Particle Size Distribution and13C Content of Dissolved Organic Matter in a Salt Marsh

2015 ◽  
pp. 161-173
Author(s):  
John A. Calder ◽  
Fie Kearsley
Keyword(s):  
Particle Size ◽  
Organic Matter ◽  
Salt Marsh ◽  
Particle Size Distribution ◽  
Dissolved Organic Matter ◽  
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>

WITHIN-PEDON VARIABILITY IN SOIL PROPERTIES

1982 ◽  
Vol 62 (4) ◽  
pp. 631-639 ◽  
Author(s):  
G. T. PATTERSON ◽  
G. J. WALL
Keyword(s):  
Particle Size ◽  
Organic Matter ◽  
Calcium Carbonate ◽  
Particle Size Distribution ◽  
Soil Properties ◽  
Size Distribution ◽  
Organic Matter Content ◽  
Matter Content ◽  
Soil Drainage ◽  
Soil Material

Replicate soil samples (2–20) from the A, B and C horizons of 41 pedons were collected to measure within-pedon variability of particle size distribution, organic matter content, calcium carbonate equivalent and pH. Variability in soil properties was examined in relation to the mode of origin of the soil material, soil horizonation and soil drainage. Variance in particle size distribution was significantly influenced by mode of deposition as well as by soil horizons, while soil drainage had no significant influence on the variation in particle size distribution. Variance in calcium carbonate equivalent and organic matter content was not influenced by soil drainage or mode of deposition. The number of replicate samples required for statistically reliable evaluation of a pedon at given confidence limits was determined for the soil properties studied. The results of these calculations indicate the need for up to five replicate samples to achieve satisfactory levels of accuracy at the 95% confidence level for some of the soil properties studied.

scholarly journals Pedotransfer functions to estimate water retention parameters of soils in northeastern Brazil

2013 ◽  
Vol 37 (2) ◽  
pp. 379-391 ◽  
Author(s):  
Alexandre Hugo Cezar Barros ◽  
Quirijn de Jong van Lier ◽  
Aline de Holanda Nunes Maia ◽  
Fábio Vale Scarpare
Keyword(s):  
Particle Size ◽  
Organic Matter ◽  
Particle Size Distribution ◽  
Water Content ◽  
Size Distribution ◽  
Water Retention ◽  
Northeastern Brazil ◽  
Pedotransfer Functions ◽  
Residual Water ◽  
Specific Pressure

Pedotransfer functions (PTF) were developed to estimate the parameters (α, n, θr and θs) of the van Genuchten model (1980) to describe soil water retention curves. The data came from various sources, mainly from studies conducted by universities in Northeast Brazil, by the Brazilian Agricultural Research Corporation (Embrapa) and by a corporation for the development of the São Francisco and Parnaíba river basins (Codevasf), totaling 786 retention curves, which were divided into two data sets: 85 % for the development of PTFs, and 15 % for testing and validation, considered independent data. Aside from the development of general PTFs for all soils together, specific PTFs were developed for the soil classes Ultisols, Oxisols, Entisols, and Alfisols by multiple regression techniques, using a stepwise procedure (forward and backward) to select the best predictors. Two types of PTFs were developed: the first included all predictors (soil density, proportions of sand, silt, clay, and organic matter), and the second only the proportions of sand, silt and clay. The evaluation of adequacy of the PTFs was based on the correlation coefficient (R) and Willmott index (d). To evaluate the PTF for the moisture content at specific pressure heads, we used the root mean square error (RMSE). The PTF-predicted retention curve is relatively poor, except for the residual water content. The inclusion of organic matter as a PTF predictor improved the prediction of parameter a of van Genuchten. The performance of soil-class-specific PTFs was not better than of the general PTF. Except for the water content of saturated soil estimated by particle size distribution, the tested models for water content prediction at specific pressure heads proved satisfactory. Predictions of water content at pressure heads more negative than -0.6 m, using a PTF considering particle size distribution, are only slightly lower than those obtained by PTFs including bulk density and organic matter content.

Relationships between particle size, fabric and other factors in some Australian soils

Soil Research ◽  
1979 ◽  
Vol 17 (1) ◽  
pp. 29 ◽  
Author(s):  
R Brewer
Keyword(s):  
Particle Size ◽  
Organic Matter ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Thin Sections ◽  
Fine Grained ◽  
Related Distribution

Soil fabrics at the level of related distribution of f-matrix (usually finer material) to f-members (usually coarser units) are considered in relation to particle size distribution for a number of randomly selected Australian profiles. Three major fabric continua are recognized: the chlamydic iunctic and matrigranic sequences. The majority of samples in the first two sequences have ratios of clay to silt greater and less than one, respectively, and successive stages correlate with increasing proportions of silt plus clay; fabrics of samples that fall out of sequence in relation to percentage of silt plus clay are explained on the basis of composition and/or specific processes, especially fine-grained carbonates, organic matter, faunal activity, and illuviation. The matrigranic sequence does not correlate with particle size distribution, but seems to be related to composition and/or specific processes such as faunal activity. The usefulness of the results lies in the possibility of using the conclusions to reduce the number of thin sections required to characterize areas of soil, particularly within restricted areas.

Use of sonication to determine the size distributions of soil particles and organic matter

2009 ◽  
Vol 89 (4) ◽  
pp. 413-419 ◽  
Author(s):  
X M Yang ◽  
C F Drury ◽  
W D Reynolds ◽  
D C MacTavish
Keyword(s):  
Particle Size ◽  
Organic Matter ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Size Distributions ◽  
Silt Loam ◽  
Clay Loam ◽  
Mineral Particles ◽  
Water Suspensions ◽  
Primary Mineral

Applying ultrasound energy to soil-water suspensions (sonication) is an established method of determining the size distributions of soil primary mineral particles and associated organic matter. The size distributions may vary, however, with sonication input energy and soil type. The objective of this study was to determine the effects of sonication input energy on the size distributions of soil mineral particles and organic matter for a range of soil textures and carbon contents typical of agricultural soils in southwestern Ontario. The soils included a Brookston clay loam, a Brookston clay, a Huron silt loam, a Perth silt loam and a Harrow sandy loam. All soils were under no-tillage management. Nine sonication energies ranging from 50 to 1500 J mL–1 were applied to soil-water suspensions (1:4 mass ratio), and the soil particle size distribution results were compared with those obtained using the standard chemical dispersion (pipette) method. The three medium- and coarse-textured soils (Huron, Perth, Harrow) required about 250 J mL–1 for complete dissociation of soil aggregates, while the two fine-textured soils (Brookston) required sonication energies of 600-750 J mL–1. Increasing sonication energy increased the amount of soil organic carbon (SOC) measured in the clay-size fraction and decreased the amounts in the sand and silt fractions. Therefore, accurate determinations of particle size distribution and SOC contents require an initial assessment of the amount of sonication energy required for the complete dispersion of the particle size fractions. For the Brookston clay loam and Brookston clay soils, 40–52% less particulate SOC was found in the sand fraction at 750 J mL–1 sonication energy than that obtained using the standard pipette method, indicating particle size reduction by sonication of particle organic matter. It should be noted that the sand-size SOC typically represents a small fraction. Furthermore, sonication had a minor effect on the SOC content of the clay fraction. It was concluded that sonication is a viable technique for determining the size distribution of soil primary mineral particles, as well as the amount of SOC associated with the silt and clay fractions. Key words: Sonication, ultrasound energy, particle size distribution, organic carbon fractionation, clay soil

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