The fundamental cause of frost heave and salt expansion of saline soil is the water condensation and salt crystallization during the freezing process. Therefore, controlling the water and salt content is crucial to inhibit the expansion behaviors of saline soil. Recently, electroosmosis has been demonstrated to accelerate soil dewatering by driving hydrated cations. However, its efficiency in mitigating the salt-induced freezing damages of saline soil requires further improvement. In this study, a series of comparative experiments were conducted to investigate the synergistic effects of electroosmosis and calcium chloride (CaCl2) on inhibiting the deformation of sodium sulfate saline soil. The results demonstrated that electroosmosis combined with CaCl2 dramatically increased the cumulative drainage volume by improving soil conductivity. Under the external electric field, excess Na+ and SO42- ions migrated towards the cathode and anode, respectively, with a portion being removed from the soil via electroosmotic flow. These processes collectively contributed to a significant reduction in the crystallization-induced deformation of saline soil. Additionally, abundant Ca2+ ions migrated to cathode under the electric force and reacted with OH- ions or soluble silicate to form cementing substances, significantly improving the mechanical strength and freeze-thaw resistance of the soil. Among all electrochemical treatment groups, the soil sample treated with 10 % CaCl2 exhibited optimal performance, with a 71 % increase in drainage volume, a 180 similar to 443 % enhancement in shear strength, and a 65.1 % reduction in freezing deformation. However, excessive addition of CaCl2 resulted in the degradation of soil strength, microstructure, and freeze-thaw resistance.
The brick walls of ancient buildings have got a lot of tiny and closely connected pores inside, so they can soak up water really well. This can easily cause problems like getting powdery and having efflorescence. To stop water from spoiling the grey bricks, this paper focuses on the brick walls of historical buildings in Kaifeng City. Based on our investigation, we study the distribution features of the problems. This paper tells about using the method of negative pressure infiltration to change the grey bricks. We measure all kinds of basic indicators and analyze how different ratios of modifiers affect the water properties and dry-wet cycle tests of the grey bricks. We look at the changes in the inside shape through SEM to show how it changes the grey bricks of ancient buildings. Second, we improve the wet walls by using a way that combines blocking and drainage. The main things we studied and the conclusions are like this: We use sodium methyl silicate and acrylamide polymer as modifiers to soak the historical grey bricks under negative pressure. We figure out the best ratio through orthogonal experiments. We analyze things like the water vapor permeability, how long it takes for a water drop to go through, the compressive strength, the water absorption rate, and the height of water absorption of the modified bricks. The results show that the crosslinking agent and acrylamide monomer have a big influence on how high the capillary water goes up in the modified bricks. The air permeability of the modified grey bricks with acrylamide polymer goes down a bit, but it's still okay. The surface of the modified grey bricks is very hydrophobic and there are fewer pores inside. The mechanical properties of the modified grey bricks get better in different degrees. The water absorption rate and the height of capillary water absorption go down. The modified grey bricks can really cut down the erosion of water on the wall when used in real life. They can reduce salt crystallization and efflorescence caused by rising water, and so make the brick walls of historical buildings last longer. This is super important for protecting historical buildings in Kaifeng City and taking care of other similar structures. Also, by using a way that combines blocking and drainage, and putting polymer infiltration reinforcement and the ventilation of the moisture drainage pipe together, the results show that this combination can really lower the height that capillary water goes up in the brick wall. So we get a way to control how wet the wall is.
Biodegradable mulch films are essential for reducing plastic pollution in agriculture; however, current production methods often rely on complex and costly chemical processes. This study presents an innovative, ecofriendly approach to developing fully biodegradable mulch films using untreated vegetable stalks and sodium alginate through a simple blending method. By eliminating the need for pretreatment, this process significantly reduces energy consumption and maximizes agricultural waste utilization. The optimized film formulation (30 % vegetable stalk, 3 % solution, 40 % glycerin) demonstrated excellent mechanical and barrier properties, including tensile strength (6.8 MPa), elongation at break (29 %), water vapor permeability (1.88 x 10-12 g & sdot;cm-1 & sdot;Pa-1 & sdot;s-1), and UV-blocking efficiency (98.5 %), and thermal insulation and moisture retention properties. Rheological analysis showed that the addition of vegetable stalks impacted the film-forming solution's properties, enhancing processing and application performance. Additionally, the films facilitated seed germination and maintained functionality on the surface of moist soil, while rapidly degrading when buried in moist soil. Life Cycle Assessment confirmed that the biodegradable films significantly reduce environmental impacts, supporting their potential for widespread adoption in sustainable agricultural practices. This study provides a scalable and cost-effective strategy for converting agricultural residues into high-performance biodegradable films, addressing the need for sustainable solutions in agriculture and environmental protection.
Magnaporthe oryzae causes a fungal disease that poses a serious risk to global food security. Nanoagrochemicals are perceived as sustainable, economical, and environmentally friendly alternatives to traditional pesticides. Plant immune activators can be applied as the active ingredients of nanopesticides to control diseases in agriculture, but their use is limited and corresponding research is lacking. In this study, a nanodelivery system (PBZ@CaCO3@SG) for the on-demand release of a plant immune activator (probenazole; PBZ) was prepared using nano-CaCO3 after coating with sodium alginate-gelatin (SG). In vitro, at 48 h, the release rate reached 97.9% and 88.4% at pH 4.5 and 6.0, respectively, which greatly exceeded that under neutral conditions (pH 7.4), with acid-responsive release characteristics. Moreover, it responded quickly to the acidic microenvironment generated during M. oryzae infestation and rationally released PBZ, effectively improving plant resistance to M. oryzae and minimizing disease. Notably, M. oryzae infection was markedly reduced, by 60.6%, after PBZ@CaCO3@SG treatment. Mechanistically, PBZ@CaCO3@SG enhanced both physical barrier formation and systemic acquired resistance in rice, enhancing resistance to M. oryzae. It also showed good biosafety for both microbial communities and earthworms in the soil. This comprehensive study revealed multiple mechanisms by which PBZ@CaCO3@SG interacts with plants and pathogens, inhibits damage, and maintains nontarget biosafety, emphasizing its great potential for plant disease management.
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.
Sodium hydroxide (NaOH)-sodium silicate-GGBS (ground granulated blast furnace slag) effectively stabilises sulfate-bearing soils by controlling swelling and enhancing strength. However, its dynamic behaviour under cyclic loading remains poorly understood. This study employed GGBS activated by sodium silicate and sodium hydroxide to stabilise sulfate-bearing soils. The dynamic mechanical properties, mineralogy, and microstructure were investigated. The results showed that the permanent strain (epsilon(p)) of sodium hydroxide-sodium silicate-GGBS-stabilised soil, with a ratio of sodium silicate to GGBS ranging from 1:9 to 3:7 after soaking (0.74%-1.3%), was lower than that of soil stabilised with cement after soaking (2.06%). The resilient modulus (E-d) and energy dissipation (W) of sodium hydroxide-sodium silicate-GGBS-stabilised soil did not change as the ratio of sodium silicate to GGBS increased. Compared to cement (E-d = 2.58 MPa, W = 19.96 kJ/m(3)), sulfate-bearing soil stabilised with sodium hydroxide-sodium silicate-GGBS exhibited better E-d (4.84 MPa) and lower W (15.93 kJ/m(3)) at a ratio of sodium silicate to GGBS of 2:8. Ettringite was absent in sodium hydroxide-sodium silicate-GGBS-stabilised soils but dominated pore spaces in cement-stabilised soil after soaking. Microscopic defects caused by soil swelling were observed through microscopic analysis, which had a significant negative impact on the dynamic mechanical properties of sulfate-bearing soils. This affected the application of sulfate-bearing soil in geotechnical engineering.
Salinity is a common environmental stress that disrupts physiological and biochemical processes in plants, inhibiting growth. Silicon is a key element that enhances plant tolerance to such abiotic stresses. This study examined the effects of silicon supplementation on physiological, biochemical, and molecular responses of GF677 and GN15 rootstocks under NaCl-induced salinity stress. The experiment was conducted in a greenhouse using a factorial design with two rootstocks, three NaCl concentrations (0, 50, and 100 mM), and three silicon levels (0, 1, and 2 mM) in a randomized complete block design with three replicates. Salinity significantly reduced growth parameters, including shoot and root fresh and dry weights, RWC, and photosynthetic activity, with GN15 being more sensitive to salt stress than GF677. Silicon supplementation, especially at 2 mM, alleviated NaCl-induced damage, enhancing biomass retention and RWC under moderate and high NaCl levels. Additionally, silicon reduced electrolyte leakage, lipid peroxidation, and hydrogen peroxide accumulation, suggesting a protective role against oxidative stress. Biochemical analyses showed that silicon increased the accumulation of osmolytes such as proline, soluble sugars, glycine betaine, and total soluble protein, particularly in GF677. Silicon also boosted antioxidant enzyme activities, mitigating oxidative damage. In terms of mineral nutrition, silicon reduced Na+ and Cl- accumulation in leaves and roots, with the greatest reduction observed at 2 mM Si. Gene expression analysis indicated that NaCl stress upregulated key salt tolerance genes, including HKT1, AVP1, NHX1, and SOS1, with silicon application further enhancing their expression, particularly in GF677. The highest levels of gene expression were found in plants treated with both NaCl and 2 mM Si, suggesting that silicon improves salt tolerance by modulating gene expression. In conclusion, this study demonstrates the potential of silicon as an effective mitigator of NaCl stress in GF677 and GN15 rootstocks, particularly under moderate to high salinity conditions. Silicon supplementation enhances plant growth, osmotic regulation, reduces oxidative damage, and modulates gene expression for salt tolerance. Further research is needed to assess silicon's effectiveness under soil-based conditions and its applicability to other rootstocks and orchard environments. This study is the first to concurrently evaluate the physiological, biochemical, and molecular responses of GF677 and GN15 rootstocks to silicon application under salt stress conditions.
To assess the stabilizing effect of sodium alginate (SA) on cement soil subjected to dry-wet cycles, a comprehensive study was conducted involving UCS tests, dynamic triaxial tests, SEM analysis, and XRD analysis. The results showed that after 11 dry-wet cycles, the residual strength of the cement soil was 11.25 kPa with a 90.1% strength loss rate, while the SA-modified soil had a 72% loss rate and a residual strength of 432 kPa. Dynamic strain increased and dynamic elastic modulus decreased with higher dynamic stress, while higher loading frequencies reduced dynamic strain and increased dynamic elastic modulus. Increased cycle counts led to higher dynamic strain and lower dynamic elastic modulus. The damping ratio curves shifted downward with higher frequencies and moved rightward with more cycles. SEM and XRD analyses revealed that SA formed reticular cementitious materials that encapsulated soil particles and aggregated fines into larger particles. Sodium alginate significantly enhanced the soil's resistance to dry-wet cycles, providing valuable insights for coastal and soft soil subgrade engineering design.
The soft soil in the coastal region of South China is taken as the research object, and the slag/fly ash activated by sodium silicate is used to solidify it. Results show that the single-doped slag or fly ash has a limited effect on enhancing the strength of silt soft soil. However, with a 28-day curing age, the strength of solidified soil increases with slag content but decreases with the increase in fly ash content. Incorporating sodium silicate significantly affects the strength of the solidified soil, with reinforced soil strength gradually rising with the sodium silicate content. The maximum strength achieved by solidifying the soft soil sample with slag activated by sodium silicate reaches 850 kPa, 2.55 times higher than that of single-doped slag. The optimal sodium silicate content for samples with 5 % and 10 % and 15 % and 20 % slag content are 4 % and 3 %, respectively. Similarly, the maximum strength obtained by solidifying the soft soil sample with fly ash activated by sodium silicate is 483 kPa, 1.71 times higher than that of single-doped fly ash. The optimal sodium silicate content for samples with 5 % and 10 % and 15 % and 20 % fly ash is 3 % and 4 %, respectively. Furthermore, the solidification effect of sodium silicate-activated slag on soft soil is superior to that of sodium silicate-activated fly ash. Microscopic testing reveals the formation of cementing material within the solidified soil, binding the soil particles together. This cementing material corresponds to the hydration product C-(A)-S-H. Due to the higher alkali activity of slag compared to fly ash, it generates a greater amount of C-(A)-S-H hydration cementitious material, filling the pores and enhancing the cementation between soil particles, thereby improving the strength of the solidified soil. Consequently, the solidification effect is enhanced.
Iron (Fe) is an essential trace element for plant growth, but its availability in saline soils is limited. Salt stress aggravates Fe-deficiency stress in plants. We report the effects of adding sodium nitroprusside (SNP) on peanut seedlings in saline and Fe-deficient environments. Seedlings were grown hydroponically. Seedling growth was compared after adding SNP to nutrient solutions: salt (100 mM NaCl), Fe (0 mu mol L- 1 EDTA-Fe), and combined Fe + salt (Fe + 100 mM NaCl). Combined salt and Fe-deficiency yellowed peanut leaves, caused severe oxidative stress, and inhibited seedling growth. Addition of SNP alleviated this damage, with each seedling height, fresh dry weight, and root viability increasing. Adding SNP promoted reduction in Fe3+, the transport of Fe from underground to aboveground seedling parts, and from the cell wall to organelles and soluble parts. SNP increased contents of active Fe and chlorophyll in leaves, alleviated new-leaf yellowing, increased antioxidant enzyme activities and osmotic regulator contents, and removed excess reactive oxygen species, and MDA content and electrolyte extravasation rates in leaves and roots, thereby maintaining membrane structure stability. SNP promoted absorption of K, Ca, and Mg and their transport to shoots, increased Fe availability, and improved the ion imbalance and toxicity caused by salt and Fe stress. Salt stress worsened Fe deficiency stress in peanut, but adding SNP alleviated this. SNP promoted the reduction and transport of Fe in peanut, and increased Fe availability, improving the reduction and absorption of Fe in the environmental medium by roots.