Poly(butylene adipate-co-terephthalate) (PBAT) is a promising polymer with excellent mechanical properties and biodegradability. However, knowledge gaps between its degradation and mineralization processes in soil hampers its environmental impact and application potential. In this study, we elucidated the degradation process of PBAT, starting with the degradation of high-molecular-weight polymers into 30 intermediates, before ultimately mineralized into CO2. Bacteria and fungi drove the degradation and mineralization of these intermediates. We discovered that PBAT was synergistically degraded by combinations of 27 bacterial and fungal biomarkers rather than by single biomarkers dominated by Bacteroidota, Acidobacteriota, and Ascomycota. These combinations of related functional genes perform various functions at every stage of PBAT degradation, including breaking down molecular structures, degrading intermediates, and mineralization. Bacterial biomarkers showed greater diversity than fungal biomarkers in degrading PBAT. Our findings provide useful insights into the degradation of PBAT in soil and a foundation for systematically evaluating and controlling the environmental behavior and safety of PBAT in soil.

Earthquake-induced soil liquefaction causes ground and foundation failures, and it challenges the scientific community to explore the liquefaction problem in deep deposit under strong shaking. Due to the capacity limitation of physical modelling facility, it is difficult to reproduce soil liquefaction response of deep sand ground by centrifuge shaking table test. To address this problem, a suite of centrifuge model tests were conducted with the aid of Iai's Type III generalized scaling law (i.e., GSL) to observe the liquefaction response of deep sand ground, where Models 1 and 2 were used to validate the GSL and Model 3 with the validated GSL stands for the deep sand ground with prototype depth of 80 m. The test results of Models 1 and 2 indicate that GSL generally performs well for small-strain shear modulus, nonlinear dynamic response of acceleration and the generation of excess pore water pressure, but leaves considerable errors for post-shaking dissipation process and ground settlement with large plastic strain. The test results of Model 3 indicate that liquefaction is also possible in depth of 30-40 m under shaking event of PBA = 0.4 g and Mw = 7.5. For deeper depth without triggering of liquefaction, a depthdependent power function relationship between the peak excess pore water pressure and Arias intensity has been established. The test results also revealed that consolidation and earthquake shaking history contribute to the development of soil anisotropy in a deep ground, leading to a continuous increase of anisotropy degree, which could be evaluated using the small-strain shear moduli in different stress planes under orthogonal stress conditions.

This study investigated seasonal changes in litter and soil organic carbon contents of deciduous and coniferous forests at two altitudes (500 and 1000 m a.s.l.), which were used as proxies for temperature changes. To this aim, adjacent pine (P500 and P1000) and deciduous forests (downy oak forest at 500 m a.s.l. and beech forest at 1000 m a.s.l., D500 and D1000, respectively) were selected within two areas along the western slope of a calcareous massif of the Apennine chain (central Italy). Periodic sampling was carried out within each site (a total of 19 sampling dates: 6 in autumn, 4 in winter and spring, and 5 in summer), taking each time an aliquot of the upper mineral soil horizon and measuring litter thickness and CO2 emission from the soil. The samples were then analyzed for their content of organic C, total N, water-soluble organic C and N (WEOC and WEN, respectively), and the natural abundance of 13C and 15N. Soil and litter C and N stocks were calculated. The chemical and isotopic data suggested that organic C and N transformations from litter to the upper mineral soil horizon were controlled not only by temperature but also by the quality (i.e. C:N ratio) of the plant material. In particular, the more the temperature decreased, the more the quality of the organic matter would influence the process. This was clearly showed by the greater 13C fractionation from litter to soil organic matter (SOM) in D1000 than in P1000, which would indicate a higher degree of transformation under the same thermal condition of the plant residues from the deciduous forest, which were characterized by a more balanced C:N ratio than the pine litter. However, while at 500 m altitude a significant SOM 13C fractionation and a parallel increase in soil CO2 emissions occurred in the warmer seasons, no seasonal delta 13C variation was observed at 1000 m for both forests, despite the different quality of SOM derived from deciduous and coniferous forests. Our findings suggested that organic C and N transformations from litter to the upper soil mineral horizon were greatly controlled by the quality of the plant residues, whereas soil temperature would seem to be the major driver for the seasonal evolution of SOM. This study, by considering two different vegetation types (deciduous and coniferous), allowed to evaluate the combined interactions between the plant residue quality and temperature in controlling litter and SOM mineralisation/accumulation processes.

The soilbags reinforcement has been widely used for soft soil foundation improvement due to its high compressive strength and deformation modulus considering the time limit of many projects and the characteristics of the reclaimed soil. However, despite the strength and deformation properties of soilbags reinforcement, the drainage characteristics of soilbags reinforcement is a crucial factor that creates a large challenge to foundation improvement for soft soil. Thus, this study developed a four-staged surcharge preloading on soilbags-reinforced soft soil foundation and focused on its drainage consolidation effectiveness. The contrasting laboratory tests were performed in four identical experimental boxes with clayey soil from the Nanjing, China. Four-staged preloading were applied on the soilbags-reinforced testing model, respectively, the data of the settlement and water discharge during the test are monitored, and after the tests, the water content and shear strength at different positions are measured. And three contrasting tests considering the possible drainage channels of soilbags reinforcement were also conducted. The results show that the consolidation effect is achieved with the soilbags reinforcement in terms of the settlement, pore water pressure, water content and shear strength after consolidation.

Soil freeze-thaw state influences multiple terrestrial ecosystem processes, such as soil hydrology and carbon cycling. However, knowledge of historical long-term changes in the timing, duration, and temperature of freeze-thaw processes remains insufficient, and studies exploring the combined or individual contributions of climatic factors-such as air temperature, precipitation, snow depth, and wind speed-are rare, particularly in current thermokarst landscapes induced by abrupt permafrost thawing. Based on ERA5-Land reanalysis, MODIS observations, and integrated thermokarst landform maps, we found that: 1) Hourly soil temperature from the reanalysis effectively captured the temporal variations of in-situ observations, with Pearson' r of 0.66-0.91. 2) Despite an insignificant decrease in daily freeze-thaw cycles in 1981-2022, other indicators in the Qinghai-Tibet Plateau (QTP) changed significantly, including delayed freezing onset (0.113 d yr- 1), advanced thawing onset (-0.22 d yr- 1), reduced frozen days (-0.365 d yr- 1), increased frozen temperature (0.014 degrees C yr- 1), and decreased daily freeze-thaw temperature range (-0.015 degrees C yr- 1). 3) Total contributions indicated air temperature was the dominant climatic driver of these changes, while indicators characterizing daily freeze-thaw cycles were influenced mainly by the combined effects of increased precipitation and air temperature, with remarkable spatial heterogeneity. 4) When regionally averaged, completely thawed days increased faster in the thermokarstaffected areas than in their primarily distributed grasslands-alpine steppe (47.69%) and alpine meadow (22.64%)-likely because of their stronger warming effect of precipitation. Locally, paired comparison within 3 x 3 pixel windows from MODIS data revealed consistent results, which were pronounced when the thermokarst-affected area exceeded about 38% per 1 km2. Conclusively, the warming and wetting climate has significantly altered soil freeze-thaw processes on the QTP, with the frozen soil environment in thermokarstaffected areas, dominated by thermokarst lakes, undergoing more rapid degradation. These insights are crucial for predicting freeze-thaw dynamics and assessing their ecological impacts on alpine grasslands.

PurposeThis paper aims to develop a probabilistic framework which combines uncoupled cofferdam stability analysis, random forest and Monte Carlo simulation for cofferdam reliability analysis.Design/methodology/approachThe finite element method and limit equilibrium method are used to calculate the seepage field and stability of cofferdam, respectively. Sufficient training and validating random samples are generated to obtain a random forest surrogate model with acceptable accuracy. The calibrated random forest model combined with MCS is used to conduct cofferdam reliability analysis. The proposed methodology is illustrated using a typical cofferdam model.FindingsThe numerical simulation results demonstrate that a larger pore water pressure leads to a lower stability of the cofferdam and vice versa. The increase in the slope angle significantly reduces the stability of cofferdam on the corresponding side, while the stability of cofferdam on the other side is mainly affected by the internal pore water pressure. The increase in the width and height of the reverse pressure platform significantly enhances the stability of cofferdam, and the changes in the angle of the reverse pressure platform affect the stability of cofferdam to some extent. The probability of failure (Pf) of cofferdam increases gradually with increasing vertical and horizontal scales of fluctuation, coefficient of variation, and cross-correlation coefficient when the degradation degree of soil properties is low. It is worth noting that the effect of vertical and horizontal scales of fluctuation, coefficient of variation, and cross-correlation coefficient on the Pf of cofferdam changes significantly when degradation coefficient decreases to a critical value.Practical implicationsA geotechnical engineer could use the proposed method to perform cofferdam reliability analysis.Originality/valueThe reliability of cofferdam can be efficiently and accurately studied using the proposed framework.

Tillage operation aims to create a favorable environment for seed germination of agricultural crop production practices. Physio-mechanical properties of soil directly affecting soil behaviors and determinants in initial conditions affecting soil failure. An absence in understanding how soil physio-mechanical properties affect agrotechnical operations at different tillage depths, especially in study area, and lacks insights into their associations and practical implications for optimizing tillage and soil health. This study presents an experimental investigation of the physio-mechanical properties of agricultural soil in Bukito Kebele, Loka Abaya woreda of Sidama Regional state, Ethiopia. The objective was to identify these properties under varying agro-technical soil depth conditions. Randomized Complete Block Design (RCBD) field experimental design was spotted to take soil samples using appropriate sample equipment and further lab analysis was conducted. Loka Abaya farm soil is loam, offering balanced texture for drainage, water retention, and nutrient availability. Moisture content reaches a maximum of 24.36%, with a linear relationship between soil depth and moisture content. The Atterberg limits of the soil (LL: 37.5-40%, PL: 25-27.5%, PI: 10-15%) indicate low plasticity and low clay content, consistent with loamy or silty soils. The results also show that soil cohesion is low in the topsoil (surface layers) but increases significantly at depths of 10-15 cm. Soil resistance decreases with depth due to reduced compaction and increased pore space in subsurface layers. Bulk density peaks at 1.28 g/cm3 at 10 cm depth due to high organic matter decomposition, then decreases to 1.20 g/cm3 at 15-20 cm, likely from reduced organic matter and root activity in subsurface layers. Correlations analysis reveals that soil moisture strongly increases with depth (r = 0.99, p < 0.01), indicating that deeper tillage may be necessary in arid regions to access moist soil layers. Sandy soils, which show a strong link between plastic limit and sand percentage (r = 0.97, p < 0.01), require adequate moisture during tillage to prevent erosion. Moist, cohesive soils are less compacted (r = - 0.92, p < 0.05) and easier to till, while cohesive soils resist penetration (r = - 0.90, p < 0.05), highlighting the need for efficient tillage equipment to minimize energy use. Overall, soil moisture, texture, and cohesion are critical factors for optimizing tillage practices and enhancing soil health. The study's site-specific nature limits its broader applicability, its focus on physical properties few mechanical property, overviews chemical and biological aspects, and further research is required to understand the long-term impacts of tillage on soil structure and productivity.

The aim of this study is to reveal the influence of frozen soil anisotropy and thermal-hydraulic-mechanical coupling effects on the frost heave deformation behavior of sheet pile walls (SPWS) through numerical simulation and experimental verification. In this research, a thermal-hydraulic-mechanical (THM) model of frozen soils is improved by integrating the anisotropic frost deformation firstly. Then, considering the shear characteristics of soil-structure interface, a finite element analysis of SPWS during freezing is conducted based on the proposed THM model. The simulation results are then validated by a small-scale simulation test. The results shown that, the pile is subjected to large bending moments and normal stress at the junction between the embedded and the cantilever section. Embedment depth of pile is suggested to set be 1/3 to 1 time the overall lenth, which having a greater effect on antiing the frost deformation. Numerical simulation considering the anisotropic of frozen soil is closer to the experimental results than traditional calculation methods. The THM numerical method can well characterize the directional relationship between temperature gradient and pile deformation. In seasonal frozen soil areas, deformation numerical simulation that can be further developed by considering the effects of multiple freeze-thaw cycles in subsequent research.

Black truffle, Tuber melanosporum Vittad., production is increasing due to an improvement in cultivation management and to the demand for this highly appreciated fungus. However, this intensification of truffle cultivation has led to the appearance of problems related to pest incidence. Specifically, the truffle beetle, Leiodes cinnamomeus (Panzer, 1793) (Coleoptera: Leiodidae), causes significant losses in black truffle marketability. However, its biology is still poorly known, and no effective agro-ecological methods exist to mitigate its damage to the truffles. This study aimed at assessing the population dynamics of L. cinnamomeus over four seasons (2019-2023) in an orchard located in NE Spain and relating these dynamics to weather variables and damage to truffle fruit bodies. Moreover, we described the diversity of arthropods captured in the traps in search of potential natural enemies of this beetle. The maximum population peak was observed in November, except for a single season in which it occurred in December. Moreover, the sex ratio was balanced (0.54 on average), but it varied over the growing season and among years. Significant and positive relationships of the population density of truffle beetles with air temperature and relative humidity were observed. The number of beetles per trap and day was strongly linked to heat accumulation. Finally, the Carabid Percus (Pseudopercus) patruelis (L. Daufour, 1820) was identified as a natural enemy of L. cinnamomeus. These results could be used in the future for monitoring and predicting truffle beetle populations.

Arbuscular mycorrhizal (AM) fungi are important plant symbionts that provide plants with nutrients and water as well as support plant defences against pests and disease. Consequently, they present a promising alternative to using environmentally damaging and costly fertilisers and pesticides in agricultural systems. However, our limited understanding of how agricultural practices impact AM fungal diversity and functions is a key impediment to using them effectively in agriculture. We assessed how organic and conventional agricultural management systems shaped AM fungal communities. We also investigated how AM fungal communities derived from these agricultural management systems affected crop biomass and development. Six soil samples from five organically and five conventionally managed agricultural sites were used to cultivate Sorghum bicolor. Plant growth, plant nutrient concentrations and AM fungal colonisation rates were analysed alongside DNA metabarcoding of community composition. We observed that soil from conventional agricultural fields resulted in a pronounced reduction in sorghum biomass (-53.6%) and a significant delay in flowering compared to plants grown without AM fungi. Sorghum biomass was also reduced with soil from the organic system, but to a lesser extent (-30%) and without a delay in flowering. Organic systems were associated with a large proportion of AM fungal taxa (50.5% of VTs) not found in conventional systems, including Diversispora (r(2) = 0.09, p < 0.001), Archaeospora (r(2) = 0.07, p < 0.001) and Glomus (r(2) = 0.25, p < 0.001) spp., but also shared a large proportion of taxa with conventional systems (42.3% of VTs). Conventional systems had relatively few unique taxa (7.2% of VTs). Our results suggest that conventional agricultural practices selected against AM fungi that were, in this context, more beneficial for host plants. In contrast, organic management practices mitigate this negative effect, likely due to the presence of specific key AM fungal taxa. However, this mitigation is only partial, as less beneficial AM fungal taxa still persist, probably due to abiotic factors associated with agricultural management and the sensitivity of AM fungi to these factors. This persistence explains why the effect is not entirely eradicated. Read the free Plain Language Summary for this article on the Journal blog.