Search Results (654)

The insertion into the soil stratum to be evaluated is the factor that most affects the results obtained by the vane shear test (VST). According to the literature, it has been identified that there is a disturbance in the fabric and even in the movement of soil particles around the probe. The current study allowed the VST to be carried out on kaolinitic clayey soils reconstituted in the laboratory at different historical preconsolidation artificial stresses. The influence of the disturbance on the alteration of the soil analysed is directly linked to the thickness of the vane blades and their corresponding vane area ratio (VA). For this reason, a digital image correlation (DIC) technique was proposed to analyse images taken during the test’s development. The alteration produced by the disturbance was recorded, and the result obtained was compared with previous studies. This analysis established the effect on the reconstituted samples by employing a disturbance parameter specific to this study. Full article

(1) Background: The increasing soil and water pollution in agriculture is mainly due to the uncontrolled use of synthetic fertilizers. As the responsibility to adopt sustainable agricultural practices grows, biofertilizers may offer a solution to reduce the use of chemical inputs and improve crop productivity. This study focused on evaluating the physiological effects of Trichoderma asperellum, Bacillus sp., and seaweed extracts (Ulva lactuca and Solieria spp.) on the cultivation of serrano pepper plants. (2) Methods: Five treatments were carried out: control (T1), T. asperellum (T2), Bacillus sp. (T3), seaweed extract (T4), and their combination (T5). The microbial inoculants were applied to the root zone, while the seaweed extracts were applied to the foliage. Leaf samples were collected at the end of the vegetative phase to evaluate physiological and agronomic traits. (3) Results: The application of T3 significantly increased leaf area (12.34%), biomass (11.91%), and yield (10.7%) while decreasing the SPAD, chlorophyll, and carotenoid contents. T4 resulted in the highest nitrate reductase activity, while T5 resulted in the peak total chlorophyll content. No significant differences were observed in nitrate reductase activity between T4 and the control or in the carotenoid content between T1, T2, T4, and T5. (4) Conclusions: Bacillus sp. demonstrated agronomic benefits despite a decrease in pigments, supporting its application in the sustainable production of peppers. Full article

Rice cultivation has the ability to ameliorate saline soils, but this monoculture pattern can lead to negative plant–soil feedback. In a previous study, we investigated the effects of long-term rice cultivation on saline soil chemistry, salt ions, root characteristics, and agglomerate formation, and concluded that the optimal rice planting period is 5 years. However, we do not know which crop rotation is most effective in improving this negative soil feedback and enhancing soil quality. In this study, we carried out an experiment on saline land planted with rice over 5 years and set up four different rotations, including rice–Hunan Jizi, rice–maize, rice–sweet sorghum, and rice–soybean, with perennial rice planting as CK, to analyze soil texture under different treatments. Physicochemical properties and enzyme activities were also analyzed under different treatments, and the soil quality index (SQI) was constructed using principal component analysis and correlation analysis for comprehensive evaluation of each treatment. The results showed that (1) the saline-alkali soil texture of perennial rice planting in the Yinbei Plain was silty soil, and different rice drought rotation methods changed the soil texture from silty to silty loam, which improved the fractal dimension of the soil. The fractal dimension of saline-alkali soil was significantly positively correlated with the clay volume content, negatively correlated with silt volume content, and negatively correlated with sand volume content. (2) There was no risk of structural degradation (SI > 9%) in saline-alkali soil planted in perennial rice, and it appeared that RS (rice–soybean) could improve the stability coefficient of soil structure in the 0~40 cm soil layer. (3) Different rice and drought rotation methods could significantly affect the physical and chemical properties and enzyme activities of soil, and the quality of soil in the 0~40 cm soil layer was evaluated; RS (rice–soybean) and RC (rice–maize) were suitable for rice drought rotation in the Yinbei area. The structural equation model showed that salinity and soil nutrients were the key factors restricting the improvement of saline-alkali soil quality in Yinbei. These results will deepen the current understanding of bio-modified saline soils. Full article

In the saline soil area of western China, the concrete is simultaneously subjected to cyclic loading and sulfate attack. To reveal the effect of sulfate attack on fatigue performance of normal concrete (NC) and hybrid fiber-reinforced rubber concrete (HFRRC), the uniaxial compression test and cyclic loading test were carried out on the specimens after sulfate erosion. The loading strain, plastic strain, and elastic strain of the concrete were compared and analyzed. The compressive strength, fatigue resistance, and strain energy of the concrete were compared and analyzed. Ultrasonic Pulse Velocity (UPV) measurements were also used to quantify the damage in sulfate attack tests. The results indicate that the fatigue failure stress of concrete is lower than its uniaxial compressive strength. The fatigue resistance coefficient of HFRRC is always higher than that of NC. Under the cyclic loading with the same level, the stress–strain curve of HFRRC is denser than that of NC, exhibiting good elasticity. The energy evolution is independent of whether or not sulfate attacks, but its growth rate is affected by sulfate erosion time. It can provide an experimental and theoretical foundation for the application of HFRRC in engineering structures subjected to repeated loads in sulfate environments. Full article

The environmental legacy of mining operations presents significant challenges in managing impacts on ecosystems, public health, and safety. In Sardinia (Italy), the mining history has left a particularly severe burden of abandoned sites, making remediation a regional priority. To address this issue and to effectively prioritize interventions at abandoned mining sites, a relative risk assessment approach was developed by the Sardinia Regional Administration and the Italian National Institute for Environmental Protection and Research. The aim of this paper is to highlight the results and information obtainable with the above-mentioned approach through its application to a real case: the Montevecchio Levante mining district in southwestern Sardinia. The study provides a detailed identification of the factors underlying the high intervention priority associated with the site under investigation. An analytical quantification of the contribution of the main contaminants to the overall risk was carried out through the calculation of specific risk indices. At the same time, the environmental matrices most involved in the contamination mechanisms were identified. The results indicate that the overall risk is largely driven by the presence of carcinogenic contaminants, with cadmium and lead contributing primarily to the risks associated with surface water and soil, respectively. The findings provide a solid basis for developing targeted strategies to mitigate ecological and public health risks in abandoned mining areas. Full article

Aiming at key issues in harvesting film-covered potatoes in hilly and mountainous areas—incomplete residual film collection, poor potato–soil separation, and high damage from potato-collecting devices—this study developed a crawler self-propelled potato harvester suitable for these regions. This study first expounds the overall structure and working principle of the potato harvester and then conducts principal analysis and structural design for key components (film-collecting device, digging device, primary conveying and separating device, secondary conveying and separating device, and intelligent potato-collecting device) from the perspectives of material force and movement. Finally, field performance tests were carried out in Huangzhong County, Xining City, Qinghai Province. The test results show that the machine can achieve an operation effect with a potato harvest loss rate of 2.4%, a potato damage rate of 1.4%, an impurity content rate of 2.8%, a skin-breaking rate of 2.7%, and a residual film cleaning rate of 89.6%, meeting the potato harvesting needs of this region. The lightweight self-propelled crawler potato harvester designed in this paper can realize functions such as residual film collection, potato–soil vibration separation, manual auxiliary sorting, and intelligent potato boxing, providing technical and equipment references for the harvesting of film-covered potatoes in complex terrain areas. Full article

Heavy machinery degrades agricultural soils, with severity influenced by wheel type, contact area, and soil moisture. Tropical agriculture is characterized by the constant maintenance of straw on the ground. This permanent cover, among other benefits, can mitigate the stress imposed by wheels on the physical structure of the soil. This study aimed to evaluate the effect of tire types and straw amounts on soil stresses. Static studies were carried out under controlled conditions in a static tire test unit (STTU), equipped with standardized sensors and systems that simulated real farming conditions. Three tire models were tested: road truck double wheelset—2 × 275/80R22.5 (p1); agricultural radial tire—600/50R22.5 (p2); and bias-ply tire—600/50-22.5 (p3) on four contact surfaces (rigid surface; bare soil; soil with 15 and 30 Mg ha⁻¹ straw cover). We performed comparative statistical tests and subsurface stress simulations for each tire and surface condition. On the hard surface, the contact areas were 4.7 to 6.8 times smaller than on bare soil. Straw increased the tire’s contact area, reducing compaction and subsoil stresses. Highest pressure was imposed by the road tire (p1) and lowest by the radial tire (p2). Adding 15 Mg ha⁻¹ of straw reduced soil SPR by 18%, while increasing it to 30 Mg ha⁻¹ led to an additional 8% reduction. Tire selection and effective straw management improve soil conservation and agriculture sustainability. Full article

As emerging pollutants, antibiotic resistance genes (ARGs) have been recognized as originating from diverse sources. Among these, the use of livestock feed and veterinary drugs was identified as the primary source of ARGs in livestock manure. ARGs were found to be widely distributed in global environments, particularly in agriculture-related soils, water bodies, and the atmosphere, posing potential threats to ecological environments and human health. This paper reviewed the degradation mechanisms of ARGs during aerobic composting of livestock manure and the safety evaluation of compost products. Aerobic composting was demonstrated to be an effective method for degrading ARGs, primarily through mechanisms such as high-temperature elimination of ARG-carrying microorganisms, reduction in host bacterial abundance, and inhibition of horizontal gene transfer. Factors including the physicochemical properties of the composting substrate, the use of additives, and the presence of antibiotic and heavy metal residues were shown to influence the degradation efficiency of ARGs, with compost temperature being the core factor. The safety of organic fertilizers encompassed multiple aspects, including heavy metal content, seed germination index, and risk assessments based on ARG residues. The analysis indicated that deficiencies existed in areas such as the persistence of thermotolerant bacteria carrying ARGs, the dissemination of extracellular antibiotic resistance genes (eARGs), and virus-mediated gene transfer. Future research should focus on (1) the removal of thermotolerant bacteria harboring ARGs; (2) the decomposition of eARGs or the blocking of their transmission pathways; (3) the optimization of ultra-high temperature composting parameters; and (4) the analysis of interactions between viruses and resistant hosts. This study reviews the mechanisms, influencing factors, and safety assessment of aerobic composting for degrading ARGs in livestock manure. It not only deepens the understanding of this important environmental biotechnology process but also provides a crucial knowledge base and practical guidance for effectively controlling ARG pollution, ensuring agricultural environmental safety, and protecting public health. Additionally, it clearly outlines the key paths for future technological optimization, thus holding significant implications for the environment, agriculture, and public health. Full article

In the earthquakes that occurred in the Pazarcık (Mw = 7.7) and Elbistan (Mw = 7.6) districts of Kahramanmaraş Province on 6 February 2023, many buildings collapsed in the Hayrullah neighborhood of the Onikişubat district. In this study, we investigated whether there was a soil amplification effect on the damage occurring in the Hayrullah neighborhood of the Onikişubat district of Kahramanmaraş Province. Firstly, borehole, SPT, MASW (multi-channel surface wave analysis), microtremor, electrical resistivity tomography (ERT), and vertical electrical sounding (VES) tests were carried out in the field to determine the engineering properties and behavior of soil. Laboratory tests were also conducted using samples obtained from bore holes and field tests. Then, an idealized soil profile was created using the laboratory and field test results, and site dynamic soil behavior analyses were performed on the extracted profile. According to The Turkish Building Code (TBC 2018), the earthquake level DD-2 design spectra of the project site were determined and the average design spectrum was created. Considering the seismicity of the project site and TBC (2018) criteria (according to site-specific faulting, distance, and average shear wave velocity), 11 earthquake ground motion sets were selected and harmonized with DD-2 spectra in short, medium, and long periods. Using scaled motions, the soil profile was excited with 22 different earthquake scenarios and the results were obtained for the equivalent and non-linear models. The analysis showed that the soft soil conditions in the area amplified ground shaking by up to 2.8 times, especially for longer periods (1.0–2.5 s). This level of amplification was consistent with the damage observed in mid- to high-rise buildings, highlighting the important role of local site effects in the structural losses seen during the Kahramanmaraş earthquakes. Full article

Cost-effective methods for improving soil fertility and mitigating the negative impact of heavy metal contamination in agricultural soils are currently under investigation. This study aimed to evaluate the impact of soil lead (Pb) contamination and the application of secondary pulp and paper mill sludge on the relative growth rate (RGR) and its determinants, as well as the specific absorption rate (SAR) of nutrients of Lactuca sativa L. For the 46-day pot experiment, which was carried out in 2022 under controlled conditions at the Karelian Research Centre of RAS, sandy loam soil was used, to which Pb was added at rates of 0, 50, and 250 mg Pb(NO₃)₂ kg⁻¹. Secondary sludge was applied with each watering at concentrations of 0%, 20%, and 40%. RGR values varied significantly, primarily due to changes in net assimilation rate (NAR) rather than specific leaf area. Positive relationships were found between RGR and NAR, and RGR and SAR of nitrogen and phosphorus, but not potassium. Sludge applications can stimulate NAR at early stages of plant growth. For plants grown on soil with the highest Pb concentration studied, secondary sludge reduced root lead content by an average of 35%. Soil contamination with lead increased nutrient SAR by 79 and 39% when applied as 20 and 40% sludge, respectively, while 40% sludge increased nitrogen SAR by 51% but did not change phosphorus and potassium SAR. A sludge-mediated reduction in root Pb content and an increase in NAR suggest that secondary paper sludge may contribute to the remediation of Pb-contaminated soils and reduce the toxicity of heavy metals to plants. The results may help in finding new ways to manage soil fertility, especially for contaminated soils. Full article

The rapid increase in population and the corresponding increase in developments have necessitated the stabilization of areas with poor soil conditions. Due to consolidation settlement, the soft grounds available are deemed unsuitable for such structures. This paper presents the use of cement additives to build sand–cement columns in saturated clayey soils. The approach significantly reduces consolidation settlement and increases the bearing capacity, providing a viable solution to foundation problems. Consolidation tests were conducted on saturated clay specimens and sand–cement columns arranged in various patterns. A 5% cement content by the dry weight of the sand was used in building sand–cement columns. The results showed that the consolidation settlement rate was high due to the extra drainage formed by the widened pores in the sand–cement columns. The extra drainage caused more water to leave the specimen in a given time. However, after full contact between the loading platen and sand–cement columns, the rate of consolidation settlement decreased. At this stage, sand–cement participated in carrying the load. Additionally, the effect of vertical drainage on speeding up consolidation at higher stress levels was minimal, as the widened pores in the sand–cement columns began to close. Full article

The use of trees to revegetate urban areas contaminated by mining activity is a low-cost, low-maintenance technique, of which the success will depend on the plant species, planting methods, and geochemical processes at the soil-plant interface. This study analyzed the evolution of mineral composition in the rooting soil, tree, and herbaceous vegetation on soils contaminated by As, Cd, Cu, Co, Pb, and Zn. An in-situ experiment was carried out in Lubumbashi (South-eastern DR Congo) with six tree species (Acacia auriculiformis, Albizia lebbeck, Delonix regia, Leucaena leucocephala, Mangifera indica, and Syzygium guineense), in 0.187 m³ pits amended with municipal compost and limestone. After planting in the amended and unamended (control) pits, soil samples were taken for chemical analysis. Eighteen months after planting, a floristic inventory was carried out to assess the spontaneous colonization of herbaceous species. The results show an increase in metal concentrations in the rooting soil between 2019 and 2023 (Cu: 725 ± 136 to 6141 ± 1853 mg kg⁻¹; As: 16.2 ± 1.4 to 95 ± 28.5 mg kg⁻¹; Cd: 2.7 ± 1.3 to 8.7 ± 2.0 mg kg⁻¹; Co: 151 ± 36.3 to 182 ± 113 mg kg⁻¹; Zn: 558 ± 418 to 1098 ± 1037 mg kg⁻¹), with a stable pH and a decrease in nutrients (P, K, Ca, and Fe). The trees planted in the amended pits showed better height and diameter growth and greater survival than the controls, reaching average heights of 8 m and a DBH of up to 22 cm four years after planting. A total of 13 spontaneous herbaceous species were recorded, with an increased abundance during the second inventory. These results confirm the effectiveness of pit amendment for the rapid revegetation of urban soils polluted by trace metals. Full article

The data on the volumetric radon activity of the Akchatau territory were systematized in the context of radioecological safety. Radon (Rn²²² and Rn²²⁰) and indoor radon (isotopes Po, Pb, and Bi) make a significant contribution to radon radiation in residential and industrial premises. Increased radon concentration in a number of areas is associated with the Akchatau tungsten–molybdenum mine. The source of radon in geological terms is acid leucocratic granites in the northwestern and southeastern parts of the studied territory. Seasonal assessment of radon radiation was carried out using modern devices “Alfarad Plus” and “Ramon-Radon”. Frequency analysis of the average annual equivalent equilibrium concentration (EEC) in 181 premises showed that only in 47.5% of the premises does the volumetric radon activity not exceed the current standards (200 Bq/m³). Differentiated values of radon concentration were obtained in cases where daily and seasonal observations were carried out. In 43.1% of premises, the effective dose varies from 6.6 mSv/year to 33 mSv/year, and for 9.4% of premises, from 33 mSv/year to 680 mSv/year. The increased radon concentration is caused by high exhalation from the soil surface, the radioactivity of building materials, and low air exchange in the surveyed premises. In the northwestern part of Akchatau, anomalous zones were found where the exposure dose rate of gamma radiation exceeds 0.6 mkSv/hour. An objective assessment of radon largely depends on a number of factors that take into account the geological, technical, atmospheric, and climatic conditions of the region. Therefore, when planning an optimal radon rehabilitation strategy, it is necessary to take the following factors into account: the design features of residential premises and socio-economic conditions. Practical recommendations are given for radiation-ecological and hygienic monitoring of radon safety levels in the environment to reduce effective doses on the population. Full article

The increasing global oil consumption has led to significant soil contamination by hydrocarbons, notably diesel-range hydrocarbons. Soil bioremediation through bacterial bioaugmentation is an alternative to increase the degradation of organic pollutants such as petroleum products. Bioremediation is a sustainable practice that contributes to the Sustainable Development Goals (SDGs) because it is environmentally friendly, reduces the impact of human activities, and avoids the use of invasive and destructive methods in soil restoration. This study examines the bioremediation potential of hydrocarbonoclastic bacteria isolated from soil close to areas with a risk of spills due to pipelines carrying hydrocarbons. Among the isolated strains, Arthrobacter globiformis, Pantoea agglomerans, and Nitratireductor soli exhibited hydrocarbonoclast activity, achieving diesel removal of up to 90% in short-chain alkanes and up to 60% in long-chain hydrocarbons. The results from in silico studies, which included molecular docking and molecular dynamics simulations, suggest that the diesel removal activity can be explained by the bioavailability of the linear alkanes and their affinity for alkane monooxygenase AlkB present in the studied microorganisms, since long-chain hydrocarbons had lower enzyme affinity and lower aqueous solubility. The correlation of the experimental results with the computational analysis allows for greater insight into the processes involved in the microbial degradation of hydrocarbons with varying chain lengths. Furthermore, this methodology establishes a cost-effective approximation tool for the evaluation of the feasibility of using different microorganisms in bioremediation processes. Full article

Organic farming is becoming increasingly important in agricultural production, especially in mountain and foothill areas. In organic farms, unlike conventional ones, no mineral fertilization or chemical plant protection is used, which often limits the economic efficiency of production. It is commonly believed that conventional farming poses a threat to biodiversity due to the use of mineral fertilization, chemical plant protection, and highly productive crop varieties, and the products obtained are in many respects of lower quality than those from organic farms. The aim of this work is to compare the quality and fertility of soils and the biodiversity of grasslands in organic and conventional farms, using the example of a foothill area within the commune of Kamienna Góra located in the Western Sudetes. Thirty-three areas representing 11 farms that produce dairy cattle in a grazing system were selected for analysis. The properties of soils in organic and conventional farms and their nutrient status did not differ significantly, except for the content of available potassium, which was higher in the group of organic farms. This fact seems to be related to the type of parent rock. All soils had acidic, slightly acidic, or strongly acidic pH levels. The greatest differences between pastures in organic and conventional farms concerned the sward species composition and biodiversity indices. Grasslands in organic farms were much richer in species, which was reflected by the species richness (SR) index and the F-fidelity index. The species inventoried clearly formed two groups that are characteristic of organic and conventional grasslands. The greater biodiversity of grasslands in organic farms did not have a significant effect on the fodder value of the sward, which should be considered good, allowing producers to participate in short supply chains. However, in all farms, regardless of their type, it would be advisable to carry out gentle liming. Full article