Basic Physical Properties Of Soil Research Articles

The Effects of Hedgerows Shading on Soil Temperature and Gravimetric Soil Water Content

This study sets out to examine the effects of hedgerow shading on soil physical properties, specifically soil gravimetric water content and soil temperature. Analyses of both soil parameters were conducted at two locations with different shade proportion. The aim of the study was to address the links between hedgerow shading and basic physical soil properties which could be significant both for agricultural production and for ecological processes in agroecosystems. At both locations, soil samples and measurements were taken at different distances from hedgerow and in different time intervals. Diurnal shading variation at certain distances from the hedgerow on Location 1 and 2 was calculated with the software toll for Arboriculturists. At Location 1 shading is consistently high throughout the year, ranging from 76 to 100%. In contrast, shading at Location 2 varies from 1 to 25%. The results reveal that hedgerows at Location 1, do not have a statistically significant impact on gravimetric soil water content and soil temperature across the entire plot surface. Additionally, the percentage of shading is only marginally decreases with distance. Conversely, Location 2 exhibits an increase in soil temperature and a slight but (non-significant) decrease in soil gravimetric watercontent as the distance from the hedgerow increases., The total mean shading at Location 2 is considerably lower compared to Location 1, and the shading percentage declines more at the distance from the hedgerow increases. Overall, lower soil temperatures and higher gravimetric soil water content where observed at the more shaded Location 1. The research outcomes are helpful in agricultural production planning as well as in the evaluation of hedgerows for the needs of agricultural policy.

Development Characteristics and Sensitivity Analysis of Expansive Soil Slope

According to laboratory tests of soil samples of Wangyan highway landslide, the mechanism of formation of landslide and the degree of sensitivity of various factors to slope stability are analyzed. It is found that the landslide is destroyed by the properties of expansive soil, the existence of water in the cracks, the loading of artificial filling, and the traction of old landslide. The soil samples were tested for SEM and MIP tests by lyophilization, and the particle morphology, the mode of combination, porosity, and connectivity of the sliding zone soil were observed by a scanning electron microscope. Results show that the sliding zone developed many microfissures and the clay minerals arranged tightly, the pore of size < 0.1 μm was 60% in undisturbed soil, and the pores of different sizes were distributed uniform in reconstituted soil. The undisturbed soil had typical nonlinear rheological property; The deformation rate of reconstituted was bigger; When the load was 50 kPa and 200 kPa, an expansion phenomena occurred in the sliding zone, which indicated that microstructure could influence the deformation. The strength attenuation of expansive soil slope due to the high content of montmorillonite in the sliding body and the high water content in the cracks are two major factors of the Wangyan highway landslide. Based on the results of previous studies, the a , n , and m values of fitting parameters of Fredlund-Xing soil-water characteristic curve are predicted by using the basic physical properties of soil. It is found that the air intake value and residual suction value of filled soil (loose and broken) and completely weathered sandstone are small, and the water holding capacity in the middle suction range is relatively good. Then, the finite difference software Flac3D was used to build a three-dimensional geological model. The influence of water content, highway load, filling weight, and slope angle on slope stability is considered comprehensively. The order of sensitivity of slope stability about various factors is as follows: water content > slope angle > highway load > filling weight . The results of research can provide a scientific basis for the treatment, protection, and reinforcement of the Wangyan highway landslide.

Knowledge Based Prediction of Standard Penetration Resistance of Soil Using Geotechnical Database

The current study aimed at predicting standard penetration resistance (N) of soil using particle sizes and Atterberg's limits. The geotechnical database was created subsequent to the field and laboratory testing. The sample collection points were distributed in a mesh grid pattern to have uniform sampling consistency. Artificial Neural Networks (ANN) were trained on the database to build a knowledge-based understanding of the interrelation of the given soil parameters. To check the efficacy of the model, the validation was carried out by predicting standard penetration resistance (N) for another 30 samples which were not included in the training data (444 samples). The trained ANN model has been found to predict N values in close agreement with the N values measured in the field. The novelty of the research work is the standard penetration prediction employing basic physical properties of soil. This proves the efficacy of the proposed model for the target civil engineering application. Doi: 10.28991/CEJ-SP2021-07-01 Full Text: PDF

Soil particle density as affected by soil texture and soil organic matter: 2. Predicting the effect of the mineral composition of particle-size fractions

The particle density of soil (ρS) represents one of the basic physical properties of soil. However, measurement of this parameter is not part of common routine soil inventories in most countries. Therefore, pedotransfer functions (PTFs) were developed to calculate ρS. Here, we used a complex, hierarchically structured PTF to calculate ρS, separating the soil mineral substance (SMS) into clay, silt and sand fractions as well as separating the soil organic matter (SOM) into heavy-density and low-density fractions. This PTF was recently published, and here, we introduced an additional hierarchical level to consider the particle size fraction-dependent effect of the mineral composition on ρS. This extended PTF was calibrated and validated using data from soils of 16 German long-term experiments contrasting in soil texture and in soil mineral composition. Χ-ray diffraction analysis was applied to identify the mineralogical composition of the clay, silt and sand fractions. We fitted the particle densities of the identified minerals occurring in the respective particle size fractions by minimising the squared differences between the measured and predicted ρS. The model performed very well (RMSE = 0.011 Mg m−3 soil). According to the mechanistic base of the model and its hierarchical structure, it is very easy to include available information about the composition of any fraction or subfraction of soil mineral substances and to use the model to calculate the ρS corresponding to the specific site conditions.

IMPACT OF REK BITOLA UPON PHYSICAL AND CHEMICAL PROPERTIES OF THE SOIL

Contamination of soil by air sediment emitted from coal based thermal power plants is one of the basic ecological issue. The aim of this research is to define the impact of production of REK Bitola on the soils from defined microlocality in Pelagonia basin. Chemical, mineralogical and granulometric analyses were performed upon the soil samples. Also basic physical properties of the soil are determined. The chemical composition of the air sediment was also determined. According to the measured values and statistical data of REK Bitola, an average cumulative deposited quantity of air sediment is calculated, as well as the cumulative deposited quantity of trace elements in soil. The deposited air sediment has a negative impact on some of the basic physical and chemical properties of soil, but has no significant effect on the change in porosity and soil properties resulting from it.

Wyznaczanie modułu odciążenie – obciążenie powtórne dla gruntów głębokiego podłoża

Soil parameters from triaxial tests are required for application of hardening soil small strain model in the geotechnical numerical analyses. In addition to the parameters such as the initial stiffness modulus (E0), stiffness modulus at 50% of the deviatoric stress value (E50), unloading– –reloading modulus (Eur) should be evaluated. The paper presents the test results for soil samples collected from the boreholes approximately 80 m deep. The main focus is put on evaluation of Eur parameter as requiring more advance tests in comparison to E0 and E50 parameters that may be evaluated on the basis of standard triaxial tests with shear wave velocity measurement. Based on the triaxial test results a correlation formula is proposed between Eur modulus and basic physical properties of soil and changes of effective stress values. The triaxial test procedures aimed at evaluation of E0, E50 and Eur are also presented.

The Influence of Basic Physical Properties of Soil on its Electrical Resistivity Value under Loose and Dense Condition

Electrical resistivity technique has become a famous alternative tool in subsurface characterization. In the past, several interpretations of electrical resistivity results were unable to be delivered in a strong justification due to lack of appreciation of soil mechanics. Traditionally, interpreters will come out with different conclusion which commonly from qualitative point of view thus creating some uncertainty regarding the result reliability. Most engineers desire to apply any techniques in their project which are able to provide some clear justification with strong, reliable and meaningful results. In order to reduce the problem, this study presents the influence of basic physical properties of soil due to the electrical resistivity value under loose and dense condition. Two different conditions of soil embankment model were tested under electrical resistivity test and basic geotechnical test. It was found that the electrical resistivity value (ERV, ρ) was highly influenced by the variations of soil basic physical properties (BPP) with particular reference to moisture content (w), densities (ρbulk/dry), void ratio (e), porosity (η) and particle grain fraction (d) of soil. Strong relationship between ERV and BPP can be clearly presents such as ρ ∞ 1/w, ρ ∞ 1/ρbulk/dry, ρ ∞ e and ρ ∞ η. This study therefore contributes a means of ERV data interpretation using BPP in order to reduce ambiguity of ERV result and interpretation discussed among related persons such as geophysicist, engineers and geologist who applied these electrical resistivity techniques in subsurface profile assessment.

The impact of different tillage treatments on hydraulic conductivity of loamy soil

Water infiltration into the soil profile, surface runoff and soil erosion in arable lands depend on the conditions of the top layer. The tillage treatment of the top layer plays a key role in changes of the hydro-physical properties, mainly saturated hydraulic conductivity Ks of the surface layer. The aim of this study was to asses the impact of different tillage treatments on hydraulic conductivity in the locality Bohaté Málkovice. Field experimental works in this area were performed in 2009 and were repeted in 2011 on Haplic Chernozem, medium heavy loamy soil. The experimental area was divided into two parts; top layer of these plots was cultivated by applying conventional and reduced tillage treatment. Both these plots were sown with spring barley (Hordeum vulgare). For the field measurement of water infiltration into the soil was used double-ring infiltrometer (2009, 2011) and Minidisk infiltrometer (2011). Near the point were the infiltration was measured, the soil samples were always collected for laboratory determination of basic physical properties of soil (bulk density, porosity, initial and saturated water content, aeration of the soil) and saturated hydraulic conductivity Ks. For laboratory determination of Ks was used permeameter with constant gradient.For evaluation of saturated hydraulic conductivity Ks using the double-ring infiltration method was used Philip’s three-parameter equation and for evaluation of unsaturated hydraulic conductivity K(h) using Minidisk infiltrometer was used Zang’s method. After two years of using repeatedly applied different tillage treatments was significantly influenced saturated hydraulic conductivity Ks. The Ks value increased approximately six times for reduced tillage and more than three times for conventional tillage. Laboratory determined average values of Ks were compared with the average estimates of Ks from infiltration tests. The results were burdened by a number of errors (compaction, preferential flow). These mean values were higher for conventional and reduced tillage. Unsaturated hydraulic conductivity K(−2cm) for reduced tillage was higher, for conventional tillage decreased approximately three times.

Soils and Fertilizers for Master Gardeners: Soil Physical Properties

Revised! SL268, a 4-page illustrated fact sheet by Amy L. Shober, is part of series entitled Soils and Fertilizers for Master Gardeners. It describes some of the basic physical properties of soil. Includes reference. Published by the UF Department of Soil and Water Science, January 2009.