Understanding soil organic carbon (SOC) distribution and its environmental controls in permafrost regions is essential for achieving carbon neutrality and mitigating climate change. This study examines the spatial pattern of SOC and its drivers in the Headwater Area of the Yellow River (HAYR), northeastern Qinghai-Xizang Plateau (QXP), a region highly susceptible to permafrost degradation. Field investigations at topsoils of 86 sites over three summers (2021-2023) provided data on SOC, vegetation structure, and soil properties. Moreover, the spatial distribution of key permafrost parameters was simulated: temperature at the top of permafrost (TTOP), active layer thickness (ALT), and maximum seasonal freezing depth (MSFD) using the TTOP model and Stefan Equation. Results reveal a distinct latitudinal SOC gradient (high south, low north), primarily mediated by vegetation structure, soil properties, and permafrost parameters. Vegetation coverage and above-ground biomass showed positive correlation with SOC, while soil bulk density (SBD) exhibited a negative correlation. Climate warming trends resulted in increased ALT and TTOP. Random Forest analysis identified SBD as the most important predictor of SOC variability, which explains 38.20% of the variance, followed by ALT and vegetation coverage. These findings likely enhance the understanding of carbon storage controls in vulnerable alpine permafrost ecosystems and provide insights to mitigate carbon release under climate change.
The existence of rock weathering products has an important effect on the infiltration of water in the soil. Understanding the mechanism of water infiltration in a mixed soil and weathered rock debris medium is highly important for soil science and hydrology. The purpose of this study is to explore the effects of mudstone hydrolysis on water infiltration in the soil under different mixing ratios (0-70 %) of weathered mudstone contents. Soil column experiments and numerical modelling were used to study the processes of hydrolysis of weathered mudstone and water infiltration in the mixed medium. The results revealed that water immersion can cause the dense mudstone surface to fall off, thus forming pores, and that the amount of these pores first increase but then decrease over time. The disintegration of post-hydrolysis mudstone debris occurs mainly among particles ranging from 2-2000 mu m, predominantly transforming sand particles into finer fractions. Increasing the mudstone content in the soil from 0 % to 50 % enhances the infiltration rate and cumulative infiltration volume. However, when the mudstone content exceeds 50 %, these parameters decrease. The mudstone weathering products promote water infiltration in the soil within a certain range of mudstone contents, but as the ratio of weathered products increases, excessive amounts of mudstone hinder the movement of water in the soil. The identified transformation phenomenon suggests that the infiltration capacity of mixed soil will not scale linearly with mudstone content. The findings enable some mitigation strategies of geologic hazards based on the hydrological stability in heterogeneous environments.
The hydraulic effect of plant roots reduces precipitation infiltration and enhances shallow slope stability. However, after root death and decay, soil permeability increases while water-retention capacity decreases. The time-varying mechanisms governing the hydraulic properties of root-soil composites after root decay remain unclear. This study examines the evolution of soil pore structure following root decay. A time-varying soil water retention curve (SWRC) model was developed to characterize changes in water-retention capacity. Additionally, a time-varying saturated infiltration coefficient model and a permeability coefficient prediction model were established to describe variations in hydraulic properties. A one-dimensional soil column infiltration test was conducted on root-soil composites at different stages of root decay to investigate the time-dependent changes in hydraulic properties. The reliability of the proposed models was validated using experimental results. The findings indicate the following: After root death, root biomass, diameter, length, and number decreased with increasing decay time, stabilizing after four months. Root decay led to a reduction in root volume ratio, which altered soil structure and enhanced the permeability of root-soil composites. Longer decay periods increased soil porosity, modifying the soil water characteristic curve and reducing water-retention capacity. Creeping roots decayed more significantly than fibrous roots due to their distinct morphological traits, making changes in hydraulic properties more pronounced in the topsoil. Therefore, plant root decay negatively affects soil hydraulic properties by continuously altering soil pore structure. These findings provide a crucial foundation for understanding the time-dependent mechanisms of hydraulic property variations in root-soil composites during plant root decay.
Alpine tundra ecosystems, like their arctic counterparts, have historically been the sites of considerable soil organic carbon (SOC) storage due to climatic factors that suppressed microbial activity. While climatic factors are important, heterotopic soil respiration (and SOC storage) may be influenced by a range of soil characteristics. In this study, we measured soil respiration, soil temperature, soil moisture, soil nutrient concentrations, soil pH, and soil texture in 4 alpine tundra sites located in Rocky Mountain National Park, Colorado, USA from June 2015 - September 2021. We also used geospatial modeling to visualize predicted climate changes in this system over the 21st century. Finally, we measured SOC concentrations over the seven-year study. We found that soil respiration was significantly correlated with soil temperature, soil moisture, and soil texture. All other parameters were not significantly correlated with soil respiration. We also found that SOC concentrations did not change significantly over the course of the seven-year study. The predictive models show that by the end of the century, over the majority of the park, the mean maximum air temperature will increase, the amount of snowfall will decrease, soil moisture will decrease, and the number of snow-free days will increase. These results suggest that SOC is not currently being lost from this system at a high rate. In addition, it appears that with a changing climate, soil respiration may increase with warming, but the overall increase may be limited by decreased soil moisture and in some cases, high soil temperatures.
Land-cover changes and new ecosystem trajectories in Interior Alaska have altered the structure and function of landscapes, with regional warming trends altering carbon and water cycling. Notably, these changes include the increased distribution of tall woody vegetation, trees and shrubs, in landscapes that historically only supported low shrub vegetation cover. In Denali National Park, Alaska, this phenomenon has altered primary succession pathways towards tundra ecosystems with the establishment and expansion of balsam poplar (Populus balsamifera) trees. In this study, we examine how snow, soil, and vegetation processes interact within this altered successional pathway towards further landscape change following glacial recession. In a sequence of outflow terraces, we found that variations in snow depth, functional soil depth, leaf area index, overstory height, and understory height were all significantly correlated with each other, with those effects largely explained by the presence of poplar. Poplar-dominated plots had deeper snowpacks, deeper functional soil depths, taller overstory and shrub heights, and greater LAI than in non-poplar plots of the same landscape age. These findings suggest a feedback cycle where the establishment of taller vegetation (here, poplar) alters ecosystem processes in the following notable ways: taller vegetation is able to trap more snow by reducing wind exposure and limiting sublimation; this snow provides water through additional snowmelt and insulation, keeping soils warmer and lessening permafrost development, leading to deeper functional soil depths. This feedback demonstrates poplar's ability to modify the environment as an ecosystem engineer, engineering a trajectory away from the otherwise expected permafrost-underlain tundra.
Small organic compounds (SOCs) are widespread environmental pollutants that pose a significant threat to ecosystem health and human well-being. In this study, the FrmA gene from Escherichia coli was overexpressed alone or in combination with FrmB in Arabidopsis thaliana and their resistance to multiple SOCs was investigated. The transgenic plants exhibited varying degrees of increased tolerance to methanol, formic acid, toluene, and phenol, extending beyond the known role of FrmA in formaldehyde metabolism. Biochemical and histochemical analyses showed reduced oxidative damage, especially in the FrmA/BOE lines, as evidenced by lower malondialdehyde (MDA), H2O2 and O-2(center dot-) levels, indicating improved scavenging of reactive oxygen species (ROS). SOC treatment led to significantly higher levels of glutathione (GSH) and, to a lesser extent, ascorbic acid (AsA) in the transgenic plants than in the wild-types. After methanol exposure, GSH levels increased by 95 % and 72 % in the FrmA/BOE and FrmAOE plants, respectively, while showing no significant increase in the wild-type plants. The transgenic plants also maintained higher GSH:GSSG and AsA:DHA ratios, exhibited upregulated glutathione reductase (GR) and dehydroascorbate reductase (DHAR) activities, and correspondingly increased gene expression. In addition, the photosynthetic parameters of the transgenic plants were less affected by SOC stress, which represents a significant photosynthetic advantage. These results emphasize the potential of genetically engineered plants for phytoremediation and crop improvement, as they exhibit increased tolerance to multiple hazardous SOCs. This research lays the foundation for sustainable approaches to combat pollution and improve plant resilience in the face of escalating environmental problems.
BACKGROUND Weed-resistance phenomena have increased dramatically in recent years. Bioherbicides can offer a sustainable alternative to chemical weed control but they often have low water solubility and therefore low efficacy in the field. The research reported here represents the first study on the field efficacy against weeds of a nanoencapsulated bioherbicide mimic of aminophenoxazinones, namely DiS-NH2 (2,2 '-disulphanediyldianiline). Field experiments were carried out across three different locations to evaluate the bioherbicide disulphide mimic at standard (T1, 0.75 g m(-2)) and double (T2, 1.5 g m(-2)) doses when compared to no weed control (NC) and chemical weed controlled (PC) in durum wheat. RESULTS The nanoencapsulated bioherbicide displayed better soil permeability than the free compound and also showed lower ecotoxicity on comparing the toxic doses on the Caenorhabditis elegans nematode model. It was found that T2 gave the best performance in terms of phytotoxicity (-57% weed biomass when compared with NC) and crop yield enhancement (3.2 versus 2.2 Mg ha(-1) grain yield), while T1 showed comparable results to PC. T1 and T2 did not cause shifts in weed communities and this is consistent with a broad spectrum of phytotoxicity. Moreover, the nanoparticle formulation tested in this study provided stable results across all three locations. CONCLUSION It is reported here for the first time that a nanoencapsulated DiS-NH2 bioherbicide mimic provided an efficient post-emergence and contact bioherbicide that can control a wide range of weed species in durum wheat without damaging the crop. The mimic also has low ecotoxicity and improved soil permeability. (c) 2025 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
Shear strength of hydrate-bearing sediment is an essential parameter for assessing landslide potential of hydrate reservoirs under exploration conditions. However, the characteristics and simulation of this shear strength under varying dissociation conditions have not been thoroughly investigated. To this end, a series of triaxial compression tests were first carried out on sediments with varying initial hydrate saturations along dissociation pathways. Combining measured data with microscale analysis, the underlying mechanism for the evolution of shear strength in hydrate-bearing sediment was studied under varying partial dissociation pathways. Moreover, a shear strength model for hydrate-bearing sediment was proposed, taking into account the hydrate saturation and the unhydrated water content. Apart from the parameters derived from the hydrate characteristic curve, only one additional model parameter is required. The proposed model was validated using measured data on hydrate sediments. The results indicate that the proposed model can effectively capture the shear strength behavior of hydrate-bearing sediment under varying dissociation paths. Finally, a sensitivity analysis of the model parameters was conducted to characterize the proposed model. (c) 2025 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).
Forest soil is crucial in climate change mitigation, food security, and biogeochemical nutrient cycling. Mixed Sal forests enhance soil organic matter, improve nutrient availability, and regulate pH dynamics. However, anthropogenic disturbances, including deforestation and land-use changes, significantly alter forest cover, leading to shifts in soil physicochemical and microbial properties. These impacts necessitate rigorous monitoring and comprehensive assessment. Therefore, we investigated the effects of contrasting conditions- closed (no human activities) and open (human interferences) mixed Sal Forest on the vertical and seasonal dynamics of microbial biomass carbon (SMBC). Results revealed that the closed mixed Sal Forest had significantly higher SMBC than the open mixed Sal Forest across the soil profile (D1-D5) with a strong seasonal effect. Closed mixed Sal Forest had 60% higher SMBC in D1 than open mixed Sal Forest while it reduced with depth and 17.1 to 56.7% higher SMBC in the subsurface to bottom-most soil profile (D2-D5). Moreover, SMBC was higher in the monsoon period in both forests. The SMBC reduced by 24.2 to 45.1% in the post-monsoon period while reduction was more intense in the pre-monsoon period (48.1 to 68.2%) compared to the monsoon period under closed mixed Sal Forest. Similarly, the decline was more intense in the open mixed Sal Forest, where SMBC declined 12.1 to 54% in the post-monsoon period and 56.1 to 76.2% in the pre-monsoon period compared to the monsoon period. The study indicates that human interference in mixed Sal forests leads to loss of forest cover, negatively affecting microbiological properties and reducing soil fertility, which weakens the forest's resilience to climate change. Additionally, SMBC exhibits seasonal variations, reflecting responses to environmental conditions. These results underline the need to reduce human disturbances and enhance forest conservation strategies to ensure soil sustainability and ecosystem stability.
Losses in agricultural produce have significant social, economic, and environmental implications. Despite efforts to increase yields, inadequate pre-and post-harvest practices often lead to losses and threaten food security. These losses also waste crucial resources like water, soil, and energy utilized in crop production. Minimizing agricultural produce losses is more crucial and cost-effective than simply increasing production. Understanding the factors that influence losses, the locations where they occur, and the types of losses that take place is key to developing effective control strategies. Specialized research and analysis are necessary for this purpose. Raising public awareness about the causes and prevention of agricultural produce losses is crucial. The review aimed to understand losses in agricultural produce emphasize the importance of efficient management strategies and seek improved solutions to reduce losses across the supply chain. The review is anticipated to provide valuable insights into the complex nature of agricultural produce losses and their impact on food security. The review focused on the losses in agricultural produce by looking at the different types of losses, their causes, and when they occur in the production process. It also evaluated the necessary services and infrastructure to reduce these losses at various stages. Additionally, the review highlighted the social and economic benefits of minimizing agricultural losses, including enhanced food security, decreased financial losses, and the promotion of a more sustainable agricultural system.