Surface Soil Layer Research Articles

Modelling pesticide degradation and leaching in conservation agriculture: Effect of no-till and mulching

No-till and mulching are typical management operations in conservation agriculture (CA). To model pesticide degradation and leaching under a CA scenario, as compared to a conventional-tillage scenario (CT), the mulch module of the agro-hydrological model Daisy was extended. A Daisy soil column was parameterized with measurements of topsoil, mulch, and a realistic subsoil, and tested against published experimental data of pesticide fate in laboratory soil columns covered by mulch. Uncertainty and sensitivity analyses of the new Daisy version were conducted for a series of weather, soil, pesticide, and mulch parameters, using 4939 Monte Carlo simulations under each scenario. Results showed that there was no systematic difference in pesticide leaching from the topsoil (to the subsoil and directly to drains via drain-connected biopores) between CA and CT, but pesticide degradation and sorption were significantly different; degradation in the mulch and uppermost soil surface layer (0–3.5 cm) was larger in CA while degradation was larger in CT when considering the whole topsoil (0–30 cm). This difference for the whole topsoil could be explained by pesticide interception in CA in the part of the mulch not in direct contact with the soil where degradation is assumed not to occur. The sensitivity analysis highlighted non-influential parameters and seven parameters out of twenty-five to be better estimated to improve the accuracy of the predictions.

Light Intensity: A Key Ecological Factor in Determining the Growth of Pseudolarix amabilis Seedlings

The notable absence of juvenile Pseudolarix amabilis trees in forest understories suggests their vulnerability to ecological niche competition, leading to limited survival prospects. This study examines the key factors limiting the growth of P. amabilis seedlings by investigating the effects of five ecological factors: light intensity, rainfall, groundwater level, soil type, and type of fertilization, on the growth of one-year-old P. amabilis seedlings. Our results demonstrate that increasing the light intensity promotes plant growth by augmenting the leaf count, leaf biomass, plant height, stem biomass, root biomass, and total biomass. Further analysis reveals that increased light intensity influences biomass allocation, reducing the specific leaf area and leaf–stem biomass ratio, and favoring root and stem growth over leaf investment. Rainfall, groundwater level, fertilization type, and rhizosphere soil type primarily influence root growth by impacting the soil’s physicochemical properties. Specifically, rising groundwater levels lower the soil temperature and increase the soil moisture, total potassium content, and soil pH, leading to reductions in root biomass, plant height, net height increment, leaf number, and total biomass. When groundwater levels reach 21 cm and 28 cm, submerging the surface soil layer, root biomass decreases by 1.6 g/plant (−51.6%) and 2.3 g/plant (−74.2%), respectively. Further analysis reveals a gradual decrease in the root–shoot ratio above the 14 cm groundwater level, while the specific leaf area and leaf–stem biomass ratio remains unaffected, indicating stronger belowground root stress compared to aboveground stem and leaf components. The results highlight light intensity as the key ecological factor determining the growth of P. amabilis seedlings. These findings underscore the importance of considering light intensity in the management of natural stands, the cultivation of artificial forests, and the nursery cultivation of endangered P. amabilis.

Unraveling nitrogen loss in paddy soils: A study of anaerobic nitrogen transformation in response to various irrigation practice

Soil nitrogen (N) transformation processes, encompassing denitrification, anaerobic ammonium oxidation (anammox), and anaerobic ammonium oxidation coupled with iron reduction (Feammox), constitute the primary mechanisms of soil dinitrogen (N2) loss. Despite the significance of these processes, there is a notable gap in research regarding the assessment of managed fertilization and irrigation impacts on anaerobic N transformations in paddy soil, crucial for achieving sustainable soil fertility management. This study addressed the gap by investigating the contributions of soil denitrification, anammox, and Feammox to N2 loss in paddy soil across varying soil depths, employing different fertilization and irrigation practices by utilizing N stable isotope technique for comprehensive insights. The results showed that anaerobic N transformation processes decreased with increasing soil depth under alternate wetting and drying (AWD) irrigation, but increased with the increasing soil depth under conventional continuous flooding (CF) irrigation. The denitrification and anammox rates varied from 0.41 to 2.12 mg N kg−1 d−1 and 0.062–0.394 mg N kg−1 d−1, respectively, which accounted for 84.3–88.1% and 11.8–15.7% of the total soil N2 loss. Significant correlations were found among denitrification rate and anammox rate (r = 0.986, p < 0.01), Fe (Ⅲ) reduction rate and denitrification rate (r = 0.527, p < 0.05), and Fe(Ⅲ) reduction rate and anammox rate (r = 0.622, p < 0.05). Moreover, nitrogen loss was more pronounced in the surface layer of the paddy soil compared to the deep layer. The study revealed that denitrification predominantly contributed to N loss in the surface soil, while Feammox emerged as a significant N loss pathway at depths ranging from 20 to 40 cm, accounting for up to 26.1% of the N loss. It was concluded that fertilization, irrigation, and soil depth significantly influenced anaerobic N transformation processes. In addition, the CF irrigation practice is best option to reduce N loss under managed fertilization. Furthermore, the role of microbial communities and their response to varying soil depths, fertilization practices, and irrigation methods could enhance our understanding on nitrogen loss pathways should be explored in future study.

Dredging wastewater discharge from shrimp ponds affects mangrove soil physical-chemical properties and enzyme activities

Dredging wastewater discharge is a significant environmental concern for mariculture near mangrove ecosystems. However, little attention has been paid to its effects on the soil physical-chemical properties and enzyme activities in mangrove habitats. This study compared the soil physical-chemical properties and enzyme activities in the polluted area that received dredging wastewater from a shrimp pond with those in the control area without wastewater to explore the effects of wastewater discharge on the soil physical-chemical properties and enzyme activities. Variations in soil physical-chemical properties and enzyme activities across different tidal flat areas and depths were also examined. The polluted area exhibited lower soil salinity (10.47 ± 0.58 vs. 15.64 ± 0.54) and moisture content (41.85 ± 1.03 % vs. 45.81 ± 1.06 %) than the control area. Wastewater discharge increased soil enzyme activities, (acid phosphatase, protease, and catalase), resulting in higher inorganic nitrogen (13.20 ± 0.00 μg g−1 vs. 11.60 ± 0.03 μg g−1) but lower total nitrogen (0.93 ± 0.01 mg g−1 vs. 1.62 ± 0.11 mg g−1) in the contaminated zone. From the control to polluted area, there was an approximate increase of 0.43 and 0.83 mg g−1 in soil total phosphorus and soluble phosphate, driven by increased acid phosphatase. However, soil humus and organic matter decreased by 0.04 and 1.22 %, respectively, because of wastewater discharge. The impact of wastewater discharge on the soil physical-chemical properties and enzyme activities was most pronounced in the landward and surface soil layers (0–5 cm). The results showed that wastewater discharge altered soil physical-chemical properties and enzyme activities, accumulating soil bioavailable nutrients (inorganic nitrogen and soluble phosphate), but at the cost of reduced soil quality, especially organic matter, further adversely affecting the overall health of mangrove ecosystems. Prioritizing the management of wastewater discharged from mariculture adjacent to mangrove forests is crucial for mangrove conservation.

Research on mining-induced surface soil cracking mechanism and development depth of downward fracture

In order to reveal the cracking mechanism of surface soil layer caused by coal seam mining, and explore theoretical methods for predicting the development depth of downward fractures during mining. Based on the background of the No. 1–2 upper coal seam mining in Daliuta Coal Mine, combining with fracture mechanics, soil mechanics, physical similarity simulation and numerical calculation methods. The mining-induced cracking mechanism and criterion of surface soil layer were analyzed, the crack development pattern and expansion mechanism were revealed, and the prediction formula of downward crack development depth of surface soil layer was put forward. The research results show that surface cracks mainly occur in the tensile zone, the concentrated tensile stress produced by the subsidence of overburden in the tensile zone can lead to soil cracking. When the surface maximum horizontal tensile deformation exceeds the limit horizontal deformation of soil, the soil layer cracks, and the cracking criterion of the surface soil layer was given accordingly. The soil crack of coal seam mining belongs to the mixed mode crack, and the soil cracks tip starts cracking and expanding along the direction of the maximum principal stress, therefore, the initiation crack angle of soil crack tip was obtained, and the fracture criterion of soil crack was proposed. With the crack propagation and development, the microcosmic crack becomes the macroscopic downward fracture. When the horizontal stress of the soil decreases to the cohesive force of the soil, the downward fracture stops develop, and the calculation formula for the development depth of mining-induced downward fracture was proposed. The development and evolution law of downward fracture was revealed, after the surface cracks, with the advance of the longwall face, the downward crack continues to extend and develop to the deep. Downward fracture develops on the ground surface at the open cut side, the mined-out area and in front of the longwall face, the maximum development depth of downward fracture tends to be stable when the longwall face advances to a certain distance. According to the physical simulation, numerical calculation and theoretical calculation, the development depth of downward fracture in No 1–2 upper coal seam mining is 8.11 m, 8.21 m and 8.14 m respectively. The theoretical prediction formula is reliable, and the results can provide a new method for the research of the development depth of mining-induced surface downward fracture.

Conversion of Marginalized Tea Lands into Timber Plantations and its Impact on Soil Organic Carbon Content: A Case Study in Central Highlands of Sri Lanka

Tea (Camellia sinensis) plantations can be in production for about 100 years under well-managed conditions. However, soil degradation makes the tea lands marginalized and uneconomical. Land use conversion is an option for marginalized tea lands that could gain numerous environmental and economic benefits. This study estimated and compared the soil organic carbon stocks (SOC) in the surface soil layer (0–30 cm) of marginalized tea lands against those converted to timber plantations in the Badulla and Nuwaraeliya districts. Disturbed and undisturbed soil samples were collected from the top layer (0-30 cm) of the selected sites of marginalized tea lands and those converted to timber plantations for analysis. Organic matter percentage in the site-level dry soil samples was analysed using the loss on ignition method. The final carbon stocks (t C ha-1) for samples from both land use types were then estimated using the SOC percentages and bulk density estimates. The carbon stocks for the soil samples collected at marginalized tea lands and the marginalized tea lands converted to timber plantations were then statistically analysed (descriptive statistics, normality tests and two-sample t-tests) using Minitab 21.2 software. The pH of marginal tea lands (5.34±0.14) and the marginal tea lands converted to timber plantations (5.20±0.13) was slightly acidic in nature. The bulk density estimates of marginalized tea lands and marginalized tea lands converted to timber plantations were very close and estimated as 1.15±0.02. The statistical analysis showed that overall mean SOC was significantly higher under the marginalized tea lands converted to timber plantations (155.3±10.0 t C ha-1) compared to the marginalized tea lands (126.7±5.8 t C ha-1). Land use conversion has increased the SOC stocks gradually after forest establishment. The increased carbon stocks could be attributed to consistent addition of litter layer on the soil, less soil disturbance, and retarded soil erosion contributing to the buildup of soil organic matter and SOC. On the other hand, low carbon stocks in the marginalized tea land could be attributed to unsustainable agronomical practices. Our findings suggest that converting marginalized tea lands in central highlands into timber plantations could enhance the sequestration of atmospheric CO2, significantly contributing to climate change mitigation.&#x0D; Keywords: Soil organic carbon, Land use change, Climate change, Tea plantations

GIS Interpolation and Mapping of Soil Physicochemical Properties in Deep Medium Black Soils of Established Citrus Orchards

Soil properties are an important factor for orchard establishment, precise nutrient management and sustainable production of fruit crops. Therefore, it is important to assess the spatial distribution of fundamental soil properties in well-established orchards. Hence an attempt has been made to assess the extent of soil properties and its spatial distribution in citrus orchards in medium black soils of Madhya Pradesh. The present study was conducted for the assessment of the spatial distribution of physicochemical properties viz. pH, electrical conductivity (EC) and soil organic carbon (SOC) of citrus orchards in medium-deep black soils of India. Results revealed that soil pH ranged from 6.83-8.84 (mean 7.80), soil EC varied from 0.07-0.34dS m-1 (mean 0.18 dS m-1) and soil organic carbon ranged from 0.13-0.89% (mean 0.47%) in 0-20 cm of surface soil layer. Geostatistical analysis showed that the slope of the prediction function of best-fit model (exponential) for soil pH, EC and SOC was 0.31, 0.22 and 0.77, respectively. The corresponding values of root mean square error (RMSE) were 0.35, 0.03, and 0.14. Interpolation of soil properties indicated that 89.2 % area had soil pH between 7.20 to 8.00, 83.4 % area had soil EC between 0.10 to 0.20 dS m-1, while&gt;90 % area had SOC content ranged from 0.25 to 0.75%. Geo-statistical analysis revealed that spatial dependency was moderate for pH and strong spatial dependency was estimated for EC and SOC content. Based on RMSE and slope of prediction function, an exponential model was best-fit model in ordinary kriging for interpolation of measured soil properties.

MINERAL-ORGANIC COMPOSITE FOR IMMOBILIZING PBIN SOIL SUBJECTED TO AIDED PHYTOSTABILIZATION

The content of Pb in the surface layer of soil is largely connected with the influence of anthropogenicfactors. The degradation of soil caused by the presence of increased heavy metal contents has ledto the search for or improvement of effective remediation methods. The study made use of thetechnique of aided phytostabilisation for immobilizing Pb in the soil using a composite based ondolomite and compost (CDC) as a soil amendment, as well as Lolium perenne L. The efficiency wasassessed in terms of determining the Pb content in the soil, roots and above-ground parts of thetest plant with the use of the atomic absorption spectrometry method. The application of CDC tosoil had a positive influence on increasing the production of plant biomass and the pH of the soil,with the Pb being higher in the roots than in the above-ground parts of Lolium perenne L. Uponcompleting the experiment, the soil amendment was found to have had a positive influence ondecreasing the average Pb content in the soil (by 18%) as well as the CaCl2-extractable Pb forms(23%). In the case of the contents of this element in the roots and above-ground parts, on the otherhand, the influence was +53% and –36% respectively.

A study on the soil seed bank of Nyala area, south Darfur, Sudan

This research is an ecological study on the vegetation of Nyala area, South Darfur State, Sudan. The main objectives of this research is determination of soil seed bank of species in the study area. The collected plant species were identified checked via the aid of the herbarium of the Department of Botany, Faculty of Science, University of Khartoum. Twenty-seven plant species have been identified from the study of soil seed bank. The most dominant of these species were Euphorbia aegyptiaca, Dactyloctenium eagypticum, Eragrostis tenella, Corchorus trilocularis and Amaranthus graecizans. The number of dead seeds/m2 on the upper soil surface layer (0-5 cm) was 12150, while that of live seeds was 5560. The number of dead seeds/m2 for the lower soil depth (5-10 cm) was 9707 and that of live seeds was 3254 seeds/m2. Statistical analysis of the data of the soil seed bank showed that there were statistically significant differences between the number of dead and live seeds/m2 at the same soil depth and among different soil depths.

Оценка состояния урбаноземов по содержанию поллютантов

Abstract. The purpose of the study is to assess the ecological state of soils within urbanozems in relation to the degree of contamination with heavy metals using the example of the urban aggromeration of Orenburg. Methods. Sampling was carried out at 4 sites in the sanitary protection zone of industrial enterprises in Orenburg. Determination of mobile forms of heavy metals Cd, Co, Cr, Cu, Mn, Ni, Pb, Zn in the samples was carried out by atomic absorption spectrophotometry. In the studied areas, the pollution index or concentration coefficient was taken into account, while taking into account the reference values of heavy metals. Contamination with toxic elements of soils in the reference areas was determined using the PINemerow coefficient. The pollution index of urban areas was calculated as the arithmetic or geometric mean of PINemerow for all reference areas in the city. Statistical processing of the material was carried out using the universal program Statistica 10. The scientific novelty of the work lies in the fact that for the first time data were obtained characterizing the accumulation of heavy metals in the sanitary protection zones of industrial enterprises in the city of Orenburg, and they were ranked according to the pollution index. Results. The analysis of the data obtained made it possible to reveal an increased content of Pb, Zn in all soil layers in the reference plot No. 1. The soils of site No. 2 had an increased content of Cu, Pb, Zn in the soil horizon of 20-30 cm, Pb was also found at a depth of 0-10 cm, which is explained by the passage of a major highway near the enterprise. Soil samples at a depth of 0-10 cm of site No. 3 were contaminated by 4 parameters (Cd, Mn, Pb, Zn) and had an average degree of anthropogenic pollution, which is due to the fact that the surface soils of the sanitary protection zone of the site are located near the enterprise associated with the processing of petroleum products. On the contrary, the studied areas No. 1; 2 and 4 sanitary protection zones of enterprises can be classified as low pollution. On the territory of the sanitary protection zone of site No. 4, an increased accumulation of Mn was found in the surface layers of soils.

Vegetation restoration improved aggregation stability and aggregated-associated carbon preservation in the karst areas of Guizhou Province, southwest China.

The change in the soil carbon bank is closely related to the carbon dioxide in the atmosphere, and the vegetation litter input can change the soil organic carbon content. However, due to various factors, such as soil type, climate, and plant species, the effects of vegetation restoration on the soil vary. Currently, research on aggregate-associated carbon has focused on single vegetation and soil surface layers, and the changes in soil aggregate stability and carbon sequestration under different vegetation restoration modes and in deeper soil layers remain unclear. Therefore, this study aimed to explore the differences and relationships between stability and the carbon preservation capacity (CPC) under different vegetation restoration modes and to clarify the main influencing factors of aggregate carbon preservation. Grassland (GL), shrubland (SL), woodland (WL), and garden plots (GP) were sampled, and they were compared with farmland (FL) as the control. Soil samples of 0-40 cm were collected. The soil aggregate distribution, aggregate-associated organic carbon concentration, CPC, and stability indicators, including the mean weight diameter (MWD), fractal dimension (D), soil erodibility (K), and geometric mean diameter (GMD), were measured. The results showed that at 0-40 cm, vegetation restoration significantly increased the >2 mm aggregate proportions, aggregate stability, soil organic carbon (SOC) content, CPC, and soil erosion resistance. The >2 mm fractions of the GL and SL were at a significantly greater proportion at 0-40 cm than that of the other vegetation types but the CPC was only significantly different between 0 and 10 cm when compared with the other vegetation types (P<0.05). The >2 mm aggregates showed a significant positive correlation with the CPC, MWD, and GMD (P<0.01), and there was a significant negative correlation with the D and K (P<0.05). The SOC and CPC of all the vegetation types were mainly distributed in the 0.25-2 mm and <0.25 mm aggregate fractions. The MWD, GMD, SOC, and CPC all gradually decreased with increasing soil depth. Overall, the effects of vegetation recovery on soil carbon sequestration and soil stability were related to vegetation type, aggregate particle size, and soil depth, and the GL and SL restoration patterns may be more suitable in this study area. Therefore, to improve the soil quality and the sequestration of organic carbon and reduce soil erosion, the protection of vegetation should be strengthened and the policy of returning farmland to forest should be prioritized.

Peculiarities of legal relations in the field of restoration of lands and soils of Ukraine damaged by the armed aggression of the Russian Federation

The article examines the peculiarities of legal relations in the field of restoration of lands and soils of Ukraine, which suffered as a result of the armed aggression of the Russian Federation. As a result of the full-scale invasion of Russia on more than a third of the territory of Ukraine, there is already or there is a risk of systemic disturbance of the surface layer of soils or their contamination (mines, oil products, unexploded ordnance, etc.). So, with the beginning of a full-scale invasion, the state of Ukraine received a new challenge - the degradation of land and soil as a result of military operations. Therefore, the problem of restoration of these natural objects has become extremely Legal relations in the field of land and soil restoration are an integral part of land legal relations and have essential features (public nature, volitional nature, dominance of the imperative method of legal regulation, specific subject composition, inequality of the parties to these legal relations, etc.). The article examines lands and soils as objects of restoration, since it is the specificity of objects that largely determines the peculiarities of legal relations in this area.&#x0D; Restoration of lands and soils is: a legally secured system of measures; aimed at returning their original qualitative state; is carried out through their reclamation, conservation, melioration and other measures provided for by law.&#x0D; Legal relations in the field of restoration of the lands and soils of Ukraine, which suffered as a result of the armed aggression of the Russian Federation, are social relations that are formed in the field of returning these natural objects to their original qualitative state, deteriorated due to the action of factors caused by military actions. Legal relations in this area have significant features, since lands and soils are non-reproducible, but renewable natural objects. The specificity of land and soil restoration is that this process is subject to their qualitative condition. Since such significant damage is caused to the lands and soils of Ukraine for the first time since the Second World War, the system of national land protection legislation needs to be reformed. The Law of Ukraine “On Land Protection” does not meet today’s needs. An urgent need today is the development and adoption of the Law of Ukraine “On Protection and Restoration of Lands and Soils”.

Study on Modeling and Evaluating Alfalfa Yield and Optimal Water Use Efficiency in the Agro-Pastoral Ecotone of Northern China.

The agro-pastoral ecotone in northern China is the main production area of agriculture and animal husbandry, in which agricultural development relies entirely on groundwater. Due to the increasing water consumption of groundwater year by year, groundwater resources are becoming increasingly scarce. The substantial water demand and low germination rate in the first year are the main characteristics of alfalfa (Medicago sativa L.) yield in the agro-pastoral ecotone in northern China. Due to unscientific irrigation, water resources are seriously wasted, which restricts the development of local agriculture and animal husbandry. The study constructed the Dssat-Forages-Alfalfa model and used soil water content, leaf area index, and yield data collected with in situ observation experiments in 2022 and 2023 to calibrate and validate the parameters. The study found ARE < 10%, ENRMS < 15%, and R2 ≥ 0.85. The model simulation accuracy was acceptable. The study revealed that the water consumption at the surface soil layer (0-20 cm) was more than 6~12% and 13~31% than that at the 20-40 cm and 40-60 cm soil layers, respectively. The study showed when the irrigation quota was 30 mm, the annual yield of alfalfa (Medicago sativa L.) (7435 kg/ha) was consistent with that of the irrigation quota of 33 mm, and increased by 3.99% to 5.34% and 6.86% to 10.67% compared with that of irrigation quotas of 27 mm and 24 mm, respectively. To ensure the germination rate of alfalfa (Medicago sativa L.), it is recommended to control the initial soil water content at 0.8 θfc~1.0 θfc, with an irrigation quota of 30 mm, which was the best scheme for water-use efficiency and economic yield. The study aimed to provide technological support for the rational utilization of groundwater and the scientific improvement of alfalfa yield in the agro-pastoral ecotone in northern China.

Factors controlling the spatial heterogeneity of soil organic carbon concentrations and stocks in a boreal forest

Boreal soils play a crucial role in the global terrestrial carbon cycle, serving as significant carbon reservoirs. However, this region is experiencing rapid climate change which poses a threat to the stability of the soil carbon pool. To understand the carbon balance in the boreal region, it is essential to obtain accurate estimates of soil organic carbon (SOC) stocks. The objective of this study was to investigate factors controlling the spatial heterogeneity of SOC concentrations and stocks in a boreal forested catchment and to quantify spatial variability of SOC concentrations and stocks using a random forest-based regression kriging approach. Soil carbon content, gravel content and bulk density were obtained from the surface soil layer (0–30 cm) of 106 samples across a 390 ha catchment in northwestern Ontario, Canada. Spatial attributes including elevation, wetness index, distance to nearest ridge, relative position index, plan curvature, profile curvature and normalized difference vegetation index were used in the random forest-based regression kriging to estimate spatial heterogeneity of SOC stocks and concentrations across the catchment. Our results showed that shallow soils in well-drained upland areas contained low to moderate SOC concentrations (1.2–16.2%) while depressional wetlands had high concentrations (19.2–54.0%). Topographic variables, including wetness index were the strongest predictors of SOC concentrations, but SOC stocks were very heterogeneous across the study site (12.9–139.0 Mg ha−1) and were not well explained by topographic or vegetation variables. The gravel content was highly variable (0–29.0%), and without accounting for this fraction, SOC stocks were overestimated by 52.5% in this landscape. These results emphasize the substantial catchment scale variability in SOC stocks in boreal landscapes and underscore the significance of considering both landscape-scale drivers and intrinsic soil properties when estimating soil carbon in this region. By understanding these factors, we can better manage and protect the important carbon stores in boreal soils.

Responses of soil micro-eukaryotic communities to decadal drainage in a Siberian wet tussock tundra.

Climate warming holds the potential to cause extensive drying of wetlands in the Arctic, but the warming-drying effects on belowground ecosystems, particularly micro-eukaryotes, remain poorly understood. We investigated the responses of soil micro-eukaryotic communities, including fungi, protists, and microbial metazoa, to decadal drainage manipulation in a Siberian wet tundra using both amplicon and shotgun metagenomic sequencing. Our results indicate that drainage treatment increased the abundance of both fungal and non-fungal micro-eukaryotic communities, with key groups such as Ascomycota (mostly order Helotiales), Nematoda, and Tardigrada being notably abundant in drained sites. Functional traits analysis showed an increase in litter saprotrophic fungi and protistan consumers, indicating their increased activities in drained sites. The effects of drainage were more pronounced in the surface soil layer than the deeper layer, as soils dry and warm from the surface. Marked compositional shifts were observed for both communities, with fungal communities being more strongly influenced by drainage-induced vegetation change than the lowered water table itself, while the vegetation effect on non-fungal micro-eukaryotes was moderate. These findings provide insights into how belowground micro-eukaryotic communities respond to the widespread drying of wetlands in the Arctic and improve our predictive understanding of future ecosystem changes.

Variations in soil physico-chemical properties, soil stocks, and soil stoichiometry under different soil layers, the major forest region Liupan Mountains of Northwest China.

Liupan Mountains are an important region in China in the context of forest cover and vegetation due to huge afforestation and plantation practices, which brought changes in soil physio-chemical properties, soil stocks, and soil stoichiometries are rarely been understood. The study aims to explore the distribution of soil nutrients at 1-m soil depth in the plantation forest region. The soil samples at five depth increments (0-20, 20-40, 40-60, 60-80, and 80-100 cm) were collected and analyzed for different soil physio-chemical characteristics. The results showed a significant variation in soil bulk density (BD), soil porosity, pH, cation exchange capacity (CEC), and electric conductivity (EC) values. More soil BD (1.41 g cm-3) and pH (6.97) were noticed in the deep soil layer (80-100 cm), while the highest values of porosity (60.6%), EC (0.09 mS cm-1), and CEC (32.9 c mol kg-1) were reflected in the uppermost soil layer (0-20 cm). Similarly, the highest contents of soil organic carbon (SOC), total phosphorus (TP), available phosphorus (AP), total nitrogen (TN), and available potassium (AK) were calculated in the surface soil layer (0-20 cm). With increasing soil depth increment a decreasing trend in the SOC and other nutrient concentration were found, whereas the soil total potassium (TK) produced a negative correlation with soil layer depth. The entire results produced the distribution of SOCs and TNs (stocks) at various soil depths in forestland patterns were 0→20cm > 20→40cm > 40→60cm ≥ 60→80cm ≥ 80→100 cm. Furthermore, the stoichiometric ratios of C, N, and P, the C/P, and N/P ratios showed maximum values (66.49 and 5.46) in 0-20 cm and lowest values (23.78 and 1.91) in 80-100 cm soil layer depth. Though the C/N ratio was statistically similar across the whole soil profile (0-100 cm). These results highlighted that the soil depth increments might largely be attributed to fluctuations in soil physio-chemical properties, soil stocks, and soil stoichiometries. Further study is needed to draw more conclusions on nutrient dynamics, soil stocks, and soil stoichiometry in these forests.

NUMERICAL ANALYSES TO OBSERVE THE PERFORMANCE OF A MONUMENTAL BUILDING AT THE UNIVERSITY OF BENGKULU, INDONESIA

The Integrated Laboratory Building of Political and Social Science Faculty, located in a seismic-prone area, has been the subject of a comprehensive study of its performance using seismic response analysis. This research has yielded significant findings, gathering crucial secondary data, such as soil layers, bedrock depth, building structure, and earthquake wave information. The seismic response analysis, conducted by referencing the synthetic earthquake wave from the Bengkulu–Mentawai earthquake in 2007, with a magnitude of Mw 8.6, has provided a comprehensive overview of the earthquake waves at the foundation soil layers. The data, analysed using the finite element method to understand the structural response, revealed that the Peak Ground Acceleration (PGA) and amplification factor at the surface soil layer are 0.220g and 1.429, respectively. The most critical PGA and amplification factors at the foundation soil layer are 0.147g and 0.955. Structural analysis has revealed internal forces and beam elements experiencing over-strength, necessitating retrofitting the affected structural elements to reduce the impact. One practical and highly effective method of retrofitting involves increasing the beam dimensions by 53.12%. With retrofitting, the impact of structural deformation can be minimised, enhancing the building’s resilience in case of an earthquake of equal or greater magnitude. These findings underscore the importance of our research and highlight the significant role of engineers, architects, and researchers in ensuring the safety and longevity of structures in seismic-prone areas.

Determination of 2,4-dichlorophenoxyacetic acid and its metabolite in soils by gas chromatography-mass spectrometry after pre-concentration using magnetic charcoal based on rice husk

A method for determining 2,4-dichlorophenoxyacetic acid (2,4-D) and its metabolite 2,4-dichlorophenol (2,4-DСР) in soils is proposed. 2,4-D and 2,4-DСР were extracted from the soil by an alkali solution. The analytes were recovered from the extract using a sorbent based on magnetite nanoparticles and coal obtained by burning rice husk, and desorbed by methanol. 2,4-D and 2,4-DСР in the concentrate thus obtained were converted to methyl esters and determined using the GC-MS method. The quantification limit (LOQ) of 2,4-D and 2,4-DCP were 3.0 μg/kg and 0.08 μg/kg, respectively. Leached black soil (from the border of Stavropol and Krasnodar Territories) was selected as a real object for analyzing the distribution of the herbicide "Ballerina" (ethylhexyl ester of 2,4-D) and its degradation product. A day after applying the herbicide, the concentration of 2,4-D in the surface layer of the soil was 119 μg/kg. Atmospheric precipitation has a significant effect on motion of 2,4-D along the soil profile. The most significant decrease in the concentration of 2,4-D was observed between 3 and 10 days after application of the herbicide. A month after application of the herbicide, the concentration of 2,4-D was 31, 18 and 11 μg/kg at the depths of 10, 30 and 50 cm, respectively; no 2,4-D was detected in the surface soil layer. Detectable amounts of 2,4-DСР appeared on 16-th day after application of the herbicide; 2,4-DСР degrades much slower than 2,4-D. After 1.5 months, the concentration of 2,4-DСР was 0.53, 0.45 and 0.22 μg/kg at the depths of 10, 30 and 50 cm, respectively. At the same time, 2,4-D was not detected throughout the soil profile.

POST-FIRE CONDITION AND RESTORATION OF FORESTS ON THE TERRITORY OF KOSTANAY REGION

The results of field studies of post-fire condition and reforestation of Kostanay region are presented. The purpose of the research is to study and analyze the post-fire condition and forest regeneration in the territory of Kostanay region. It was established that the magnitude of post-fire tree declines and their radial growth in stands of the main forest-forming species are determined by the type and intensity of fire. Taking into account the types of forest landscapes using space images, we have identified 7 key and control (background) sites that characterize the disturbed and background undisturbed forest cover. Among them, the most affected by the forest fire are key areas No5 and No7, where a top fire of medium intensity occurred. The forest litter of these key areas was completely burned in a severe fire, the soil seed stock was destroyed, and low intensity of natural regeneration is expected. The average grade of all studied key sites is estimated by us as III and it is connected with untimely harvesting, which resulted in the reduction of annual growth of the plantation. Sanitary condition of plantations in key sites No1, No5, No7 is unsatisfactory in comparison with other sites. Soils of the investigated key sites are not compacted and favorable for growth. In key plot No.1 there was a compacted crust in the surface soil layer. Uneven natural regeneration of common pine after the fire is observed. Predominantly friendly seed sprouting is associated with more moistened lowlands and loosened soil areas. Factors impeding the natural renewal of pine forests include deep burning of the forest floor and soil cover, mechanical effects on the soil and seedlings of the equipment used to develop harems, the mushroom wavy rhizina (Rhizina undulata) which affects the roots of coniferous trees.

Intensity of the impact made by a gas-jet emitter on the surface layer of the loamy soil: research results

Intensity of the impact made by a gas-jet emitter on the surface layer of the loamy soil: research results