Percentage Of Clay Research Articles

2-YEAR GRAIN SIZE MONITORING OF THE RIVERBED SEDIMENTS FROM DANUBE DELTA

The Danube Delta was studied following the Geo-Eco-Mar expeditions in the summer and autumn of 2019 and 2020, respectively, from a sedimentological, faunal and environmental quality point of view. The grain size analyses of the sediments from the bed of the Chilia, Tulcea, Sulina, St. George Branches, as well as the meanders of the Dunărea Veche and Tătaru identified two types of sediments: sediments in which the sand fraction predominates, consisting, in general, of fine sand, and the fractions silt and clay have, in most cases, very low cumulative percentages, often below 1%; clay-silty sediments (muds), consisting predominantly of silt and clay, present in areas where the water velocity has low values. The presence of gravel is also noted, but subordinate to the sandy fractions. Gravel elements are an indicator of human impact in the area. In general, sediments also contain organogenic material, consisting of shells, fragments and plant remains. The interpretation of the data resulting from the granulometric analyzes (the percentages of clay, silt, sand, gravel and textural parameters) highlighted the dynamic conditions in which these sediments specific to the deltaic environment were deposited. In general, the amount of sand varies from one season to another and from one year to another, especially near the banks, with an increase in the sand content in the autumn season. Sandy sediments illustrate a faster flow regime, are well sorted, and are generally present in the central part of the Danube Branches bed.

Integrated modification of silicon carbide ceramic armor via kaolin and Soda-lime glass for enhanced ballistic protection: Fabrication, characterization, and performance analysis

This work proposed the introduction of a new approach to modify plate ceramics for armor. Two additives were used, kaolin and soda-lime glass, which were added to silicon carbide in variable weight ratios: 5, 10, and 15 wt.% for the kaolin, while the glass was added at 5, 15, and 30 wt.%. The samples were formed using axial pressing and then sintered at 1100 °C. It was found that increasing the percentage of clay and glass leads to a decrease in porosity, an increase in density, and a decrease in the water absorption of samples. The mechanical properties (hardness and diametrical compression) increased with the increase in the proportion of kaolin, and the thermal conductivity also increased. Also, a scanning electron microscope was used. Finally, the specimen was examined by a ballistic test, and it successfully provided safety for people against bullets who were shot by rifle AK-47. This article contributed to the provision of high-efficiency and low-cost bulletproof shields from available cheap materials (kaolin, glass, and silicon carbide).

The Impact of Group- and Single-Tree-Selection Cuttings on Runoff and Sediment Yield in Mixed Broadleaved Forests, Northern Iran

Silvicultural treatment and the forest harvesting operations using different methods can lead to an increase in the production of runoff and sediment by changing the canopy and soil surface where they are conducted. In order to investigate this issue, sampling plots were established in the Namkhaneh district of the Kheyrud forest with three replications for every treatment: control stand and tree harvesting systems using single-selection cuttings and group-selection cuttings. The amount of runoff and sediment was collected and estimated from precipitation over a period of one year. Also, some soil physical properties such as bulk density, penetration resistance, sand, silt, and clay content, soil moisture, and soil organic matter were measured. The results showed that tree harvesting systems has a significant effect on runoff, the runoff coefficient, and sediment but the season (growing season and fall) and the combined effect of tree harvesting systems and the season have no significant effect on the runoff coefficient and sediment. The mean runoffs of each rainfall event for the control, single-tree, and group-selection treatments were 5.67, 8.42, and 10.28 mm, respectively, and the sediment amounts were 3.42, 6.70, and 11.82 gr/m2, respectively. Furthermore, the total annual erosion amounts of the control, selection, and grouping treatments were 0.427, 0.838, and 2.178 t/ha, respectively. The bulk density, penetration resistance, and percentage of sand and silt were positively related and the percentages of clay and organic matter were negatively related with the amount of runoff and sediment. In the method of individual selection cuttings, the damage to the forest in terms of the amount of runoff and soil erosion was less than for the group-selection cuttings. Forest harvesting by the selection method (single-selection and group-selection) has caused different changes in the vegetation canopy. The final summary of our results could be the advice to predominantly use the single-selection method in high-slope stands.

Heavy Metal Pollution in Soils near Ilesha Gold Mining Area, Nigeria

Background The discovery of extensive gold deposits has raised concerns about potential heavy metal contamination in waterways and adjacent soils, particularly in developing nations like Nigeria where environmental regulations may not be stringent enough. Objective A research study was conducted to assess the levels of heavy metals in surface soils (0 to 25 cm deep) across 30 sites within three selected areas (Epe, Igun, and Ijana) located in the gold mining region of Ilesha, Osun State Nigeria. Methods The study employed an atomic absorption spectrophotometer to measure the total concentrations of heavy metals, specifically arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn). Furthermore, the research encompassed an examination of various physicochemical properties of the soil samples, including organic matter content, pH levels, organic carbon content, calcium content, phosphorus levels, cation exchange capacity, and particle size distribution. Results Results showed a range mean concentration with standard deviation of As, Cd, Co, Cr, Cu, Ni, Pb and Zn of 1.0 – 7.1 ± 1.77 mg kg-1, 0.9 – 4.2 ± 0.84 mg kg-1, 1.0 – 6.0 ± 1.29 mg kg-1, 1.1 – 6.4 ± 1.57 mg kg-1, 2.90 – 20.9± 4.00 mg kg-1, 1.1 – 6.4 ±1.56 mg kg-1, 0.7 – 6.7 ±1.26 mg kg-1 and 11.7 – 70.7± 17.75 mg kg-1, respectively. The investigation of soils in three specific locations revealed significant contamination by heavy metals. However, it is worth noting that the concentrations of these metals fell below the established intervention levels outlined by environmental protection agencies such as the World Health Organization and the Food and Agriculture Organization. The distribution of heavy metals and their availability exhibited a direct correlation with the distance from the mining sites, spanning from 0 to 900 meters. Two critical factors influencing the concentration of heavy metals in these areas were identified as soil particle size, specifically the clay percentage, and pH levels. Conclusion Despite the presence of heavy metal pollution in the soils of Epe, Igun, and Ijana, they managed to maintain metal levels below the intervention thresholds set by environmental protection agencies, with the exception of cadmium (Cd).

Impacts of Organic and Non-Organic Cultivation Practices on Soil Fertility Parameters of Selected Paddy Lands Based on the Duration of Cultivation in Wet and Intermediate Climate Zones of Sri Lanka

Sri Lanka has been practicing the cultivation of rice as its main staple food in two major agricultural techniques; organic and non-organic. The major aim of the present study was to analyze and compare the time duration-based impacts of the above two agricultural practices on paddy soil fertility indicators as the preliminary step of a long-term research project. Organic and non-organic paddy fields that have been cultivated for 2 seasons in Thorapitiya in the Matale district were selected as short-term cultivated lands. Land cultivated for 10 years organically in Homagama and land with a non-organic cultivation history of 20 years in Kottawa was selected as long-term cultivated lands. A total number of 35 samples were collected including the control samples from adjacent uncultivated land during the first phase of the Maha season 2021/2022. The samples were dried, sieved and then analyzed in their physical and chemical properties; color, texture, particle size distribution, pH, electrical conductivity (EC), organic carbon content (OCC), total nitrogen content (TNC), available phosphorus content (APC), exchangeable potassium content (EPC), and exchangeable magnesium content (EMC). The soil samples from Thorapitiya had a reddish-brown nature while most of the samples from Kottawa and Homagama had a grayish-brown color. Higher clay percentages were found in the soil samples from long-term organically cultivated lands in Homagama. The uniformity coefficient (Cu) values for soils from study areas except Homagama lie in the range for well-graded soil while the coefficient of gradation (Cc) values of all three areas were not in the above range. Short-term cultivation using organic and non-organic fertilizers did not show a significant difference in soil texture, pH, EC, APC, EPC, and EMC values. Most of their cultivated lands had a lower pH (~5.5–6.0) than the corresponding control plots (~5.8–6.4). The TNC levels in non-organically cultivated lands were significantly higher than in organic lands. Practicing agricultural activities for a prolonged period has resulted in significant differences in soil texture, pH, EC, OCC, TNC and APC between organic and non-organic lands. Higher OCC and lower pH, EC and APC values have been obtained for long-term organically cultivated lands than their non-organic counterparts. The TNC, APC and EPC levels were higher in most of the long- term organic and non-organic lands than in their control samples. Several amendments have to be made to bring the fertility parameters to an optimum level in long-term cultivated lands. 
 Keywords: Soil fertility, Paddy soil, Cultivation history, Organic cultivation, Non-organic cultivation

The ratio of denitrification end-products were influenced by soil pH and clay content across different texture classes in Oklahoma soils

Nitrous oxide (N2O) is a potent greenhouse gas that contributes to stratospheric ozone depletion and global climate change. Soil denitrification has two potential end-products, N2O and dinitrogen (N2), and the ratio of these end-products (N2O:(N2O+N2) or the N2O ratio) is controlled by various factors. This study aims to quantify the influence of soil pH on the ratio of denitrification end-products in Oklahoma soils with different soil textures. Six natural grassland soils encompassing three distinct soil textures were incubated in the laboratory under natural and modified pH with an overall tested pH ranging from 2 to 10. Denitrification end-products were measured in the laboratory using the acetylene inhibition technique and further estimated using a process-based biogeochemical model. Both the laboratory and model results showed that soil pH and texture influenced the ratio of the denitrification end-products. Generally, as soil pH increased the N2O ratio decreased, although both lab and model results indicated that this relationship was not linear. Soil texture may have an indirect effect on the N2O ratio, as two soils of the same texture could have different N2O ratios. However, clay percentage of the soil did show a linear positive correlation with the N2O ratio, suggesting components of soil texture may be more influential than others. Overall, soil pH was a controlling factor in the ratio of denitrification end-products and the newly observed nonlinear relationship warrants further study, particularly when considering its effects in different soil textures.

Fertigation frequency is a useful tool for nitrate management in intensive open-field agriculture

The main source of nitrogen for most cultivated plants is nitrate. Agriculture has overused this nutrient, resulting in serious environmental problems in various parts of the world. The common practice in open intensive horticultural fields with clay-loam soils with a high water retention capacity (e.g., high percentage of clay) is to irrigate two to four times per week. Technically and logistically, this is much easier than one or more irrigation events per day. However, the loss of nutrients and water below the root zone may occur, with the consequent loss of efficiency. In this work, two cultivation cycles in an open-field endive crop were carried out under plastic soil mulching. We compared three fertigation strategies based on different frequencies of fertigation events; low fertigation frequency (LF, two to three fertigation events per week that simulates common farmer practice), medium fertigation frequency (MF, one fertigation event per day), and high fertigation frequency (HF, three fertigation events per day). The three fertigation strategies applied equal water and fertilizers doses per week. The high fertigation frequency increased volumetric water content in the upper soil profile, while the low fertigation frequency in the lower soil profile. The results demonstrated that HF fertigation increases shoot fresh weight (harvest yield) by increasing shoot water content, but did not improve shoot nutrient uptake or nitrogen nutritional status. The important finding, from the environment point of view, is that high and medium fertigation frequencies decreased nitrate concentration in the root influence zone, where it may be prone to leaching due to heavy rain events.

Characterization of controlling factors for soil organic carbon stocks in one Karst region of Southwest China.

Soil organic carbon (SOC) contributes the most significant portion of carbon storage in the terrestrial ecosystem. The potential for variability in carbon losses from soil can lead to severe consequences such as climate change. While extensive studies have been conducted to characterize how land cover type, soil texture, and topography impact the distribution of SOC stocks across different ecosystems, little is known about in Karst Region. Here, we characterized SOC stocks with intensive sampling at the local scale (495 representative samples) via Random Forest Regression (RF) and Principal Component Analysis (PCA). Our findings revealed significant differences in SOC stock among land cover types, with croplands exhibiting the lowest SOC stocks, indicating that management practices could play a crucial role in SOC stocks. Conversely, there was little correlation between SOC stock and clay percentage, suggesting that soil texture was not a primary factor influencing SOC at a local scale. Further, Annual Precipitation was identified as the key driving factor for the dynamics of SOC stocks with the help of RF and PCA. A substantial SOC deficit was observed in most soils in this study, as evaluated by a SOC/clay ratio, indicating a significant potential in SOC sequestration with practical measures in the karst region. As such, future research focused on simulating SOC dynamics in the context of climate change should consider the controlling factors at a local scale and summarize them carefully during the up-scaling process.

Physicochemical Soil Analysis of Rejuvenated Cocoa Plantation Farms in Obaagun Area of Osun State

Theobroma cacao, which is also known as cacao tree is an important commercial plantation crop of the world used in the production of a variety of products such as cocoa powder, chocolate products, beverages, butter, biscuits, wine, soap, cream, cocoa bread, livestock feeds among others. This study evaluated the soil quality of rejuvenated cocoa plantation farms in Obagun area of Osun state, it compares the soil qualities and properties of these cocoa plantations and determine if the soils in the area are well suitable for cocoa cultivation. Twenty-four (24) soil samples each were collected from 2 cocoa plantations (A and B) of similar ages and agricultural practices. The samples were collected from the depths of 0-15cm and 15-30cm from the two sites respectively. The physical properties were analyzed to know the percentage of sand, clay and silt. The chemical properties were analyzed for particle sizes, pH, hydrogen, organic carbon, organic matter, total nitrogen, available phosphorus, cation exchange capacity, base saturation, sodium, potassium, calcium, magnesium, and the heavy metals were also analyzed for zinc, iron, manganese, copper, lead, cadmium, chromium, and cobalt. When analyzing the physical properties of the two sites, it was observed that silt as the highest percentage of soil particles with 79.72% on site B at a depth of 0-15cm and clay as the lowest percentage of soil particles of 6.58% at a depth of 0-15cm on site B. Analyzing the chemical properties on both sites, it was observed that base saturation as the highest percentage with a value of 96.94% on site B at a depth 0-15cm and Hydrogen as the lowest percentage of 0.10 on site B at a depth of 15-30cm. The presence of heavy metal was also evaluated, it was observed that zinc as the highest value of 0.93mgkg-1 on site A at a depth of 0-15cm and both copper and chromium are absent on site A at a depth of 15-30 cm. The long-term residence of the cocoa plantation on the soil resulted in the decline of micronutrients in the soil. There is need for the soil nutrients to be replenished to ensure continued good production of the cocoa plantation.

Correlations between soil properties and spectral index (healthy vegetation) in soybean crops

Precision agricultural technologies, such as the use of spatial variability of soil properties, have been extensively studied for soybean cultivation. The objective of this study was to analyze the spatial variability of soil properties cultivated with soybean and to correlate the healthy vegetation (HV) spectral index with the bands B8A (classifying vegetation - 865 nm), B11 (measuring the moisture content of soil and vegetation - 1610 nm), B02 blue (useful for soil and vegetation discrimination - 490 nm). A sampling grid was installed for data collection in an area of 2,126.02 ha, with 270 regular points and 98 random points, totaling 368 points. For the soil, the contents of P (resin), K+, Ca2+, Mg2+, H+, Al3+, pH values, sum of bases (SB), cation exchange capacity (CEC), and base saturation were determined at a depth of 0.0 to 0.20 m. Most of the soil properties had exponential and spherical dependence. Clay percentages and Ca, Mg, and P contents had positive spatial correlation with the healthy vegetation spectral index (HV) while no spatial correlation was observed for pH, B, K, silt, sand, S, H+Al, Al, SB, and CEC. The sensor image used in this study in relation to HV showed good application for observing the spatial variability of the soil properties and soybean yield.

Engineering assessment of Lateritic soils of Obiaruku highway sections in South-southern, Nigeria

In order to determine the suitability of lateritic soils for the paving structures of highways, an engineering examination of some numbers of unsuccessful routes and highways in Obiaruku, southern Nigeria, was conducted. Thirty-two (32) lateritic bulk soil samples were taken for road construction-related index and strength testing from three stable and five failing sections. Compared to soils from the failed parts of A-7-6, which indicate poor-quality sub-grade materials, the soils from the stable sections have a greater specific gravity (2.49–2.85) and a lower percentage of clay (23.90%), indicating A-2-6 on the AASHTO classification system. Pores water pressure developed as a result of the high water absorption capacity, high proportion of fine particles (> 40%), and high values of linear shrinkage (> 8%) of the majority of soils from failed sections, leading to a loss in soil index strength. The degree of instability observed is caused by the predominance of fines in lateritic soils, low California bearing ratio (16–39% un-soaked), intermediate and high OMC above recommendation for most soil samples (12.6–19.1), maximum dry density (MDD) (<2000 kg/m3), and liquid limit (35.1–53.0). The lateritic soils of failed sections have poor geotechnical qualities, which suggest that they are not appropriate for use as sub-grade materials in other engineering constructions or even in the construction of new roads. For an accurate assessment of the sub-grade soils for highways, the significance of lateritic soils in detail sampling is emphasized. The findings of this study will be helpful in the rehabilitation and reconstruction of the road's failing parts, and it is advised that this investigation be well documented for future use.

A Study on the Role of Clay Nanoparticles and Temperature on the Creep Behavior of Polyethylene Matrix Nanocomposite

Objective: In the current research, the creep behavior of polyethylene (PE) matrix nanocomposites reinforced with different content of clay nano particles (i.e., 0, 1, 3, 5, 10wt%) at different temperatures (25 and 50℃) has been investigated. Methods: In order to produce composite samples of pure PE reinforced with different percentages of clay (0, 1, 3, 5 and 10% by weight), a twin extruder was used in the temperature range of 200-230℃. Also, to produce the standard samples, an injection machine was used using in the temperature range of 220-230℃. The samples were subjected to a constant load, typically around 0.7 to 0.8 times the yield strength, at 25 and 50℃ , and at constant strain rate of 0.1min-1. Results: The creep investigations showed that for PE and its nanocomposites the creep trend could be divided into primary, secondary, and tertiary stages. The length of each stage depended strongly on both temperature and the stress level at which the samples tested as well as the clay content. It was observed that adding nano particles in small amounts (1wt%) led to an increase in the length of the creep life of PE and it also improved this property in both temperatures. Conclusion: It was observed that increasing test temperature from causes to decrease the creep strength as well as a rapid onset of plastic deformation for all materials including PE and its nanocomposites. PE nanocomposites with higher than 1wt% clay exhibited a noticeable drop in creep strength particularly at 50℃.

Landslide Potential in Cihanjuang, Cimanggung, Sumedang, West Java Province

Landslides occurred in the Cihanjuang area, Cimanggung, Sumedang Regency, West Java on January, 9th 2021 with 40 fatalities and several buildings severely damaged. This area is in the form of hills with a fairly steep slope and housing is built on it. Geologically, the research area is composed of Undecomposed Young Volcanoes (Qyu) in the form of tuffaceous sand, lapilli, breccias, lava, and agglomerates. The research aims to determine the potential and volume of landslides. The research method used is conducting geotechnical testing and carrying out topographical mapping. Geotechnical tests carried out were water content, specific gravity, sieve analysis, hydrometer, and direct shear strength. The geotechnical test results showed that water content: 16.37% – 31.26%, cohesion: 59.2 kPa – 112.7 kPa, and internal friction angle: 6.30° – 30.50°, percentage of gravel and sand 11.10 % – 34.90 %, percentage of silt and clay 65.10 % – 88.90 %. According to USCS, this soil sample includes the MH-CH-OH classification Topographical mapping was carried out covering an area of 7.006 hectares. The internal friction angle is relatively steep, and the percentage of gravel and sand is quite high, so water infiltration becomes easy, so the Cimanggung area has a high potential for landslides. From the topographic mapping, the volume of the landslide was around 161.981 m³. To maintain slope stability and avoid landslides, apart from planting strong-rooted plants in areas with high elevations, they also manage the drainage by making waterways on the northwest and southeast sides of the steep slopes to the main road.

TiO2-kaolinite composite photocatalyst for industrial organic waste decontamination

The industrially feasible TiO2-clay based photocatalysts are essential to overcome the practical barriers that are intrinsic to currently available clay-based photocatalysts. The present study demonstrates the fabrication of heterogeneous photocatalyst consisting of TiO2 and kaolinite (TKCP) that has shown improved catalytic activity and strength, ensuring industrial viable photocatalyst. TKCP is prepared via an economical method, employing mechanical compression and dehydroxylation, forming TiO2-clay hybrid matrix. Amount of clay primarily determines mechanical strength and photocatalytic efficiency of TKCP where TKCP with the lowest clay percentage results in a homogeneous matrix that consists of tiny TiO2 particles embedded clay sheet-like structure. The TiO2 particles embedded clay sheet-like structure is responsible for the high specific surface area and small pore size, increasing the active surface that is available for effective disintegration of organic contaminants. By increasing clay fraction in TKCP, a significant increase in surface defects can be observed due to large clay fragments and TiO2 agglomerates, which results in flexural strength and catalytic activity decrease. Methylene blue degradation on TKCP with the maximum TiO2 percentage results in the highest pseudo first-order rate constant of 0.58 h−1, exhibiting improved photocatalytic activity due to well-organized matrix and high specific surface area (82.79 m2 g−1). TKCP can be obtained in variable sizes and shapes that ensure dynamic wastewater treatment applications.

Physico-Chemical Properties of Surface Soil in Ashoknagar District of Madhya Pradesh for Agricultural Production

Looking at the crop production and soil related constraints in different village of Ashoknagar District of Madhya Pradesh we found it important to characterize the soils of the village. For this purpose, one hundred twenty-five GPS-based surface soil samples (0-15 cm) were collected from five blocks (Mungaoli, Chanderi, Ishagarh, Ashoknagar and Sadora) of Ashoknagar district from April to May 2017-2018. Soils were studied for their physical and chemical characteristics - status of sand,silt,clay percent varied from 36.6-56.7%, 3.9-38% and 25.2-42.4%, with the mean value of 47.5%, 17.2% or 35.1%, respectively and soil pH, EC, OC, Calcium carbonate, total Nitrogen or available sulphur were observed in the range of 7.2– 8.6, 0.32 - 0.62dSm‑1, 2.14 - 7.06 gkg-1, 0.5 –3.5 % 0.01-0.24 % and 4.36 – 40.25 mg kg-1under different villages of the investigated area with the average value of 8.0, 0.45dSm‑1, 4.35gkg-1, 1.7% and 0.11 %,14.68 mg kg-1 respectively. The availability of sulphur increased with an increase in organic carbon and clay content in the soil.

How much organic carbon could the soil store? The carbon sequestration potential of Australian soil.

Soil is a huge carbon (C) reservoir, but where and how much extra C can be stored is unknown. Current methods to estimate the maximum amount of mineral-associated organic carbon (MAOC) stabilized in the fine fraction (clay + silt, ) fit through the MAOC versus clay + silt relationship, not their maxima, making their estimates more uncertain and unreliable. We need a function that 'envelopes' that relationship. Here, using 5089 observations, we estimated that the uppermost 30 cm of Australian soil holds 13 Gt (10-18 Gt) of MAOC. We then fitted frontier lines, by soil type, to the relationship between MAOC and the percentage of clay + silt to estimate the maximum amounts of MAOC that Australian soils could store in their current environments, and calculated the MAOC deficit, or C sequestration potential. We propagated the uncertainties from the frontier line fitting and mapped the estimates of these values over Australia using machine learning and kriging with external drift. The maps show regions where the soil is more in MAOC deficit and has greater sequestration potential. The modelling shows that the variation over the whole continent is determined mainly by climate, linked to vegetation and soil mineralogy. We find that the MAOC deficit in Australian soil is 40 Gt (25-60 Gt). The deficit in the vast rangelands is 20.84 Gt (13.97-29.70 Gt) and the deficit in cropping soil is 1.63 Gt (1.12-2.32 Gt). Management could increase C sequestration in these regions if the climate allowed it. Our findings provide new information on the C sequestration potential of Australian soils and highlight priority regions for soil management. Australia could benefit environmentally, socially and economically by unlocking even a tiny portion of its soil's C sequestration potential.

Effect of Accelerated Physical Weathering of Coarse Soils and Wetting and drying Cycle on Some Soil Physical Properties

soil samples were collected in May the 5th, 2021 from wadi Al-Muhammadi) Al-Mohammadi valley(in Al-Anbar governorate in western Iraq. The trail consisted of four treatments. In the first treatment, the sample Is passed through a 2000 μm metal sieve, while in the fourth treatment the sample is crushed or milled to size 70μm sieve. In the second treatment, the mixture ratio of soil was 25:75 (natural: Crushed). In the third treatment, the mixture ration of soil was 50:50 (natural: crushed). This paper determined in the soil coefficients for penetration, the density sustainability, soil porosity, as well as scanning soil aggregates using an electronic microscope samples passed through cycle of wetting and drying the results showed that the decrease was evident in soil penetration resistance in recent cycles in conjunction with the decrease in soil bulk density significant because of mechanical pulverization and cycles of wetting and drying along with an increase in soil porosity. the proportion of soil cracks resulting from shrinkage and swelling has been calculated and It was found that it increases with the percentage of clay in the soil. The electron microscope images show the soil was influenced by the mechanical pulverization during the first three cycles, as for the wetting and drying cycles, their effect appeared in the last cycles, the partial transformation of mica to mineral 2:1 was observed with the progression of wetting and drying cycles.

Large Triaxial tests on Marginal soil admixed with Randomly Distributed with coir fiber and fly ash

The Due to a lack of suitable granular soils, it has become necessary for various construction types to use marginal soils (soils of lower strength) at various work sites. Typically, soil with higher percentages of silt and clay (finer particles) exhibits unfavourable engineering characteristics, making it unsuitable for a variety of construction-related operations. These soils are typically possessing plasticity in nature and have low strength, especially when it comes to shear strength. Common approaches like admixture stabilisation are being implemented to enhance the strength characteristics of these soils. The quality of these marginal soils to make them amenable for construction is also being improved by the chemical additives. By adopting such procedures that involve chemical admixing for the process of modifying marginal soils, the cost of construction process rises. In this work, an effort was undertaken with regard to examine the efficacy of modifying marginal soil admixing with cement/lime and with dispersed randomly with coir fibre as reinforcing material. Additionally, shear testing was carried out by admixing fly ash. The objective of the present work is to investigate the shear strength characteristics modified marginal soil and could be affected by the reinforcement of coir fibres. Using the proposed marginal soil, a number of significant triaxial laboratory works were carried out. The experimental study is intended to provide a workable answer for increasing the shear strength of marginal soil. It was observed that the shear strength of marginal soil modified/admixed with ordinary Portland cement and reinforced with random distribution of 2 percent coir fibre and admixed with 10 percent fly ash was roughly one and half to two times that of plain marginal soil.

Effect of environmental drivers of fish assemblage and diversity patterns in temporal scale in Mongra Reservoir: A case study from one of the tributaries of Mahanadi Basin, Central India

AbstractInfluence of seasonal variations in environmental parameters on fish assemblage and species diversity patterns was studied in a tropical reservoir of Central India during March 2021 to February 2022. A total of 41 species belonging to 7 orders, 15 families and 29 genera were recorded with highest diversity during post‐monsoon season compared to the pre‐monsoon season and monsoon season. The fish abundance similarity between the monsoon and post‐monsoon reached a maximum of 89%. Seasonal variations in the mean species abundance, Simpson dominance index, Shannon diversity index, Pielou's evenness index and Margalef's richness index were determined. One‐way ANOVA revealed a significant difference (P < 0.05) at the temporal scale. There was a significant seasonal difference in species abundance (P = 0.0006) and evenness index (P = 0.02) among the diversity indices. During the study period, three ‘vulnerable’ species, three ‘near threatened’ species and two ‘endangered’ species were caught. Carnivore dominance was evident throughout the year in the trophic guild of fishes. The Pearson correlation test revealed that water pH, dissolved oxygen, sediment organic carbon and clay percentage were positively correlated to all four diversity indices. Simpson and Margalef species richness diversity indices were positively correlated to sediment pH. Fish abundance was positively associated with sediment pH, silt, phosphorus and nitrogen content. Canonical correspondence analysis was used to investigate the relationships between fish assemblages and environmental conditions. Among the 19 physicochemical parameters, nine (dissolved oxygen, total dissolved solids, conductivity, transparency, hardness, phosphate and chlorophyll‐a, sediment nitrogen and phosphorus) characteristics were shown to be statistically significant (P < 0.05) in determining fish diversity. Dissolved oxygen, total dissolved solids, conductivity, transparency, hardness, phosphate and chlorophyll‐a of water and sediment nitrogen and phosphorus qualities were the key factors for the species abundance. The reservoir boasts a diverse fish population that allows multi‐species fishing and generates revenue for numerous local fishers. Fish habitats should be protected in order to maintain diversity and long‐term ecological benefits.

Dynamic geospatial modeling of mycotoxin contamination of corn in Illinois: unveiling critical factors and predictive insights with machine learning.

Mycotoxin contamination of corn is a pervasive problem that negatively impacts human and animal health and causes economic losses to the agricultural industry worldwide. Historical aflatoxin (AFL) and fumonisin (FUM) mycotoxin contamination data of corn, daily weather data, satellite data, dynamic geospatial soil properties, and land usage parameters were modeled to identify factors significantly contributing to the outbreaks of mycotoxin contamination of corn grown in Illinois (IL), AFL >20 ppb, and FUM >5 ppm. Two methods were used: a gradient boosting machine (GBM) and a neural network (NN). Both the GBM and NN models were dynamic at a state-county geospatial level because they used GPS coordinates of the counties linked to soil properties. GBM identified temperature and precipitation prior to sowing as significant influential factors contributing to high AFL and FUM contamination. AFL-GBM showed that a higher aflatoxin risk index (ARI) in January, March, July, and November led to higher AFL contamination in the southern regions of IL. Higher values of corn-specific normalized difference vegetation index (NDVI) in July led to lower AFL contamination in Central and Southern IL, while higher wheat-specific NDVI values in February led to higher AFL. FUM-GBM showed that temperature in July and October, precipitation in February, and NDVI values in March are positively correlated with high contamination throughout IL. Furthermore, the dynamic geospatial models showed that soil characteristics were correlated with AFL and FUM contamination. Greater calcium carbonate content in soil was negatively correlated with AFL contamination, which was noticeable in Southern IL. Greater soil moisture and available water-holding capacity throughout Southern IL were positively correlated with high FUM contamination. The higher clay percentage in the northeastern areas of IL negatively correlated with FUM contamination. NN models showed high class-specific performance for 1-year predictive validation for AFL (73%) and FUM (85%), highlighting their accuracy for annual mycotoxin prediction. Our models revealed that soil, NDVI, year-specific weekly average precipitation, and temperature were the most important factors that correlated with mycotoxin contamination. These findings serve as reliable guidelines for future modeling efforts to identify novel data inputs for the prediction of AFL and FUM outbreaks and potential farm-level management practices.