Soil Clay Mineralogy Research Articles

On kaolinitic and mixed mineralogy classes of shrink - swell soils

Spatially associated red (Typic Hapludalf) and black (Vertic Eutropept) soils developed on the Deccan plateau in the Western Ghats of India were analysed for clay mineralogy and also physical properties relating to shrink–swell. This was done in order to examine a possible correlation between shrink–swell phenomena and the content of expansible clay minerals, and to reconcile the apparent incompatibility between such a correlation and the classification of some Vertisols into kaolinitic, illitic, and mixed mineralogy classes. The fine clay mineralogy of the red soil was dominated by interstratified smectite/kaolinite with a little amount of smectite, but it had low cation exchange capacities and other associated non-vertic physical properties. Some of the smectite was interlayered with chlorite. This red soil is grouped into the kaolinitic mineralogy class. The fine clay mineralogy of the black soil was dominated by a highly smectitic interstratified smectite/kaolinite and also some smectite, which also shows some interlayering with chlorite. This soil has vertic physical properties but has a mixed mineralogy classification. The results suggest that there is an incompatibility between marked shrink–swell characteristics and mineralogical classification of soils in Soil Taxonomy, in view of the fact that it is smectite content which governs the vertic character of soils.

Soil pH and organic C dynamics in tropical forest soils: Evidence from laboratory and simulation studies

Acidic soil pH may affect decomposition of added organic materials in humid tropical forest soils. Our objective was to determine the effects of soil pH on decomposition of added organic materials to tropical forest soils of different soil texture and clay mineralogy. Release of 14CO 2 and microbial biomass 14C were measured during a 270-d incubation at 25°C after either [ 14C]glucose or 14C-labeled blue grama grass ( Bouteloua gracilis) material had been added to 13 tropical forest smectitic, kaolinitic, oxidic or allophanic mineralogies. Initial soil pH ranged from 3.9 to 6.7. An additional investigation examined 14CO 2 release from kaolinitic or oxidic forest soils to which either Ca(OH) 2 or CaSO 4 had been previously applied to obtain 5 soil pH values. Initial soil pH and cumulative 14CO 2 release in glucose-amended soils were positively related only after 1 and 4 d. In contrast, plant-residue-amended soils had positive relationships between initial soil pH and cumulative 14CO 2 release after 7 d and continued with that relationship up to 270 d. Microbial biomass 14C was reduced at lower pH values in both glucose-and plant-residue-amended soils after 270 d. Water-extractable 14C was also higher at pH > 5.5 in plant-residue-amended soils after 58 d. Differences in soil texture and clay mineralogy had no apparent effect on the relationship between soil pH and decomposition. Simulated results of the experiment using the CENTURY Soil Organic Matter Model diverged from observed results for soils with pH < 6.5. Further research is required to determine the effects of acidic soil pH on decomposition rates of stable C pools and to develop functions for simulation models to account for the short- and long-term effects of soil acidity on decomposition.

Clay mineralogy of soils from upper north Thailand

Abstract A total of about 80 soil samples from 20 profiles distributed in Upper North Thailand were examined for the composition of the clay mineralogy. The soils from upland areas consisted of principally kaolinite and those from lowland areas (paddy fields) showed a mixed mineralogy characterized by the presence of kaolinite or illite, or both. Such characteristics of the clay mineralogy were almost the same as those reported so far, and the results are summarized in the APPENDIX. In this report the description deals with which showed some “exceptional” features of clay mineralogical compositions as follows: Mae Suya soil (a Typic Haplustult) which showed randomly mixed layers containing large amounts of illite and illite-vermiculite in addition to kaolinite; Mae Lana Jobo soil (an Oxic Paleustult) which was dominated by gibbsite with considerable amounts of vermiculite and kaolinite; and Khok Yai soil (an Oxic Haplustalf) which was characterized by the presence of mixed layers with large amounts of ill...

Clay Mineralogy of Some Typical Upland Field Soils in Fukui Prefecture

Clay Mineralogy of Some Typical Upland Field Soils in Fukui Prefecture

Clay mineralogy of agricultural soils (Ap horizon) in Västergötland, SW Sweden

Abstract The mineralogy of the clay‐size fraction of 15 samples from cultivated soils was determined using X‐ray diffraction methods. All of the samples contain mica, vermiculite, kaolinite and mixed‐layer minerals, but the proportions of these vary. The regional mineralogic trends are discussed in relation to the possible influences of grain size, relief, sediment‐source variations, time of exposure and climate. The geologic factors are largely related to the geographic distribution of the former glaciomarine, marine and terrestrial environments that successively existed in SW Sweden following the Weichselian glaciation. Although all of these factors have been involved to some extent, there is a tendency for weathering products (kaolinite, vermiculite and mixed‐layer minerals) to be most abundant in areas with greater relief, precipitation and exposure time. However, the grain‐size variations that we documented in this study would directly influence permeability and the intensity of weathering processes at each site, and this seems to best explain the compositional trends. The Lake Vänern basin has, in general, fine‐grained sediments from the late‐stage, shoreline recession. These silty clays have a less‐weathered composition than the coarser‐grained samples from more peripheral areas in Västergötland where greater relief and precipitation are also consistent with the observed mineral‐weathering trends. Although modified and less complete than studies of entire soil‐profiles, the mineralogic and grain‐size information derived from the cultivated soil horizon (Ap) is a valuable complement for both geologic and pedologic modelling. Stevens, R.L. & Bayard, E., 1994: Clay mineralogy of agricultural soils (Ap horizon) in Västergötland, SW Sweden. GFF, Vol. 116 (Pt. 2, June), pp. 87–91. Stockholm. ISSN 1103–5897.

Holocene palaeoenvironmental record preserved in a paraglacial alluvial fan, Sunwapta Pass, Jasper National Park, Alberta, Canada

The soil stratigraphy of a 1.5 m section in the distal portion of a paraglacial alluvial fan in Sunwapta Pass, Jasper National Park, has been examined as part of a long-term investigation into Holocene palaeoenvironments of the area. The section is complex and its characteristics are a result of both episodic sediment inputs and pedogenesis. A series of sediments comprising debris-flows and aeolian material including three discrete tephra layers (Mazama, St. Helens Yn, Bridge River) underlie the present day soil. Multiple criteria, including stratigraphy, radiocarbon dates, glass shard morphology, and electron microprobe analysis of glass and titanomagnetite composition, confirmed the identity of the tephras. Most fan development occurred before deposition of Mazama tephra. Pedogenesis has been active on the fan throughout the Holocene. Soils have formed between phases of sediment deposition during periods of greater relative site stability. Soil horizonation is best developed where tephric material has influenced soil chemistry and clay mineralogy leading to the formation of Brunisols. The sequence of events inferred from the Icefield Fan's stratigraphy accord well with the Holocene palaeoenvironmental history inferred from other sites in the Canadian Rockies.

Clay Mineralogy of Some Typical Paddy soils in Reman District, Soutwest Part of Fukui Prefecture

Clay Mineralogy of Some Typical Paddy soils in Reman District, Soutwest Part of Fukui Prefecture

Clay Mineralogy of Some Typical Paddy soils in Reihoku District, Northeast Part of Fukui Prefecture

Clay Mineralogy of Some Typical Paddy soils in Reihoku District, Northeast Part of Fukui Prefecture

Microaggregate Stability of Kaolinitic and Illitic Soils Determined by Ultrasonic Energy

Seal formation, runoff, and soil erosion depend closely on aggregate stability. The objective of this study was to identify stable and unstable soils and the effect of exchangeable sodium percentage (ESP) thereon, using the microaggregate stability test. Six predominantly kaolinitic and illitic soils from South Africa, with ESP adjusted to 1, 7, 15, or 25, were used in this study. Two-gram samples of microaggregates (<105 µm) were subjected to a range of ultrasonic energy levels up to 600 J mL−1. After sonification, particle-size distribution was determined by a light-scattering technique using a laser particle sizer. Undispersed clay (UDC) percentage, which is the fraction of the clay that is left undispersed after sonification, was used to characterize microaggregate stability. According to the distribution of their UDC percentages with respect to energy level, the six soils were divided into three groups: unstable, semistable, and stable soils. In the unstable soils, UDC percentage dropped exponentially with energy level. In the stable soils, UDC percentage decreased linearly with an increase in energy level. In both groups ESP had an insignificant effect on microaggregate stability. In the semistable soils, ESP had a significant effect on microaggregate stability. Samples with ESP = 1 behaved like the stable soils and samples with ESP > 1 behaved like unstable soils. Microaggregate stability depended strongly on the soil clay mineralogy. The microaggregate stability determination proved to be a sensitive indication for soil susceptibility to seal formation, runoff, and erosion.

Relationship of K forms and release characteristics with clay mineralogy

The relationship between K forms (water soluble K, NH 40Ac- and HN0 3-extractable K) and characteristics of laboratory release of non-exchangeable K were examined as a function of clay mineralogy and taxonomy, using samples from some agriculturally important bench mark soil series of India. Potassium release characteristics were studied in samples of soils having NH 40Ac- and HN0 3-extractable K in the vicinity of the modal values in the various series. The release of “external” and “lattice” K was was computed from the “K release curve” and computed estimates were compared within and across the soil groups. Generally, kaolinitic soils were low, mixed and illitic soils WERE medium, and smectitic soils were high in NH 40Ac-K. In the estimates of HN0 3-K, kaolinitic, mixed and smectitic soils were low, and illitic soils were high. The amounts and rates of K release were positively and significantly correlated with the measured K reserves. The K release was greatest in illitic and least in kaolinitic soils. The results show that while kaolinitic soils are low in both NH 40Ac-K and HN0 3-K and also in the release of their non-exchangeable K, the situation is different in smectitic and illitic soils. Although smectitic soils are high in NH 40Ac-K, their HN0 3-K is modest and the rate of K release is moderate. On the other hand, illitic soils have modest amounts of NH 40Ac-K but high amounts of HN0 3-K, and are associated with high K release rates. Hence, it is advisable to consider the amount of both the exchangeable and non-exchangeable K and clay mineralogy of soils in arriving at a judgement of K release and availability in soils.

Kinetics of release of potassium by sodium tetraphenyl boron from some top soil samples of Red (Alfisols), Black (Vertisols) and Alluvial (Inceptisols and Entisols) soils of India

Alluvial (Inceptisols and Entisols) soils containing illite as dominant clay mineral released significantly higher amounts of K to 0.3 M NaTPB than smectitic Black (Vertisols) and kaolinitic Red (Alfisols) soils. Exchange rate indices derived from the plots of K released to 0.3 M NaTPB versus log t were also higher for illitic soils than for kaolinitic and smectitic soils. Magnitudes of both surface and internal K released from different soils were in the sequence: illitic > smectitic > kaolinitic. Data of K release to 0.3 M NaTPB could be described by first order rate equation. In parabolic plots, existence of a linear relationship throughout the period of exchange with NaTPB indicated the absence of film diffusion controlled processes. Diffusion coefficients calculated from radial diffusion equation were dependent upon texture and clay mineralogy of soils and decreased sharply with time for kaolinitic and smectitic soils. Illitic soils, however, maintained higher values of diffusion coefficients over extended periods of time.

Clay mineralogy of soils formed in tuffaceous greywacke, Southland, New Zealand, in relation to genesis, soil properties and classification

The clay mineralogy of 12 soils (Dystrochrepts, a Eutrochrept, a Cryochrept and a Placaquept) formed in tuffaceous greywacke parent rocks is presented and discussed. In a New Zealand context, the soils are unusual because of their base-rich parent material which has been partly pre-weathered to smectite and kaolin minerals in geological time. Superimposed on this assemblage are the affects of present climate and soil drainage, which have altered smectite and vermiculite to dioctahedral (aluminous) chlorite. Conventional laboratory treatments cause dioctahedral chlorite to revert fully to smectite or vermiculite, or alternatively partially to interlayered hydrous mica. The labile nature of the interlayer Al is evident in high KCI-Al values. Allophane and gibbsite occur in acid upland soils that are also trace-element deficient. More intense leaching of upland soils with respect to lowland soils accounts for the upland soils' clay mineralogy and trace element deficiencies. The soils fall into three mineralogy classes of Soil Taxonomy and six classes of the proposed Whitton and Childs revision. The classes are not readily usable in the field, and subgroup or family distinctions based on simple chemical tests are suggested.

Aspects of climatic influence on the clay mineralogy and geochemistry of soils, palaeosols and clastic sedimentary rocks

Climate strongly influences soil clay mineralogy and bulk chemical composition. In humid climates chemical weathering is at its most intense and virtually all ‘primary’ bedrock minerals suffer complete breakdown. They are replaced by authigenic hydrated oxides of Fe and Al together with halloysite and kaolinite in deep profiles. These minerals develop where the residence time of water in the soil is slight. Longer residence times lead to higher solute concentrations and the stabilization of smectite. Authigenic palygorskite and sepiolite may form in highly saline, alkaline soils. The stability of these precipitated minerals is problematic: they may be metastable or even unstable. All other clays found in soils are unstable, being incomplete, solid-state hydrolysis products of substrate minerals. The balance between stable, metastable and unstable minerals and the rate of profile development are both much influenced by temperature, rainfall and activities of soil biota; themselves reflecting climate. Bedrock influence is greatest under conditions of low to moderate precipitation where unstable minerals persist. Local topography, however, also strongly influences both the rate and products of chemical weathering, quite independently of climate. On the grand scale, tectonic factors may constrain the time available for profiles to develop, hence the extent to which bedrock minerals survive or are altered. Mountain soils reflect local climate and bedrock composition much more than latitude. The sediments delivered to major basins today do not reflect global soil distribution patterns. The bulk composition of suspended sediment entering the Indian Ocean, for example, is rather similar to that entering the Arctic Ocean. Sediment dispersal patterns can also confuse climatic signals: a problem not encountered with palaeosols. Authigenic clays formed within sedimentary basins and post-depositional (burial) alteration of both sediments and buried soil profiles must lead to interpretational ambiguities. Climatic signals are likely to survive best in bulk compositional data (although diagenetic reactions at depths in excess of about 2 km do not appear to be isochemical) and in the distribution of more stable yet climatically sensitive minerals (kaolinite as opposed to illite, chlorite).

Environmental Influences on Soil Chemistry in Central Semiarid Tanzania

AbstractThis study assessed the effectiveness of landscape features for predicting the variation in a set of chemical properties from 81 soil profiles sampled in a 236‐km2 site in central Tanzania. Soil samples were treated as points and coded by horizon and by groups, including landform, parent material, vegetation type, vegetation percent cover, and presence or absence of hypogeal termites. The variation captured by these groups in eight soil chemical properties (organic C, total N, acid‐extractable P, exchangeable cations, and extractable Al) was assessed using analysis of variance, Duncan's multiple range test, and discriminant analysis. Soil development fits the catena model along hillslope transects, but lateral subsurface transport of dissolved Fe and cations has produced plinthite and highly base‐saturated horizons just above the lithic or paralithic contact downslope of transitions between ferruginous sediments and granitic sediments. Nevertheless, biotic factors (vegetation type and density of termites) captured more variation than other groups at the regional level. Vegetation species composition and the density and type of termites in central Tanzania reflect soil depth, texture, clay mineralogy, and drainage characteristics influenced by landform and parent material. Root symbioses of native miombo and Acacia spp. woodlands may also modify local soil chemistry via selective uptake of C and exchangeable cations. Termites contribute to the depletion of organic C, total N, and associated nutrients throughout the soils they occupy in this region.

Relationship Between Soil Potassium Forms and Mineralogy

AbstractThe relationship between soil K forms (water soluble, exchangeable, HNO3‐extractable, and mineral) as a function of clay mineralogy and taxonomy, was determined using 102 soils from the continental USA and Puerto Rico, representing 10 soil orders. These relationships may have use in evaluating potential soil K fertility and prediction of K cycling and plant uptake. The soils were divided into three groups (kaolinitic, mixed, and smectitic) based on dominant mineralogy of the clay fraction. For each group of soils, water soluble K was related to exchangeable K content (r2 of 0.86 to 0.96), with exchangeable K solubility increasing from smectitic, mixed, to kaolinitic soils. For each group, exchangeable K was also related to HNO3‐extractable K (r2 of 0.81 to 0.83), thus, the capacity to supply K under continuous cropping, is greater for smectitic than kaolinitic soils of similar exchangeable K contents. Mineral K was a function of clay content for each soil group (r2 of 0.66 to 0.90). Using these relationships, water soluble (2–37 mg kg−1), HNO3‐extractable (21–2691 mg kg−1), and mineral K contents (1.59–16.93 mg kg−1) of 60 independent soils, were closely predicted (r2 of 0.78 to 0.96) from exchangeable K, clay content, and clay mineralogy. These results indicate that determination of both exchangeable and HNO3‐extractable K could give a better indication of the potential K supplying power of a soil. Further, the relationships obtained will allow determination of initial soil K pool sizes from readily available soil taxonomic, clay mineralogy, and chemical properties, for use in modeling the cycling and plant uptake of soil K.

THE EFFECTS OF EROSION ON SOIL PORE DISTRIBUTIONS AND ROOT RAMIFICATION IN FINE-TEXTURED ILLINOIS SOILS1

I studied the effects of erosion on pore size distributions and corn root ramification with depth, using Hg intrusion porosimetry. In particular, I examined the paired erosion phases of two fine-textured Illinois soils, one dominated by smectite and the other by hydrous mica. Total porosites of each moist, clayey soil sample were reduced as much as 8% when oven-dried, having the potential to alter pore size classes and corresponding volumes. The proposed method requires sampling fine-textured soils in the field when the profiles are moist (approximately at field capacity) and transporting them to the laboratory in moisture tins. In the laboratory, soil samples are rapidly frozen in liquid N and freeze-dried prior to being intruded with Hg using a porosimeter. The freeze-dried method was selected so measured soil pore sizes approximated those that the corn root tips would encounter when growing into soils at a similar moisture content. The water retention differences (WRD) measured by water-release methods appeared to correlate well with the freeze-dried (50 to 0.5 μm in equivalent diameter) pore class volumes that were not subjected to shrinkage upon drying or swelling associated with unconfined soil sample saturation and equilibration methods. The pore size classes and corresponding volumes varied with soil series, clay mineralogy, and depth. For both the subsoil and parent material, the fine-textured Clarence soils dominated by hydrous mica had much smaller transmission pore volumes and water storage volumes. Topsoil loss resulted in a greater reduction in rooting volume and water-storage capacity of the Clarence soils and resulted in greater corn yield reductions. Efforts to restore the soil productivity of the Clarence and Hoyleton soils will require an increase in the total soil porosity, water-storage pore volumes, transmission pore volumes, and rooting depth.

ADSORPTION AND DESORPTION OF MALEIC HYDRAZIDE AS A FUNCTION OF SOIL PROPERTIES

The relationships between maleic hydrazide (MH) adsorption and selected properties for 22 soils were studied by determining adsorption isotherms in aqueous media and calculating simple correlation coefficients among Kf values, from Freundlich equation isotherms, and the soil properties. The results of these correlations showed that MH adsorption by soils was essentially dependent upon specific surface area, clay content, and pH, but not organic matter content. When the soils were grouped according to their mineralogical components, MH adsorption-soil property relationships were shown to be dependent upon the soil clay mineralogy. For one group of soils with phyllosilicates as essential clay mineral components and free iron content (Fet) below 5%, MH adsorption was directly related to clay content and surface area, and the free iron oxides content (Fef) was inversely related to MH adsorption capacity. For a second group of soils with iron oxides and oxyhydroxides as essential clay mineral components and Fef > 5%, soil pH was the only variable related to MH adsorption. Desorption of MH from soils showed a hysteresis effect that was attributed partially to MH precipitation, or biodegradation, or both.

The Nature of Vermiculite in Adirondack Soils and Till

AbstractThe clay and bulk mineralogy of soil and till from 26 Adirondack watersheds was studied. The materials consist typically of quartz, K-feldspar, plagioclase, mica, vermiculite, and kaolinite. Talc, smectite, halloysite, and hornblende are present in some samples. The clay fraction of the soils is composed predominantly of vermiculite, likely derived from the transformation of a mica precursor, and kaolinite. The soil vermiculite commonly contains hydroxy-Al interlayers which are especially prevalent in the B-horizon samples. Despite significant variation in the type of bedrock and the composition of heavy mineral assemblages in these watersheds, the clay mineralogy is remarkably uniform. This finding supports earlier suggestions that the occurrence of vermiculite in soils is more dependent on climate than on the nature of the parent material.

The soil clays of Great Britain: I. England and Wales

AbstractThe mineralogy of the clay fractions (&lt;2 µm) of the major soils of England and Wales is reviewed, and the data presented in terms of the 1:250 000 National Soil Map. Most soils developed in pre-Rhaetic sediments are dominated by mica with lesser amounts of chlorite and kaolin. Exceptions are soils developed in calcareous Coal Measure shales which have significant smectite contents, and freely drained soils in Keuper Marl which contain swelling chlorite, sepiolite and palygorskite. Soils developed in post-Triassic sediments are dominated generally by expansible minerals, except for those developed in Lower Lias and Estuarine Series rocks (Jurassic) which are dominated by mica and kaolin respectively. The presence of loess in soils seems to be associated with the occurrence of a complex interstratified mineral with X-ray diffraction properties akin to vermiculite. Weathering of soil clays is most marked in the wetter uplands, but over most of lowland England is detectable only by slight changes in non-exchangeable potassium content and cation-exchange capacity towards the soil surface. Applications of soil clay mineralogy in the fields of plant nutrition and soil mechanics are discussed, in particular the production of maps showing mineralogical provinces.

GENETIC PANS OF THREE SOILS OF THE SOUTHERN COASTAL PLAINS OF THE UNITED STATES

An investigation was undertaken to determine morphological, physical, chemical. and mineralogical properties of pans having fragic characteristics in horizons of selected Southern Coastal Plain Soils. Soil sories involved were Carnegie (Plinthic Paleudults), Cowarts (Typic Hapludults) and Irvington (Plinthic Fragiudults). Pans were strongly indurated at the top and hardness gradually decreased with depth. Pans were firm when moist and very hard when dry and ranged from 15 to 45 cm in thickness. There was no evidence that particle size distribution was related to pan formation. Organic matter Content, pH, and available P of the epipedon were higher than subsurface horizons although magnitude varied from soil to soil. Cation exchange capacity was fairly consistent in a given horizon for each pedon and was related to organic matter and clay content. Exchangeable Mg content of pans was higher than exchangeable Ca. Pans did not influence the distribution of exchangeable Na, K, Zn, Fé,. and Mn. Horizons having fragic characteristics were not related to gross soil mineralogy or clay mineralogy: Close packing of particles and possible surface tension effects due to the structure of the water molecule apparently influenced the bonding which, resulted in the brittleness in the pan formations. (Key words: Genetic pans, Gragipans, pans, Sub surface horizon).