bluuebunny/crossref_metadata_2025_split huggingface dataset:
SOIL CLASSIFICATION IN THE SOIL SURVEY OF ENGLAND AND WALES
Authors: AVERY B. W. 
Published: July 2006

SummaryThe development of soil classification as a basis for soil mapping in England and Wales is briefly reviewed, and a system for future use is described. The things classified are soil profiles, and classes are defined by relatively permanent characteristics that can be observed or measured in the field, or inferred within limits from field examination by comparison with analysed samples. Profile classes are defined at four categorical levels by progressive division, and are termed major groups, groups, subgroups, and soil series respectively.Classes in the three higher categories are defined partly by the composition of the soil material and partly by the presence or absence of particular diagnostic horizons, or evidence of recent alluvial origin, within specified depths. Soil series are distinguished by other characteristics, chiefly lithologic, not differentiating in higher categories. Most of the soil groups, regarded as the principal category above the soil series, are closely paralleled in other European systems, in the U.S.D.A. system (7th Approximation with subsequent amendments), or in both. Compared with the system used hitherto, the main innovations are the use of specific soil properties to define classes at all categorical levels, and the separation at group level of classes based primarily on inherited lithologic characteristics.The soil‐profile classification provides a uniform basis for identifying soil map units, considered as classes of delineated soil bodies. When a map unit is identified by the name of a profile class, it is implied that most of the soil in each delineation conforms to that class, and that unconforming inclusions belong to one or more closely related classes or occupy an insignificant proportionate area. Map units identified by land attributes not differentiating in the profile classification are termed phases.
HUMUS TYPE DISCRIMINATION USING PATTERN RECOGNITION OF THE MASS SPECTRA OF VOLATILE PYROLYSIS PRODUCTS
Authors: BRACEWELL J. M. , ROBERTSON G. W. 
Published: July 2006

SummaryMull and mor humus can be distinguished in freely drained British surface soils by the pyrolysis products derived from whole soil samples. About i milligram of soil is pyrolysed at 770 °C in a Curie point apparatus and a sample of the volatile decomposition products is allowed to enter a low‐resolution mass spectrometer. A numerical value (the ‘Discriminator Value’) which will discriminate between the two humus types is then calculated from the spectrum of each sample. This is performed by multiplying the intensity of each mass peak by a weight factor and then summing the weighted intensities up to mass 110The weight factors are obtained empirically by taking sets of spectra from clearly distinguished mull and mor samples and applying a computerized learning machine procedure. Once obtained, they are relatively easily applied to spectra from other soils.The method places all samples on a numerical scale on which mull types appear positive up to about 20 × 108 and mor types negative down to about ‐15 × 103, intermediate types being recognized in about the middle of the range. It is indicated that the most important pyrolysis products active in the discrimination process are the olefin hydrocarbons, particularly ethylene, which are produced in greater abundance from mor humus.
AN ANALYSIS OF PORE SIZE IN ILLITE‐KAOLINITE MIXTURES
Authors: SILLS I. D. , AYLMORE L. A. G. , QUIRK J. P. 
Published: July 2006

SummaryWhen API‐9 kaolinite and Willalooka illite clays were mixed in various proportions, the pore‐size distributions obtained using nitrogen sorption and mercury injection techniques were found to be characteristic of neither of the components but showed a progressive reduction in the pore size as the concentration of illite was increased. The plate separation of the mixtures showed a marked decrease with initial added illite, approaching that of the illite when the mixture contained approximately 40 per cent illite. This is indicative of a homogeneous mixture in which the fine illite particles fill in the pores bounded by the relatively coarse kaolinite particles.The relationship between particle dimensions (derived from crystallographic parameters and specific surface area) and pore size of single clays and clay mixtures is consistent with a model in which slit‐shaped pores result from the parallel interleaving of clay crystals for the single clays. Some deviations occur for the mixtures.
CLAY MINERAL DISTRIBUTION AND ORIGIN IN THE SOIL TYPES OF ISRAEL
Authors: GAL M. , AMIEL A. J. , RAVIKOVITCH S. 
Published: July 2006

SummaryThe mineralogical composition of clays (< 2μm) in representative profiles of all soil types of Israel was investigated. The soils were classified according to their clay mineral assemblages into three groups.I. Montmorillonitic soils. Montmorillonite is the dominant mineral and exceeds 65 per cent of the total minerals found; each of the other minerals comprises less than 15 per cent.2. Montmorillonitic‐kaolinitic soils. The soil clay fractions contain 50‐60 per cent montmorillonite and 15‐25 per cent kaolinite, generally adding up to more than 75 per cent of the clay fraction.3. Montmorillonitic‐calcitic soils. The clays contain more than 10 per cent calcite. Montmorillonite is the dominant clay mineral (except for one soil type, mountain rendzina, where calcite is dominant).The first and second assemblages are typical of the soils of the Mediterranean zone, whereas the soils of the desert zone are characterized by the third assemblage.The origin of montmorillonite, kaolinite, and illite, the three main clay minerals, was found to be detritic, as was the origin of palygorskite which was mainly found in the calcite rich soils of the desert zone.The cation exchange capacity of montmorillonite seems to be higher under higher precipitation. Montmorillonite content and cation exchange capacity of the clays were found to be highly correlated. The carbonate content of the clay fraction and the amount of carbonate in the soil were also highly correlated.
TIME DEPENDENCE OF COMPRESSIBILITY FOR REMOULDED AND UNDISTURBED SOILS
Authors: DEXTER A. R. , TANNER D. W. 
Published: July 2006

SummaryRemoulded soils compress more rapidly than undisturbed soils at the same initial density and water content. Soils with larger particles compress more rapidly than those with smaller particles. Soils compress more slowly when they are more densely packed. Soils expand more slowly than they compress between the same two pressures.Implications of these results are that soils which are not tilled would be less susceptible to compaction, and that tractors and other vehicles would cause less compaction when travelling at higher speeds.
THE COVARIANCE OF PHOSPHATE SORPTION WITH OTHER SOIL PROPERTIES IN SOME BRITISH AND TROPICAL SOILS
Authors: LOPEZ‐HERNANDEZ DANILO , BURNHAM C. P. 
Published: July 2006

SummaryPhosphate sorption capacity estimated by Piper's (1942) ‘anion exchange capacity’ and Bache and Williams's (1971) phosphate sorption index were correlated with soil pH, clay, organic matter, ‘free iron oxides’ and ‘extractable aluminium’ (McLean et al., 1958) for topsoil and subsoil samples from twenty tropical and twenty British acidic soil profiles. These two groups of soils did not differ significantly in phosphate sorption. Extractable aluminium and free iron oxide were well correlated with phosphate sorption, free iron oxide being superior to aluminium in freely drained British soils but not in poorly drained ones. Organic matter content correlated well with phosphate sorption for the poorly drained British soils, and for the tropical soils when sorption capacitywas measured using a high phosphate concentration.
THE REMOVAL OF ORGANIC MATTER FROM SOIL EXTRACTS BY BROMINE OXIDATION
Authors: MITCHELL B. D. , SMITH B. F. L. 
Published: July 2006

SummaryBrown‐coloured extracts are frequently obtained when chemical dissolution techniques are applied to soils. The colour, arising from the presence of organic material, interferes in subsequent spectrophotometric determinations of extractable inorganic components. A bromine oxidation method for the complete removal of interfering organic matter has been devised. This involves the oxidation of the organic matter with alkaline bromine solution and the subsequent removal of excess bromine by acid and heat treatment. To test the effectiveness of the method extracts from chemical dissolution procedures, containing organic matter, were examined before and after bromine treatment by ultra‐violet and infra‐red adsorption and mass spectrometric techniques.
FULVIC ACID. II. INTERACTION WITH METAL IONS
Authors: MacCARTHY PATRICK , O'CINNEIDE S. 
Published: July 2006

SummaryEvidence is presented, based on sequestration, chemical behaviour, ultra‐violet and infra‐red spectroscopy, to indicate the formation between the non‐cationic fraction of fulvic acid and a variety of transition metal ions, of stable soluble complexes and also of insoluble complexes over the complete pH range. The soluble complexes formed under alkaline conditions are negatively charged. The fulvic material is very effective in competing with other ligands for the metal ions. Mechanisms for the flocculation of the soil organic matter in the presence of heavy metal ions are discussed. The formation of inert complexes between cobalt and the fulvic material is also demonstrated and its implications to the study of metallo‐organic complexes are discussed.
ANNUAL SOIL MOISTURE REGIMES IN THE ROOTING ZONE ACROSS THE PRAIRIE‐FOREST BOUNDARY OF SOUTH‐WEST ALBERTA
Authors: HARRIS STUART A. 
Published: July 2006

SummaryVegetation cover is shown to play a major role in determining the soil moisture content in the Front Range of the Rocky Mountains near Calgary. Thus lodge‐pole pine abstracts more moisture from the soil both in summer and winter than aspen, while least moisture loss is experienced on bare soil. Clearly vegetation cover must be kept constant when comparing two soils. Additional important variables are aspect and parent material. It was also found that permanent (IS bar) wilting‐point, as commonly used, bears little relation to the permanent wilting‐point of even the more moisture‐loving native trees studied. They all do not wilt until a much lower moisture content is reached.
THE INFLUENCE OF ORGANIC MATTER, CHALK, AND SESQUIOXIDES ON THE SOLUBILITY OF IODIDE, ELEMENTAL IODINE, AND IODATE INCUBATED WITH SOIL
Authors: WHITEHEAD D. C. 
Published: July 2006

SummaryIodine in each of the forms iodide, elemental iodine, and iodate was added, at a rate of 5 mg/kg to a sandy loam and to mixtures of the soil with composted grass roots, chalk and sesquixoides, and its solubility determined after various periods of incubation.With iodide, solubility in both 0.01 M CaCl2 and 1.0 M NK4 acetate (pH 4.8) declined rapidly over the period o to 3 days and subsequently reached approximate equilibrium levels of 2.8 per cent solubility in CaCl2 and 7.8 per cent in NH4 acetate, these values being the means of samples incubated for 48, 103, and 160 days. The partial (5 per cent) replacement of the soil by composted grass roots had no appreciable effect on the solubility of added iodide, while chalk, incorporated at a rate of 5 per cent, depressed the solubility of iodide in CaCl2 to 1.8 per cent but caused a slight increase in solubility in NH4 acetate. The incorporation of 2 per cent hydrated ferric oxide or of 2 per cent hydrated aluminium oxide reduced the solubility of iodide in CaCl2 to 0.1 and 0.3 per cent, and in NH4, acetate to 3.8 and 5.7 per cent respectively. Elemental iodine was similar to iodide in its solubility in the two extractants and in its response to the various soil treatments. Iodate, however, differed considerably from the other two forms of iodine. With soil alone, and with the soil/chalk mixture, its decline in solubility with increasing incubation time was relatively slow, although after 160 days its solubility was similar to that of iodide and elemental iodine. The incorporation of composted grass roots caused a rapid reduction in iodate solubility, suggesting that the organic matter accelerated the reduction of iodate to elemental iodine or iodide. With the treatments involving the incorporation of ferric and aluminium oxides, there appeared to be considerable sorption of iodate during the 16 h extraction period and the effects of these materials on iodate solubility during incubation were therefore difficult to assess.
THE EFFECT OF THE EVAPORATION OF ENTRAINED LIQUID ON SOIL FABRIC
Authors: GALLAVAN R. C. , GREENE–KELLY R. 
Published: July 2006

SummaryThe evaporation of polyethylene glycol zoo from three remoulded clay soils and a clay aerogel was observed by scanning–electron and incident‐light microscopy. Neither flexing of the fabric during recession of the liquid film, nor reorganization of clay domains during shrinkage, was detected.
WELL–POINT TECHNIQUES AND THE SHALLOW WATER TABLE IN BOULDER CLAY
Authors: VISVALINGAM M. 
Published: July 2006

SummaryThe reliability of water‐table measurements in clay soil is currently under review (Twocock, 1971; Bonell, 1971; Visvalingam, 1972). This paper summarizes some of the experimental results from a boulder clay catchment in East Yorkshire. The experiments investigated the functioning characteristics of cased auger holes and piezometers in clay soil and compared the results with observations made with a neutron moisture probe. It appears that well‐point technique, especially piezometers, are extremely unreliable in clay soil. The measured water level is demonstrated to be influenced by not only the position of the ‘water table’ but also the permeability of the soil; in which context the type, diameter, and length of tubing, as well as the time of installation, become important considerations.
ZINC ADSORPTION AND DIFFUSION IN GOETHITE PASTES
Authors: BAR‐YOSEF B. , POSNER A. M. , QUIRK J. P. 
Published: July 2006

SummaryZinc diffusion in goethite (α‐FeOOH) was examined theoretically and experimentally. Concentration profiles of zinc diffusion after various periods of time were determined in physically and chemically defined oxide pastes using a tracer technique. Apparent diffusion coefficients were calculated as a function of diffusible zinc concentration from these results and compared with values obtained indirectly from slopes of adsorption isotherms and experimentally determined impedance factors of the conducting media. To deal with a wide range of experimental conditions, a model for calculating zinc adsorption was applied and evaluated. Changes in pH across the diffusion profile due to zinc transport were postulated to account for some of the results. Where these effects were minimal, the agreement between the diffusion coefficients obtained by the direct and indirect methods was satisfactory. The contribution of surface diffusion to the total transport of zinc in the goethite paste was estimated to be very small.
HUMUS TYPE DISCRIMINATION FROM MASS SPECTRA BY A SIMPLIFIED STATISTICAL TREATMENT
Authors: BRACEWELL J. M. , ROBERTSON G. W. , STEPHEN G. J. M. 
Published: July 2006

SummaryThe calculation of a discriminator between mull and mor humus types from the mass spectra of soil pyrolysis products, described earlier by Bracewell and Robertson (1973), used IIO normalized peak heights; these can be reduced to thirteen and the calculation simplified. Assumption of class for some soils, which was necessary in the previous method of obtaining the pattern classifier, has been obviated by the use of principal components analysis.
PRECIPITATION OF AMORPHOUS ALUMINOSILICATES FROM SOLUTIONS CONTAINING MONOMERIC SILICA AND ALUMINIUM IONS
Authors: WADA KOJI , KUBO HIROSHI 
Published: July 2006

SummaryMonomeric silica solutions were mixed with solutions containing AlCl3, or Al(OH)2‐55Cl0‐45 to give a SiO2/Al2O3, ratio varying from 8 to 8.0 and were kept at pH 6–0, 7.0, or 8.0 over a period of about I year. All precipitates which formed from solutions with SiO2/Al2O3 ratios of 1–0 or higher were X‐ray amorphous. The SiO2/Al2O2, ratio of the precipitate varied in the range from 1.0 to 3.0. It increased with the Si concentration and the SiO2/Al2O3 ratio of the parent solution and with reaction time. The pH did not affect the SiO2/Al2O3 ratio of the precipitate but did affect its dispersion and flocculation. Al3+ and Al(OH)2.55+0.45 reacted differently with silica and yielded different reaction products. These differences were interpreted in terms of the stability of hydroxy‐Al polymer units in the reaction. The amount of NaOH per Al atom which was required to reach and maintain the same pH, increased with the increasing SiO2/A12O ratio of the precipitate, but the value was generally lower than that predicted from ‘one in four’ substitution of Si by Al in four‐fold co‐ordination. A ‘neutralization’ of the positive charge on the hydroxy‐Al cations by silica was pointed out also to be a cause of the extra acidity. Implications of these observations on synthetic amorphous aluminosilicates to the genesis, structure, and properties of their natural counterparts were discussed.
LIQUID LIMIT DETERMINATION OF ARABLE TOPSOILS USING A DROP‐CONE PENETROMETER
Authors: CAMPBELL D. J. 
Published: July 2006

SummaryThe drop‐cone method, in which a 30° cone of mass 80 g is allowed to sink into a soil sample at a selection of moisture contents, is described and examined as a possible alternative to the Casagrande device for liquid limit determination. The methods are compared for 13 arable topsoils. The drop‐cone method, which uses apparatus that is readily available commercially, is shown to have advantages in ease of conduct of the test and in greatly improved reproducibility between operators.
SOIL GENESIS IN RELATION TO GROUNDWATER AND SOIL MOISTURE REGIMES NEAR VEGREVILLE, ALBERTA1
Authors: MACLEAN A. H. , PAWLUK S. 
Published: July 2006

SummaryThe study was designed to obtain information on flow and salinity of the groundwater, and on moisture regimes above the water table at selected sites near Vegreville, Alberta, and to relate this information to features of soil genesis revealed by soil mapping and analysis. All soils on the lower slopes, unlike those at upper elevations, contained accumulations of salts and gypsum, but the depth of salt accumulation and therefore the kind of soil appeared to be related only partly to current groundwater flow directions and the depth of the water table. The sodium content of the discharging groundwater and past flow conditions also appeared to be important. Lateral flow above the water table is suggested as being of possible importance in desalinization of surface horizons.
QUANTITATIVE PEDOLOGICAL STUDIES ON SOILS DERIVED FROM SILURIAN MUDSTONES
Authors: EVANS L. J. , ADAMS W. A. 
Published: July 2006

SummaryUsing the acid‐resistant residue of soil fine earth as internal standard, the redistribution and losses of SiO2, Al2O3, MgO, K2O, Na2O, and TiO2 were determined for an upland developmental sequence of five profiles on Silurian scree. The mobilization of Al, Fe, and Mg was related to chlorite breakdown. Of these constituents Fe began to be released at an early stage of weathering whereas A1 release lagged behind Fe and Mg; although substantial amounts of Fe and A1 were mobilized in highly weathered horizons. Subsequently, whereas mobilized Fe was almost completely redeposited in illuvial horizons, little of the mobilized A1 was retained by the soils. Amounts of Fe and A1 extracted by 0.1M potassium pyrophosphate were compared with redistribution computed using the internal standard. The concentrations in drainage water of soil constituents mobilized during pedogenesis were estimated and compared with measured concentrations in stream water draining the catchment.
SIMULATION OF THE WATER BALANCE OF SOIL COLUMNS AND FALLOW SOILS
Authors: ROWSE H. R. 
Published: July 2006

SummaryA model is described that predicts the evaporation of water from, and the distribution of water in, a soil column evaporating into a constant environment. It is based on a numerical solution of the flow equation and requires only the initial water distribution in the column, the equilibrium (air‐dry) water content at the soil surface and the relationship between volumetric water content and diffusivity. The model predictions show good agreement with a published analytical solution and with experimental results.Modifications to the model that allow for rewetting of the sod by rainfall, and changes in atmospheric conditions above the soil, enable predictions to be made of the water balance of a fallow field. In general, good agreement was obtained with the measured distribution of water deficits in the soil profile, although the predicted water content of the surface 2.5 cm of soil showed systematic differences from the measured values. The reasons for this are discussed.
THE EFFECT OF PARTICLE MORPHOLOGY ON THE K‐Ca EXCHANGE PROPERTIES OF MONTMORILLONITE
Authors: LEE R. , ROWELL D. L. 
Published: July 2006

SummaryAdsorption isotherms for K on to Ca montmorillonite (< 2 μm and < 0.1 μm. e.s.d. fractions) at ionic strengths from 3 × 10−2M to 3 × 10−5M have been analysed by the methods of Van Bladel and Laudelout (1967) and show that negatively charged sites in the lamellae of both size fractions are the same but when these lamellae are intermeshed in crystals, potassium is favoured, probably in wedge sites between adjacent lamellae. The effectiveness of these wedge sites is lost at zero ionic strength.
SCANNING ELECTRON MICROSCOPE STUDIES OF A SURFACE WATER GLEY
Authors: MCHARDY W. J. , BIRNIE A. C. 
Published: July 2006

SummarySpecific features of a gley soil developed on varved lacustrine clay have been studied by scanning electron microscopy and electron probe microanalysis. Individual clay platelets can be clearly observed in the red‐brown parent material but they cannot be resolved in the gleyed surfaces which have a smooth skin‐like texture. Ochreous mottles are shown to have a porous blocky structure, the surfaces of the blocks being coated with globular iron oxide. Areas of manganese staining have a characteristic sponge‐like morphology.
REACTIONS BETWEEN METALS AND HUMIFIED ORGANIC MATTER
Authors: BLOOMFIELD C. , KELSO W. I. , PRUDEN G. 
Published: July 2006

SummaryWe studied the properties of the soluble and dispersed compounds of Cu, Mn, Co, Ni, Pb, Zn, and Cd formed by the action of aerobically decomposing plant matter on the respective metal oxides. The metals were mobilized partly in association with colloidal humified organic matter, and partly in true solution as complexes that seemed to be anionic.In the presence of a clay soil there was no net mobilization of colloidally bound Cu, but the dialysable Cu complex was not appreciably sorbed by the mineral colloids and was leached from the reaction mixture.The metals were not precipitated under alkaline conditions from the dialysable complex forms. Material with similar complexing properties was found in the dialysable fractions of a soil organic matter extract, of water squeezed from a raw peat, and of laboratory lysimeter solutions from a podzol under Calluna.Below about pH 6 the exchange of Cu on a soil clay was not affected by the presence of colloidal decomposition products of lucerne. With Co, Ni, and Zn the corresponding pH value was about 4, and the critical value for Cu in the presence of colloidal soil organic matter was also about 4. Below these values the metal and organic matter sorption curves were diametrically opposed so that under these conditions Cu is apparently not strongly bonded to colloidal organic matter.