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.

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.

The efficacy and environmental effects of using metal-organic frameworks (MOFs) for the remediation of arsenic (As)-contaminated soil, a significant global problem, remain unclear. This study evaluated MIL-88A(Fe) and MIL101(Fe) coupled with ramie (Boehmeria nivea L.) for As-contaminated soil remediation. A soil incubation experiment revealed that 10,000 mg kg-1 MIL-88A(Fe) and MIL-101(Fe) reduced As bioavailability by 77.1 % and 65.0 %, respectively, and increased residual As fractions by 8 % and 7 % through Fe-As co-precipitation and adsorption. Divergent environmental effects emerged, which were probably due to differences in the framework structures and organic ligands: MIL-88A(Fe) improved soil urease activity and bacterial diversity, whereas MIL101(Fe) induced acidification (decreasing soil pH by 25 %) and salinity stress (elevating soil electrical conductivity (EC) by 946 %). A pot experiment showed that 1000 mg kg-1 MOFs enhanced ramie biomass via As immobilization, whereas 5000 mg kg-1 MIL-101(Fe) suppressed growth because exposure to the MOF caused root damage. The MOFs enriched Pseudomonas (As-oxidizing) and suppressed Dokdonella (pathogenic), enhancing plant resilience. Notably, 100 mg kg-1 MIL-101(Fe) increased As translocation to stems (14.8 %) and leaves (27.6 %). Hydroponic analyses showed that 50-200 mg L-1 MIL-101(Fe) mitigated As-induced chlorophyll degradation (elevating Soil and plant analyzer development (SPAD) by 12.8 %-28.3 %), whereas 500 and 1000 mg L-1 induced oxidative stress (reducing SPAD by 4.2 %-10.7 %). This study provides valuable insights into using Fe-based MOFs in soil remediation and highlights their beneficial and harmful effects.

As a prevalent problematic soil in geotechnical engineering, organic-rich soil exhibits inferior engineering characteristics that necessitate stabilization treatment in practical applications. Among various soil improvement techniques, chemical stabilization using Portland cement (PC) has gained widespread adoption due to its operational convenience. However, conventional PC involves not only environmental burdens associated with resource- and energy-intensive production processes and carbon emissions but also substantial interference from organic matter (OM) during its hydration process, inhibiting the formation of cementitious bonds. To address these challenges, this study proposes an innovative green stabilization approach using reactive MgO carbonation technology. A comprehensive investigation was conducted to evaluate the physicochemical evolution, mechanical behavior, and microstructural characteristics of organic soils under varying OM contents and carbonation durations. Key findings revealed that unconfined compressive strength demonstrated a linear inverse relationship with OM content while exhibiting time-dependent enhancement during carbonation. Strength development correlated positively with mass gain and dry density but inversely with water content. Microanalytical results indicated OM-dependent phase transformations, showing decreased nesquehonite crystallization and increased dypingite/hydromagnesite formation with ascending OM content. Mechanism analysis suggested that OM content regulated carbonation product speciation and aggregate morphology, thereby governing the coupled processes of particle cementation, pore structure refinement, and mechanical strengthening. This research demonstrates the technical viability of MgO carbonation for organic soil stabilization while contributing to sustainable geotechnical practices through carbon sequestration.

Salinity is an important environmental stressor in arid, semi-arid, and coastal regions, primarily due to poor drainage, excessive fertilization, and proximity to the sea. Treating plants with exogenous organic acids may enhance their ability to survive under stressful conditions. In the present experiment, the effects of oxalic acid (OA) on strawberry plant growth and fruit quality were studied under salinity conditions. Day-neutral 'Albion' strawberry cultivar strawberry plants were planted in pots and 1 month after planting, salinity (35 mM Sodium chloride) and OA treatments (2.5, 5, 10 and 20 mM) were carried out. The plants were evaluated 60 days after the treatment's initiation. OA treatments decreased the electrical conductivity (EC) value of the soil under salinity. Salinity stress decreased root:shoot dry weight and the relative growth rate of plant biomass. OA treatments improved leaf cortical cell expansion and xylem conduit diameter under salinity conditions. L-ascorbic acid and malic acid increased with OA treatments. The study revealed that a 10-mM dose of OA was more effective than the other doses, indicating reduced salt stress damage. The results demonstrate that OA can be effectively used in strawberry cultivation under saline conditions.

Application of organic mulches has repeatedly been shown to reduce infestation with Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), the Colorado potato beetle (CPB). In order to determine if the nutritional status of potatoes as affected by mulch could explain the mulch effects in potatoes against CPB, we determined potato leaf nutrient composition in unmulched control plots and plots mulched with grass-clover or triticale-vetch and assessed mulch effects on CPB damage and development in the field during 3 years and under controlled conditions. In mulched plots, foliar Mo, Cl, and K contents were consistently higher than those without mulch, and leaf damage by CPB was reduced significantly. In addition, increased B contents were associated with undamaged plant material, while higher Zn contents were associated with leaves damaged by CPB. Under controlled conditions, CPB fitness was not affected by mulch application. Overall, reduced CPB damage could not be clearly attributed to altered foliar nutrient contents due to mulching. It is thus more likely that CPB reductions in mulched systems are due to mechanisms other than an altered nutrient balance.

Excessive heavy metal pollutants in soil seriously damage ecological systems and the environment. Dianthus spiculifolius shows strong tolerance to Cd/Pb and readily accumulates both metals. Isocitrate dehydrogenase (IDH) is key enzyme in the tricarboxylic acid cycle, which is involved in the plant response to a variety of abiotic stresses. Previous transcriptomic analyses suggested that DsIDH in D. spiculifolius plays a role in Cd/Pb detoxification. In this study, we found that the transcript level of DsIDH was significantly increased under Cd/Pb stress. Transiently expressed DsIDH localized at the chloroplasts in tobacco leaves. Transgenic yeast lines overexpressing DsIDH showed increased tolerance to Cd and Pb and decreased accumulation of Cd and Pb. Compared with their respective wild types, transgenic Arabidopsis and D. spiculifolius overexpressing DsIDH showed increased IDH activity, increased tolerance to Cd/Pb, and decreased heavy metal contents. The increased activity of IDH significantly accelerated the decomposition of isocitrate and increased the production of alpha-ketoglutaric acid and NADPH, which reduced damage caused by the reactive oxygen species produced in response to Cd and Pb stresses. The DsIDH might be a novel tolerance-related candidate gene useful for decreasing the storage of toxic heavy metals in crops.

The remediation and management of old municipal solid waste (MSW) landfills are pivotal for advancing urban ecological sustainability. This study aims to systematically assess the mechanical properties, environmental behaviors, and synergistic mechanisms of remediated landfill-mined soil-like material (SLM) through advanced oxidation and stabilization processes. The results indicate that synergistic remediation with advanced oxidation and stabilization processes significantly increased the mechanical strength of stabilized SLM to over 0.6 MPa, and reduced the organic content by about 20 %, making it suitable for reuse in geotechnical engineering. The choice of oxidizing agents markedly affected the mechanical properties of stabilized SLM; for example, the application of sodium percarbonate in conjunction with stabilized materials further enhances the strength by simultaneously promoting the pozzolanic reaction. Furthermore, the heavy metal leaching behaviors of the stabilized SLM were found to be environmentally safe. The enhanced performance of stabilized SLM is primarily attributed to the synergistic effects of oxidation and pozzolanic reactions. The advanced oxidation process decreases organic matter content and increases its stability by reducing the proportion of readily decomposable O-alkyl C. Concurrently, pozzolanic reactions produce ettringite crystals and C-(A)-S-H gels, which not only fill micropores and improve particle bonding but also aid in heavy metal immobilization through surface adsorption, complexation, and physical encapsulation. These insights provide a comprehensive understanding of the remediation processes and resource recovery potential of SLM from old MSW landfills.

Late frost is a major challenge to stone and pome fruit production in northern New Mexico. In this study, we planted three cultivars of peach (Prunus persica L.)-Challenger, China Pearl, and Contender-on three rootstocks-Nemaguard (P. persica), GF677 (P. persica 3 P. dulcis), and RootpacVR R (P. cerasifera 3 P. dulcis)-in a high tunnel outfitted with thermostat-controlled propane heaters and fans to assess the feasibility of frost protection during bloom and fruitlet stage. In 2017, we planted the trees on Nemaguard rootstocks at 4 3 10 ft spacing and trained them in an open vase system. Due to severe leaf chlorosis, two rows of trees were removed and tissue cultured GF677 and RootpacVR R were planted in May 2018 and budded onsite in Aug 2018. In 2021, we began securing the sidewalls and the doors of the high tunnel and setting up heaters, which we continued until 2023. In 2021, it appeared that buds were damaged by extreme cold sometime in February, before the high tunnel was closed. In 2022 and 2023, the high tunnel system was sufficient to protect blooms and fruitlets from frost and yielded an average of 15.8 kg/tree in 2022 and 12.3 kg/tree in 2023. There was no significant difference between the cultivars in either year. There were, however, significant differences between rootstocks in 2022, with Nemaguard averaging 24.3 kg/tree across cultivars, whereas GF677 and RootpacVR R averaged 11.2 and 11.8 kg/tree, respectively, across cultivars because trees on Nemaguard rootstock were planted almost 2 years earlier than the rest. Comparing peach rootstocks, GF677 and RootpacVR R were more suitable for high pH soil in New Mexico than Nemaguard. Cherry had limited fruit set during this study. In 2022 and 2023, we observed blackened pistils and deformed flowers without petals, stamens, and pistils. More research is needed for cherry high tunnel production in northern New Mexico.

Addressing saline soil issues while ensuring agricultural productivity requires innovative technologies. This study investigated the impact of adding an innovative remediation preparation, specifically leguminous compost containing 50 g (LCT+CS-1), 100 g (LCT+CS-2), or 150 g of corn silk kg-1 (LCT+CS-3), to saline soil (ECe = 11.05 dS m-1) on soil characteristics and fenugreek plant performance during the 2022/2023 and 2023/2024 seasons. All organic supplementations significantly improved soil organic matter content, nutrient levels, and enzyme activities (urease, acid and alkaline phosphatase, and catalase) while reducing soil pH and Na+ content compared to the control. These results reflected decreased Na+ content, oxidative stress indicators (hydrogen peroxide and superoxide radicals), and oxidative damage (leaf electrolyte leakage and malondialdehyde levels) in fenugreek plants. On the other hand, leaf integrity (chlorophyll and carotenoid contents, membrane stability index, and relative water content) and nutrient contents improved. Furthermore, K+/Na+ ratio, osmoregulatory compounds (soluble sugars and proline), antioxidant levels (glutathione, ascorbate, phenols, and flavonoids), and antioxidant activity increased notably. Thus, notable increases in plant growth and yield traits and seed quality (trigonelline, nicotinic acid, total phenols, and flavonoids) were achieved. LCT+CS-2 was the most effective treatment for saline soil (ECe = 11.05 dS m-1), alleviating salinity effects and improving fenugreek growth, yield, and seed quality traits.