Soil Sites Research Articles

ЭНДОФИТНЫЕ ШТАММЫ БАКТЕРИЙ В ТЕХНОЛОГИИ ВОЗДЕЛЫВАНИЯ КУКУРУЗЫ НА ЗЕРНО

The study of the effect of endophytic bacterial strains on the formation of the general habitus of the corn plant during the growing season, as well as the effect on grain yield, was carried out in the conditions of the Ancestral region of the Republic of Tatarstan in 2022-2023. The soil of the experimental site was represented by a subtype of gray forest, the variety was heavy loamy. Endophytic bacterial strains were used in corn crops in the form of leaf dressing with a rate of 1.0 l/ha during the growing season in the 7-8 leaf phase. The technology of cultivation of corn for grain was generally accepted for the Republic of Tatarstan. A two-factor experiment was laid: hybrids (factor A) - early maturing Nur and ROSS-195, mid-early ‒ Krasnodarskiy-230; preparations of endophytic bacterial strains (factor B) - without application (control), KS-25, KS-31, KS-38, KS-54, Consortium and PS-17 (standard). The years of research were characterized as moderately arid in terms of climatic conditions. The preparations had a positive effect on the height of plants, above-ground mass and leaf area, which were determined in the phases of paniculation, cob formation and milk ripeness. The Nur hybrid responded positively to the treatment of crops with preparations KS-25, KS-38 and KS-54, the ROSS-195 hybrid - Consortium, KS-31 and KS-38, Krasnodarskiy-230 - KS-31 and KS-54. The highest aboveground mass in the experiment in the milk ripeness phase of the Nur hybrid was noted in the variant with KS-38 (48.25 t/ha), in the ROSS-195 and Krasnodarskiy-230 hybrids ‒ with KS-54 (67.38 and 58.25 t/ha, respectively). The largest leaf area was observed in the cob formation phase of the Nur hybrid when used in the KS-31 variants, in the ROSS-195 and Krasnodarskiy-230 hybrids when treated with the Consortium preparation. The grain yield of the Nur hybrid in variants with the PS-17, KS-38 and KS-25 preparations increased by 9.6…27.6%, the ROSS-195 hybrid when sprayed with KS-38 and KS ‒ by 15.3…19.7%, the Krasnodarskiy-230 hybrid when using KS-25, KS-54 and PS-17 ‒ by 9.0…28.1%. Preparations with endophytic bacterial strains increased the protein content in the hybrid grain by 0.15…0.73%.

Vegetation community recovery on restored bottomland hardwood forests in northeast Indiana, USA.

Vegetation communities in restored bottomland hardwood forests in northeast Indiana were studied 6-21 years after restoration to assess progress toward restoration objectives. The study focused on four sites that were restored to compensate for resource injuries after contaminant releases. The restored sites were compared with four reference-site conditions, including crops (prerestoration condition), old field communities representing a no-management alternative, locally sampled second-growth mature forests, and forest community types described by the US National Vegetation Classification (USNVC), which represent ideal or defining conditions of recognized vegetation communities. Fixed-area plots provided data on field-sampled environmental variables, vegetation, soil, and hydrological conditions for crops, old fields, restored areas, and mature forests. The USNVC database provided quantitative data for three historically and geographically relevant reference forest community types for comparison with the sampled communities. Results of nonmetric multidimensional scaling based on species cover revealed clear gradients relating to site age and canopy development. Along those gradients, restored areas demonstrated increasing similarity to mature forest reference communities in terms of floristic composition. Specifically, the floristic quality of restored areas was significantly greater than that of crops and old fields. Furthermore, soil health measurements of physical, chemical, and hydrological conditions indicated significant improvements in restored site soils compared with prerestoration conditions represented by cropland soils. Descriptions and data from the USNVC provided ecological context for restoration target conditions and facilitated the assessment of restoration recovery along a trajectory from starting conditions to those target conditions. Descriptions by USNVC also helped identify deviations from the intended restoration objectives (e.g., invasive species recruitment) and potential adaptive management actions to return sites to their intended trajectories. Integr Environ Assess Manag 2024;20:1917-1938. Published 2024. This article is a U.S. Government work and is in the public domain in the USA. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Environment, plant genetics, and their interaction shape important aspects of sunflower rhizosphere microbial communities.

Associations with soil microorganisms are crucial for plants' overall health and functioning. While much work has been done to understand drivers of rhizosphere microbiome structure and function, the relative importance of geography, climate, soil properties, and plant genetics remains unclear, as results have been mixed and comprehensive studies across many sites and genotypes are limited. Rhizosphere microbiomes are crucial for crop resistance to pathogens, stress tolerance, nutrient availability, and ultimately yield. Here, we quantify the relative roles of plant genotype, environment, and their interaction in shaping soil rhizosphere communities, using 16S and ITS gene sequencing of rhizosphere soils from 10 genotypes of cultivated sunflower (Helianthus annuus) at 15 sites across the Great Plains of the United States. While site generally outweighed genotype overall in terms of effects on archaeal, bacterial, and fungal richness, community composition, and taxa relative abundances, there was also a significant interaction such that genotype exerted a significant influence on archaeal, bacterial, and fungal microbiomes in certain sites. Site effects were attributed to a combination of spatial distance and differences in climate and soil properties. Microbial taxa that were previously associated with resistance to the fungal necrotrophic pathogen Sclerotinia were present in most sites but differed significantly in relative abundance across sites. Our results have implications for plant breeding and agronomic microbiome manipulations for agricultural improvement across different geographic regions.IMPORTANCEDespite the importance of plant breeding in agriculture, we still have a limited understanding of how plant genetic variation shapes soil microbiome composition across broad geographic regions. Using 15 sites across the Great Plains of North America, we show that cultivated sunflower rhizosphere archaeal, bacterial, and fungal communities are driven primarily by site soil and climatic differences, but genotype can interact with site to influence the composition, especially in warmer and drier sites with lower overall microbial richness. We also show that all taxa that were previously found to be associated with resistance to the fungal pathogen Sclerotinia sclerotiorum were widespread but significantly affected by site, while a subset was also significantly affected by genotype. Our results contribute to a broader understanding of rhizosphere archaeal, bacterial, and fungal community assembly and provide foundational knowledge for plant breeding efforts and potential future microbiome manipulations in agriculture.

Estimation of corn hybrids of different early maturity by fodder productivity in the conditions of the forest-meadow zone of the Middle Urals

The paper presents the results of assessing the feed productivity of various ultra-early and early-maturing corn hybrids created by the All-Russian Research Institute of Corn. In the Sverdlovsk region, 12 corn hybrids with FAO 140–180 were studied in 2019–2023. The soil of the research site is dark gray, forest, slightly podzolized, heavy loamy. On average, over 5 years, the highest dry matter content is 32.4… 36.1 % were recorded in the FAO 140–150 group, among which hybrids K 140 (35.0 %) and Mashuk 140 (36.1 %) stand out. In the FAO 140 group (K 140, Nur), the starch content in dry matter reached a maximum of 31.1… 30.4 per cent, while for FAO 180 (Sheehan) it was only 24.7 per cent. The maximum productivity on average over the years of research was observed in hybrids FAO 170–180 Mashuk 172 and Shihan (34.8 t/ha). The minimum for hybrids FAO 140 K 140 (26.3 t/ha) and Mashuk 140 (26.5 t/ha). Against the background of heat deficit (2019), the maximum productivity was in the FAO 140–150 groups: K 140 (3.88 t/ha), Nur (4.03 t/ha), Mashuk 140 (3.99 t/ha), K 150 (4.11 t/ha). In terms of the collection of the target component – starch, the highest productivity on average for 5 years was shown by hybrids of the FAO 140–150 group: Nur (2.93 t/ha), K 150 (2.81 t/ha) and Mashuk 140 (2.68 t/ha). It has been established that that in the conditions of the Middle Urals, from the set of hybrids bred by the All-Russian Research Institute of Corn, the highest fodder productivity is – K 140, Nur, Mashuk 140, K 150.

Simplified site response analysis for regional seismic risk assessments

Seismic risk assessment on a regional scale requires an estimation of ground motion intensity and its spatial variation over large geographical areas. This task is particularly challenging in the presence of very soft soil deposits where significant amplification occurs at specific frequencies that are often referred to as local resonances. It is often not feasible to conduct a nonlinear site response analysis at thousands of sites of interest across a region such as an urban area due to the computational effort involved and the required detailed information on soil profiles at each site. Thus, in regional seismic risk analyses the hazard is typically represented by a field of response spectral ordinates estimated by ground motion models. This study proposes a simplified site response analysis procedure to improve the characterization of spectral ordinates to be used in regional seismic risk assessments. In the proposed procedure, reduced-order models are used to conduct site response analysis using very few parameters to transform response spectra at rock outcrop into response spectra at the surface of each of the sites. A particular emphasis is given to soft-soil sites characterized by low shear-wave velocities overlaid on rock or firm soils. A non-uniform continuous shear beam model with a parabolic variation of shear modulus along the depth and modal damping is used in combination with Random Vibration Theory. It is shown that the proposed approach provides better estimates than those of ground motion models or physics-based ground motion simulation models which often cannot capture the local resonances. Site-specific validation of the shear beam model and overall simplified site response analysis is performed at four soft-soil sites in San Francisco, California. Despite its simplicity, it is shown that the proposed procedure adequately captures the amplitudes and spectral shapes of the motions. It is also shown that in conjunction with ground motion models or physics-based models, the proposed simplified site response analysis procedure can be used to efficiently simulate the seismic hazard on a regional scale through an example of a regional seismic hazard analysis of 160 softer soil sites in Downtown San Francisco during the Loma Prieta earthquake.

Regional study of site effects on the high-frequency spectral-decay parameter

The high-frequency spectral-decay parameter κ has been used in the field of engineering seismology for several decades. The zero-distance κ value (κ0) is a site parameter in ground motion models and strong motion synthesis. Using surface-borehole pairs of strong motion records from the strong-motion seismograph network KiK-net, we explored the effect of site soil on κ0, specifically the contribution from ground motion directionality. In the target area (138°E−143°E, 36°N–40°N), and records from earthquakes at 50 pairs of stations were collected. All horizontal orthogonal records were rotated from 0° to 180° with an increment of 10° to capture the difference between the average κ0 on two horizontal components and the median value of the rotated κ0 at surface and borehole stations. The same process was applied to Δκ0, the difference between surface station κ0 and borehole station κ0, to measure the contribution by soil column. The nonlinear behavior of soils led to large shear strains, reduced stiffness, and decreased resonance frequency. Thus, the effect of soil nonlinearity on κ is investigated. In the same area, strong ground motion records with peak ground acceleration >100 cm/s2 were selected to identify the soil nonlinearity by the moving time window deconvolution method, and the temporal variation of time-average shear wave velocity and κ at the 50 surface stations were assessed.

Progress in Seismic Isolation Technology Research in Soft Soil Sites: A Review

Soft soil sites can amplify the peak acceleration by a factor of 1.5 to 3.5 and exhibit the filtering effect on seismic waves. This effect results in the attenuation of high frequencies, amplification of low frequencies, and extension of the predominant period of ground motion. Consequently, soft soil sites have a more pronounced impact on isolation buildings constructed on them. The seismic isolation structure design typically involves assuming rigid foundation for calculations. However, the soil properties can significantly impact the dynamic response of the structure, affecting factors such as input ground motion, changes in vibration characteristics, radiation energy dissipation, and material damping energy dissipation. Therefore, neglecting these influences and relying solely on the rigid foundation assumption for calculations can lead to significant errors in the final seismic response analysis of the structure. Currently, there are numerous LNG storage tanks, museums, and other isolation buildings constructed on soft soil sites. Therefore, research on seismic isolation measures for soft soil sites holds significant practical importance. In light of this, this paper, firstly, provides a systematic summary of seismic isolation strategies and engineering applications for soft soil sites. Secondly, it further discusses advancements in research on the dynamic interactions of soil–isolated structures, covering analytical methods, numerical investigations, and experimental studies on soft soil sites. Lastly, the paper concludes with insights on current research progress and prospects for further studies.

Quantitative Assessments of the Liquefaction Hazard of Soils considering Possible Strong Earthquakes in Seismically Active Regions of Russia

Introduction The seismogenic liquefaction of the soil poses a great hazard to society and the environment. Therefore, it is actively studied in many countries. In Russian engineering and seismological practice, this area is not sufficiently developed. The deterministic approach still prevails in Russian research on this topic. More modern probabilistic estimates are very rare. Methods This paper describes examples of both deterministic and probabilistic assessments of the seismogenic liquefaction hazard performed in certain areas of the Russian territory with different seismogeological conditions. Deterministic estimates were made using the Iwasaki-Seed-Finn methods and their modifications. Probability distribution functions of a random variable, the “seismic potential of liquefaction” (SPL), were developed for probabilistic estimates. These functions are regional in nature and take into account two types of uncertainties. The first is the uncertainty in achieving “critical” values by the SPL value in the event of potentially dangerous earthquake sources for a given location. The second is the uncertainty in the very occurrence of these sources in a given place for a given period of time. The “critical” SPL values are determined by the strength properties of the site soils. All estimates are based on multivariate calculations using various models of strong ground motions and seismicity. In all cases, the probability of liquefaction of water-saturated sandy and sandy-loam deposits was estimated which were found near the seabed and at depths of up to 80 m in the waters of Pogibi cape (the coast of Sakhalin island), in the districts of Sochi and Novorossiysk, as well as in land conditions (Stavropol, Krasnodar). Results The results of the research made it possible to correctly (at the quantitative level) take into account this component of the seismic hazard of the studied territories. Conclusion The variants of practical use of the obtained data are offered. An assessment of the possibilities and limitations of the developed methodology is made, and ways to improve it are outlined.

Microbiome Geographic Population Structure (mGPS) Detects Fine-Scale Geography.

Over the past decade, sequencing data generated by large microbiome projects showed that taxa exhibit patchy geographical distribution, raising questions about the geospatial dynamics that shape natural microbiomes and the spread of antimicrobial resistance (AMR) genes. Answering these questions requires distinguishing between local and non-local microorganisms and identifying the source sites for the latter. Predicting the source sites and migration routes of microbiota has been envisioned for decades but was hampered by the lack of data, tools, and understanding of the processes governing biodiversity. State-of-the-art biogeographical tools suffer from low resolution and cannot predict biogeographical patterns at a scale relevant to ecological, medical, or epidemiological applications. Analyzing urban, soil, and marine microorganisms, we found that some taxa exhibit regional-specific composition and abundance, suggesting they can be used as biogeographical biomarkers. We developed the Microbiome Geographic Population Structure (mGPS), a machine-learning-based tool that utilizes microbial relative sequence abundances to yield a fine-scale source site for microorganisms. mGPS predicted the source city for 92% of the samples and the within-city source for 82% of the samples, though they were often only a few hundred meters apart. mGPS also predicted soil and marine sampling sites for 86% and 74% of the samples, respectively. We demonstrated that mGPS differentiated local from non-local microorganisms and used it to trace the global spread of AMR genes. mGPS's ability to localize samples to their waterbody, country, city, and transit stations opens new possibilities in tracing microbiomes and has applications in forensics, medicine, and epidemiology.

Soil degradation around Orji municipal solid waste dump site: a spatial assessment.

The present study assessed the impact of municipal solid waste dump on the degradation of soil around Orji dump site. A total of 15 soil samples were collected for this study. Twelve soil samples were collected around the dump site at 0m, 10m, and 20m distance and three from Imo State University (IMSU) research farm as control. The samples were collected from the east, west, north, and south of the dump site. The samples were subjected to laboratory analyses. The mean results obtained indicate that the values of the dump site soil parameters analyzed ranged from 86.67 to 89.00% (sand), 4.33 to 5.67% (silt), 7.00 to 7.67% (clay), 6.80 to 7.50 (pH), 4.33 to 7.00 dS m-1 electric conductivity (EC), 0.0028 to 0.0045mgkg-1 (salinity), 2.36 to 3.76% soil organic matter (SOM), 24.13 to 38.93 cmolc kg-1 cation exchange capacity (CEC), 4.50 to 9.57 cmolc kg-1 calcium (Ca), and 1.0 to 2.25 cmolc kg-1 magnesium (Mg). At the control, mean values were 81.24% (sand), 6.39% (silt), 12.45% (clay), 5.69 (pH), 0.47 dS m-1 (EC), 0.0005mgkg-1 (salinity), 1.99% (SOM), 5.08 cmolc kg-1 (CEC), 2.17 cmolc kg-1 (Ca), and 1.67 cmolc kg-1 (Mg). These values showed substantial enrichment. Correlations indicate that EC, salinity, and CEC majorly determined the availability of most of the parameters analyzed. Soil degradation index (SDI) was used to determine degradation around the dump site. It ranged from 2.546.61% (0m) to 1573.50% (10m) and 1.603.73% (20m). Thus, distance affected the rate of soil degradation in all directions away from the dump site.

Studies on Effect of Genotypes and Planting Time on Growth and Corm Characters of Gladiolus

Gladiolus is an important cut flower crop, grown commercially in many parts of the globe. This flower has gained popularity owing to its incomparable beauty, attractive colours, various sizes and shapes of florets, variable spike length and long vase life. Gladiolus produces beautiful spikes from December to March in the plains and from June to September in the hills of India.Gladiolus is very rich in its varietal wealth therefore, varietal evaluation in a particular growing condition becomes necessity of time to find out suitable variety for a particular region. Improvement of any crop is a continuous process and long process as well and, in this crop, tremendous scope is available to improve the existing cultivars, besides, other economical plants, the growth and development of gladiolus is governed by its genetic makeup and environmental factors of the growing region and various management practices. Among the various agro-techniques, the optimum planting time is of outmost importance. The Present investigation efforts aim to standard time of planting and suitability of varieties for local climate and edaphic conditions of the Nalanda (Bihar). A field investigation was conducted during winter season of 2018-19 at Research Farm of Nalanda College of Horticulture, Noorsarai, Nalanda, Bihar. Corms of gladiolus cultivars viz., Red Beauty, Candyman, White Prosperity and Intrepid were planted at different planting dates. The soils of experimental site are newly formed alluvial soils with pH 7.40. The experiment consisted of 16 treatment combinations with four (04) varieties and four planting dates (D1- 25th Sept., D2- 10th October and D3- 25th Oct. and D4-10th Nov.) were laid out in split-plot-design with three replications. Minimum days to sprouting of corm (16.33 days), number of leaves per plant (11.27), length of leaves (86.87cm.) were with D2V2. However, maximum plant height (146.07 cm.) was in D2V1. Minimum days to initiation of spike (80.47 days), days taken to open first floret (95.07 days) and maximum length of spike (126.07cm.) were observed in D2V1. On the other hand, maximum numbers of florets per spike (21.20), fresh weight of flower spike (170.25 gm.), floret diameter (11.17cm.) and vase life (14.80 days) were in D2V3. Highest values for no. of corms per plant (1.40) and no. of cormels per plant (111.53) were noticed in D2V3. Besides, corm diameter (7.53 cm) and average weight of corm per plant (123.08 gm.) were found maximum in D2V1.

Bioprospecting for sustainable and eco-friendly bioproducts: A case study of multi-enzyme production by soil microbes

Microbial multi-enzyme production is a promising research area involving microbes that can simultaneously synthesize numerous enzymes for the degradation of substrates with environmental sustainability and other industrial applications as the focus. During this study, we isolated, screened, and identified some multi-enzyme-producing microbes from three soil sites in Ibadan: Apete Dumpsite (ADS); Botanical Garden University of Ibadan- (BGUI); and Eleyele Cassava Processing Field- (ECPF). Precisely 500 g of soil were collected per point at different depths (0–10, 10–20, and 20–30 cm) and further analyzed. The microbial load and type and enzyme assays were determined. The highest average microbial count (6.9 × 108 CFU/g) was recorded in the ECPF soil sample at 0–10 cm depth, while the lowest microbial count of 3.3 × 105 CFU/g at 20–30 cm soil depth in BGUI. Multi-enzyme-producing microbes were identified phenotypically and molecularly. This study revealed an inverse relationship between microbial community composition and soil depth. Bacterial and fungal genera had higher species richness, biodiversity, and evenness than yeast from all sampled points. With significant amylolytic, proteolytic, lipolytic, cellulolytic, and pectinolytic activities, 22 of the 193 isolates were identified as multienzyme producers. The blasted 16S rRNA and ITS rRNA amplicon sequences compared with sequences in the NCBI gene bank identified Bacillus, Roseomonas, Aeromonas, Phanerochaete, Aspergillus, Fusarium, Trametes, and Rigidoporus species. Results from this study show that topsoils (0–10 cm), rich with organic matter, are good reservoirs of multienzyme-producing microorganisms- applicable for environmental sustainability and in other important industries for waste management, food processing, and biomaterial production.

Soil properties and yield of mung bean [VIGNA RADIATA (L.) WILCZEK] as influenced by tillage and phosphorous fertilizer management on sandy loam soil in Chitwan, Nepal

Phosphorous application combined with a variety of tillage methods promotes the growth and development of mungbeans and sustainably improves soil health. A field experiment was conducted in Mangalpur, Nepal from February to May of 2021 and 2022 to investigate the impact of varying tillage practices and phosphorous doses on the growth, development, and yield of mung beans, while also analyzing changes in soil physicochemical properties on sandy loam soil. The research was conducted in a 2-factorial split-plot design with three replications. After completion of the study, the plant height (59.43 cm), nodule plant-1 (15.84), pod plant−1 (23.65), and seed yield (1087.76 kgha−1) were significantly higher when phosphorous was applied at 40 kgha−1 and 60 kgha−1. Among different tillage practices, significantly greater plant height (57.21 cm), nodule per plant (15.76), pod plant−1 (24.99), seed pod-1 (10.76), seed yield (1089.92 kgha−1), and 1000-seed weight (48.23 g) were observed in conventional tillage. P at 60 kgha−1 resulted in significantly higher total soil nitrogen (0.207 %) and available P (30.65 kgha−1). Similarly, for tillage practices, statistically higher total soil nitrogen (0.23 %) and available phosphorous (32.45 kgha−1) were observed in zero tillage practices. Furthermore, pH was seen to be significantly higher in conventional tillage (6.12) followed by strip (5.79). A combination of conventional tillage with 40 kgha−1 was observed better in short-term conditions however, for better growth and yield of mung bean and sustainable health of the soil, zero tillage with 40 kgha−1 phosphorous can be suggested for sandy loam soil and environmental conditions present in the study site in the long-term.

Compositional-geochemical characterization and multi-element pollution and risk assessment of potentially toxic elements in the urban landfill soil

Urban areas are characterized by the presence of various pollution sources including landfills. During the recent decade, urban landfills were investigated as a source of pollution by potentially toxic elements and potential deposits for landfill mining. The contents of Cr, V, Ti, Ca, K, Mo, Zr, Sr, Rb, As, Zn, Cu, Co, Fe, Mn, Pb, Ba in soils of Vanadzor city landfill site (VL) were determined using the X-ray fluorescence spectrometer to assess multi-element pollution and ecological risk and to identify potentially toxic elements geochemical associations through the application of compositional data analysis. The results showed that Cr, Mo, Zn, Cu, and Pb displayed significant values (>100%) of coefficient of variation suggesting their anthropogenic origin. Moreover, these elements, except Cr, displayed outliers and extreme values in the same sampling sites located directly on the reclaimed part of the landfill. The median contents of Zn, Pb, Cu, Cr, Cd, and As exceeded the global median values by 8.2, 9.8, 19.0, 4.6, 6.1, and 4.5 times, respectively. The multi-element pollution assessment showed that an extremely hazardous level of pollution was observed on the reclaimed part of the VL. From this site, a trend of decrease in the pollution level was observed in the eastern and western directions. In contrast, an allowable level of pollution was observed in the northern part - toward the direction of the above-located hill. The VL was found to be in an inferior ecological condition (a very high level of potential ecological risk was observed), which might also have a negative impact on the ecosystems located in its vicinity. The hierarchical clustering has revealed that the studied elements are grouped in two geochemical associations: a naturally formed - Co, Fe, V, Ti, Mn, Sr, Zr, Rb, K, Ba, As; and an anthropogenic one - Zn, Pb, Cu, Ca.

Organic Carbon and Ca‐Rich Carbonate Detections in Soils of the Northern Plains, Mars: Evaluation of Unreported Data From the Mars Phoenix Scout's Thermal Evolved Gas Analyzer (TEGA)

AbstractThe Thermal Evolved Gas Analyzer (TEGA) analysis of surface and icy subsurface Phoenix landing site soils consisted of low (300–700°C) and high (>700°C) temperature CO2 evolutions that were attributed to organic carbon (83–1,484 μgC/g) and Ca‐rich carbonate (1.1–2.6 wt.%). Total carbon abundances ranged from 1,143 to 4,905 µgC/g, which is the highest soil carbon concentration so far detected on Mars. Low temperature CO2 was attributed to oxidized organic C (e.g., oxalates, acetates), while hydrocarbon combustion was indicated in two soils by the detection of coevolved CO2 and O2 (perchlorate). Combustion reactions may have prevented the detection of hydrocarbon masses in the Phoenix landing site soils. Organic C was likely derived from meteoritic and igneous/hydrothermal sources, but microbiological sources cannot be excluded. CO2 evolved at high temperatures was consistent with Ca‐rich carbonate along with possible minor contributions from macromolecular organic carbon and mineral/glass vesicle CO2. Carbon detected in the Phoenix landing site soil and other landing site soils and sands (e.g., Gale/Jezero craters) would be consistent with global organic C and carbonate in soils and sand across Mars. However, oxidizing water thin films derived from the near‐surface ice in the Phoenix soils favor Ca‐carbonate over Fe‐carbonate, which is likely more stable in the ice‐free regions of Mars (e.g., Gale/Jezero craters). The global carbon budget on Mars inferred from these results emphasizes that Mars Sample Return should yield carbon bearing soil/rock that would allow the identification of the origin of carbon and any possible connections to ancient martian microbiology.

Seismic response of deep soft soil sites with varying shear wave velocities

The variations in seismic response between deep soft soil sites with different shear wave velocities were not fully understood. This study focuses on the seismic response of deep soft soil sites in the lower reaches of the Yangtze River, China. A nonlinear dynamic finite element model was developed for two representative deep soft soil sites with borehole profiles and the shear wave velocity tested by the single borehole method. Two nonlinear cyclic constitutive models are used and thus compared through the site seismic response. To accurately calibrate the nonlinear cyclic model parameters, resonant column tests were conducted on 21 soil samples collected from the two boreholes. The results show that the peak ground acceleration (PGA) under low-frequency (Liuan) input motion was higher for soft soil sites compared to that under medium- and high-frequency (Kobe and Nahanni) input motions. The PGA amplification factor for deep soft soil sites under different input motions can be approximated by an exponential function. The peak ground acceleration tends to be lower as the equivalent shear wave velocity (Vse) decreases. The shapes of the spectral acceleration were similar for the two sites, despite a substantial difference in the Vse between them. Additionally, a crossover point was observed in the spectral acceleration for the two sites. The period corresponding to this crossover point increased with increasing intensity of input motions, indicating that the sites became softer with higher intensity and thus generally exhibited a longer characteristic period of the spectral acceleration. This paper also highlights the significance of selecting nonlinear constitutive models and the precise calibration of model parameters in the seismic response analysis of deep soft soil sites, providing a scientific basis for future similar site analyses.

Ground failures and foundation performances in Adıyaman–Gölbaşı following the 6 February 2023 Kahramanmaraş–Türkiye Earthquake Sequence

The 6 February 2023 Kahramanmaraş–Türkiye earthquake sequence (M7.8 and M7.6) presents an exceptional opportunity to investigate both the effects of local soil conditions on damage patterns under strong shaking conditions and the performance of building foundations in areas that experienced ground failure. The significant ground failure and structural damage in Adıyaman–Gölbaşı triggered an intensive series of detailed reconnaissance and field surveys. This article aims to present the resulting database of observations on ground failures, building, and foundation performances. The field reconnaissance of ground failures and their effects on building performances involved aerial and walk-down surveys, including high-quality photographs taken across the town. In addition, data on building damage statistics compiled by the Ministry of Environment, Urbanization, and Climate Change were accessed and analyzed. The subsurface characteristics of the town were characterized using available data from pre-earthquake site investigation campaigns employed for town planning purposes. It is concluded that the ground failures in the town primarily resulted from soil liquefaction and cyclic softening. Most of the poor building and foundation performances and ground failures were documented in the northern part of Atatürk Boulevard, closer to the lake of Gölbaşı, where soil site characteristics were unfavorable. This revealed once again the significant effects of local soil site conditions, particularly soil liquefaction, on the intensified ground failures, foundation, and structural damage levels.

Tree carbon stock and seasonal influence on soil properties in shivpuri-nagarjun national park, nepal

The carbon stock stored within the biomass of tree species is vital in the forest ecosystem as it contributes significantly to the carbon balance. In addition, the physicochemical properties of soil play a critical role, in influencing overall ecosystem health. This study has analyzed the carbon stock and influence of seasonal change on soil physicochemical properties along soil depths in the Shivpuri Nagarjun National Park (SNNP), Nepal. The above-ground biomass carbon stock was found to be 227.09 t/ha and below-ground stock was 45.42 t/ha. Tree species Castanopsis tribuloides exhibited the highest values of above and below-ground tree carbon stock. The soil of the study site was sandy loam and slightly acidic. High temperature and moisture in the monsoon season were followed by an increased bulk density during the pre-monsoon with deeper soil layers. The sand, silt, and clay contents did not differ significantly across the seasons and depths. The key soil nutrients, like carbon, total nitrogen, phosphorus, and potassium were high during the monsoon season at the topsoil layer, which gradually declined with increasing depth in all seasons. The study highlights that the total tree carbon stock in the study site is 272.51 t/ha, with significant seasonal and depth-related variations in soil attributes. The monsoon season, characterized by maximum soil moisture and higher concentrations of essential soil components, is crucial in influencing soil physicochemical properties and offers important insights for forest conservation and management. Bangladesh J. Bot. 53(3): 567-576, 2024 (September)

Method of Investigation of Soil Contamination with Heavy Metals at the Sites of Explosions

The study evaluates the method of investigation of soil contamination with heavy metals at the sites of explosions. Results of method application were obtained. Soil samples were collected in location selected as the typical place were explosions take place for explosive objects destruction. For the qualitative and quantitative analysis of soil samples, the "KBr tablets" method was used. Obtained pellets were investigated with spectral-analytical installation created on the basis of infrared-spectrometer IKS-21 and thermal imager LAND-814. IR spectrometric research was carried out in the most informative spectral range of wavelengths of 7.5...14 μm. Proposed method of investigation of soil contamination with heavy metals at the sites of explosions allowed to identify presence of such metals as Al, Cu, Fe, Mg, Ni and Zn in soil samples of explosion site. Mg, Ni and Zn show stable presence in the soil of explosion site with low amount. Al, Cu and Fe we have seen sharp decrease of logarithmic transmittance value at the depth of 10…15 cm which means that these elements are accumulated at these depths of soil after explosions.

Plant investigation and the impact on earthen site soil properties in the east city wall of the Sanxingdui site

In southern China, vegetation on exposed earthen sites serves not only to mitigate erosion but also alters their visual appearance, leading to biodeterioration. However, how plants influence the properties of earthen sites is virtually unknown. This study undertook an ecological investigation of the original habitat in the east city wall of the Sanxingdui site, analyzing its soil properties and investigating plant-soil interactions. Research findings indicate that existing plant communities are not conducive to biodiversity nor site presentation. Plants exert a direct influence within a vertical range extending 0–40 cm beneath the site; root content correlates negatively with soil pH value but positively with organic matter content. The herbaceous community (E-2 and E-3) exhibits higher clay content than the arbor community (E-1) within this range. The above conclusions exhibit statistical significance. This study offers a scientific elucidation of the ecological parameters governing plant communities concerning the conservation of earthen sites, and provides an initial influence range of plant communities and biodegradation on the east city wall of the Sanxingdui sites, thereby revealing the technical potential for employing plants as a soft capping for earthen sites in the open air from the function method.