Mineralogy and potassium release from some Western Australian soils and their size fractions

Soil Research ◽  
2001 ◽  
Vol 39 (4) ◽  
pp. 813 ◽  
Author(s):  
Y. Pal ◽  
R. J. Gilkes ◽  
M. T. F. Wong
Keyword(s):  
Initial Period ◽  
Clay Fraction ◽  
Unit Weight ◽  
Release Process ◽  
Partial Explanation ◽  
Size Fractions ◽  
Diffusion Controlled ◽  
Elovich Equation ◽  
Western Australian ◽  
K Release

Seven surface horizon soils and their sand, silt, and clay fractions were characterised for mineralogy, and K release by extracting samples with 1 mM CaCl 2 solution daily for 10 days. The low silt content is characteristic of many Western Australian soils, which may provide a partial explanation of the paucity of available K in soils that contain little silt-size primary minerals. The sand and silt fractions were dominated by quartz and contained significant amounts of K-feldspars. The clay fraction was dominated by kaolinite, and some samples contained illite/mica, inhibited vermiculite, and gibbsite. On a per unit weight basis the clay-fraction released the largest amount of K followed in sequence by the silt and sand. The contribution of size fractions to total K release by the soil ranged from 50 to 87%, 2 to 7%, and 10 to 44% for the clay, silt, and sand, respectively. Linear plots of K release versus time 1/2 for the soils, and the sand and silt fractions, indicated that a parabolic diffusion equation adequately describes the K release process. For some clay samples this diffusion controlled kinetic is not strictly obeyed during the initial period of K desorption due to rapid exchange of adsorbed K at sites on external surfaces. The Elovich equation plots show a discontinuity in slope and support the hypothesis of the multireactive nature of K exchange sites for these soils. The parabolic diffusion rate constant closely predicted K supply to plants as it has a close positive relationship (r = 0.99) with total K uptake by ryegrass for 260 days of growth.

Mineral sources of potassium to plants for seven soils from south-western Australia

Soil Research ◽  
2002 ◽  
Vol 40 (8) ◽  
pp. 1357 ◽  
Author(s):  
Y. Pal ◽  
R. J. Gilkes ◽  
M. T. F. Wong
Keyword(s):  
Clay Fraction ◽  
Mineralogical Composition ◽  
High Specific Surface Area ◽  
K Uptake ◽  
Size Fractions ◽  
Silicate Structure ◽  
Constant Rate ◽  
Incomplete Removal ◽  
Congruent Dissolution ◽  
K Release

This investigation was conducted with surface horizon samples from 7 south-western Australian soils and their 3 size fractions (sand, silt, and clay). The K release of these materials was measured for several extractants; the highest amounts of K were released from the clay (<2 μm) fraction. The presence of sand-size feldspars and incomplete removal of attached organic matter resulted in sand releasing significant amounts of K. The proportions of total K released in boiling 1 m HNO3 by the sand, silt, and clay fractions ranged from 0.4 to 3.4%, 2.6 to 36.3%, and 11.2 to 51.4%, respectively, and from 2.0% to 22.9% for the whole soils. Cumulative K uptake by 6 harvests of ryegrass over 260 days ranged from 0.26 to 1.23 cmol/kg soil.The clay fraction released higher proportions of total K to acid compared with the sand and silt size fractions because of the high specific surface area of the clay and because it contained proportionately higher amounts of illite, which releases K by both ion exchange and dissolution, whereas K release from feldspars requires congruent dissolution of the silicate structure. The differences in contents of StepK (relatively available fraction of the non-exchangeable K) and CRK (constant rate K) for 1 m HNO3 dissolution of these soils and size fractions reflect differences in mineralogical composition between the soils and size fractions. The low contents of StepK for the sand fraction indicated that K was strongly retained by feldspars. The soils with high CRK values had significant amounts of illite in the clay fraction. Values of CRK were positively related to cumulative K uptake and cumulative dry matter yield of ryegrass.

scholarly journals Spatial variability of particle size fractions of an Oxisol cultivated with conilon coffee

Revista CERES ◽  
2012 ◽  
Vol 59 (6) ◽  
pp. 867-872 ◽  
Author(s):  
Julião Soares de Souza Lima ◽  
Rone Batista de Oliveira ◽  
Samuel de Assis Silva
Keyword(s):  
Particle Size ◽  
Spatial Variability ◽  
Clay Fraction ◽  
Soil Samples ◽  
Landscape Configuration ◽  
Sand Fraction ◽  
Size Fractions ◽  
Particle Size Fractions ◽  
Average Value ◽  
Significant Difference

Information on the spatial distribution of particle size fractions is essential for use planning and management of soils. The aim of this work to was to study the spatial variability of particle size fractions of a Typic Hapludox cultivated with conilon coffee. The soil samples were collected at depths of 0-0.20 and 0.20-0.40 m in the coffee canopy projection, totaling 109 georeferentiated points. At the depth of 0.2-0.4 m the clay fraction showed average value significantly higher, while the sand fraction showed was higher in the depth of 0-0.20 m. The silt showed no significant difference between the two depths. The particle size fractions showed medium and high spatial variability. The levels of total sand and clay have positive and negative correlation, respectively, with the altitude of the sampling points, indicating the influence of landscape configuration.

STUDIES ON THE DYNAMICS OF "RECENTLY" CLAY-FIXED NH4+ USING 15N

1980 ◽  
Vol 60 (1) ◽  
pp. 61-70 ◽  
Author(s):  
C. G. KOWALENKO ◽  
G. J. ROSS
Keyword(s):  
Particle Size ◽  
Clay Fraction ◽  
Extraction Methods ◽  
Size Fractions ◽  
Particle Size Fractions ◽  
Fine Clay ◽  
Tracer Methods ◽  
Field And Laboratory Conditions ◽  
The Relationship ◽  
Fast Release

The dynamics of fixation and release of NH4+ in soils were studied using tracer N under field and laboratory conditions. Field data showed that release of fixed NH4+ was relatively slow after an initial moderately fast release. Forty months of field weathering of Bainsville soil left 3.48 kg 15N/ha in the 75-cm profile of the 13.5 kg 15N/ha applied and most (76%) of this recovered 15N was fixed NH4+–N. The relative quantitative importance of recently fixed NH4+ in the various particle size fractions was not in the same order as the native fixed NH4+. The fine silt fraction (2–5 μm) fixed a larger amount (whole soil basis) than the fine clay fraction (< 0.2 μm). The coarse clay fraction (0.2–2 μm) fixed the most NH4+ added as well as being the fraction containing the most native fixed NH4+. Sand size fractions were shown to contain native fixed NH4+ and were capable of fixing a small amount of added NH4+. Measurements of recently fixed NH4+–N in various particle sizes covering four time intervals (up to 40 mo) of field weathering under fallow showed that the 0.2 to 2-μm fraction was quantitatively most important, the < 0.2-μm fraction most readily released recently fixed NH4+ and the 2 to 5-μm fraction was the most stable with respect to recently fixed NH4+. Plant growth affected the relative stability of the recently fixed NH4+ in the various particle size fractions. Laboratory studies of three Brookston soil samples revealed higher estimates of fixation of NH4+ by direct tracer methods than by indirect extraction methods. This discrepancy was assumed to have been caused by some exchange of added NH4+ with native fixed NH4+ and by some NH4+ being fixed on other sites. The relationship between mineralogical and related analyses to fixation of NH4+ was discussed.

Properties of soil kaolins from Thailand

Clay Minerals ◽  
2003 ◽  
Vol 38 (1) ◽  
pp. 71-94 ◽  
Author(s):  
R. D. Hart ◽  
W. Wiriyakitnateekul ◽  
R. J . Gilkes
Keyword(s):  
Interlayer Space ◽  
Clay Fraction ◽  
Domain Size ◽  
Structural Formula ◽  
Exchange Capacity ◽  
X Ray Diffraction ◽  
Parent Materials ◽  
Fe Content ◽  
Western Australian ◽  
Australian Soil

AbstractPurified kaolins from Thai soil on diverse parent materials were characterized using analytical transmission electon microscopy, X-ray diffraction, thermogravimetric analysis and chemical analysis. The properties of Thai soil kaolins appear to be more diverse than Indonesian and Western Australian soil kaolins investigated using the same analytical procedures; this difference may reflect the greater range of parent materials for the Thai soils. The kaolins show a variety of crystal morphologies including euhedral hexagonal to subhedral platy crystals, tubes and laths and several morphologies were present in most samples. TEM-EDS enabled analysis of single crystals of each morphology present within a sample. Tubular or lath-shaped crystals usually have lower %Fe2O3 contents than hexagonal platy crystals in the same sample. The relationships between crystal size and Fe content within morphological populations were also examined by TEM-EDS. Generally, smaller kaolin crystals display a wider range of Fe concentration than the larger kaolin crystals in the same sample. Increasing Fe concentration in bulk samples is closely correlated to decreasing coherently scattering domain size (R2= 0.57), increasing cation exchange capacity (R2= 0.44) and increasing specific surface area (R2= 0.65). However the properties of the deferrated soil kaolins, including their Fe content, are not related to forms of Fe, (total Fe, amorphous or organic) in the untreated clay fraction of the soil.Inhibited vermiculite is a common minor constituent of these clay fractions and its average structural formula derived from EDS data indicates that it was formed by Al replacing K in muscovite. One Al3+ion occupies the interlayer space previously occupied by three K+ions. As the distances between these Al3+cations in the interlayer space is large it is proposed that isolated or loosely associated hydrated Al3+groups such as Al(OH2)63+exist that resist exchange by other cations due to hydrogen bonding with the adjacent tetrahedral oxygen surfaces

scholarly journals FEATURES OF PHOSPHORUS ACCUMULATION IN THE BOTTOM SEDIMENTS OF THE IVANKOVO RESERVOIR

2021 ◽  
Vol 6(16) (4) ◽  
pp. 139-153
Author(s):  
E.V. Gatalskaya ◽  
N.A. Belkina
Keyword(s):  
Bottom Sediments ◽  
Main Part ◽  
Clay Fraction ◽  
Size Fractions ◽  
Secondary Pollution ◽  
Ivankovo Reservoir ◽  
Phosphorus Accumulation ◽  
Suspended Form

The distribution of phosphorus in the bottom sediments of the Ivankovo reservoir, the forms of phosphorus and its content in different size fractions of the sediment were studied. It is shown that the main part of phosphorus is in mineral form and is contained in the clay fraction of sediment, which increases the risk of secondary pollution of water with phosphorus, due to its flow from bottom sediments in suspended form in the active dynamic zones of the reservoir. The estimation of the diffusion input of soluble forms of phosphorus from the bottom sediments of the reservoir accumulation zones was performed.

Distribution of Organic Matter in the Particle Size Fractions of Lateritic Soil (Plinthosol)

2012 ◽  
Vol 63 (4) ◽  
pp. 9-15 ◽  
Author(s):  
Zygmunt Brogowski ◽  
Wojciech Kwasowski
Keyword(s):  
Particle Size ◽  
Organic Matter ◽  
Organic Compounds ◽  
Soil Profile ◽  
Clay Fraction ◽  
Basaltic Rock ◽  
Lateritic Soil ◽  
Size Fractions ◽  
Particle Size Fractions ◽  
Opposite Trend

Abstract The distribution of organic matter in the genetic horizons of lateritic soil within a 100-cm profile to the basaltic parent rock is almost except for horizon Ap. Assuming that the sum of organic matter in 100 cm of the soil profile is 100%, 25.7% of these compounds occur in horizon Ap, whereas in the remaining horizons this value varies within 18-19.2%. In all size fractions, except the clay fraction in diameter of <0.002 mm, the content of organic matter decreases to a certain depth, and increases again in the deepest horizon located directly on the solid basaltic rock. The clay fraction displays an opposite trend; the content of organic matter in them increases with depth. In the horizon at the depth of 60-80 cm, the clay fraction <0.002 mm accumulates half of the total sum of organic compounds of all the remaining fractions. Such distribution of organic matter in soil and among its particle size probably results from the character of the basaltic weathered debris, as well as climate and vegetation covering the studied area.

Assessment of sediment toxicity by metal speciation in different particle-size fractions of river sediment

2003 ◽  
Vol 47 (7-8) ◽  
pp. 233-241 ◽  
Author(s):  
J.G. Lin ◽  
S.Y. Chen ◽  
C.R. Su
Keyword(s):  
Heavy Metals ◽  
Particle Size ◽  
Aquatic Ecosystem ◽  
Metal Speciation ◽  
Sediment Toxicity ◽  
Clay Fraction ◽  
Potential Toxicity ◽  
Size Fractions ◽  
Particle Size Fractions ◽  
Mn Oxide

Mobility and toxicity of metals associated with sediments are generally affected by metal speciation and granular compositions. Due to the various speciation patterns of heavy metals in sediments, it is not reliable to assess the potential toxicity of heavy metals on the aquatic environment with the total concentrations of heavy metals in sediments. The purposes of this study were to investigate the distribution of metal speciation in different particle-size fractions of sediments collected from two rivers (the Ke-Ya River and Ell-Ren River) in Taiwan, and to assess their potential toxicity to the aquatic ecosystem. Metals in the exchangeable, carbonate-bound and Fe/Mn oxide-bound forms obtained by sequential extraction were considered to be mobile and related with anthropogenic pollution. The degree of metal pollution and potential toxicity of sediments were higher in the lower reaches of both rivers. The metal speciation in sediments had a bimodal distribution over particle-size fractions. Heavy metals were subject to accumulation in the silt/clay fraction (&lt;25μmm) and coarse sand (420-2,000μmm). By normalizing the sum of the exchangeable, carbonate-bound, and Fe/Mn oxide-bound metals, it suggested that the potential toxicity to the aquatic ecosystem was caused by the fine sediments as well as coarse sediments.

Mass Transfer Model for Coated Urea Particle in Controlling-Release Process

2012 ◽  
Vol 560-561 ◽  
pp. 1119-1125
Author(s):  
Shi Xiong Hao ◽  
Xing Yong Liu ◽  
Zu Xiao Yu
Keyword(s):  
Effective Diffusion ◽  
Correlation Coefficients ◽  
Nutrient Release ◽  
Mass Conservation ◽  
Transfer Model ◽  
Release Process ◽  
Inverse Proportion ◽  
Diffusion Controlled ◽  
Coated Urea ◽  
Release Data

Based on mass conservation and Fick’s diffusion law, a model for describing the nutrient release from coated urea particles was proposed. This model was verified by the release data of three novel paraffin- rosin coated urea in distilled water. The results indicate that the model is effective in describing and predicting the delivery behaviors for a diffusion-controlled coated- urea and their correlation coefficients R2 are 0.9976, 0.9973 and 0.9984, respectively. The model shows that the nutrient release rate for coated urea is direct proportion to effective diffusion coefficient Deff, inverse proportion to diameter’s square of urea granule and inverse proportion to the coating thickness.

scholarly journals PROBABILITY OF PARTICLE-SIZE FRACTIONS OCCURRENCE IN DIFFERENT LANDFORMS

2018 ◽  
Vol 26 (4) ◽  
pp. 352-359
Author(s):  
Julião Soares de Souza Lima ◽  
Samuel Assis Silva ◽  
Daniel Pena Pereira ◽  
Marcelo Soares Altoé
Keyword(s):  
Particle Size ◽  
Clay Fraction ◽  
Spherical Model ◽  
Fine Sand ◽  
Coarse Sand ◽  
Indicator Kriging ◽  
Size Fractions ◽  
Particle Size Fractions ◽  
Probability Of Occurrence ◽  
Present Pattern

Knowing the variation of particle-size fractions, considering the relief forms, contributes for understanding the variation of other soil attributes. This work aimed to study the spatial distribution of the probability of particle-size fractions occurrence (clay, silt, very fine sand, fine sand, coarse sand, and total sand) in a clayey Oxisol with predominance of concave and convex curvatures. A sampling grid with 94 sampling points in 33x33m spacing at a depth of 0–0.20 m was built using a GPS. The spatial analysis was performed through indicator kriging. The spherical model was fit for all soil fractions, with ranges varying from 130 m to 280 m. In the region of convex curvature, the clay fraction presented the highest probability of occurrence (0.75 to 1.00), whereas in the concave region the coarse sand and total sand fractions presented the highest probability of occurrence. The very fine sand fraction and the silt did not present pattern of distribution in relation to the dominant curvatures of the relief.

scholarly journals Influence of Soil Properties and Composition, and Applied Hydraulic Pressures on Sample Quality of Pusan Clays

2017 ◽  
Vol 2 (1) ◽  
pp. 32
Author(s):  
Ganapathi Rao Konni
Keyword(s):  
Soil Properties ◽  
Minimum Degree ◽  
Critical Role ◽  
Clay Fraction ◽  
Unit Weight ◽  
Hydraulic Pressure ◽  
Contributing Factors ◽  
Sample Quality ◽  
Clay Deposits ◽  
Sample Disturbance

Obtaining  good quality samples from soft marine clay deposits is a challenge and it is being seen that the sample disturbance is inevitable even though lot of research has suggested using more sophisticated samplers, sampling methods, and special care being taken while handling and transportation of the samples. Hence, author doubt that apart from the above, there could also be other parameters playing critical role on the sample quality. Therefore, in the current study, sampling tube geometry is maintained same, especially angle of cutting edge and area ratio which are found to be key influencing factors and hence its impact on the current study is ignored. In the current study in order to assess the other contributing factors behind the additional sample disturbance, a special attention is given to find out other possible parameters that could also influence the sample quality. As a result of this study, it is found that the soil properties such as; silt and sand content in the soil, clay fraction, hydraulic pressure applied to penetrate the sampler, rigidity index of the soil, initial void ratio, plasticity index, and unit weight of the soil also contribute to sample disturbance. Since these properties, except hydraulic pressure, are soil inherent properties, there is always a certain minimum degree of sample disturbance associated with these soil inherent properties depending on the magnitude of these parameters. Unfortunately, the soil properties cannot be changed and thus a minimum sample disturbance is inevitable.    

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