By analyzing data from different ecosystems and climatic zones, the study aims to clarify the global patterns of microbial necromass carbon stability and the key factors influencing it. 【Result】 The results showed that the global average stability of microbial necromass carbon was 3.09. Among different ecosystems, forests had the highest average value (3.94), while deserts had the lowest (1.09). In terms of climate zones, the highest average value was found in the polar regions (4.14), and the lowest in arid climate zones (1.69). In different aridity index regions, the stability of microbial necromass carbon was lowest in extremely arid areas (0.75) and highest in semi-humid regions (3.77). Also, microbial necromass carbon stability exhibits distinct characteristics across different regions. 【Conclusion】 Overall, microbial necromass carbon stability tends to be lower under conditions of higher annual mean temperature or greater annual evaporation, indicating a negative correlation between climatic conditions and microbial necromass carbon stability. Soil organic carbon, total nitrogen, and microbial biomass nitrogen were identified as key regulators of microbial necromass carbon stability, with positive correlations to its stability. Moreover, annual mean temperature and evaporation indirectly affected microbial necromass carbon stability by influencing the levels of soil organic carbon, total nitrogen, and total phosphorus. The study highlighted the global spatial distribution of microbial necromass carbon stability and the major driving factors behind it. These findings provide valuable theoretical support for developing soil management strategies that focus on protecting and enhancing organic carbon based on the stability of necromass. Such strategies can help maintain and improve soil health, carbon sequestration, and ecosystem functioning in the face of changing environmental conditions.

Abstract:【Objective】 Straw returning is an effective measure to increase the amount of soil organic carbon (SOC) in agroecosystems. The objective of this study was to study the temporal dynamic of SOC in Mollisols during long-term straw return. 【Method】 Based on an 18-year long-term field experiment using a maize-soybean rotation cropping system in the typical black soil region, the temporal dynamic of topsoil (0-20 cm) organic carbon was studied under three treatments: no fertilizer (NF), mineral fertilizer (NPK), and mineral fertilizer with straw return (NPKS). Furthermore, physical and chemical fraction methods were applied to study the effect of straw return on SOC pools. 【Result】 The results showed that: (1) Compared with the initial (2004) soil, the SOC content significantly increased by 12.97% in the NPKS treatment, with an annual increase of 0.18 g·kg^-1, and the SOC content significantly decreased by 3.90% in the NF treatment, while no significant change was found in NPK treatment.(2) There was a significant positive correlation between SOC content and year and the cumulative carbon input in the NPKS treatment. In particular, a significant relationship between SOC and cumulative carbon was observed from 2004 to 2015 under NPKS, while not from 2015 to 2022, indicating that the increase of SOC caused by straw return mainly occurred in the first 11 years, and after 11 years, the SOC reached a state of equilibrium. (3) The NPKS treatment increased the carbon content in free light fraction (fLFC), occluded light fraction (oLFC), the heavy fraction (HFC), humic acid (HAC), fulvic acid (FAC), and humin (HMC) by 47.77%, 34.77%, 11.18%, 13.00%, 6.32%, and 11.71%, respectively. Straw return improved the C proportion in labile fractions(fLFC and oLFC) and decreased the proportion of HFC, but the contribution of HFC to SOC improvement was more than 80%. Thus, the stable HFC was a key component for the long-term sequestration of SOC. In addition, straw return increased the ratio of HA/FA, consequently, increasing the humification degree of soil organic matter. 【Conclusion】 Long-term continuous straw return can effectively improve the content of SOC and its fractions in black soil, but after 11 years of continuous straw return, SOC will stop growing and reach a new equilibrium. Although the labile SOC was elevated at a higher percentage than the stable SOC, the stable SOC still plays a crucial role in maintaining the stability and quantity of SOC.

Abstract:【Objective】 Soil organic carbon (SOC) is one of the key factors influencing crop yield in the Shajiang black soil region, and straw returning is an effective method for continuously improving SOC. However, the accumulation characteristics of plant- and microbial-derived carbon and their relative contribution to SOC under different straw returning methods (no-tillage with straw returning, NTS; rotary tillage with straw returning, RTS; deep ploughing with straw returning, DPS) remain poorly understood. Therefore, this study aims to explore these characteristics and contributions of plant- and microbial-derived carbon at 0-10, 10-20 and 20-40 cm soil depths of Shajiang black soil under different straw returning methods. 【Method】 A seven-year field experiment was conducted using lignin phenols and amino sugars as biomarkers. Mixed soil samples were collected from depths of 0-10, 10-20, and 20-40 cm. The content of plant- and microbial-derived carbon and their contributions to SOC were calculated based on the biomarkers content. 【Results】 The results revealed that, RTS and DPS significantly increased the SOC content of each soil depth, with an increase of 113% (P < 0.05). In contrast, the effects of NTS on SOC were mainly concentrated at the 0-10 cm depth after seven years, showing a phenomenon of surface accumulation in SOC. There was no significant difference in lignin phenol content between NTS and RTS (P > 0.05), however, at the 10-20 cm and 20-40 cm depths under DPS treatment, lignin phenol content increased by 57.3% and 36.3%, respectively (P < 0.05), despite a marked decrease at the 0-10 cm depth (P > 0.05). Additionally, the relative contents of Vanillyl (V) and Syringyl (S) phenols under DPS were significantly increased (P < 0.05) and the degree of oxidative degradation of lignin at the 10-40 cm depth was lower than that under NTS and RTS. Furthermore, amino sugar content showed no significant difference between NTS and RTS at each soil depth. However, under DPS, amino sugar content at the 10-20 and 20-40 cm depths increased by 45.6% and 35.8% in comparison with RTS, respectively (P < 0.05). The variation trend of Glucosamine (GluN) and Galactosamine (GalN) with soil depth was similar to amino sugar content, but at the 0-20 cm depth, Muramic acid (MurN) content under NTS and DPS was lower than that of RTS, with a highest decrease of 47.2%. Interestingly, DPS promoted the transformation of microbial community towards fungi, with the carbon ratio of fungal necromass to bacterial necromass at the 10-20 and 20-40 cm depths increasing by 177% and 58.0%, respectively, compared to RTS (P < 0.05). 【Conclusion】 The substantial increase in SOC content primarily results from a significant rise in crop residue content observed in the topsoil (0-10 cm) under NTS and RTS, as well as in the deeper soil (10-40 cm) following DPS. Our findings suggest that DPS promotes the accumulation of plant- and microbial-derived carbon at deeper soil depths, increases the contribution of microbial carbon to SOC and enhances the stability of carbon pool, which is crucial for the efficient utilization of straw resources and improvement of soil quality in Shajiang black soil region.

Abstract:【Objective】 The mineralization process of soil organic carbon (SOC) and its components is complex. For example, particulate organic matter (POM) and mineral-associated organic matter (MAOM) are two components with different physicochemical properties and turnover rates. However, few studies have paid attention to the differences in the response of these different components to climatic factors. Thus, this study aimed to investigate the differences in the mineralization of POM and MAOM under different temperatures and moisture conditions and provide a basis for the estimation and prediction of CO₂ emission fluxes in the context of global climate change. 【Method】 The soil of Xilingol grassland in Inner Mongolia was collected to obtain POM and MAOM using a physical grading method and controlling the same mass of each fraction. Bulk soil was incubated under optimum conditions for 180 days, and POM and MAOM were incubated at different temperature and moisture conditions for 60 days to investigate the differences in mineralization of the two fractions and their response to temperature and moisture. 【Result】 After 180 days of incubation experiments under optimal conditions, the cumulative CO₂ emission from the grassland soil reached 2688 mg kg^-1. MAOC in the grassland soil was relatively large, which accounted for 60% to 75% of TOC. Under different temperature conditions, the mineralization rates of both POM and MAOM increased with increasing temperature, while the two fractions responded differently to soil moisture content. There was a positive but insignificant correlation between the CO₂ emission rate of MAOM and soil moisture, while there was no significant correlation between the CO₂ emission rate of POM and soil moisture. It was also found that MAOM was much larger than POM in terms of cumulative CO₂ emissions per unit of soil mass, while POM was much larger than MAOM in terms of cumulative CO₂ emissions per unit of organic carbon. 【Conclusion】 The mineralization of grassland soils MAOM and POM showed significant differences in response to temperature and moisture, suggesting that the mechanisms controlling the mineralization of these two carbon pools are different. The cumulative CO₂ emission per unit of organic carbon in POM was much larger than that in MAOM, suggesting that the carbon in POM is more easily mineralized under the same conditions. Thus, distinguishing between POM and MAOM helps to better understand SOC turnover and provides a scientific basis for improving the SOC mineralization model.

Abstract:Farmland shelterbelt systems are crucial for improving soil moisture and carbon conditions, ensuring crop production, and enhancing the quality of the ecological environment. However, while serving as a barrier to agricultural ecosystems, farmland shelterbelts also compete with crops for nutrients and moisture resources, resulting in both positive and negative environmental effects. Therefore, exploring the factors influencing the spatiotemporal variations of moisture and carbon conditions within farmland shelterbelts with typical configuration is essential to effectively enhance the ecological benefits of farmland shelterbelt systems, scientifically constructing shelterbelt forests, and improving the ecological environment. In this study, we selected typical configurations of farmland shelterbelt systems, including two-row, four-row, five-row, and eight-row forest belts in the Hetao Irrigation Area. We measured the soil moisture storage (SMS) and soil carbon stocks (SCS) across various spatial positions at different horizontal distances from the shelterbelts(0.3H, 1H, 2H, 3H, 4H, where H represents the height of mature trees) and at different depths(0-20 cm, 20-40 cm, 40-60 cm, 60-80 cm, 80-100 cm), as well as at different temporal scales (early, mid, and late growing seasons across various months). Additionally, the study examined ecological environmental factors, including soil properties, vegetation attributes, and microclimatic factors, to investigate the key factors influencing soil moisture storage and soil carbon stocks within farmland shelterbelt systems. The results showed that: (1) SMS and SCS were highest in the four-row forest belts, with 240.2 mm and 26.7 kg·m^-2, respectively, and lowest in the two-row forest belts, with 195.4 mm and 16.1 kg·m^-2, respectively. Overall, the general pattern of soil moisture storage and soil carbon stocks across different shelterbelt configurations was four-row > eight-row > five-row > two-row. (2) For the temporal scale, the highest mean SMS (277.7 mm) was recorded in May, while the highest mean SCS (22.04 kg·m^-2) was recorded in October. Regarding the horizontal distance, SMS exhibited an increasing trend with distance from the shelterbelt, whereas SCS displayed a decreasing trend. In terms of vertical depth, SMS increased with depth, while SCS gradually decreased as depth increased. (3) Farmland shelterbelts significantly reduce wind speed, solar radiation, and air temperature while enhancing relative humidity and minimizing soil evaporation, with the four-row forest belts exhibiting optimal microclimatic regulation and overall benefits. (4) The ranking of ecological environmental factors affecting soil moisture storage and soil carbon stocks was as follows: soil properties > microclimate factors > vegetation attributes. By analyzing and evaluating the effects of each environmental factor on SMS and SCS under different patterns of farmland shelterbelt systems, this study provides a theoretical basis and scientific foundation for constructing farmland shelterbelt ecosystems.

Abstract:【Objective】 Salvia miltiorrhiza Bunge, commonly known as Danshen, is a perennial herbaceous plant that is a traditional and widely used medicinal herb in China. Intensive cultivation has led to frequent outbreaks of soil-borne diseases, notably root rot, which significantly limits the yield and quality of Danshen. 【Method】 This study compared the antagonistic abilities of four Lysobacter strains isolated from the rhizosphere of Solidago canadensis against the root rot pathogen Fusarium oxysporum 220. To identify the most efficient fermentation substrate for the selected strain, microbial solid-state fermentation was conducted using tobacco stalk, rice straw, sorghum straw, corn straw, and Solidago canadensis straw. Based on the optimal fermentation substrate, a bio-organic fertilizer(BOF) was prepared. Subsequently, pot experiments were conducted to evaluate the effectiveness of this BOF in controlling Danshen root rot. Finally, based on metagenomic sequencing, the key microbial groups and functional genes enriched by BOF were analyzed. 【Result】 The results of the study demonstrated that the Lysobacter enzymogenes strain Le395 exhibited strong antagonistic effects against the root rot pathogen F. oxysporum 220. In the organic fertilizer raw material screening experiment, it was found that the optimal fermentation substrate for strain Le395 was Solidago canadensis straw. In the pot experiment, it was observed that the application of the BOF effectively controlled Danshe root rot disease. Compared to the control group(CK), the disease incidence was reduced by 50.3%, and the disease index decreased by 50.2%. Additionally, the BOF showed significant growth-promoting effects. The above-ground fresh biomass of the plants treated with BOF increased by 163.1%, while the below-ground fresh biomass increased by 147.0% compared to the CK group. Finally, qPCR and metagenomics sequencing analyses revealed that the application of Le395 BOF significantly decreased the abundance of Fusarium and F. oxysporum in the rhizosphere of Danshen. It also increased the abundance of Lysobacter and L. enzymogenes, while modulating the rhizosphere microbial community structure and enhancing the abundance of disease resistance- and growth promotion-related functional genes in the rhizosphere. 【Conclusion】 These findings provide a theoretical and technical foundation for developing an ecological and sustainable strategy for controlling Danshen root rot using bio-organic fertilizer.

Abstract:【Objective】 Arbuscular mycorrhizal fungi (AMF) play a crucial role in soil microbial ecological networks and can form symbiotic structures with about 80% of plants, making them a key component of sustainable soil management. 【Methods】 In order to reveal the response mechanism of soil AMF and their ecological network to straw return in the fluvo-aquic soil area of North China Plain, experimental plots with different straw return treatments were chosen under long-term wheat-maize rotation, and high-throughput sequencing and ecological network analyses were applied to elucidate the composition of soil mycorrhizal practices and fertilization treatments. The experiment was set up with five treatments and three replications, including T1: straw removal + PK fertilizer; T2: straw mulching + PK fertilizer; T3: straw removal + NPK fertilizer; T4: straw mulching + NPK fertilizer; and T5: straw burying + NPK fertilizer. 【Results】 The results showed that: (1) Straw incorporation with NPK fertilizer significantly decreased soil pH and increased the content of soil organic matter, total nitrogen, ammonium nitrogen, available potassium, and available phosphorus (P < 0.05). This suggests that the combination of straw and NPK fertilizer is effective in enhancing soil fertility. (2) Different treatments of straw burial and nitrogen fertilizer application significantly affected the community composition of AMF, however, there was no significant difference in the alpha diversity of the communities. Nevertheless, Glomus and Paraglomus were the main dominant genera of the AMF community in the fluvo-aquic soil, highlighting their important role in these ecosystems. (3) Co-occurrence network analysis revealed seven distinct ecological network modules. Notably, the species abundance in module VI showed a significant positive correlation with several soil nutrient indices, including organic matter, nitrate nitrogen, available phosphorus, available potassium, and total nitrogen (P < 0.05). This module also exhibited a significant positive correlation with N-acetylglucosaminidase activity, an enzyme involved in nitrogen cycling (P < 0.05). Conversely, the species abundance in module VI was significantly negatively correlated with soil pH (P < 0.05). 【Conclusion】 Different straw returning methods can effectively regulate soil fertility by improving soil physicochemical properties, modulating the structure and diversity of soil microbial communities, and adjusting AMF network interactions. By understanding the complex interactions between AMF communities and soil management practices, we can develop more effective strategies for maintaining soil health and productivity. This research provides valuable insights into the mechanisms by which straw returning and fertilization treatments influence AMF communities and their ecological networks, offering a foundation for future studies and practical applications in sustainable agriculture.

Abstract:【Objective】 Ralstonia solanacearum, a highly virulent plant pathogenic bacterium, causes bacterial wilt in tomatoes and other crops. This causes host death and significant yield losses, posing a serious threat to agricultural economies. The rhizosphere, as a critical environment for plant-microbe interactions, plays a decisive role in determining the outcome of pathogen invasion and plant health. However, the interactions between bacteria and fungi in the rhizosphere under pathogen invasion remain unclear, thus, limiting the understanding of the microbial changes associated with bacterial wilt disease. 【Method】 This study investigated the impact of R. solanacearum invasion on the composition and interaction networks of bacterial and fungal communities in the rhizosphere of diseased and healthy tomato plants. Quantitative real-time PCR (qPCR) was employed to quantify microbial abundances, while high-throughput amplicon sequencing was used to characterize the diversity and structure of bacterial and fungal communities. By comparing the microbial co-occurrence network in rhizosphere soils of diseased and healthy tomato plants, the study aimed to elucidate how pathogen invasion affects the microbial community structure and their ecological interactions. 【Result】 The results showed significant differences in the bacterial communities between the rhizospheres of diseased and healthy plants. The rhizosphere of diseased plants was invaded by a higher abundance of R. solanacearum, while the rhizosphere of healthy plants was significantly enriched with bacteria from the phyla Actinobacteria and Firmicutes, which include a greater number of beneficial bacteria with potential for biological control. Moreover, pathogen invasion reduced the ecological niche breadth and qPCR counts of fungi in the rhizosphere. Co-occurrence network analysis revealed that the bacterial-fungal network in diseased rhizospheres was more complex, with a significantly higher proportion of fungal nodes (46.7% compared to 31.0% in healthy rhizospheres). Among them, Ascomycota species emerged as key network nodes, indicating that pathogen invasion enhanced the close associations between bacteria and fungi(particularly Ascomycota species). In the direct bacterial-fungal interactions, the proportion of negative correlations in diseased rhizospheres (46.3%) was notably higher than in healthy rhizospheres (35.4%), suggesting that pathogen-induced interactions were predominantly antagonistic. Additionally, in the bacteria-fungi networks, Ascomycota and Actinobacteria were identified as key fungal and bacterial taxa, serving as biological indicators in diseased and healthy rhizospheres, with significant positive (R² = 0.393, P = 0.002) and negative (R² = 0.523, P = 0.000 2) correlations with pathogen abundance, respectively. 【Conclusion】 These results elucidate the disruptive effects of R. solanacearum on rhizosphere microbial communities, particularly the bacterial-fungal ecological interactions, and highlight the changes in rhizosphere microbial structures under bacterial wilt. This study provides a theoretical foundation for developing future strategies to control bacterial wilt in tomatoes.

Abstract:【Objective】 Continuous advancements have been achieved in optimizing the formulation, application strategies, and overall applicability of seaweed-derived fertilizers. However, a mechanistic understanding of how their key functional components modulate soil processes remains incomplete. This study investigated the impact of brown algae substances, central functional constituents of seaweed fertilizers, on soil properties, carbon fractions, carbon turnover-related enzymes, and associated greenhouse gas emissions. 【Method】 In this study, a soil incubation experiment was conducted with five treatments: control (CK), brown seaweed powder treatment(Sea), sodium alginate treatment with a viscosity of 66 mPa·s (Alg66), sodium alginate treatment with a viscosity of 360 mPa·s(Alg360), and fucoidan treatment (Fuc). The soil was incubated at 25 ℃ for 112 days and sampled periodically to determine the soil properties, carbon composition, enzyme activity, and greenhouse gas emissions. On the 56th and 112th day of incubation, the effects of adding different brown algae substances on soil β-glucosidase(BG), cellobiohydrolase(CBH), β-xylosidase (BX), and N-acetyl-β-glucosaminidase (NAG) and particulate organic carbon (POC), mineral-associated organic carbon (MOC), dissolved organic carbon (DOC), and easily oxidizable organic carbon (EOC) were determined. Nitrous oxide (N₂O), carbon dioxide (CO₂), and methane (CH₄)emissions were monitored during the first 50 days of incubation. 【Result】 The results showed that the addition of different brown algae substances had varying effects on the soil properties. Compared to CK, the addition of brown seaweed substances significantly increased soil organic carbon and total nitrogen content. The most significant effects on organic carbon and total nitrogen were Fuc treatment and Sea treatment, respectively. The Sea treatment enhanced soil available phosphorus and potassium content by 19.83% and 260.23%, respectively. Conversely, the brown algae polysaccharide treatments (Alg66, Alg360, Fuc) decreased soil available phosphorus by 17.67%, 2.74%, and 20.15% and soil available potassium by 11.41%, 3.85%, and 6.36%, respectively. Also, the Fuc treatment significantly improved the activated carbon component content, particularly the dissolved organic carbon, which was significantly different from other treatments at the end of the incubation period, and 6.34 times that of CK. The Fuc treatment also increased the enzyme activities of soil BG, CBH, BX, and NAG. Compared to the CK, the addition of brown algal substances increased CO₂ emissions, while the addition of Alg66 and Alg360 reduced N₂O emissions. There was no significant difference in the effect of all treatments on CH₄ emission. Therefore, new fertilizers that combine soil improvement and greenhouse gas reduction functions can be developed by optimizing the component ratios of brown algae substances. 【Conclusion】 Brown algae substances can enhance soil carbon and nitrogen nutrients, whereas fucoidan can significantly enhance soil enzyme activity and active carbon components and sodium alginate can reduce N₂O emissions. These results show that brown algae substances have a certain potential for green enhancement, with different components exerting varying effects on soil properties, thus, showing potential for the development of brown algae substances for the production of new fertilizers.

Abstract:【Objective】 Biocrusts are critical surface covers in desert ecosystems that play an essential role in enhancing soil organic carbon(SOC) sequestration through various biological and physicochemical processes. Despite extensive research on biocrust functions, the contribution of microbial necromass carbon(MNC) under biocrust(BSCs) coverage to SOC and its influencing factors remains unclear. This study aims to address this knowledge gap by analyzing the role of cyanobacterial, lichen, and moss crusts in the Mu Us Desert. 【Method】 Soil samples were collected from the cyanobacterial, lichen, and moss crust layers, as well as from the underlying soil(0-5 cm depth), to investigate their physicochemical properties and amino sugar contents as proxies for MNC. Contributions of fungal necromass carbon(FNC) and bacterial necromass carbon(BNC) to SOC were evaluated, and their relationships with soil pH, nitrogen content, exchangeable calcium ions, soil moisture, and particulate organic carbon(POC) versus mineral-associated organic carbon(MAOC) fractions were assessed. 【Result】 The results revealed that: (1) MNC constituted approximately 57.7%, 47.9%, and 22.5% of SOC in cyanobacterial, lichen, and moss crusts, respectively, while in the underlying soil, MNC contributed 40.7%, 40.2%, and 28.5% of SOC for the respective crust types.(2) Across all crust types, FNC contributed significantly more to SOC than BNC, with average contributions of 28.4%±10.7% and 11.2%±4.8%, respectively.(3) MNC, especially FNC, had a stronger influence on the POC fraction compared to MAOC, suggesting its dominant role in labile carbon pools.(4) Positive correlations were found between FNC and BNC and soil nitrogen contents(ammonium, nitrate, and total nitrogen) as well as SOC. Conversely, significant negative correlations were observed with soil pH, exchangeable calcium ions, and moisture content. These findings indicate that soil properties strongly regulate the dynamics of MNC in biocrust-covered soils.(5) The spatial variability of MNC contributions highlights the critical role of crust type and underlying soil characteristics in shaping microbial-derived SOC. 【Conclusion】 This study highlights that the contribution of MNC to SOC diminishes from cyanobacterial to lichen to moss crusts, with FNC consistently being the dominant component. MNC primarily contributes to the POC fraction, underscoring its role in maintaining active carbon pools. Soil nitrogen content, SOC, pH, exchangeable calcium ions, and soil moisture emerged as key factors influencing the accumulation and decomposition of MNC. These insights enhance our understanding of microbial-mediated soil carbon cycling and sequestration mechanisms in arid ecosystems. Furthermore, the findings underscore the importance of preserving biocrust integrity to sustain carbon storage functions in desert landscapes. The results provide a scientific foundation for devising carbon management strategies aimed at mitigating desertification, enhancing carbon sequestration, and fostering sustainable development in desert regions.

Abstract:【Objective】 The global wolfberry(Lycium barbarum L.) industry is undergoing a paradigm shift from traditional Ningxia-dominated production to multipolar cultivation systems across Northwest China. In this transitional context, developing sustainable soil management strategies becomes imperative for maintaining agricultural productivity and ecosystem resilience. While cover crop intercropping has emerged as an advanced agroecological practice demonstrating dual benefits in fruit quality enhancement and environmental stewardship, conventional field management approaches; particularly long-term monoculture and chemical fertilizer overapplication, continue to compromise both yield and phytochemical quality of wolfberry. This study systematically investigates the rhizosphere engineering effects of wolfberry/forage radish (Raphanus sativus L.) intercropping coupled with organic fertilization, focusing on its mechanistic impacts on soil microbiome restructuring and metabolic reprogramming. 【Method】 This study investigated the effects of wolfberry (Lycium barbarum L.)/radish (Raphanus sativus L.) intercropping with manure on edaphic microbial communities and metabolite profiles through a split-plot field experiment (2019-2021) in arid northwestern China. It also considered the effects of cover crop planting patterns on soil microbial community structure, metabolite composition, and yield of wolfberry orchards. Three organic fertilization regimes(0, 6 660 kg·hm^-2, and 13 320 kg·hm^-2) were applied under two planting systems: monoculture (M) and intercropping(I). Using Illumina high-throughput sequencing technology, quantitative PCR methods, and liquid chromatography-tandem mass spectrometry (LC-MS), microbial information and metabolites were measured. The correlation between soil physicochemical properties, microbial diversity, key metabolite components, crop yield and its differential metabolites, microbial diversity index, and environmental factors under different planting modes was analyzed. 【Result】 Compared with the traditional wolfberry monoculture, intercropping significantly enhanced soil multifunctionality, increasing surface soil electrical conductivity(EC) by 29.66%, organic carbon (SOC) by 47.80%, total nitrogen (TN) by 39.09%, available nitrogen (AN) by 46.23%, available potassium (AK) by 36.64%, and microbial biomass nitrogen (MBN) by 22.56%compared with monoculture (P<0.05). Additionally, intercropping enhanced soil microbial diversity, with the bacterial Shannon index increasing by 4%and the Simpson index decreasing by 43.04%. Metabolomic analysis identified 867 metabolites, including 84 differentially abundant compounds such as lipids, organic acids, phenylpropanoids, and carbohydrates. Among these, two key metabolites were positively correlated with yield enhancement. Consequently, wolfberry yield increased significantly by 6.36%. 【Conclusion】 These findings indicated that cover crop intercropping improved soil microecological conditions, induced specific metabolite shifts, and effectively enhanced wolfberry productivity, demonstrating its applicability in sustainable wolfberry cultivation systems.