scholarly journals Soil Structure and Soil Organic Matter of Selected Soil Types in Different Ecosystems

2013 ◽  
Vol 59 (1) ◽  
pp. 1-8
Author(s):  
Erika Tobiašová ◽  
Vladimír Šimanský ◽  
Bożena Dębska ◽  
Magdalena Banach-Szott
Keyword(s):  
Particle Size ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Soil Structure ◽  
Soil Types ◽  
Productive Capacity ◽  
Important Indicator

In this study, differences in soil structure in different ecosystems (forest, meadow, urban, and agro-ecosystem) and soil types (Haplic Chernozem, Haplic Luvisol, Haplic Stagnosol) with a dependence on the influence of quantity and quality of soil organic matter and the particle size distribution on fraction composition of soil aggregates were compared. Soils had different productive capacity and particle size distribution. The most favourable soil structure was in the agro-ecosystem, then in forest, meadow, and urban ecosystem. The worst soil structure was in Haplic Stagnosol. An important indicator in assessing of ecosystem influence, water-resistant macro-aggregates of the 0.5-1 mm size fraction seems to be. This fraction was the only one which was statistically significantly influenced by the ecosystem, and also the only one which was not statistically significantly influenced by the soil type. This fraction also was not influenced either with the quantity and quality of soil organic matter, or with the particle size distribution. The quantity of soil organic matter is reflected in relation to the fractional composition of dry-sieved aggregates and its quality in relation to waterresistant aggregates. Large fractions of water-resistant macro-aggregates were in positive correlation with C : N ratio, the amount of extracted humus substances, or stability and quality of humic acids; while smaller fractions were in negative correlation just with these parameters. Clay and silt fractions had a positive influence on waterresistant macro-aggregates formation, while sand fraction had negative and vice versa.

scholarly journals The aggregate stability of the soil in respect to the uniform aggregate stability indicator

2007 ◽  
pp. 83-99
Author(s):  
Andrea Huisz
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Soil Structure ◽  
Aggregate Stability ◽  
Stability Index ◽  
Soil Types ◽  
Fundamental Properties ◽  
Efficient Protection ◽  
Wet Sieving

Soil structure and its quality are fundamental properties because they control many processes in soils. Tillage, crop and other factors influence soil structure. Efficient protection of it needs indication of changes in soil structure. A new Normalized Stability Index proposed by Six et al. (2000) tries to evaluate these changes, which was compared with some former used indices. The most common method (wet sieving) was modified to reduce the confounding effects of different particle size distribution of different soil types and method used to the investigation. Changes in soil structure caused by tillage and crop management therefore have been made quantitative and comparable. In this paper, we review the new method and Normalized Stability Index proposed by Six et al. (2000) and present the results of our investigations.

The Quality of U100 Sampling

1986 ◽  
Vol 2 (1) ◽  
pp. 419-423
Author(s):  
I. L. Whyte
Keyword(s):  
Particle Size ◽  
Moisture Content ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
General Purpose ◽  
Volume Changes ◽  
Sample Quality ◽  
Class 1 ◽  
Sample Disturbance

AbstractThe origins and development of the U100 (U4) thick-walled open-drive sampler are reviewed. The requirements of CP 2001 and BS 5930 are examined in relation to sample quality, and these are shown to be too favourable. Causes of sample disturbance are considered, particularly those due to volume changes, and shown to depend on moisture content, plasticity and particle size distribution. Quality classes possible with conventional U100 samples are suggested, and Classes 3 or 4 are to be generally expected. Class 1 samples are improbable. It is recommended that a general purpose sampler such as the U100 should have a maximum inside clearance of 1% and not ‘about 1%’ as recommended in BS 5930.

Effect of the particulate morphology of resin on the gelation process of PVC plastisols

2017 ◽  
Vol 37 (8) ◽  
pp. 757-764 ◽  
Author(s):  
Yubi Ji ◽  
Zhao Yang ◽  
Min Shi ◽  
Hong Tan
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Key Factors ◽  
Factors Affecting ◽  
Gelation Process ◽  
Secondary Particles ◽  
Poly Vinyl Chloride ◽  
Opposite Behavior

Abstract The gelation process of poly(vinyl chloride) (PVC) plastisol is very important to ensure the quality of the product and is affected by the type of resins, plasticizers, and other additives. In this study, the gelation process of the as-prepared PVC plastisol was characterized by measuring the evolution of vibrational viscosity with temperature or time using a vibrational viscometer. Furthermore, the effect of some commercial resins with different particulate morphologies on the gelation process was investigated by synchronously combining scanning election microscopy and laser particle size analyses. The results of this study proved that the particle size distribution and the aggregation degree of the secondary particles of a resin are the key factors affecting the gelation process. For the resin with bimodal particle size distribution, the closer the aggregation of the secondary particles, the slower the gel speed; however, an opposite behavior was observed for the resins with unimodal particle size distribution.

Evaluating the Integral Suspension Pressure method for measuring the particle size distribution in soils with high organic matter content

2020 ◽  
Author(s):  
Cristina Contreras ◽  
Sara Acevedo ◽  
Sofía Martínez ◽  
Carlos Bonilla
Keyword(s):  
Particle Size ◽  
Organic Matter ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Soil Analysis ◽  
Organic Matter Content ◽  
Matter Content ◽  
New Methodologies ◽  
Pre Treatment ◽  
Standard Techniques

<p>Typical information in soil databases is the soil texture and particle size distribution. These properties are used for soil description or predicting other soil properties such as bulk density or hydraulic conductivity. Measuring particle size distribution with standards methods such as the pipette or hydrometer is time-consuming because of the sample pre-treatment used to remove organic matter or iron and the sample post-treatment. Nowadays, there are new methodologies for determining soil particle size distribution, such as the Integral Suspension Pressure (ISP) method, which measures the silt content in a semi-automatized process. Thus, the main objective of this study was to evaluate the suitability of the ISP method compared to standard techniques used in soil analysis and evaluate the effect of organic matter content in the ISP measurements. The main results showed that the ISP method is equivalent in accuracy to the pipette, especially for soils rich in silt or sand content. Also, the results demonstrate the convenience of removing the soil organic matter when using the ISP for soils with more than 1.5% organic matter.</p>

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