High Silt Content Research Articles

Structure and properties of paleosols of the last two interglacial cycles of the Khovaling Loess Plateau, Tajikistan (Obi–Mazar section)

Abstract Significant thicknesses, a large number of paleosols, and an impressive chronological framework place the loess–paleosol series of the Afghan-Tajik depression on a par with the famous sections of the Chinese Loess Plateau. Based on the results of field stratigraphy, description of the macro- and micromorphological structure, field magnetic susceptibility measurements, and study of the chemical and grain-size compositions, a comprehensive characterization of the structure, properties, and formation conditions of paleosol horizons and loess layers was carried out. Three loess units and two pedocomplexes are distinguished in the late and upper middle Pleistocene deposits of the Obi-Mazar section. These sediments are characterized by high silt and carbonate content and the presence of loess with pedogenic features. Pedocomplex PC1, consisting of three paleosols, according to the stratigraphic position and absolute dating, corresponds to MIS 5. Pedocomplex PC2, consisting of two developed paleosols separated by loess, is correlated with MIS 7. The properties of the studied paleosols together with modern soil distribution in the region allow for the reconstruction of the soil type of PC1 and PC2 of the Obi-Mazar section with the genesis of the Calcisols–Kastanozems groups.

Review of Analytical Studies on The Failure of Granular Anchor Piles in Expansive Soil

Abstract: Soft ground, characterized by a high content of clay, silt, peat, and loose sand, is generally unsuitable for constructing large structures due to insufficient stability. Ground improvement techniques, such as the use of stone columns (or granular piles), are often implemented in these areas to enhance load-bearing capacity and minimize settlement. The Granular Anchor Pile (GAP) is an advanced version of the stone column that includes an anchor to boost its tensile load-bearing or pullout capacity. In this study, formulations from various authors regarding the pullout capacity of anchors embedded in clayey soils are analyzed to assess the contributions of pile failure and anchor failure to overall GAP failure. The results indicate that GAP failure occurs due to two main factors: 50%–65% of the anchor length failing, and 35%–50% of the pile length failing. This breakdown helps in understanding the role of each component in the overall pullout capacity of GAP

Structures and properties of the late pleistocene paleosols of the loess-soil section of Obi-Mazar (Tajikistan)

The loess-soil series of Central Asia cover the history of subaerial sedimentation of the last 2–2.5 mln years. Significant thicknesses, a large number of paleosols, and an impressive chronology place the loess-soil series of the Afghan-Tajik depression on a par with the famous sections of the Loess Plateau of China. The study of the most significant sections located within the Khovaling Loess Plateau makes it possible to develop a regional chronostratigraphic chart, to study the structure and conditions of formation of the main stratigraphic benchmarks–buried paleosols. The present study is devoted to the clarification of the structural features of loess and paleosols of the Late Pleistocene in one of the sections of the Khovaling–Obi-Mazar Plateau. Based on the results of stratigraphic dissection, description of the macro- and micromorphological structure, magnetic susceptibility analysis, study of the chemical and granulometric composition, a comprehensive description of the structure and properties was carried out and the most probable conditions for the formation of paleosols and loess were established. In the Late Pleistocene part of the section, two loess layers and a pedocomplex PC1 with three welded paleosols, consisting of a total of 7 horizons, are distinguished. The deposits are characterized by high silt content, carbon content, and the presence of signs of pedogenesis and biological activity in all layers of the studied section. Available data indicate the presence of a poorly developed MIS 3 paleosol in the upper loess layer. The developed pedocomplex PC1 of Obi-Mazar, according to its stratigraphic position, structural features, and magnetic susceptibility data, belongs to the MIS 5. According to preliminary data, its formation occurred in semi-humid and humid conditions under forest vegetation, which contributed to the biogenic segregation of Fe-Mn compounds, as well as intra- and interhorizon redistribution of carbonates due to diagenetic processes. Towards the end of the Last Interglacial, gradual aridization occurred, due to which the upper paleosol to be the least developed.

Landscape and soil cover diversity in Polissia and Forest-Steppe of Ukraine

Recent research has revealed the patterns of spatial and temporal variability of crop yields for the Polissia and the Forest-Steppe regions of Ukraine. In addition, the approaches to differentiating agroeconomic and agroecological components in the variability of the productive potential of the territories were developed. Approaches have been developed to quantify the spatial and temporal variability of soil erosion for individual areas of the region. The issue of assessing the impact of erosion processes on crop yields at the regional level remains unresolved. The diversity of landscapes and soil cover in Polissia and the Forest-Steppe of Ukraine was assessed in this article. The research covered 10 administrative regions of the north and northwest of Ukraine, which are located mainly within mixed forests (Polissia) and the eastern European forest steppe (Forest-Steppe). Part of the territory is tangential to the Carpathian mountain forests and the Pontic steppe. Within the study area, 30 WRB soils were identified. The largest area is occupied by Phaeozems Albic (21.7% of the total area of the region). These soils are located mainly in the southern and central parts of the region. In the north of the region, Phaeozems Albic form an almost continuous cover, and to the north, the areas of these soils become island-like. Phaeozems Luvic cover 12.1% of the region's territory. The Phaeozems group also includes Phaeozems Gleyic (0.93%), Phaeozems Haplic (0.13%), and Phaeozems Sodic (1.78%). Albeluvisols Umbric (17.1%) occupy a significant part of the region's territory. These soils occupy the north of the region and extend south along the Dnipro River floodplain. Spatially close to these soils are Albeluvisols Gleyic (12.8%). In the western part of the region, in Prykarpattia, there are Albeluvisols Stagnic (0.82%). The organic carbon content in the soils of the administrative districts of the region in the 0-5 cm layer was 5.2±3.3% and ranged 0.5% to 23.9%. In the layers of 5–15 and 15–30 cm, this figure decreased to 1.9 ± 1.1% and 1.9 ± 1.0%, respectively. In the 30–60 cm layer, the organic carbon content was 1.4 ± 0.8% and ranged 0.1% to 6.1%. The lowest organic carbon content was observed in the north central part of the region, and the highest content was observed in the north-east and north-west of the region. In the south of the region, there was found a strip of soils with moderate organic carbon content. The lowest content of organic carbon is characteristic of Albeluvisols and Podzols, which are located in the north of the region. In turn, the highest content of organic carbon is characteristic of organogenic Histosols, which, together with Albeluvisols and Podzols, form the basis of the soil cover structure of the territories in the northeast and northwest of the region. It should be noted that the agronomic role of these soils is insignificant, and their organic carbon content cannot be considered as a traditional indicator of fertility. Nevertheless, organic carbon is a reliable indicator of the anti-erosion properties of both natural and agricultural soils. The organic carbon content of Chernozems is quite high, which is a factor in the high fertility of these soils and their importance in agricultural production. The organic carbon content of Fluvisols and Gleysols is naturally high. The importance of these hydromorphic soils is due to their high productive potential, which ensures their use in agriculture. It is also worth noting their high seed protection potential. Phaeozems cover a large area of the region and contain a high level of organic carbon. These soils form the basis of agricultural production and forestry in the region. The silt content in the region's soils measured 45.6 ± 8.5%, ranging 19.1% to 57.6%. The north of the region is represented by soils with the lowest silt content (19–41%). In the center, in the west of the region, there is a zone with the highest silt content (53–58%). In other parts of the region, there are transitional levels of silt content in the soil. The clay content in the soils was 30.7 ± 13.8% and ranged 7.4% to 36.0%. The zone with the lowest clay content in soils has been formed in the north. The highest clay content in soils is typical for the southern part in the center of the region. The sand content in soils is highest in the northern part of the region, and the lowest in the southwestern and southern parts of the region.

How restoration engineering measures can enhance the ecological value of intertidal flats

Restoration engineering measures, such as managed realignments or building groins, modify the environmental characteristics of coastal intertidal ecosystems. Creating physical modifications that are beneficial to an intertidal system's ecology necessitates an in‐depth understanding of the relationships between the abiotic and biotic components of a given intertidal habitat. In this study, we evaluate how hydrodynamics and sediment characteristics drive the development of the benthic macrofauna community during the first 5 years following engineering measures to enhance benthic macrofauna diversity at three locations. The creation of low‐energy habitats through groins (Knuitershoek and Baalhoek) and a managed realignment dike breach (Perkpolder) led to the accumulation of fine sediments in all three impact sites. Biomass of benthic macrofauna quickly increased between 2016 and 2020, with successional processes being more important in Perkpolder, where the habitat was started completely from scratch due to a managed realignment, than at Knuitershoek or Baalhoek, where habitat conditions were improved by adding groins. In addition, the density of benthos‐eating birds, especially oystercatchers, increased at some of the modified sites. While a low‐energy habitat may harbor more diverse assemblages of benthic macrofauna than a highly dynamic one, the extremely high silt content, which is typical for low‐energy habitats, may slow benthic community development. The observed increase of biomass at our impact sites highlights the value of the interventions, while the delays in the response of the benthic macrofauna community emphasizes the need for extensive monitoring both in time and space and the identification of underlying abiotic–biotic mechanisms.

Role of aggregates in the forming process of tephric loess dunes distributed along the Pacific coast of eastern Japan

The Pacific coast of eastern Japan contains specific aeolian landforms of geomorphological interest in terms of their formation processes in humid climates and Holocene paleoenvironments. Wind erosion landforms, characterised by blowouts, were observed at the heads of coastal cliffs which consisted of marine gravel sediments, weathered volcanic ash layers (WVALs) and black soil layers (BSLs). The blowouts were accompanied by downwind tephric loess dunes. We analysed the physicochemical properties of the WVAL, BSL and dune sediment samples. The results revealed that clay and silt contents in dune sediments were 5–48% and 20–35%, respectively. The fine particles were in the form of aggregates in the WVALs, BSLs and dune sediments, with contributions from andic properties. WVAL and BSL aggregates were prone to movement in saltation, depositing into the dunes in a formation process similar to that of clay dunes in semiarid zones. The tephric loess dunes were characterised as clay dunes based on their high clay and silt contents. In addition, the dunes were characterised by durable aggregates derived from short-range-order minerals, such as allophane. The prevailing northeasterly winds caused by intense low pressures were responsible for dune formation in the study areas. Radiocarbon dating revealed two active wind periods. The first was approximately 1005–895 cal. BC to 358–281 cal. BC, and the second was 771–886 cal. AD to 1021–1155 cal. AD.

1 g shake table study on seismic strengthening of low-cost rammed earthen houses built of silt enriched soil using natural fiber reinforcement

Earthen houses are practiced as a traditional and low-cost housing in many countries around the globe. These houses were exposed to unacceptable earthquake (EQ) risks despite their environmental benefits. Past earthquakes including the recent past 2017 Tripura EQ has evidenced significant damages mostly in earthen/masonry houses which are built in a non-engineered manner. In this context, the current study aims to investigate the seismic behavior and failure patterns of both unreinforced and using proposed retrofitted rammed earth model houses (with and without openings) built using typical Tripura soils having higher silt content using unidirectional shake table experiments on total 26 physical models. Besides, both seismic strength and structural stability are also examined for retrofitted earthen houses. The study indicates that, proposed novel low-cost natural fiber made textile encasing reinforcement technique has exhibited promising seismic performance of such houses from the view point of structural strength and ductile behavior as compared to traditional cementitious additives and fiber blended stabilized retrofitted houses as well untreated houses. The fundamental lateral period of model unreinforced and reinforced houses found within the range of 0.08 to 0.15 s respectively which indicates increased stiffness of walls due to strengthening may decrease the lateral period maximum up to 46.67%. On the other hand, the maximum increase in seismic strength was observed in order of 4.50 to 6.31 times in the case of bitumen treated bamboo fiber textile based encased houses with L-shaped bamboo splint corner reinforcement whereas traditional cementitious stabilized method has offered maximum 1.13 to 1.83 times increment in lateral strength. Further, the effect of different parametric variations such as area of openings (doors and windows), thickness to height ratio, variation in compaction methodologies on seismic performances of unreinforced rammed earthen houses were also studied in detail. Finally, regression based closed form predictive expressions for seismic strength of rammed earthen houses and without retrofitting are proposed herein. The performed cost analysis study will also help to assess the effectiveness of proposed strengthening techniques.

Vegetation degradation alters soil physicochemical properties and potentially affects ecosystem services in green spaces of a tropical megacity (Lubumbashi, DR Congo)

Urban soils are degraded by various human pressures, including vegetation degradation, leading to changes in physical and chemical characteristics and affecting important ecosystem services. Soil physical properties are an important fertility control parameter, providing the basis for sustainable soil use in urban conditions; however, they do not receive sufficient attention in work on tropical cities. We assessed the impact of vegetation degradation in six urban green spaces (bare soils versus vegetated soils) on the physical (texture, soil bulk density and structure) and chemical (pH, cation exchange capacity (CEC), organic carbon (OC), nitrogen (N), phosphorus (P), potassium (K), copper (Cu) and manganese (Mn)) qualities of soils in a tropical megacity (Lubumbashi, DR Congo). Vegetated soils presented better physical and chemical qualities than bare soils. Vegetated soils were characterized by a high clay and silt content and a good consistency (soil structure), while bare soils were characterized by a high sand content and high bulk density. Vegetated soils were characterized by higher pH, OC, N, C/N ratio, CEC, P, and K. There was no significant difference in Mn or Cu between bare and vegetated soils. Cu was highly variable between sites (from 99 ± 61 mg.kg−1 in VS to 8559 ± 151 mg.kg−1 in BS). Our results demonstrate that the destruction of vegetation, leading to bare soil, negatively affects soil properties and may interfere with ecosystem services provided by urban soils in tropical climates. The physical properties observed in bare soils in this study, including silt, clay, and sand content, soil structure, and soil bulk density, along with chemical properties such as soil pH, cation exchange capacity, and soil organic carbon, can influence the ecosystem services provided by urban soils. These services include regulating water flow and nutrient cycling, enhancing nutrient availability, and supporting ecosystem functions through the cycling of water and nutrients.

Co‐occurring intertidal ecosystem engineers with opposing growth strategies show opposite responses to environmental gradients during establishment

Coastal vegetated ecosystems including mangroves, seagrasses, and salt marshes are often shaped by positive plant–environment feedbacks. Plants improve their own living conditions with increasing patch size and density by attenuating hydrodynamics and stabilizing sediments. As these habitat modifications are critical for survival and growth, the positive density‐dependent nature of these feedbacks can lead to establishment thresholds for young plants in absence of mature conspecifics. Although feedback strength is known to depend on hydrodynamic exposure and plant traits (e.g. stiff versus flexible stems), it remains unclear how 1) opposing morphological plant traits affect establishment in contrasting environments, and 2) whether trait plasticity influences establishment success. Here, we investigate this by transplanting two tidal species with opposing growing strategies – Spartina anglica forms tussocks of stiff stems while Zostera noltii forms patches of stress‐avoiding flexible shoots – from two different donor sites in eight experimental locations. Results show that the survival and growth of both species was most successful at field locations with diverging environmental characteristics, while overall survival was highest for Z. noltii. Mainly, S. anglica survival was highest at locations with high organic matter and silt content and higher elevation relative to the tidal amplitude. In contrast, Z. noltii survival was highest at locations with larger grainsize and lower relative elevations. Furthermore, despite initial differences in plant traits between the two donor sites of Z. noltii, we found no effects of donor origin. Contrastingly, we found a significant effect of donor origin on S. anglica growth, even though transplants from the two donor sites showed no initial trait differences. Collectively, these results suggest that the stress‐tolerance strategy of S. anglica hampers establishment in exposed conditions, whereas the stress‐avoiding Z. noltii appears to be more susceptible to stress from desiccation and silty sediments.

Physicochemical Properties as Affected by Concretionary Nodules of Oxic Rhodustalf of Southern Guinea Savanna Agroecological Zone of Nigeria

Diverse concretion types are prevalent across diverse soil types in the savanna region. However, its chemistry, mineralogy, profile, dimension, and abundance can significantly vary, influenced by the distinct weathering processes characteristic of each location. The accumulation of concretions in soil can have a considerable impact on its physical and chemical properties, especially at high concentrations. This effect largely depends on the chemical composition and mineralogy of the oxide components present [1]. Despite the potential significance of these effects, the influence of concretionary nodules on soil physicochemical properties remains underexplored. Existing studies are few and often lack detailed insights. Therefore, this study aims to investigate the physicochemical properties of soil influenced by concretionary nodules in the Oxic Rhodustalf of Southern Guinea Savannah, Nigeria. Results obtained from our analysis revealed interesting variations obtained. Three distinct textural classes were identified regarding physical properties: Sandy Loam, Sandy Clay Loam, and Loamy Sand. At various sites, the soil generally exhibited a slightly higher clay content (20.06 %) and sand content (74.04 %) compared to the concretions. However, the concretions had a higher silt content, at 7.34 %. Obbo Ile recorded the highest clay content (24.09 %) but the lowest silt and sand content among the locations. In contrast, Owu Isin had a significantly higher sand content (75.04 %). Clay content increased with depth, while sand content decreased. Although silt content generally increased, it dropped significantly after the 90-120 cm depth. Analysis of the chemical properties revealed significant variations (p < 0.05) for the parameters evaluated. The conductivity, pH in water, and CaCL2 were higher in Soil than in concretions. Similarly, the elements Na, K, Ca, and Mg also displayed higher values in soil. OM, SOC, Ex. Acidity and CEC except N (%) were significantly (p < 0.05) higher in soil than in concretions. The pH in H₂O was stable across depths and locations, with the highest value at 60-90 cm in Obbo Ile for soil and the lowest at the same depth in Owu Isin for concretions. pH measured with CaCl₂ mirrored this trend, peaking at 5.93. Conductivity decreased with depth, reaching its highest at 0-30 cm in Osi for soil. Base cations (Na, K, Ca, and Mg) were significantly higher in Obbo Ile and Osi compared to Owu Isin, with values consistently higher in soil than in concretions. Total nitrogen was highest (1.31 %) at 90-120 cm in Obbo Ile’s concretions. Soil organic carbon (SOC) peaked at 1.11 % at 0-30 cm in Owu Ile, and exchangeable acidity was highest at 90-120 cm there. Cation exchange capacity (CEC) was highest (0.35 meq/100 g) at 30-60 cm in Osi’s soil.

Hydraulic Characterization of Permeable Materials Used for Filling Mole Drain Channels in Structurally Unstable Soils

Highlights Permeable materials can be used to fill mole drains and provide support to the cavity walls in structurally unstable soils. Permeable materials extend the lifespan and improve the hydraulic performance of mole drainage systems. Darcy’s law for nonlinear porous flow explained the hydraulic performance of the permeable materials used in this study. A numerical method was established to assess the suitability of permeable materials of unknown hydraulic performance. Design guidelines were developed to assist in the planning of filled mole drainage systems installed in structurally unstable soils. Abstract. Mole drainage in soils with low permeability is a cost-effective technique for managing soil drainage. Following installation, the satisfactory performance of the system will depend on having sufficient soil fissure development extending from the soil surface to the roof of the mole channel and mole channel stability to avoid its collapse. Permeable materials such as river-run gravel and crushed stone can be used to fill mole channels to prevent channel collapse in halomorphic and high-silt content (e.g., 50%–70%) soils and extend the lifespan of the system. The objectives of this work were to: (i) characterize a range of permeable materials that can be used to fill mole drains and provide support to the cavity walls in structurally unstable soils; (ii) verify the applicability of Darcy’s law to explain the hydraulic performance of such materials, and (iii) develop a set of design and planning guidelines aimed at improving the performance of mole drainage systems that are filled with permeable materials. Five permeable materials were characterized, namely: three types of river-run gravels, crushed baked mud bricks, and crushed stone. The materials were characterized for their mechanical and hydraulic properties, and the applicability of Darcy’s law was experimentally determined. Small- and medium-sized gravels are easy to handle and apply during field installation due to their shape and flowability properties and the reduced risk of clogging when placed in the mole channel. However, the hydraulic performance of these materials would not allow for system designs longer than about 100 m, which therefore would limit their utilization in practice. Large-sized gravel offered an intermediate solution with overall satisfactory hydraulic performance. Crushed brick and crushed stone offered good alternatives to gravel, allowing for longer (e.g., >120 m) system designs for all combinations of drain spacing and drain gradient. However, their angularity, poor uniformity, and size range distribution can compromise the efficiency of handling and delivery in current mole plough systems. For all materials, the hydraulic conductivity (Kh) decreased with an increase in the hydraulic gradient. For a given hydraulic gradient, Kh was dependent on aggregate size, such that a larger D50 value led to increased Kh. The nonlinear performance of Darcy’s law was verified for all materials, and potential equations were fitted to represent such relationships, all showing acceptable fits to the nonlinear models (P<0.001). A linear relationship (P<0.05) between the parameter m of the potential model and total porosity was established. The set of equations developed by this study will enable estimating Kh based on the aggregate size distribution or as a function of the total porosity of the material. Crushed brick and crushed stone could provide a cost-effective solution for the installation of filled mole drain systems in structurally unstable soils. Keywords: Darcy’s law, Extreme rainfall, Halomorphic soils, Hydraulic conductivity, Reynolds number, Silty soils.

Formation damage challenges and solutions in cased hole gravel pack completions in deep offshore unconsolidated laminated sandstone formations in the Sakarya Field

A comprehensive experimental formation damage study for the Sakarya Field was conducted to identify production impairment mechanisms induced by operational fluids. The study reveals that the retention of operational fluids leads to irreversible reductions in gas permeability to a certain degree. This fluid retention is associated with the amount of loss and retention time of operational fluids into the reservoir, as well as the types of clays present in the gas bearing zone. Fluid retention damage is more severe for samples with lower permeability and higher silt content. While sandy plugs typically experience a reduction in permeability of less than 10%, low-permeability silty samples can exhibit reductions as high as 35%. The most effective approach to minimize this damage includes maintaining the lowest possible overbalance pressure, applying completion methodologies with minimal fluid invasion, and ensuring timely and effective cleanup. Another source of damage appears to result from acidic dissolution of native carbonate minerals and destabilization of delicate clays (e.g., chlorite). This leads to slight compaction and associated immediate reduction in permeability, reaching as high as 50% when combined with other operational fluid damage in some cases. In such environments, it is recommended to use a milder alternative acid solution that specifically targets the filter cake and debris around perforations, minimizing the dissolution of native carbonate minerals and interaction with clays. Due to the low uniaxial compressive strength (UCS) of the formation, evidence of sanding and proppant embedment was observed. To mitigate this issue, an optimum gravel pack design and execution during well completion is vital. Additionally, avoiding abrupt bean-up and bean-down during well tests and production will help limit sanding and proppant embedment. The novel experimental methodology and field implications derived from this study may serve as a guideline to solve formation damage challenges in similar fields facing similar issues. Initiating such detailed studies in the early stages of field development is critical to ensure maximum recovery from the least damaged and disturbed reservoirs.

Preparing Soil Class Distribution Maps Using Geographic Information Systems

Ten pedons were discovered in the soils of Al-Raranjiyeh located in the province of Babylon, within longitudes 44012′0" to 44030′0" east and latitudes 32012′0" to 32024′0" north. To the laboratory and make the necessary laboratory measurements on it. As the size distribution of the soil classes was measured, and then maps of the spatial distribution of these soils were drawn by means of the Geographic Information Systems (GIS) program As the results showed that these artifacts were distributed within different ranges, as the silt content was dominant in most of the horizons of the pavilions. As for the spatial distribution, the areas with a high silt content occupied the largest area.

Experimental study on bio-treatment effect of the dredged Yellow River silt based on soybean urease induced calcium carbonate precipitation

As the river with highest silt content in the world, the Yellow River is dredged annually to relieve the pressure of flood control. Prior studies indicated that the dredged Yellow River silt cannot be directly utilized as construction filling material because of the deficiency in strength and stability. In this study, soybean urease induced calcium carbonate precipitation (SICP) method was proposed to solidify the Yellow River silt for the purpose of promoting its mechanical properties. The influences of soybean powder concentration and pH value on the soybean urease activity were investigated. By estimating the urease activity of per unit mass, the soybean powder concentration with highest extraction efficiency were determined. The optimum bio-treatment recipe including cement solution concentration and grouting time of the biological solidification agent suitable for the Yellow River silt was characterized through unconfined compressive strength (UCS) test and CaCO3 content test. Meanwhile, scanning electron microscope (SEM) and X-ray diffraction (XRD) analysis of the bio-treated Yellow River silt sample verified the effectiveness of solidification from microscopic viewpoint. The findings of this study suggest that soybean urease induced calcium carbonate precipitation (SICP) method can effectively improve the geotechnical engineering properties of Yellow River silt and provide a technical approach for the resource utilization of the Yellow River silt.

Linkages between Soil Acidity, Soil Plant Nutrients and Land Use on Ferralsols in Central Uganda

A study to examine the linkages between soil acidity, soil plant nutrients and land use on Ferralsols was carried out on smallholder farms in Central Uganda. The objective of the study was to assess the effect of soil pH on soil plant nutrient availability under the current land use. The study was carried out in Mpigi, Masaka, Wakiso, Mukono and Mubende districts representing Central Uganda. Soil samples were randomly collected from Coffee, Banana, soybean, common bean, maize and virgin fields in the five districts and the pH and plant nutrient analyzed accordingly. The analysis of variance (ANOVA) showed significant difference (p<0.01) on soil nitrogen, Calcium (p< 0.05) and Magnesium (p< 0.05). When treatment was assessed, the study showed significant difference (p< 0.01) on potassium. Besides, the study also showed high concentrations of Manganese (Mn) and Iron (Fe) in addition to very high sand and low silt and clay contents. The current land use for coffee production in Masaka district recorded the lowest soil pH (4.4) followed by annual fields (pH 4.60) in Mpigi. The highest soil pH (5.7) was recorded in banana fields in Mubende. The study also recorded very low to low N, P and K. Generally, the study observed rapid soil fertility decline in smallholder farms in the region.

The Invasion of Alien Populations of Solanum elaeagnifolium in Two Mediterranean Habitats Modifies the Soil Communities in Different Ways.

We aimed to explore how the invasion of the alien plant Solanum elaeagnifolium affects soil microbial and nematode communities in Mediterranean pines (Pinus brutia) and maquis (Quercus coccifera). In each habitat, we studied soil communities from the undisturbed core of both formations and from their disturbed peripheral areas that were either invaded or not by S. elaeagnifolium. Most studied variables were affected by habitat type, while the effect of S. elaeagnifolium was different in each habitat. Compared to maquis, the soil in pines had higher silt content and lower sand content and higher water content and organic content, supporting a much larger microbial biomass (PLFA) and an abundance of microbivorous nematodes. The invasion of S. elaeagnifolium in pines had a negative effect on organic content and microbial biomass, which was reflected in most bacterivorous and fungivorous nematode genera. Herbivores were not affected. In contrast, in maquis, organic content and microbial biomass responded positively to invasion, raising the few genera of enrichment opportunists and the Enrichment Index. Most microbivores were not affected, while herbivores, mostly Paratylenchus, increased. The plants colonizing the peripheral areas in maquis probably offered a qualitative food source to microbes and root herbivores, which in pines was not sufficient to affect the much larger microbial biomass.

Characterization of Alluvial Soil for Growth of Chinese Betel (Peperomia pellucida L.)

This study aims to determine the characterization of alluvial soil as a place to grow Chinese betel (peperomia pellucida L.) in Ambon city. Parameters studied included morphological characterization of alluvial soil and description of Chinese betel nut (Peperomia pellucid a L.). The results of observations in the field and analysis of soil samples in the laboratory that have been collected are used as material to identify soil morphological characterization. Meanwhile Chinese betel nut (Peperomia pellucid a L.) collected from alluvial soil was selectively explored by exploring the research area using the Cruise Method. Furthermore, a phytochemical test was carried out to determine its phytochemical content. The results showed that the color of the soil and the rusty color of the alluvial soil in Ambon City was generally brown. The alluvial soil structure at the study site has an O horizon with a soil layer thickness of 17 cm, an A horizon with a thickness of 45 cm soil lumpy structure and a Bw horizon with a soil thickness of 30 cm and the C horizon with a thickness of 65 cm is classified as having a globular lumpy soil structure, It has a high clay and silt content. The lower the soil solum, the lower the C-organic content. The soil in Ambon city has moderate fertility. Low base saturation is associated with low C-organic content in the soil. Chinese sirih that grows on alluvial soil types in Ambon City contains several classes of compounds that are beneficial to health like flavonoids, alkaloids, tripenoids, phenolics, tannins and saponins so that they have ethnomedicin effects such as anticancer, antimicrobial, antidiabetic, antihypertensive and antioxidant activities.

Effects of Granular Gradation on the Compressibility and Permeability of Lime-Stabilized Slurry with High Water Content

Lime stabilization is one of the main methods to achieve efficient treatment and resource utilization of waste slurry. This study investigated the compressibility and permeability of lime-stabilized slurry with different granular gradations based on the ultra-low stress consolidation/permeability test and identified the stabilization mechanism of lime-stabilized slurry with high water content by mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM) tests. The test results indicated that (i) lime-stabilized slurry with high water content showed obvious evidence of remolded yield stress and (ii) the remolded yield stress increased with the increasing lime dosage. Lime was found to induce the flocculation of clay to form aggregates through ion exchange, further stabilizing them through the volcanic ash reaction, thus increasing the remolded yield strength of the stabilized slurry. The remolded yield stress of the Hangzhou stabilized slurry with a 1% lime dosage was shown to increase from 0 kPa to 5.71 kPa, while the compression index CS1 decreased by 68.8%. In addition, the pore volumes and diameters of the soil increased once the flocculation was completed, leading to increased permeability of the stabilized slurry. It was, however, observed that the stabilized slurry permeability did not increase infinitely with the increasing lime dosage, but on the contrary decreased once the lime dosage exceeded a certain threshold value. The permeability of the Hangzhou stabilized slurry was found to be one order of magnitude higher than that of the remolded slurry at the optimal dosage. Whereas for slurry with high clay content, the recommended lime dosage was established to be 2% to reduce its compressibility or enhance its permeability; for slurry with high silt content, the recommended lime dosage was ascertained to be 3%.

Manufacturing Technique of the Buddhist Monk Bodhidharma Mural Painting in Geungnakjeon Hall, Daewonsa Temple, Boseong

The manufacturing technique was studied through the structure and material characteristics of the Buddhist Monk Bodhidharma mural painting in Geungnakjeon Hall, Daewonsa Temple. The mural is painted connected to the earthen wall and the Joongkit. The earthen wall consists of an first layer, a middle layer, a finishing layer, and a painting layer. It was come to light that the first layer had a high content of loess below silt, and the finishing layer had a high content of fine sand. The painting layer was colored after preparing a ground layer using a soil mineral pigment. It was come to light that he Buddhist Monk Bodhidharma mural painting was created with the same technique as the Avalokitesvara Bodhisattva mural painting in Geungnakjeon Hall. The murals inside Geungnakjeon Hall belong to a category similar to the Joseon Dynasty’s buddhist mural painting (made of earthen) manufacturing style, but characteristic factors were found in the high fine sand content of the finishing layer, the condition of plastering according to the surface finishing technology, and the painting technique of the Joongkit. It is expected that this information can be used as an important indicator for monitoring the conservation status of murals inside the Geungnakjeon Hall of Daewonsa Temple in the future.

Migration of Salt Ions in Frozen Hydrate-Saturated Sand: Effect of Silt and Clay Particles

Permafrost composed of sand with silt and clay components may store stable and metastable gas hydrates, which can lose stability under a flux of dissolved salts from natural or production-related solutions (seawater, brines from cryopegs, drilling fluids, etc.). The flux of salt ions is controlled externally by temperature and pressure as well as by the salinity of solutions and the properties of fine-grained (<0.05 mm) components in permafrost. The effect of silt and clay percentage and mineralogy (kaolinite or montmorillonite) on the patterns of salt and water transport and the related dissociation of pore gas hydrates in frozen sand is studied in laboratory experiments. The experiments are conducted in conditions that can maintain the self-preservation of gas hydrates: a constant negative temperature of −6 °C and a pressure of 0.1 MPa. Sediments with higher clay percentages show slower migration and accumulation of salt ions and the higher critical salt concentration required for the onset of gas hydrate dissociation. The flux of Na+ to sand samples containing montmorillonite is lower than to those with kaolinite. On the other hand, salt migration and hydrate dissociation are faster in sand with higher silt contents. The experimental results form the basis for a generalized model of main mechanisms that drive salt transport in frozen hydrate-bearing sediments interacting with saline solutions.