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.

Abstract:【Objective】This study aimed to investigate the absorption and transport characteristics and mechanism of microplastics of different concentrations and particle sizes in maize seeds and seedlings.【Method】Maize was used as the test material and fluorescent-labelled polystyrene microplastics (PS-MPs) microspheres were added to the seeds during germination and to the seedlings during hydroponic exposure. This platform quantified growth-suppressive impacts of the test compound on germinative capacity and early seedling establishment, and clarified its mechanism of action.【Result】The effects of microplastics on the germination of maize seeds and the growth of seedlings exhibited significant dependence on concentration and particle size. At the seed germination stage, when examined using laser confocal electron microscopy, it was found that PS-MPs fluorescent microspheres were enriched at the position of the root hairs on the embryonic root. Furthermore, some of the microspheres penetrated the root epidermis and entered the cortical tissue, ultimately reaching the xylem vessels that are responsible for transporting water and nutrients. Their presence in these critical conductive tissues disrupted the seed germination process and induced oxidative damage. This experiment demonstrated that low concentrations (20 mg·L-1) of fluorescent PS-MPs promoted germination, whereas medium-to-high concentrations (50 and 100 mg·L-1) inhibited it.【Conclusion】This study verified the internalization and shootward translocation of microplastics in maize plants and provided preliminary insights into the absorption and translocation characteristics of microplastics within maize plants. It also sheded light on the toxic mechanisms of microplastics on maize, providing a vital experimental basis for understanding the migration and transformation patterns of microplastics within plants, thus providing scientific evidence with which to assess the impact of microplastics on agricultural ecosystems and food safety.

Abstract:【Objective】 Soil health assessment is a critical technical approach for achieving sustainable farmland management. However, existing evaluation systems often suffer from limitations such as indicator redundancy and high operational costs, which hinder their widespread application. This study aims to construct a cost-effective and efficient minimum data set (MDS) for soil health evaluation in the semi-arid farmland regions of the Loess Plateau, and to scientifically validate its reliability and applicability under local ecological conditions. 【Method】A total of 100 soil samples were collected from dryland farmlands in Wuzhai County, Shanxi Province, a representative area of the Loess Plateau. A comprehensive set of 23 soil indicators covering physicochemical and biological properties was analyzed. The MDS was established through an integrated statistical procedure that combined the principal component analysis (PCA), norm value calculation, and Pearson correlation analysis to identify the most representative and non-redundant indicators. The soil health index (SHI) was subsequently calculated using both linear and nonlinear scoring functions based on the MDS and the total data set (TDS). The performance of the MDS was evaluated by comparing SHI values derived from both data sets and further validated through correlation analysis with crop yield data. 【Result】The MDS was successfully established and included six key indicators: soil bulk density, total nitrogen, urease, cellobiohydrolase, bacterial Shannon index, and fungal Shannon index. These indicators accounted for 82.47% of the total variance explained by the TDS. Notably, biological indicators constituted two-thirds of the MDS, underscoring the vital role of microbial processes in soil health within arid regions. The SHI values calculated using the MDS showed a strong and significant positive correlation with those from the TDS under both nonlinear and linear scoring functions (P < 0.001), confirming the MDS’s capability to effectively represent the full data set. Validation with crop yield data further demonstrated that the nonlinear scoring function applied to the MDS provided a better fit (r = 0.70) than the linear function (r = 0.64), indicating its superior suitability for soil health assessment in the regions. The average SHI across the studied area was 0.49, reflecting a moderate overall soil health status. Spatially, soil health exhibited a pattern of lower values in the north and higher values in the south, largely influenced by the high erodibility of loess soils and more pronounced aridity in the northern part. 【Conclusion】This study developed a simplified yet robust MDS for soil health evaluation in semi-arid farmland systems of the Loess Plateau, effectively balancing comprehensiveness and feasibility. The results highlight the essential role of microbial diversity and functional indicators, such as enzyme activities and bacterial/fungal diversity, in evaluating soil health under dryland conditions. The spatial variation in soil health calls for region-specific management strategies, particularly in northern areas where soil erosion and moisture limitation are more severe. It is recommended that future research place greater emphasis on incorporating microbial functional parameters into soil health assessment frameworks. Moreover, integrating emerging technologies such as soil sensing and molecular tools could further enhance the efficiency and predictive power of soil health monitoring in arid and semi-arid agricultural landscapes.

Abstract:Microplastics have emerged as a widespread pollutant in agricultural soils, entering primarily through plastic film mulching, sewage irrigation, and the application of organic fertilizers. Their continuous accumulation poses a growing threat to soil ecosystem health and functionality. Therefore, a deep understanding of the impact process and mechanism of microplastics on the functioning of agricultural soil ecosystems is of great scientific significance and practical value for scientifically assessing their ecological and environmental risks, developing pollution control and remediation strategies. This review systematically examines the migration and transformation behavior of microplastics in agricultural soil and analyzes their diverse ecological effects, including alterations to soil physicochemical properties, shifts in microbial communities, impacts on soil fauna, and influence on crop growth. It also synthesizes current knowledge regarding the broader implications of microplastics on soil nutrient cycling, greenhouse gas emissions, crop productivity, and overall soil health. On this basis, key scientific questions are identified in areas such as the complex environmental behavior mechanisms of microplastics in real environments, inter-trophic interactive effects, and the systematic assessment of ecological risks and soil health. Finally, future research priorities and directions are proposed to provide a theoretical foundation for risk prevention and green remediation of microplastic pollution in agricultural soils.

Abstract:【Objective】Iron (Fe) is an essential micronutrient for plant growth. Accurate monitoring of different forms of iron (Total Fe, Available Fe, Free Fe) is essential for soil health management and agricultural production optimization. Total iron and free iron are also necessary indicators to identify certain soil types. Compared with traditional soil determination methods, spectral technology is rapid, cost-effective, and environmentally friendly, and is gradually becoming an alternative for soil Fe determination in recent years. However, there are few reports on the systematic inversion of different forms of iron by spectral technology.【Method】Based on the color parameter (CP), visible near infrared (VNIR), mid infrared (MIR) , and fusion spectrum (SF) were used to obtain data of 501 typical farmland tillage layer (0~20cm) soil samples in Guizhou Province. The spectrum was smoothed by Savitzky-Golay (SG) denoising, and then the baseline was corrected by the standard normalization (SNV) method. Partial least squares regression (PLSR) and support vector machine (SVM) were used for modeling, respectively. The system compared the predictive performance of single spectra and fused spectra for the three types of iron fractions. Moreover, the relationship between accuracy and cost of different prediction strategies was quantified using two indicators: Cost-Efficiency Ratio (CER) and Efficiency Index (EI).【Result】The results show that: (1) in the single spectral model, VNIR spectrum performed best in the prediction of total iron (determination coefficient R2 = 0.85, relative analysis deviation RPD = 2.59, root mean square error RMSE = 5.48 g·kg-1), while MIR spectrum had the highest accuracy in the prediction of free iron (R2 = 0.80, RPD = 2.23, RMSE = 4.15 g·kg-1). Also, the decision level fusion (SF3) spectrum further improved the prediction accuracy of the three forms of iron, among which the effective iron increased the most, but it was still difficult to achieve effective prediction (RPD = 1.37). Thus, using spectral technology to predict soil available iron is not recommended. (2) The cost accuracy analysis showed that the spectral technology can significantly reduce the cost (by 40%~85%) of soil iron characterization. VNIR and MIR technologies had high accuracy and were cost-effective in the prediction of total iron and free iron, and were suitable for scenarios requiring comprehensive consideration of accuracy and cost. However, the accuracy improvement of fused spectrum (SF) was limited, and the cost increased more, which is suitable for scenarios requiring higher accuracy. 【Conclusion】This study shows that spectral technology can significantly reduce the cost of soil iron content measurement on the basis of ensuring a certain prediction accuracy, and can replace the traditional methods to achieve efficient monitoring of total iron and free iron, so as to provide effective technical support for the implementation of precision agriculture.

Abstract:【Objective】 A large amount of plastic waste is produced globally every year, and landfill is the most common way to deal with plastic waste. However, plastic waste that enters landfills will continuously generate microplastics under the influence of physical, chemical, and biological factors, thereby affecting the surrounding ecological environment and human health.【Method】 In this study, the occurrence characteristics of microplastics in the soil-groundwater system of a landfill in Taizhou, Zhejiang Province, were investigated, and the ecological risk of microplastics in this area was assessed by pollution load index (PLI), polymer risk index (H), and potential ecological risk index (PERI). 【Result】 The results showed that the abundance of microplastics was 28313±7687 microplastics/kg, 7789±585 microplastics/L, 25660±2614 microplastics/kg, 183±41 microplastics/L in landfill, leachate, soil, and groundwater, respectively. The microplastics were mainly thin film and of a small size (0-50 μm). Also, the polymer composition was mainly polyethylene (PE) and polypropylene (PP). In addition, the microplastic ecological risks of the landfill""s waste, soil, leachate, and groundwater were respectively at extremely high risk, high risk, high risk, and medium risk. 【Conclusion】 Landfill sites, as an important source of microplastics, have potential impacts on the surrounding environment. This study can provide theoretical support for the assessment and control of microplastic pollution in the soil-groundwater system of landfill sites.

Abstract:【Objective】Micro- and nanoplastics have emerged as pervasive contaminants in terrestrial ecosystems. However, current research remains disproportionately focused on aquatic environments and food crops, leaving a significant knowledge gap regarding their effects on economically important non-food cash crops like tobacco, which possess high economic value and complex secondary metabolic pathways. This study systematically investigates the physiological and metabolic responses of Nicotiana benthamiana to root exposure of polystyrene nanoplastics (PS-NPs), with a particular focus on organ-specific adaptations in carbon and nitrogen metabolism under stress. Understanding these mechanisms is critical for ecological risk assessment and for safeguarding the productivity and quality in non-food cash crop systems, which have been largely neglected in the current nanoplastic research paradigm. 【Method】We employed a dual experimental approach integrating both pot cultivation and hydroponic systems to comprehensively evaluate PS-NPs effects on N. benthamiana seedlings. This integrated design enabled us to distinguish direct particle-plant interactions under controlled hydroponic conditions from more complex soil-mediated effects in pot environments. We employed metabolomics analysis coupled with detailed physiological analyses, including oxidative stress markers, antioxidant enzyme activities, and biomass measurements, to unravel the metabolic and defense networks activated under PS-NPs stress. 【Result】Pot experiments revealed a clear dose-dependent inhibition of plant growth, with PS-NPs concentrations of 150, 500, and 800 mg·kg-1 reducing plant height by 18.80%, 29.42%, and 30.67%, respectively. Hydroponic exposure induced even more striking morphological alterations, characterized by significant shoot suppression accompanied by a remarkable 43.52% and 47.20% increase in root elongation at 50 and 150 μg·mL-1. Paradoxically, the shoot fresh weight increased while dry weight accumulation was markedly reduced, indicating fundamental disruptions in carbon partitioning and structural biomass synthesis. Physiological analyses demonstrated severe oxidative stress in N. benthamiana roots, evidenced by elevated hydrogen peroxide and malondialdehyde levels alongside significantly enhanced superoxide dismutase activity, indicating activation of the antioxidant defense system. Metabolomic profiling identified extensive perturbations across multiple pathways, particularly in amino acid metabolism, carbohydrate dynamics, and organic acid transformation. It indicated that PS-NPs exposure disrupted central carbon metabolism, including carbon metabolism, galactose metabolism, and energy production pathways through glycolysis and oxidative phosphorylation. Moreover, N. benthamiana roots exhibited substantial downregulation of critical TCA cycle intermediates, including citrate and α-ketoglutarate, coupled with reduced glycolytic intermediates such as glucose-6-phosphate and fructose-6-phosphate, while simultaneously accumulating compatible solutes like isoleucine and valine. This result indicates strategic reallocation of nitrogen resources toward osmotic protection and fundamental defense mechanisms. Conversely, N. benthamiana leaves implemented an efficient carbon sequestration strategy, accumulating hexose phosphates and soluble sugars, and upregulating the biosynthesis of specialized defensive compounds, including flavonoid secondary metabolites and non-protein amino acids, demonstrating organ-specific metabolic specialization. Importantly, nitrogen metabolism of N. benthamiana leaves also shifted toward active defense and signal transduction. The pronounced upregulation of 4-aminobutyric acid (GABA) and its derivative 2,4-diaminobutyric acid marked the activation of the GABA pathway, a pivotal stress-response pathway. This pathway plays a crucial role in the reconstruction of carbon and nitrogen balance, and also assumes core functions in mitigating oxidative stress and regulating signal transduction within the N. benthamiana defense network. 【Conclusion】 This study demonstrates that PS-NPs root exposure initiates a complex adaptive response in N. benthamiana seedlings, characterized by inhibited shoot growth and dry matter accumulation, and stimulated root elongation as a stress-avoidance mechanism. PS-NPs root exposure also induced oxidative damage and triggered the comprehensive reorganization of metabolic networks. The research reveals an organ-specific defense strategy wherein roots prioritize immediate survival through osmotic adjustment and basic defense, while the leaves activate advanced chemical defense pathways, coordinated in part through GABA-mediated signaling. This study provides novel mechanistic insights into the metabolic adaptation of plants under nanoplastic stress and offers an important scientific basis for assessing the potential ecological risks of micro- and nanoplastics in terrestrial environments.