scholarly journals Collapse settlement of dump soils revealed by studies on soil samples of modelled lithology and lump-size distribution

2014 ◽  
Vol 59 (2) ◽  
Author(s):  
Henryk WOŹNIAK
Keyword(s):  
Size Distribution ◽  
Soil Samples ◽  
Lump Size

scholarly journals Hydraulic Properties of Forest Soils with Stagnic Conditions

Forests ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1113
Author(s):  
Stefan Julich ◽  
Janis Kreiselmeier ◽  
Simon Scheibler ◽  
Rainer Petzold ◽  
Kai Schwärzel ◽  
...  
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Hydraulic Properties ◽  
Water Retention ◽  
Soil Samples ◽  
Stagnant Water ◽  
Infiltration Rates ◽  
Retention Characteristic ◽  
Water Conditions

Tree species, e.g., shallow vs. deep rooting tree species, have a distinct impact on hydrological properties and pore size distribution of soils. In our study, we determined the soil hydrologic properties and pore size distribution at three forest stands and one pasture as reference on soils with stagnant water conditions. All sites are located in the Wermsdorf Forest, where historical studies have demonstrated severe silvicultural problems associated with stagnant water in the soil. The studied stands represent different stages of forest management with a young 25-year-old oak (Sessile Oak (Quercus petraea) and Red oak (Q. robur)) plantation, a 170-year-old oak stand and a 95-year-old Norway Spruce (Picea abies) stand in second rotation. We determined the infiltration rates under saturated and near-saturated conditions with a hood-infiltrometer at the topsoil as well as the saturated hydraulic conductivity and water retention characteristic from undisturbed soil samples taken from the surface and 30 cm depth. We used the bi-modal Kosugi function to calculate the water retention characteristic and applied the normalized Young-Laplace equation to determine the pore size distribution of the soil samples. Our results show that the soils of the old stands have higher amounts of transmission pores, which lead to higher infiltration rates and conductance of water into the subsoil. Moreover, the air capacity under the old oak was highest at the surface and at 30 cm depth. There was also an observable difference between the spruce and oak regarding their contrasting root system architecture. Under the oak, higher hydraulic conductivities and air capacities were observed, which may indicate a higher and wider connected macropore system. Our results confirm other findings that higher infiltration rates due to higher abundance of macropores can be found in older forest stands. Our results also demonstrate that an adapted forest management is important, especially at sites affected by stagnant water conditions. However, more measurements are needed to expand the existing data base of soil hydraulic properties of forest soils in temperate climates.

scholarly journals Risiko des Eintrags von Phosphor in den Hallwilersee durch Bodenerosion

2015 ◽  
Vol 70 (3) ◽  
pp. 193-198 ◽  
Author(s):  
S. Müller ◽  
D. Schaub
Keyword(s):  
Particle Size ◽  
Soil Erosion ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Surface Waters ◽  
Aggregate Stability ◽  
Eutrophic Lake ◽  
Soil Samples

Abstract. An important factor in the release of phosphorus by soil erosion, with corresponding consequences on the quality of surface waters, is the formation of aggregates and their stability. Around the eutrophic Lake Hallwil six arable lands were examined in five repetitions regarding aggregate and particle size distribution, P-contents of the different fractions and aggregate stability. Central to this was the use of the setting column for fractionation of soil samples. In the case of Lake Hallwil the risk of phosphorus discharges by soil erosion seems low since the phosphorus is mainly bound in aggregates which are transported over short distances only. Thus other pathways (runoff from grassland, leaching via drains) may be more important.

scholarly journals Assessment and Analysis of Precambrian Basement Soil Deposits Using Grain Size Distribution

2020 ◽  
Vol 66 (4) ◽  
pp. 235-243
Author(s):  
Gideon Layade ◽  
Charles Ogunkoya ◽  
Victor Makinde ◽  
Kehinde Ajayi
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Textural Properties ◽  
Soil Samples ◽  
Sieve Analysis ◽  
Precambrian Basement ◽  
Statistical Parameters ◽  
Fine Grained ◽  
Transportation History

AbstractThe article presents the grain size distribution of soil samples from the Precambrian basement within the purview of the textural properties, deduced transportation history and the numerical assessments using statistical parameters. The fourteen soil samples collected from the study area were subjected to sieve analysis in the laboratory for the determination of their grain size distribution. The statistical parameters’ study includes the graphic mean, skewness, sorting and kurtosis. The result of the analysis of the soil samples ranged from coarse to fine-grained samples, moderately and poorly sorted, positively and negatively skewed and the kurtosis also shows leptokurtic as the most dominant which suggests the samples poorly distributed and moderately sorted at the centre of the grain size distribution. These results also suggest the geological environment of the soil samples could be responsible for the poorly and moderately sorted exhibited by the samples deposited in the location.

Micro-morphological analysis of the effect of sampling by the volumetric ring method on soil structure

2007 ◽  
Vol 3 (1) ◽  
pp. 1-19
Author(s):  
Luiz Pires ◽  
Miguel Cooper ◽  
Nivea Dias ◽  
Osny Bacchi ◽  
Klaus Reichardt
Keyword(s):  
Image Analysis ◽  
Bulk Density ◽  
Size Distribution ◽  
Soil Structure ◽  
Soil Bulk Density ◽  
Soil Samples ◽  
Pore Shape ◽  
Sampling Device ◽  
Structure Changes ◽  
Ring Method

This report investigates the effect of sampling by the volumetric ring method on pore size number and shape distributions. Soil porosity was analyzed using the micromorphological image analysis technique, which helped to explain soil structure changes near the border of samples collected in cylinders and provided detailed information about pore shape, number, and size distribution variations along the samples. Compaction due to sampling affects mainly large irregular and rounded pores of the soils utilized in this study. When evaluating inaccuracies in density measurements due to the compacted regions caused by the sampling device the average soil bulk density for each soil resulted in the ranges of 1.72 ± 0.05 g.cm −3 for Geric Ferralsol soil, 1.66 ± 0.03 g.cm −3 for Eutric Nitosol soil and 1.33 ± 0.05 g.cm −3 for Rhodic Ferralsol soil, respectively. When calculating the average soil bulk density over smaller regions, e.g. in the center of each sample (area of 17.14 mm 2 ) results reduced to 1.64 ± 0.05 g.cm −3 with Geric Ferralsol soil, 1.56 ± 0.03 g.cm −3 with Eutric Nitosol soil and 1.29 ± 0.10 g.cm −3 with Rhodic Ferralsol soil, respectively. These results clearly indicate the effect of sampling by the volumetric ring method. The use of image analysis was essential to explain compaction differences close to the border of the samples collected using cylinders (volumetric ring method) and provided detailed information about pore shape and size distribution variations within soil samples. The results are useful as indicators of the consequences of sampling on the quality of soil samples.

scholarly journals A scaling approach, predicting the continuous form of soil moisture characteristics curve, from soil particle size distribution and bulk density data

2013 ◽  
Vol 10 (11) ◽  
pp. 14305-14329 ◽  
Author(s):  
F. Meskini-Vishkaee ◽  
M. H. Mohammadi ◽  
M. Vanclooster
Keyword(s):  
Particle Size ◽  
Soil Moisture ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Characteristic Curve ◽  
Soil Samples ◽  
Continuous Form ◽  
Packing Parameter ◽  
Physically Based ◽  
Moisture Characteristic

Abstract. A substantial number of models, predicting the Soil Moisture Characteristic Curve (SMC) from Particle Size Distribution (PSD) data, underestimate the dry range of the SMC especially in soils with high clay and organic matter contents. In this study, we applied a continuous form of the PSD model to predict the SMC and subsequently, we developed a physically based scaling approach to reduce the model's bias at the dry range of the SMC. The soil particles packing parameter, obtained from the porosity was considered as a characteristic length. The model was tested by using eighty-two soil samples, selected from the UNSODA database. The result showed that the scaling approach properly estimate the SMC for all soil samples. In comparison to the formerly used physically based SMC model, the proposed approach improved the model estimations by an average of 30% for all soil samples. However, the advantage of this new approach was larger for the fine and medium textured soils than that for the coarse textured soil. In view that in this approach there is no further need for empirical parameters, we conclude that this approach could become applicable for estimating SMC at the larger field scale.

scholarly journals Analysis of the Correlation Between Strength and Fractal Dimension of Gravelly Soil in Debris-flow Source Areas

2016 ◽  
Vol 10 (1) ◽  
pp. 866-876 ◽  
Author(s):  
He Na ◽  
Li Tao ◽  
Zhong Wei ◽  
Tom Cosgrove ◽  
Zeng Mei
Keyword(s):  
Particle Size ◽  
Fractal Dimension ◽  
Internal Friction ◽  
Particle Size Distribution ◽  
Debris Flow ◽  
Size Distribution ◽  
Fractal Theory ◽  
Soil Samples ◽  
Gravelly Soil ◽  
Cohesion Force

Particle size distribution of gravelly soil plays a crucial role in debris flow initiation. For better understanding the mechanism of debris flow formation, two crucial mechanical property parameters of the gravelly soil are required to be studied meticulously: hydraulic conductivity and strength. With the aim of measuring the composition of the gravelly soil, 182 soil samples were taken from debris flow prone areas. With the aid of a sieve test, the particle size distribution of the samples can be obtained and analyzed. Then fractal theory was employed to compute the fractal dimension of the soil samples. By analyzing the results of sieve test (particle size distribution curves) and the results of the fractal theory calculations, the relationship between fractal dimension and particle size distribution can be explored. The results illustrate that the particle compositions of the gravelly soil tends to remain uniform as the fractal dimension increases. Moreover, as the coarse particle content increases, the fractal dimension decreases. To better understand the formation mechanism of debris flows, direct shear tests were conducted. Subsequently the experimental results were analyzed. By analysis, the following conclusions can be drawn: the soil strength decreases as the fractal dimension increases, and for soils with lower moisture content and identical dry density, a linear relationship between fractal dimension and cohesion force was identified. Moreover, cohesion force and internal friction force both decrease as the fractal dimension increases, but the internal friction angle decreases slightly while the cohesion force decreases greatly. Therefore we concluded that soil strength decreased mainly due to the reduction in cohesion force.

IMPACT OF REFRACTIVE INDEX ON DETERMINING THE PARTICLE SIZE DISTRIBUTION OF SOIL SAMPLES IN THE VALLEY AND RIDGE AND PIEDMONT PROVINCES OF VIRGINIA

2020 ◽  
Author(s):  
Dhanuska B. Wijesinghe ◽  
◽  
Andrew Everett ◽  
Prabhashi W. Withana Gamage ◽  
Kristen St. John ◽  
...  
Keyword(s):  
Particle Size ◽  
Refractive Index ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Soil Samples

scholarly journals Soil structure degradation in patches of alfalfa fields

2010 ◽  
Vol 67 (5) ◽  
pp. 604-610 ◽  
Author(s):  
María Celeste Miretti ◽  
Silvia Imhoff ◽  
Alvaro Pires da Silva ◽  
Raúl Lavado
Keyword(s):  
Size Distribution ◽  
Soil Samples ◽  
Root Penetration ◽  
Mechanical Resistance ◽  
Water Release ◽  
Undisturbed Soil ◽  
Physical Quality ◽  
Soil Physical Quality ◽  
Lower Productivity ◽  
Structure Degradation

Alfalfa (Medicago sativa) is the basic forage resource for milk production in the flat Pampa of the Santa Fe Province of Argentina. However, the presence of microrelief with patches threatens the expansion of the area cultivated with alfalfa. The lower productivity in the patches is attributed to the inferior soil physical quality. The objectives of this study were to quantify indicators of soil physical quality and to establish the soil properties that would affect the alfalfa productivity in patches (PA) and normal areas (NA). Additionally, the macro and micro nutrient contents in both areas were determined. The experiment was carried out on an Aquic Argiudoll. Eighteen sampling sites, nine in NA and nine in PA were established. At each site, undisturbed soil samples (5 × 5 cm cores) were collected to measure soil bulk density (Bd), soil resistance to root penetration (PR), effective stress (σ), the water release curve and the least limiting water range (LLWR). Disturbed soil samples were also taken to determine macro and micronutrient contents, and particle size distribution. Non differences were detected for soil chemical properties between PA and NA. Aggregate size distribution indicated predominance of small aggregates in PA. Bd, PR and s were higher in PA than in NA, while the LLWR was narrower. Inadequate aeration under conditions of excessive soil moisture and inappropriate soil mechanical resistance when the soil is dry would affect alfalfa productivity. The overall results indicate that the soil physical quality in PA is lower than in NA.

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