Abstract:【Objective】Soil health is essential to achieving sustainable agricultural development. 【Method】 This study selected the soil of a typical rice-wheat rotation area in southern Jiangsu Province as the research object. By measuring physical, chemical, and biological indicators, principal component analysis was used to identify soil health indicators and determine their weights. Combined with the membership function, the soil health index was calculated and subsequently classified. The microbial community indicators were obtained via high-throughput sequencing, and the random forest model was used to screen the indicators and construct a soil health assessment system based on microbial community indicators. 【Result】The results showed that biochar application significantly increased the content of soil available phosphorus (AP), but the content of available potassium (AK) was slightly lower compared to direct straw returning. The impact of different treatments on the alpha diversity index of the fungal community was more significant compared to that of the bacterial community. Also, the minimum dataset for soil health evaluation in the typical rice-wheat rotation area in southern Jiangsu Province, selected based on principal component analysis, consisted of soil organic carbon, AP, AK, and the activities of SUC and urease. The application of nitrogen fertilizer, single straw returning, and straw carbonization returning significantly increased the soil health index, while double straw returning reduced the soil health index in the short term. Moreover, the microbial community indicators selected by the random forest model were the relative abundance of Spirochaetota, Actinobacteriota, Mortierellomycota, bacterial Chao1 index, fungal Shannon index, and the relative abundance of functional genes such as rbcL, nosZ, ureC, and soxA. 【Conclusion】 The results of this study provide a scientific foundation for the formulation of agricultural management measures in the southern Jiangsu region and offer valuable insights into the construction of a soil health system based on microbial community indicators.

Abstract:【Objective】Phosphorus-solubilizing bacteria (PSB) are ubiquitous in heavy metal-contaminated soils; however, their impacts on soil heavy metals and crop growth remain inadequately understood. 【Method】This study investigated the mechanisms and efficacy of Bacillus sp. PSB32, a Cd- and Pb-tolerant PSB strain isolated from the maize rhizosphere in the Yunnan Plateau, in removing aqueous Cd and Pb and influencing maize (Zea mays L.) growth in contaminated soils.【Result】Under Cd and Pb stress, strain PSB32 primarily removed Cd via intracellular accumulation(43.7%) and surface precipitation(43.2%), with biosorption playing a secondary role (13.0%). In contrast, Pb removal was dominated by surface adsorption (53.2%), followed by surface precipitation (28.8%) and intracellular accumulation (18.0%). Scanning electron microscopy (SEM) revealed the formation of granular precipitates on the bacterial cell surface, which were identified by X-ray diffraction (XRD) as Cd?(PO?)?, Pb?(PO?)?Cl (Pyromorphite), and Pb?(PO?)?OH. Fourier transform infrared (FTIR) spectroscopy confirmed the involvement of functional groups (e.g., -COOH, -OH, -NH?) and anionic groups (e.g., PO?3?, SO?2?) in the surface complexation of Cd and Pb. In the pot experiments, the amendment of PSB32 across the three differentially contaminated soils (contaminated farmland, tailings, and slag) led to a consistent increase of 5.90%-9.43% in the residual fraction of Cd, alongside a decrease of 7.20%-18.8% in the reducible fraction of Pb. Concurrently, the soil available phosphorus content was enhanced by 3.00%-18.7%, which contributed to a substantial promotion of maize biomass, ranging from 25.7% to 82.2%. Notably, PSB32 also increased the Cd content in maize shoots by 61.9% and 32.9% in the farmland and tailings soils, respectively, and significantly enhanced the accumulation of Cd and Pb in the roots by 365% and 35.3% in the slag soil.【Conclusion】In conclusion, Bacillus sp. PSB32 demonstrates a dual ecological function: effectively removing aqueous Cd and Pb through multiple mechanisms, and enhancing plant tolerance in contaminated soils by altering metal speciation and improving phosphorus nutrition. This strain presents a promising microbial resource for the bioremediation of heavy metal-contaminated soils.

Abstract:【Objective】The rhizosphere is the interface between plants and soil, and plants affect the composition of soil microbial communities by secreting root exudates, while rhizosphere microorganisms can affect plant physiology and development through multiple mechanisms. Therefore, the development of accurate and applicable root exudate and soil sample collection methods are very important in understanding the ecological process of plant root-soil interface. However, the in-situ collection of rhizosphere soil and root exudates remains understudied. 【Method】This paper introduced a novel device for the in-situ dynamic visualization and accurate collection of rhizosphere soil and root exudates. The device comprises a plant growth compartment, a root growth compartment, a soil compartment, and a root exudate sampling system. The device is designed by partitions, planting seeds or seedlings in the plant growth compartment, allowing the root system to extend into the lower root growth compartment through a slit at the bottom. Also, the nylon membrane isolates the soil from the root system to ensure a two-way pure exchange. On the one hand, it allows soil nutrients to infiltrate, ensuring normal plant growth, and on the other hand, it prevents particle contamination. At the same time, a multi-interface connected sampling system is set up to realize the accurate partition collection of root exudates. The sampling process is automated, with a vacuum pump controlled by a solenoid switch and a program to regularly rinse and extract secretions into the sampling bottle. For soil sampling, the depth and distance from the root system are flexibly selected, and the soil quantity is estimated by the sampling tube scale to ensure the accuracy and comprehensiveness of the experimental data. For validation, root exudates of wheat during the grain-filling stage were collected by both the device collection method and the solution collection method. The content of quercetin in the root exudates was determined by high-performance liquid chromatography. A standard curve was prepared using quercetin as the standard substance, and the content of quercetin in the root exudates was calculated. 【Result】This device innovatively integrated the functions of plant growth, root exudates sampling and rhizosphere soil collection. It realized the accurate, in-situ, continuous and dynamic collection of plant root exudates and rhizosphere soil through ingenious design, and the collection range could be accurately concentrated in the root system and the soil environment in the same area, so as to ensure the simultaneous collection of exudates and rhizosphere soil. During collection of root exudates, the content of quercetin obtained by the device collection method was close to that by the solution collection method, and it eliminated the cumbersome operations such as root stripping, supported continuous sampling at multiple time points for the same plant, and significantly improved the research efficiency of individual plants. Moreover, this method ensured the normal growth of plants, and there was no interference with soil components, and provided high accuracy. 【Conclusion】This device, with its comprehensive functions, provides efficient sampling capacity and precise control mechanism, and can serve as a powerful tool in the field of plant physiological ecology, and is conducive for promoting the in-depth development of soil microbiology research.

Abstract:【Objective】 This study investigated the community structure of aerobic methanotrophs in coastal wetlands of southeastern China and the key environmental factors shaping their distribution. 【Method】Sediment samples were collected from four coastal wetlands (Shanghai, Fuzhou, Xiamen, and Dongguan). Methane oxidation rates were determined, physicochemical properties were analyzed, and 16S rRNA amplicon sequencing was performed to resolve community composition. Redundancy analysis (RDA) was applied to assess the influence of environmental factors such as temperature, precipitation, and salinity on community distribution. 【Result】The results showed significant differences in methane oxidation rates among wetlands, with the highest rate observed in Fuzhou (0.11 mmol·L-1·d-1) and the lowest in Dongguan (0.058 mmol·L-1·d-1). Community composition also varied substantially: Methylomicrobium dominated in Shanghai and Xiamen, while Methylobacter and Methylocystis were more abundant in Fuzhou and Dongguan. RDA indicated that temperature, water content, and salinity were the major drivers of community structure, with Methylobacter abundance positively correlated with temperature, and Methylocystis abundance negatively correlated with salinity. These findings demonstrate that the community structure and metabolic activity of aerobic methanotrophs in coastal wetlands are regulated by multiple environmental factors, and regional differences are primarily shaped by the adaptive responses of functional taxa to local conditions. 【Conclusion】This study highlights the spatial heterogeneity and environmental drivers of methanotroph communities in coastal wetlands and provides theoretical insights into wetland carbon cycling processes.

Abstract:Soil pipe erosion is a special erosion process caused by the formation and expansion of underground soil pipes, which has an important contribution to the development process of gully erosion and the gravitational erosion processes such as landslide and collapse. It mainly affects the runoff-erosion-sediment transport process of slope and watershed by changing the near-surface soil hydrological conditions. However, due to its concealment and complexity of genesis, related quantification research faces great challenges. Based on the bibliometric analysis method, this paper systematically reviews the development history of soil pipe erosion research, and identifies the hot spots and development directions in the field of soil pipe erosion research. Aiming at the current research focus, this paper overviews the dynamic process of soil pipe formation, summarizes the multiple factors affecting soil pipe erosion, and analyzes the dynamic mechanism and harm of soil pipe erosion. In the future, it is necessary to innovate the monitoring methods of soil pipe erosion, clarify the dynamic mechanism of soil pipe erosion, quantify the contributions of key influencing factors, and develop a water erosion prediction model containing the processes of soil pipe erosion, so as to provide a scientific basis for soil pipe erosion risk assessment and optimization of governance measures.

Abstract:【Objective】Biodegradable plastic mulch films, which are representatively made from polybutylene adipate co-terephthalate (PBAT), have been widely used in the agricultural areas of northwest China. As a result, a large quantity of nanoplastics is left in the local soils. However, the effect of these nanoplastics on the properties of this predominantly clay soil remains understudied. 【Method】This study used clays separated from saline-alkaline soils from northwest China and PBAT-based biodegradable nanoplastics (PBAT-BNPs) as research objects. Clay rewetting was conducted to simulate the soil moisture changes during the agricultural irrigation period in Xinjiang. The effects of PBAT-BNPs on the aggregation behavior and physicochemical properties of sterilized high saline-alkaline clays were explored. 【Result】 The results showed that rewetting significantly promoted the aggregation of clays, which was further enhanced by PBAT-BNPs but was hindered by the high salinity-alkalinity of clays. During the rewetting treatment period, the cation exchange capacity of PBAT-BNP-added clays increased significantly, whereas their electrical conductivity and pH decreased noticeably. The acidic environment induced by PBAT-BNPs facilitated the dissolution of clay minerals and the release of silicate ions. Under the rewetting condition, the Al cations promoted the formation of aggregates through flocculation. Meanwhile, the release of PBAT monomers and soluble ions from clays led to a significant increase in the interlayer spacing of minerals. 【Conclusion】 This study provides a new perspective on the abiotic impacts of biodegradable nanoplastics on soil properties.

Abstract:The turnover and stabilization of soil organic carbon (SOC) play a crucial role in the terrestrial carbon cycle, contributing approximately 25% to natural climate solutions. Particulate organic carbon (POC) and mineral-associated organic carbon (MAOC) are pivotal in the soil carbon dynamics. Soil microorganisms are the primary drivers of the carbon cycle, by decomposing plant residues to form POC via the “ex vivo modification” pathway and accumulating microbial residual carbon via “in vivo turnover” pathway, which then combines with soil minerals to form MAOC. However, the role of microorganisms in POC and MAOC formation is constrained by multiple factors, including nutrient management practices, soil properties, and climatic conditions, which limit the microbial regulation of carbon sequestration in agricultural soils. This article systematically introduced the framework of POC and MAOC. The contributions of growth anabolism (living and residual microorganisms) and non-growth anabolism (enzymes and extracellular polymers) to POC and MAOC were described. This study elucidated the regulatory mechanisms governing POC and MAOC through microbial community structure and physiological functions, whilst analyzing the influencing factors. On this basis, the study systematically considered the mechanisms and approaches by which microorganisms regulate and increase SOC, providing an important basis for constructing a theory of SOC increase based on physical-biological synergistic regulation.

Abstract:As global agriculture evolves alongside the increasing demand for environmental protection, green intelligent fertilizers have emerged as a novel approach to enhancing crop productivity and resource use efficiency. This paper reviews the core concepts and development status of green intelligent fertilizers, exploring the principles of intelligent regulation within plant-microbe-environment interactions and the design and application strategies based on the rhizobiont theory. Green intelligent fertilizers operate by maximizing the biological potential of crops and microorganisms to regulate the integrated plant-microbe-soil system, thereby promoting plant growth and minimizing environmental impact. Looking ahead, breakthroughs in material innovation, process optimization, and intelligent fertilizer formulation will enable intelligent fertilizers to drive agricultural green transformation, providing critical support for global food security and environmental sustainability.

Abstract:Abstract：[Objective] With the intensification of human activities since the Industrial Revolution, there is a continuous rise in carbon dioxide concentration ([CO2]) in the atmosphere, which has become the main feature of global climate change. Rice being an important staple crop, it is important to explore its absorption and distribution of phosphorus under a long-term elevated CO2 environment. [method] In this study, a multigenerational experiment was carried out cultivating Yangdao 6 (indica) and Wuyungeng 23 (japonica) in the Free Atmospheric CO2 Enrichment System (FACE) in Changshu, Jiangsu Province. The experiment was carried out under ambient [CO2] and elevated [CO2] (increased by 200 μmol?mol-1) conditions for seven generations, and the differences in phosphorus concentration, phosphorus uptake, and phosphorus distribution ratio between the single-generation and multigenerational rice plants were evaluated. [Result] (1) Long-term elevated [CO2] had no significant effect on the phosphorus concentration of multigenerational rice plants in Yangdao 6 and Wuyungeng 23. (2) The long-term elevated [CO2] significantly increased the phosphorus uptake of shoots in single-generation and multigenerational rice plants. However, the average increase in phosphorus uptake of the shoot and panicle of the offspring plant of Yangdao 6 was lower than that of the single-generation plant. On the contrary, the average increase in phosphorus uptake of shoot, straw, and panicle of the offspring plant of Wuyungeng 23 was higher than that of the single-generation plant under elevated [CO2]. (3) The average increasing effect of elevated [CO2] on the distribution ratio of phosphorus in the straw of Wuyungeng 23 increased significantly with the increase in generations of maternal seeds under elevated [CO2] treatment. [Conclusion] The results indicate that in the past, based on the single-generation short-term FACE studies, the real effect of long-term elevated [CO2] on phosphorus uptake and distribution in rice plants could not be accurately predicted in the future. Therefore, this study provides guidelines for field-level phosphorus fertilizer management in a future high-CO2 world.

Abstract:Anoxic microsites are potential significant contributors to the inhibition of soil organic carbon loss. Soil aggregates, as potential suitable sites for the development of anoxic microsites, are closely related to the accumulation of soil organic carbon. However, few studies have investigated the impact of anoxic microsites on organic carbon within soil aggregates. This study collected dryland soils from four types of vegetation restoration and employed soil incubation and gas chromatography to measure and calculate the extent of anoxic protection. Anaerobic conditions were used to obtain soil samples from the internal and external layers of macroaggregates through the dry dissection method, and their anoxic microsite abundance and organic matter composition were compared. The results indicate that the extent of anoxic protection was 33.5% and 36% of natural shrubland and natural grassland, respectively. Planted forest exhibited a lower protection value at 15.9%, while farmland exhibited the most negligible anoxic protection at ?8.9%. And the internal layer of macroaggregates generally exhibits a high concentration of Fe2+, consequently, this region is characterized by a greater prevalence of hypoxic microenvironments. Organic matter, such as aromatics, lipids, and lignin, protected by anoxic microsites, is relatively abundant in the inner layer of aggregates. Soil respiration rate was significantly negatively correlated with the extent of anoxic protection. The aforementioned results reveal the formation mechanism, stability, and protective role of anoxic microsites within the inner layers of soil aggregates towards organic matter. The extent of anoxic protection is contingent upon a stable soil environment. These microsites selectively conserve the reducing organic matter within macroaggregates, significantly reducing the loss of soil organic carbon. This finding contributes a nuanced understanding of soil carbon cycling and carbon sequestration processes.