bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE EFFECT OF CLEARING A TROPICAL FOREST SOIL
Authors: CUNNINGHAM R. K. 
Published: July 2006

SummaryOrganic matter in tropical soils under forest is delicately balanced, the continuous addition of fresh material being offset by decomposition. The forest was removed from a soil in Ghana and three degrees of exposure were tested. Chemical and physical properties were measured from 1957 to 1960. Much organic C, total N, and organic P was lost from the soil of fully exposed plots, because soil temperatures increased and fresh organic matter was no longer provided by the forest. Rate of decomposition lessened with time. Decomposition under shade, though still rapid, was significantly slower than in exposed soil. After three years’ exposure the soil produced less mineral N and had smaller cation exchange capacity, exchangeable K, and lower pH than the shaded soil. Exposure also compacted the soil, impeded drainage through the 2–6 in. layer and made the soil erode more easily.
STUDIES ON SOIL POTASSIUM
Authors: BECKETT P. H. T. 
Published: July 2006

SummaryThe activity ratio aK/√(aCa±Mg) had the same value for all solutions in equilibrium with a chosen soil, regardless of their concentration (up to 0.06 M), or of the proportion of Ca to Mg.The activity ratio may be expected to provide a satisfactory measure of the ruling chemical potential of labile K in a soil, provided it is not used to compare soils of widely different Ca (and Mg) status, or a few soils of which the activity ratio is not independent of the concentration of the soil solution.
GLAEBULES: THEIR DEFINITION, CLASSIFICATION AND INTERPRETATION
Authors: BREWER R. , SLEEMAN J. R. 
Published: July 2006

SummaryA broad group of pedological features has been recognized by their occurrence as three‐dimensional entities embedded in the matrix of soil materials. They have been named glaebules and are divided into sub‐groups on their internal fabric, mineralogy, distinctness as a unit, and shape. These features include nodules, concretions, and septaria which have all been recognized by the petrologist, and pedodes, papules, and glaebular haloes which are newly recognized features. An attempt is made to interpret the origin of these features in terms of processes of formation and inheritance versus formation in situ. This is based on interpretation of the characteristics used for their classification.
LOSS‐ON‐IGNITION AS AN ESTIMATE OF ORGANIC MATTER AND ORGANIC CARBON IN NON‐CALCAREOUS SOILS
Authors: BALL D. F. 
Published: July 2006

SummaryExamination of data on North Wales soils shows that a good correlation exists between loss‐on‐ignition and organic C values, determined by Tinsley's method. Ignition for half an hour at 850° C, and for 16 hours at 375 ±5° C have both been employed. The latter has advantages over the former procedure. Regression lines and prediction limits for organic C from loss‐on‐ignition are given from the data obtained. Although these regressions are not necessarily expected to be generally applicable, examination of some published data suggests that closely similar expressions may be. The method, because of its simplicity, can be usefully applied in a wide range of survey, analytical and ecological studies, in spite of the known sources of error.
THE RELEASE OF HYDROGEN SULPHIDE FROM MUD
Authors: VÁMOS R. 
Published: July 2006

SummaryDamage due to Has occurring in some acidic, heavy paddy soils and peaty fishponds is usually preceded by falls in temperature and atmospheric pressure. The O2, content of the water layer increases with the fall in the temperature and, as the redox‐level sinks in the mud, the superficial layer of the mud is oxidized and H2SO4 is formed which releases H2S from the sulphide in its environment. The decrease of atmospheric pressure lifts the gases including H2S from the hollows of the mud into the water layer and thence into the atmosphere. The gases carry colloidal particles and render the water turbid. The released H2S may result in root‐rot and deficiency diseases in the rice plants, and algae bloom and fish death in the ponds.
LATERITE AND LATERITIC SOIL IN COASTAL NATAL, SOUTH AFRICA
Authors: MAUD R. R. 
Published: July 2006

SummaryA description is given of the distribution and characteristics of a vesicular laterite associated with the Early Cainozoic erosion surface in coastal Natal, together with the chemical and mineralogical characteristics of the soil formed by its decomposition. The relationship between cyclic erosion surfaces, the laterite, pre‐weathering, and the dominance of parent material in soil formation in coastal Natal clearly indicate the dependence of the processes of soil formation on the geomorphic history of this region.
THE MEASUREMENT AND MECHANISM OF ION DIFFUSION IN SOIL
Authors: NYE P. H. 
Published: July 2006

SummaryIf an exchangeable ion in soil diffuses along a liquid and solid pathway, its diffusion coefficient may be expressed as
image

where D, v, f, C are diffusion coefficient, volume fraction, impedance factor, and concentration terms and the suffixes l,S refer to liquid and solid.The self‐diffusion coefficient of the ion is then
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where D′, D′t, and D′s, are self‐diffusion coefficients. D and D′ will vary with concentration. In diffusion out of the soil to a zero sink, the appropriate average diffusion coefficient is, approximately, the self‐diffusion coefficient in the undisturbed soil. Diffusion of one ion species is influenced by other ions diffusing in the system through the diffusion potential set up. When ions are diffusing to plant roots, the diffusion potential is likely to be small.A more likely, though more complicated, expression for D than the first equation above is derived by assuming the ion to follow solid and liquid pathways in series as well as in parallel.
CHARACTERISTICS OF SOME SOLONETZIC SOILS IN THE GLACIAL LAKE EDMONTON BASIN OF ALBERTA
Authors: ARSHAD M. A. , PAWLUK S. 
Published: July 2006

SummaryA mineralogical study was made on five geographically associated Solonetzic and Chernozemic soils from the glacial Lake Edmonton basin.The investigation showed that montmorillonite was generally the dominant mineral present in the clay fraction while illite and kaolinite were next in abundance. Chlorite and interstratified clay minerals were present in very small amounts. The montmorillonite was identified as being transitional between beidellite and nontronite types. The high montmorillonite content of the B horizons of all profiles appeared to have resulted from the preferential translocation of this mineral as well as from chemical transformation of other silicate minerals.The light‐mineral analysis showed weathering of feldspars in the sola although no significant differences were noted in the distribution of heavy minerals.
ALPINE SOILS OF NORTH‐EAST SCOTLAND
Authors: ROMANS J. C. C. , STEVENS J. H. , ROBERTSON L. 
Published: July 2006

SummaryMany features of the alpine soils of NE. Scotland are related to altitude. The deep contemporary humose A horizon has formed in Post‐Boreal to recent times. Its formation was preceded by a phase of profile development characterized by very scanty A horizon development. This phase was interrupted by a stage of frost disturbance, probably equated with the Highland Re‐advance. The earliest part of the pedogenetic cycle is represented only by cryogenic redistribution of the fine fraction, within the parent material column, which occurred between 12,000 and 28,000 B.P.
DARK WELL‐DRAINED SOILS OF TUNDRA REGIONS IN WESTERN ALASKA
Authors: RIEGER S. 
Published: July 2006

SummaryFour dark well‐drained soils in tundra areas near the Bering Sea coast of Alaska have similar morphology, but physical and chemical properties reflect those of the parent materials. Three of the soils are extremely acid and have low base‐status. These, together with comparable soils in the arctic and in high mountains at lower latitudes, are classified as Cryumbrepts. One, from basic rock, with slight acidity and fairly high base‐status is classified as a Cryoboroll. These soils have some characteristic in common with Cryandepts and Cryorthods of adjacent areas, but can readily be distinguished from them in the field.
THE MEASUREMENT AND MECHANISM OF ION DIFFUSION IN SOILS III. THE EFFECT OF MOISTURE CONTENT AND SOIL‐SOLUTION CONCENTRATION ON THE SELF‐DIFFUSION OF IONS IN SOILS
Authors: ROWELL D. L. , MARTIN M. W. , NYE P. H. 
Published: July 2006

SummaryThe self‐diffusion coefficients of Cl, Na, Sr and phosphate have been measured in Upper Greensand, sandy clay loam (CEC 7.45 me/100 g.) between pF 1.8 and 5.4 and, for Na and phosphate, over a range of soil‐solution concentrations. An attempt has been made to estimate the relative contributions of solution‐ and exchangeable‐ions to diffusion. There is some indication that exchangeable Na may contribute to diffusion at the lowest moisture contents used, but little indication of this at pF 2.1 (15 per cent moisture content) when the proportion of ions on the solid was as high as possible. Exchangeable Sr appears to make no significant contribution to diffusion at any moisture content when the soil‐solution concentration is 0.1M. Exchangeable phosphate appears to make no contribution to diffusion at pF 2.1 between 5 × 10−6M and 9 × 10−4M.
CONTENT OF INOSITOL PENTA‐ AND HEXAPHOSPHATES IN SOME CANADIAN SOILS
Authors: McKERCHER R. B. , ANDERSON G. 
Published: July 2006

SummaryThe combined amounts of inositol penta‐ and hexaphosphates in a number of Canadian soils of differing origin have been measured. The esters were precipitated as barium salts from alkali extracts and purified by anion‐exchange chromatography; their identity was confirmed by paper‐partition chromatography. An alternative method involving precipitation of the esters as ferric salts in acid medium was found to give much lower values, probably because of incomplete precipitation.Values for eighteen surface soils ranged from 20 to 71 and for twelve subsoils from 18 to 43 ppm P. The amounts found were related to the contents of both total phosphate and total organic phosphate, and accounted, on average, for 6 per cent of the former and 17 per cent of the latter. A correlation of +0.67 (P < 0.01) was found with orthophosphate retention capacity but correlations with soil N and C contents were poor. Amounts of the esters were higher in forest soils than in grassland soils.
OXYGEN UPTAKE AND NITRIFICATION AT VARIOUS MOISTURE LEVELS BY SOILS AND MATS FROM IRRIGATED PASTURES
Authors: RIXON A. J. 
Published: July 2006

SummaryThe oxygen uptake and nitrification rates of the organic layer (mat) and underlying soil from two irrigated white clover (Trifolium repens L.) pastures produced on different soil types, were measured at moisture tensions ranging from pF o to 4.2. The highest rate of oxygen uptake was at pF 2 for the mats and at pF 2.8 for the soils. The highest rate of nitrification was at pF 2.8 for both mats and soils. The rate of oxygen uptake/g organic C at moisture tensions greater than pF 2 was of the same order of magnitude for both mats and soils, despite their having widely different organic C contents. This was probably due to the organic matter in both mats and soils having similar C/N ratios. At moisture tensions of pF 2 and less, the oxygen uptake/g organic C was usually greater for the mats than for the soils and this reflected the differences in physical characteristics of the two horizons.There was a greater production of nitrates in the mats than in the soils, at all moisture tensions. At low moisture tensions, there was no significant decrease in nitrates for the mats. Poorly aerated conditions prevailed at low moisture tensions in both soils and this coincided with low uptake of oxygen, respiratory quotients well in excess of unity, and a decrease in nitrate content, probably indicating denitrification.
THE EFFECTS OF DRYING AND AGEING TREE LEAVES ON THE ABILITY OF THEIR AQUEOUS EXTRACTS TO DISSOLVE FERRIC OXIDE
Authors: KING H. G. C. , BLOOMFIELD C. 
Published: July 2006

SummaryThe effect was studied of drying and ageing leaves on the ability of their water extracts to dissolve hydrous ferric oxide. Extracts of freshly collected picked and autumn‐fallen oak, beech, and larch leaves were compared with those of leaves from the same collections that were either freeze‐dried or dried at 105°C.The iron‐dissolving properties of the fallen leaves were not significantly affected by either method of drying, but drying at 105°C greatly increased the activities of picked larch and beech leaves. Freeze‐drying had relatively little effect.Larch needles lost their activity very quickly when aged aerobically for 8 months, while the activity of beech leaves decreased slowly. The activity of picked and fallen oak leaves increased dramatically during the first 1–2 weeks, and then decreased, rapidly at first; after 8 months the activity was still comparable with the initial value.There was no direct relationship between the activities of the extracts and the pH or the concentrations of polyphenols.
ANDESITE WEATHERING
Authors: HENDRICKS D. M. , WHITTIG L. D. 
Published: July 2006

SummaryPetrographic and quantitative mineralogical analyses of two andesites and their saprolite (weathered rock) from the Cascade Range in California reveal a mineral weathering sequence in the rocks related to crystal size and composition and to weathering environment. Both the hypersthene andesite and the olivine andesite studied have been subjected to moderate to intensive leaching by acid solutions percolating through the superjacent soil bodies. Although the two parent rocks differ in chemical and mineralogical composition, their weathering to saprolite has followed a similar progression. During early stages of weathering of both rocks, relatively large hypersthene phenocrysts are most resistant. Following in decreasing order of resistance in both cases are plagioclase phenocrysts and finegrained mafic minerals, olivine, and glassy matrix material. Quartz is relatively stable in the earliest weathering stages, but it decreases rapidly with increased weathering. Free iron oxides and clay increase with increased weathering. Amorphous clay dominates the early weathering stages, but as weathering progresses, kaolin increases relative to amorphous clay.
INDICATIONS OF PROVENANCE IN SOME ANGLESEY DRIFT SOILS
Authors: PETTERSSON M. 
Published: July 2006

SummaryA study of the heavy mineralogy of the fine‐sand and stone fractions and the particle‐size distribution and CEC of samples from thirty Anglesey drift‐derived soils suggests that the soil stones are an unreliable guide to the parent material of the soil as a whole. The chief lines of evidence are: the small degree of dependency of soil‐ and stone‐heavy mineralogy, the slight translocation of most stones, and the great similarity of soils containing very different stone assemblages.
SOIL TEXTURE PATTERNS IN THE ALLUVIUM OF THE LOWER INDUS PLAINS
Authors: HOLMES D. A. , WESTERN S. 
Published: July 2006

SummarySoil texture was mapped in the immature alluvial soils of the Lower Indus plain. A disadvantage of soil texture as a mapping criterion in such soils is the great complexity of their textural patterns. The geomorphological background of the Lower Indus plains is examined, and a classification of texture and textural profiles is defined. The mapping unit proposed, the‘textural association', comprises a certain range of textural profiles within a given landform, related to each other by the modes of deposition which established that landform. It seems likely that the textural association could, in more detailed surveys, form the basis of a soil series classification.
SOIL STRUCTURE IN VERTISOLS OF THE BLUE NILE CLAY PLAINS, SUDAN
Authors: DE VOS t. N. C. J. H. , VIRGO K. J. 
Published: July 2006

SummaryA survey of 1·5 million hectares of the Blue Nile clay plains has shown the majority of soils to belong to the order of Vertisols. The morphological characteristics of these soils are described and compared with similar soils in other parts of the world. Soil cracking, structure, surface mulching, and micromorphology are discussed in detail.The use of crack width is considered to be unsatisfactory as one of the criteria for differentiating Vertisols and Entisols. Cracking may prove to be a useful criterion for land suitability classification. Three different types of surface mulch have been distinguished. A separation between soils possessing surface mulches and hard crusts is recommended at the family level.The unequal stresses and strains which result from the swelling and shrinking processes are responsible for the aggregation and structure formation within these soils. Platy layers were found to restrict water penetration and root development. The term‘bicuneate’ is proposed for the description of the wedge‐like structure of the soils.The micromorphology appeared to be strongly affected by pressure: numerous slickenside faces were recognized.
HETEROGENEITY IN SILICON‐IRON MIXED HYDROXIDES
Authors: HERBILLON A. J. , VINH AN J. TRAN 
Published: July 2006

SummarySeveral mixed hydroxides obtained by co‐precipitation of FeCl2 or FeCl2 with Na2SiO2 followed by ageing and purification were studied by X‐ray diffraction, infra‐red spectroscopy, and surface‐area measurements.The compounds with molecular ratios SiO2/Fe2O3 ranging from 0·1 to 1·17 are essentially amorphous.Silica, which is not to be considered as an integral part of the gel, is chemi‐sorbed on the ferric or‘ferrosic’ phase.The good agreement between IR, DTA, and surface‐area measurements with increasing molecular ratios permits the distinction between two ranges of silica contents. In the first range, MR <·1, silica is directly chemisorbed on the adsorbant. In the MR >0·1 range, silica polymerizes as a separate phase growing upon the‘ferrosic’ or‘ferric’ phase.
CATION EXCHANGE PROPERTIES OF MICAS
Authors: NEWMAN A. C. D. 
Published: July 2006

SummaryThe abilities of 10 trioctahedral and 3 dioctahedral micas to release K by cation exchange were compared by repeatedly extracting the micas with NaCl solutions.For a chosen solution concentration and pH, the quasi‐equilibrium concentration of K in a solution in contact with a mica is largely independent of the fraction of mica K exchanged. The solution concentration ratio cK/cNa ranges from 1×10‐5 for dioctahedral micas to 1·2×10‐3 for a very reactive biotite and seems to depend on the number of mica structural‐hydroxyl groups orientated so that the OH transition moment is perpendicular to the mica basal plane. In the phlogopite‐biotite series, the most important single constituent of a mica that determines its K release is the F content.Micas that lose much negative charge when the K is exchanged release K more readily to acidic solutions. The pH of unbuffered solutions increases during the exchange of K from these micas, confirming the view that sorption of protons decreases the negative charge of the aluminosilicate layers.
QUANTITATIVE PEDOLOGICAL STUDIES ON SOILS DERIVED FROM SILURIAN MUDSTONES
Authors: ADAMS W. A. , EVANS L. J. , ABDULLA H. H. 
Published: July 2006

SummaryThe main mineralogical change during soil development on Silurian mudstone in mid‐Wales is the weathering of chlorite. Quantitative assessments of changes occurring during pedogenesis have indicated that the release of Mg, Fe, and Al from the parent rock is coincident with the textural degradation of the mudstone. Acid dissolution suggests that the iron‐rich chlorite, which is probably diagenetic and may act as a rock cement, contains most of the Mg and Fe present in the rock.
CLAY MINERALOGY OF SOME SEASONALLY FLOODED SOILS OF EAST PAKISTAN
Authors: HABIBULLAH A. K. M. , GREENLAND D. J. , BRAMMER H. 
Published: July 2006

SummaryThe clay fractions of four seasonally flooded soils from East Pakistan have been studied using X‐ray, DTA, and infra‐red methods, total chemical analysis, surface area determination, and electron microscopy. The soils represent young alluvium (Borda), a juvenile groundwater laterite (Nunni), a groundwater lateritelatosol intergrade (Noadda), and a surface‐water glei (Chhiata). Mica and kaolinite were present in all the soils, and vermiculite in all except possibly Noadda. Vermiculite, total magnesium content, and SiO2/Al2O3 ratio decreased and kaolinite increased in the sequence Borda–Nunni–Noadda. Electron micrographs indicated that in the Borda soil, which is the youngest and subjected to the longest period of annual flooding, iron hydroxides are present as gels coating the surfaces of the clay mineral particles. Such coatings are less apparent in the Nunni clay, and in the Noadda clay most of the ‘free iron oxides’ appear as small granules. The Chhiata soil has about 12.5 per cent of its clay fraction in the form of an amorphous gel rich in silica, and much of the mica and vermiculite in a randomly interstratified complex.
IRISH PLAGGEN SOILS—THEIR DISTRIBUTION, ORIGIN, AND PROPERTIES
Authors: CONRY M. J. 
Published: July 2006

SummarySoils have been described in Ireland which meet the definition of thick manmade surface horizons conforming to Plaggen epipedons (Conry, 1969). Unlike the north‐west European Plaggen soils these Irish Plaggen soils have not been formed by the prolonged addition of Plaggen material (heather sods, forest litter, or grass plaggen) and dung, but were formed by the addition of calcareous sea sand, applied either alone or mixed with stable dung. Although only small quantities of grass sods were used in the formation of the Irish Plaggen soils, they should not be separated genetically from the true Plaggen soils of NW. Europe. They occur in coastal areas, within one mile of the coast approximately, where sources of calcareous sand are readily available.These Plaggen soils generally have a loamy‐coarse‐sand to coarse‐sandy‐loam texture, a granular to single grain structure and loose to very friable consistence. Colour is directly related to the colour of the original soil. Depth varies from field to field and is related to population density.The Irish Plaggen soils are always base saturated. Phosphorus, potassium, magnesium, and sodium are very much higher than in the unsanded counterpart.Trace element deficiencies include boron, magnanese, and cobalt. Like the Plaggen soils of NW. Europe the Plaggen soils in Ireland are superior in productivity to their non‐Plaggen counterparts; not only has man's influence increased crop yield substantially, but the range of crops produced has also been enlarged. The Irish Plaggen soils show symptoms of a moisture deficit only in prolonged dry periods.
LOESS IN THE SOILS OF NORTH NORFOLK
Authors: CATT J. A. , CORBETT W. M. , HODGE C. A. H. , MADGETT P. A. , TATLER W. , WEIR A. H. 
Published: July 2006

SummaryThin silty deposits cover large areas of north‐east Norfolk, occurring mainly on gently sloping and flat plateau sites and on the floors of valleys cut in the glacial deposits. Particle size and geographic distribution of the deposits suggest that the silt is windblown. The mineralogical composition of the silt fraction resembles that of the silt of Hunstanton Till, suggesting that most of the deposit was derived as loess from outwash of the Weichselian glacier. However, at some localities the sand and clay components of the deposits were derived, at least partly, from subjacent glacial sediments of pre‐Weichselian age. The distribution of the silty deposits strongly affects the pattern of soil types and sometimes the growth of crops.