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Overseeing the relative density of soils in all types of earth structures during both construction and operation is crucial to ensure that these structures attain the necessary density and strength. Especially in linear structures that extend over significant lengths, geotechnical investigations should include planning tests that allow for determining the maximum number of geotechnical parameters, such as cone penetration tests (CPTU) or Marchetti dilatometer tests (DMT). The article presents the in situ tests aimed at assessing the relative density of sandy soils. Empirical formulas available in the literature for determining the relative density Dr from DMT gave inconsistent results compared to those obtained from dynamic soundings, especially in the near-surface zone, where high KD readings significantly overestimate relative density values. Assuming the results of DPL probe tests as reference values, a formula for the compaction index based on DMT soundings has been proposed. In contrast to the formulas commonly used in the literature, the proposed formula for the relative density depends not only on the horizontal stress index KD, but also on the dilatometer modulus ED. [ABSTRACT FROM AUTHOR]

The purpose of the study was to determine quantitative and relative indicators that significantly affect the physical properties of gray forest soils within the park ecological trail, to show changes in the compacted soil during natural recovery. Physical properties were determined in 3-fold repetition with the help of three-dimensional cylinders, followed by the calculation of their density and porosity. Population of physiologically active roots of the upper 0.5-meter layer of gray forest soils was determined by the monolith method in 5-fold repetition. It was found out that under the influence of anthropogenic trampling, the greatest degradation changes of the studied physical indicators are manifested in the upper 10-centimeter layer of gray forest soils. An increase in the density by 32.1–38.0% and solids content of the soil by 14.1–22.8%, as well as a decrease in the volume of pores by 32.0–44.3% was recorded and mass of physiologically active roots of woody plants by 84.6–91.2%. The natural restoration of soil occurs most intensively in the upper 5-cm layer. At the same time, over a 15-year period, the following changes were observed – a decrease in density by 19.5%, the content of solid particles by 9.9%, an increase in the content of pores by 39.1% and physiologically active roots woody plants by 330.0%. Quantitative and relative indicators of their physical properties obtained for anthropogenically compacted gray forest soils explain the changes in the mass of physiologically active roots of deciduous woody plants that grow in the centers with anthropogenically compacted soils.

The specific objective of this study is to find a suitable artificial neural network model for estimating the operation indicators (disturbed soil volume, effective field capacity, draft force, and energy requirement) of ploughing units (tractor disc) in various soil conditions. The experiment involved two different factors, i.e., (Ι) soil texture index and (ΙΙ) field work index, and included soil moisture content, tractor engine power, soil bulk density, tillage speed, tillage depth, and tillage width, which were linked to one dimensionless index. We assessed the effectiveness of artificial neural network and multiple linear regression models between the values predicted and the actual values using the mean absolute error criterion to test data points. When the artificial neural network model was applied, the mean absolute error values for disturbed soil volume, effective field capacity, draft force, and energy requirement were 69.41 m3·hr−1, 0.04 ha·hr−1, 1.24 kN, and 1.95 kw·hr·ha−1, respectively. In order to evaluate the behaviour of new models, the coefficient R2 was used as a criterion, where R2 values in artificial neural network were 0.9872, 0.9553, 0.9948, and 0.9718, respectively, for the aforementioned testing dataset. Simultaneously, R2 values in multiple linear regression were 0.7623, 0.696, 0.492, and 0.5572, respectively, for the same testing dataset. Based on these comparisons, it was clear that predictions using the artificial neural network models proposed are very satisfactory. [ABSTRACT FROM AUTHOR]

Until recently, mouldboard ploughing was used as the main tillage in almost the entire territory of Ukraine and Russia. However, mouldboard technologies contribute to the formation of a "plough pan", which contributes to additional soil compaction. The intensity of agricultural production exacerbated the problem of soil compaction by machine and tractor units. The over-consolidation of soil results in stunted plant root growth, lack of oxygen, and water and nutrient restrictions. Soil compaction can be reduced by deep local chiselling. The aim of the study was to determine the density of the soil at different depths during continuous traditional cultivation (reverse ploughing). The density of the soil was evaluated by resistance to penetration into the soil in a vegetable-forage crop rotation on an experimental field with continuous traditional tillage. The measurement of penetration resistance was carried out using an automatic electronic hardness tester "DATAFIELD". The boundaries of the experimental field were determined, a computer map of the experimental field was compiled with automatic "grid" of plot sizes, two-dimensional mapping was carried out, and the sequence and place of measurements were developed. As a result, the level of soil compaction at different penetration depths and resistance to root growth was determined. It has been established that with constant traditional reverse tillage, the soil at a depth of more than 10 cm is sufficiently compacted. At a depth of 15 cm, a strong compaction of the soil is observed, which indicates its physical and hydrological degradation. [ABSTRACT FROM AUTHOR]

The aim of the research was to identify the influence of environmental factors inherent in the alluvial and displaced sands of the study region on the growth of the Jack pine and the prospects for its cultivation. We found that the success of growth of Jack pine seedlings on sandy soils depends on a set of factors, which include the presence or absence, in the rhizosphere of sand, of humus impurities and genetic horizons of zonal soils, silty or loamy layers, soil density and composition of pine stands formed in the cultivation. On alluvial sands, sparse forests of Jack pine and Scots pine with a density of 0.3 units were formed. The yield of seeds from Jack pine cones was 1–2% higher than the normative values, and the mass of 1000 seeds was 50% higher. Jack pine seedlings grow according to I class of productivity on displaced sands, with an admixture of humus mass and remnants of genetic horizons of zonal soils at the root depth. In the rhizosphere of the stand, the roots of Jack pine seedlings occupied 78% of the mass of all roots that inhabited a metre-thick sand. Jack pine seedlings that fall under the canopy of Scots pine fall out of the plantations due to drying, which indicates their demand for light and appropriateness of growing Jack pine in solitary plantings or in mixed low-density plantations with Scots pine. [ABSTRACT FROM AUTHOR]

Current paper focuses on the laboratory experiments performed wit aim to test the deformation in the frozen loam soil specimens. Loam frozen soils are subject to the external effects, such as climate and environmental impacts including temperature changes. Soil heave is one of the key features restraining possible area development: construction of buildings, roads and railways. Necessarily, this requires the improvements of methods of the assessment of heave. This research evaluated the compressive strength and deformation in several specimens of the frozen soil. The approach included varying load and physical properties of soil specimens: porosity, pore filling, moisture, density of soil particles and dry soil density. Besides during the experiment, the external conditions were changed: decreased temperature and increased load pressure. The experiment is based on the UPG-MG4-01. The paper presented the laboratory tests of heave and compressive strength of the frozen soils using applied geotechnical methods. [ABSTRACT FROM AUTHOR]

The objective of the study was to quantify the differences in soil physical indicators between inter-track (uncompacted) zone and track (compacted) zone created by four passages of a wheeled tractor (Landini Globus 70/DBKL Techno). Field studies were carried out on plots of the Vicarello experimental station, Tuscany (43° 27' N, 11° 30' E). A local average annual precipitation is 678 mm and average annual air temperature is 12.7 °C with absolute extreme values -10 °C and 40 °C. Bulk density, moisture content, water-stable aggregation, and penetration resistance were determined by conventional methods in the 0–0.40 m soil layers. The results showed that the 0.05–0.10 m soil layer, compared to the 0.20–0.25 m and 0.35–0.40 m soil layers, showed a higher degree of compaction by tractor wheels. In this soil layer, significant (at P <0.05 and <0.01) differences between the inter-track and track zone were observed for bulk density (1.18 ±0.10 g.cm−3 and 1.35 ±0.10 g.cm-3) and moisture content (24.9 ±2.3% and 27.9 ±2.3% of volume). Passages of tractor even resulted in an insignificant increase of total amounts (from 66.2 ±4.7% to 68.6 ±2.7%) and mean weight-diameters (from 2.29 ±0.30 mm to 2.40 ±0.04 mm) of water-stable aggregates. There were no significant differences in average penetration resistance of the uppermost 0–0.10 m soil layers between the inter-track (0.77 ±0.26 MPa) and track zone (0.64 ±0.12 MPa). Average soil penetration resistance was significantly (P <0.001) higher in the 0–0.40 m layer of the track zone (1.07 ±0.23 MPa) than in that of the inter-track zone (0.76 ±0.11 MPa). [ABSTRACT FROM AUTHOR]

This study shows the impact of the reforestation program by some tree species (Pinus halepensis, Cupressus sempervirens and Eucalyptus camaldulensis) on the soil physicochemical parameters in south-western Algeria steppe. The study was realized on soil samples from the Touadjeur site. One hundred soil samples were taken from the field, followed by physicochemical analyses in the laboratory. A comparison of the soil elements between reforested and unreforested sites considered as a control was carried out. The results show that there are differences in the physicochemical parameters of the soil between the reforestation and the non-reforestation ones constituted by a steppe vegetation. The ANOVA one way test shows a highly significant difference change in soil physical parameters, moisture, holding capacity and saturated hydraulic conductivity, but no change in apparent density, actual density and color. Also, from a chemical point of view, the differences concern the organic matter, organic carbon, pH and certain soil contents. The main differences in soil properties between the reforestation sites and the control site, reflect the consequences of forest management adopted by the forest services, most probably the choice of reforestation species. [ABSTRACT FROM AUTHOR]

In early 2016, hop plants were introduced into Florida. By late 2016, the hop plants were showing stunted growth and were heavily parasitized by Meloidogyne javanica. In this study, we determined host susceptibility of 14 hop cultivars to M. javanica in a greenhouse experiment and monitored population development of plant-parasitic nematode species in the root zone of 17 hop cultivars planted in three newly established hop yards in Florida. Plant-parasitic nematodes in the rooting zone soil of field grown hop plants included M. javanica, Pratylenchus brachyurus, Paratrichodorus minor, Belonolaimus longicaudatus, Xiphinema setariae/vulgare complex, Mesocriconema xenoplax, and Helicotylenchus dihystera; however, soil population densities of P. minor, B. longicaudatus, X. setariae/vulgare complex, M. xenoplax, and H. dihystera remained low through the study. Root galling, M. javanica egg production, and soil population densities of M. javanica were consistently large on the ‘Canadian Red Vine’, ‘Centennial’, ‘Chinook’, and ‘Comet’ cultivars, and small on the ‘Galena’ and ‘Triple Perle’ cultivars. No differences were observed in soil population densities of P. brachyurus among hop cultivars. Overall, our study provides the first report of plant-parasitic nematode population development in the root zone on hop cultivars planted in Florida. [ABSTRACT FROM AUTHOR]

An experimental study was carried out to understand the behaviour of a laterally loaded single pile on a slope with different length/diameter (L/D) ratios driven into cohesionless soil for a relative density of 70%. Static loading was applied in both forward and reverse directions for slopes of 1V:1.5H, 1V:2H, and 1V:2.5H for a constant L/D ratio representing flexible pile behaviour. It was observed that the load ratio (load on a sandy slope to the horizontal ground) decreased with an increase in the slope's angle. The post-static behaviour of the pile under the same conditions was also studied to evaluate the elastic displacement, which increased with an increase in the slope's angle. Due to the constant passive resistance under the reverse loading, the lateral load on the slope's crest was almost equal to the horizontal ground's condition. The effect of the L/D ratio was studied by varying the length and diameter and by maintaining the other parameter as a constant. The lateral load of a pile increased with an increase in its length and diameter. [ABSTRACT FROM AUTHOR]

Application of dried plant water soluble extracts in soil Pb decontamination is rear, but advantageous due to their ecological biodegradability. Single batch laboratory scale suitability of Terminalia mantaly, Panicum maximum, Eleusine indica and water as washing solutions for Pb removal from contaminated and spiked soils at different soil pulp densities (3%, 6%, 9%, 12%, 15% and 18%) and washing time (1, 3, 6, 12, 24 and 96 h) was investigated. Washings of Terminalia mantaly and Panicum maximum proved more efficient comparatively for contaminated soil with Pb removal efficiency of 27.2±0.64% and 27.0±0.52% respectively at 3% soil pulp density and washing time of 96 h. Removal efficiency increased with increasing washing time but decreased with increasing of soil pulp density. Furthermore, water was found effective for removing Pb from spiked soils with maximum removal efficiency of 74.5±3.38% at 3% soil pulp density after 1 h washing. High exchangeable fraction of Pb (81.2%) in spiked soil makes water more suitable against other washing solutions. Statistical t-testing showed significant difference in Pb removal efficiency between contaminated and spiked soils for all four washing solutions, reflecting differences in geochemical phases of Pb in both soils. Terminalia mantaly and Panicum maximum showed promising result in soil washing and have potential for application in Pb removal from contaminated soils. However, chemical modifications are needed to enhance and improve on their efficiencies. Similarly, more information is needed to predict and model removal efficiencies when multiple washing steps are applied. [ABSTRACT FROM AUTHOR]

No nematicide has been registered for controlling plant-parasitic nematodes in sugarcane in Japan. Greenhouse and field experiments were conducted to evaluate the efficacy of the phenylpyrazole insecticide fipronil (0.3-0.45 kg a.i./ha) against the root-lesion nematode, Pratylenchus zeae, which is an important plant-parasitic nematode species associated with sugarcane ( Saccharum spp. hybrids) in Okinawa, Japan. Both experiments showed a reduction of P. zeae population densities in sugarcane roots to 27 to 56% of the non-treated control after 7 wk in the greenhouse experiment and 3 months in the field experiment (two trials). In contrast, P. zeae population densities in soil were not reduced by the fipronil treatment. At harvest, sugarcane yields in the field experiment were significantly increased by 6 to 8% in the fipronil treated plots compared to the non-treated control. The data showed that fipronil reduced numbers of P. zeae in sugarcane roots at the early stage of sugarcane seedling growth resulting in increased sugarcane yields. This is the first report of nematicidal activity of fipronil against P. zeae under field conditions. [ABSTRACT FROM AUTHOR]

The need to house population in urban areas is expected to rise to 66% in 2050, according to United Nations. The replacement of natural permeable green areas with concrete constructions and hard surfaces will be noticed. The densification of existing built-up areas is responsible for the decreasing vegetation, which results in the lack of evapotranspiration cooling the air. Such decreasing vegetation causes urban heat islands. Since roofs and pavements have a very low albedo, they absorb a lot of sunlight. Several studies have shown that natural and permeable surfaces, as in the case of green roofs, can play crucial role in mitigating this negative climate phenomenon and providing higher efficiency for the building, leading to savings. Such as water saving, what is the main idea of this research. [ABSTRACT FROM AUTHOR]

The present study wants to highlight the influence it has compacting process on the variation of hydrophysical.properties of three types of soil In solving this unfavorable soil phenomenon this paper tries to noting the main effects exerted by the compaction process on the hydrophysical.properties distribution in time and space by applying laboratory methods for determining the physical and hydraulic properties of soils in Breazu and Dancu areas. Principal physical characteristics were determined: soil density, soil bulk density, texture and soil porosity. Hydraulic properties analyzed in order to mark the variation of water regime were: hydraulic conductivity (saturated and unsaturated) and soil suction. All these basic attributes of soil were determined in laboratory methods of applying wish traced internationally. [ABSTRACT FROM AUTHOR]

Forestry machine traffic causes a number of changes that are not immediately reflected in morphological changes of surface soil. These changes are physical and chemical in nature. The change in subsurface soil CO2 concentration was one of the parameters of interest. The critical CO2 concentration is thought to fluctuate around 0.6%. The primary objective of this paper was to determine the impact of forestry machine traffic on subsurface soil CO2 concentration. We measured CO2 concentration in the areas undisturbed by machinery and in the ruts in skid trails in eight forest stands. The measurements were performed using a Vaisala MI 70 meter. The results confirmed significant differences in gas concentrations between the individual measurement sites. In the ruts of the skid trails, CO2 concentrations fluctuated in a range of 0.5 to 2.81% and significantly exceeded the critical concentration. Moisture content and bulk density had a significant impact on the change in gas concentration beneath the surface, which was confirmed by multivariate analysis of variance that revealed that the values of the coefficient of correlation fluctuated in a range of 0.39 to 0.74. [ABSTRACT FROM AUTHOR]

The loading of natural and anthropogenic soils can be determined in the field by using dynamic probing tests. This method is based on the measurement of the resistance, which the studied soil poses on the probe tip when it penetrates the soil. The most typical probe tips are cylindrical, conical and rarely cross-shaped. The penetrometer penetrates the soil by a hammer with a given mass freely falling from the height required in the test. The penetration resistance is defined by the numbers of blows required to drive the penetrometer over the defined distance ( Nk), where k = 10, 15(20) or 30 cm. The paper presents the results of heavy dynamic probing tests DPH with a hammer mass of 50 kg and penetration depth up to 30 m, carried out in an anthropogenic made ground in order to determine the soil loading for the foundation of the designed building. [ABSTRACT FROM AUTHOR]

The concept of different compositional biomass is introduced to enhance the binding properties and utilize the use of different seasonal biomasses. The effect of densification on the heating values of single pure and mixed compositional biomasses is observed with and without applying special type of pretreatment named as 'Torrefaction'. The moisture contents and bulk densities were also calculated for these briquettes. The effects of average moisture contents and bulk density (which show the swelling nature) on the heating values are also observed. The experiments have been performed on the pelletizer equipment to form briquetted biomass and bomb calorimeter was used to determine the calorific values of different briquettes. Finally, the percentage decrease in the average moisture contents of different categories of torrefied briquettes from non-torrefied briquettes were also calculated and compared. [ABSTRACT FROM AUTHOR]

In this paper, a method for the treatment of the swelling of expansive soil is numerically simulated. The method is simply based on the embedment of a geogrid (or a geomesh) in the soil. The geogrid is extended continuously inside the volume of the soil where the swell is needed to be controlled and orientated towards the direction of the swell. Soils with different swelling potentials are employed: bentonite base-Na and bentonite base-Ca samples in addition to kaolinite mixed with bentonite. A numerical analysis was carried out by the finite element method to study the swelling soil's behavior and investigate the distribution of the stresses and pore water pressures around the geocells beneath the shallow footings. The ABAQUS computer program was used as a finite element tool, and the soil is represented by the modified Drucker-Prager/cap model. The geogrid surrounding the geocell is assumed to be a linear elastic material throughout the analysis. The soil properties used in the modeling were experimentally obtained. It is concluded that the degree of saturation and the matric suction (the negative pore water pressure) decrease as the angle of friction of the geocell column material increases due to the activity of the sand fill in the dissipation of the pore water pressure and the acceleration of the drainage through its function as a drain. When the plasticity index and the active depth (the active zone is considered to be equal to the overall depth of the clay model) increase, the axial movement (swelling movement) and matric suction, as a result of the increase in the axial forces, vary between this maximum value at the top of the layer and the minimum value in the last third of the active depth and then return to a consolidation at the end of the depth layer. [ABSTRACT FROM AUTHOR]

We developed an automated miniature constant-head tension infiltrometer that measures very small infiltration rates at millimetre resolution with minimal demands on the operator. The infiltrometer is made of 2.9 mm internal radius glass tube, with an integrated bubbling tower to maintain constant negative head and a porous mesh tip to avoid air-entry. In the bubbling tower, bubble formation and release changes the electrical resistance between two electrodes at the air-inlet. Tests were conducted on repacked sieved sands, sandy loam soil and clay loam soil, packed to a soil bulk density ρd of 1200 kg m-3 or 1400 kg m-3 and tested either air-dried or at a water potential ψ of -50 kPa. The change in water volume in the infiltrometer had a linear relationship with the number of bubbles, allowing bubble rate to be converted to infiltration rate. Sorptivity measured with the infiltrometer was similar between replicates and showed expected differences from soil texture and ρd, varying from 0.15 ± 0.01 (s.e.) mm s-1/2 for 1400 kg m-3 clay loam at ψ = -50 kPa to 0.65 ± 0.06 mm s-1/2 for 1200 kg m-3 air dry sandy loam soil. An array of infiltrometers is currently being developed so many measurements can be taken simultaneously. [ABSTRACT FROM AUTHOR]