bluuebunny/crossref_metadata_2025_split huggingface dataset:
CRUSTING OF RIVER ESTATE SOIL, TRINIDAD, AND ITS EFFECT ON GASEOUS DIFFUSION, PERCOLATION, AND SEEDLING EMERGENCE
Authors: AHMAD N. , ROBLIN A. J. 
Published: July 2006

SummaryThe River Estate Loam in Trinidad is micaceous. It is weakly structured and prone to surface crusting which results in decreased gaseous diffusion, infiltration‐ percolation, and seedling emergence. Mulching with ‘Encap’ (a liquid petroleum product) increased infiltration but not seedling emergence whereas ‘Krilium’ (sodium polyacrilonitrile) was more effective in improving seedling emergence. Bagasse mulch had a beneficial effect on infiltration but in common with pen manure was not very effective in aiding seedling emergence. Thin section examination showed that the uncrusted soil had an open structure with a large volume of pores, but, on crusting, the particles became densely packed with negligible air‐spaces. Soil particles on die surface of the crust showed some degree of orientation but below the surface there was no such tendency, although particles coalesced with negligible air‐spaces. The liquid petroleum mulch prevented crust formation and maintained a stable soil structure.
QUALITY CONTROL IN SOIL SURVEY INTRODUCTION: I. THE CHOICE OF MAPPING UNIT
Authors: BIE S. W. , BECKETT P. H. T. 
Published: July 2006

SummaryThe quality of a soil map depends on its utility for practical purposes and should be judged by this standard. The Introduction to this series suggests how utility may be measured, and briefly lists decisions in the planning and execution of a soil survey which determine the utility of the resulting soil map. Subsequent papers in the series discuss their influence separately.Part I discusses the policy decision on the kind of mapping unit. It reviews different kinds of mapping units and presents a scoring procedure to compare the ceilings which each imposes on the utility of a soil map. The scoring procedure assumes that the whole extent of every mapped soil unit exactly matches its description in the map legend. On this basis it estimates the average probability that the soil profile class at any randomly located site within a survey area is correctly predicted. The score is a ceiling, attainable only if the execution of the survey were perfect, and no mapping unit contained profile classes not predicted from its legend. Even so the legends of many published soil maps achieve scores of 50 per cent or less. The paper stresses the importance of adequate aids to predict the occurrence of individual profile classes within compound mapping units containing more than one. These points are illustrated from Australian experience.
GENESIS AND MORPHOLOGY OF SOME ALPINE PSEUDOGLEY PROFILES
Authors: BOUMA J. , VAN DER PLAS L. 
Published: July 2006

SummaryTwo representative Alpine pseudogley profiles from a high Alpine region in Switzerland are described. Their genesis is mainly a function of illuviation, oxidation and reduction processes, and frost action. A relationship between soil type and vegetation was not found. The higher content of silt in the topsoil can be attributed largely to sedimentation of wind‐blown particles.
THE ADSORPTION OF ALUMINIUM FROM HYDROXY‐ALUMINIUM SOLUTIONS ON TO FITHIAN ILLITE
Authors: COLOMBERA P. M. , POSNER A. M. , QUIRK J. P. 
Published: July 2006

SummaryThe adsorption of aluminium from hydroxy‐aluminium perchlorate solutions on to Fithian illite in the presence of 0.06M and 0.5M NaClO4 is described by Langmuir‐type adsorption isotherms at constant OH/A1 ratio. The binding constant for aluminium, and the amount of aluminium that can be adsorbed, increases with increasing OH/A1 ratio of the solution from which it is adsorbed. The Langmuir‐type adsorption isotherms can be explained on the basis that hydroxy‐aluminium species present in solution are adsorbed in constant relative proportions and that the relative proportions of hydroxy‐aluminium species remain unchanged on dilution of the hydroxy‐aluminium solutions at constant ionic strength. If the ionic strength at which the isotherm is determined is decreased from 0.5M to 0.06M NaClO4, the binding constant for adsorption of aluminium is not significantly altered. This can be understood if the adsorption process is not one of exchange but rather the formation of H bonds between the hydrolysed polymer species and the surface.Negative adsorption measurement at low and increasing ionic strength indicates the changes in charge on the adsorbed hydroxy‐aluminium polymers as their concentration in solution is increased.
SOIL FLUORINE
Authors: LARSEN S. , WIDDOWSON A. E. 
Published: July 2006

SummaryThe development of techniques for measuring soluble and labile soil fluoride using a specific‐ion fluoride electrode are described. The methods evolved were used to assess the fluoride status of numerous agricultural soil samples in addition soils which had received known fluoride additions. Two soil profiles were analysed with respect to distribution with depth of soluble and labile fluoride.The equilibrium‐fluoride concentration was determined after shaking the soil with a 0.01 M CaCl, solution. Isotopically exchangeable (labile) soil fluoride was determined by use of the radioactive fluorine isotope 18F. These labile fluoride values were well correlated with the amount of soil fluoride extracted by an anionexchange resin, and the latter method was consequently adopted for further determinations of labile soil fluoride.Nearly half the 1OO agricultural soil samples examined gave fluoride concentrations < 0.2 ppm in 0.01 M CaCl, extracts whereas labile fluoride values were evenly distributed around a mean of 20 ppm. For any given pH value, there appeared be an upper limit to the solubility of soil fluoride. Application to soil of superphosphate (in the field) or of fertilizer containing fluoride (in the laboratory) brought about increases in soluble soil fluoride.
SOURCES OF ERROR IN THE DETERMINATION OF SOIL POTASSIUM ACTIVITY RATIOS BY THE Q/I PROCEDURE
Authors: MOSS P. , BECKETT P. H. T. 
Published: July 2006

SummaryEquilibrium activity ratios such as aK/(aca+Mg)½ may be determined by analysing a solution in equilibrium with a soil. The Q/I procedure is one method for establishing the composition of such a solution. Several approximations have been proposed to simplify this procedure or the necessary calculations. This paper reviews the main sources of error in the Q/I procedure.Errors may arise in the sampling, preparation, and storage of soil samples: it is best to analyse samples as soon as possible after sampling, with no preparation other than gentle sieving.The Q/I procedure rests on certain implicit assumptions which will not strictly apply if there is any substantial exchange, between exchangeable cations and soluble salts or microbially dissolved carbonates, during determinations. This paper demonstrates that such exchange does indeed occur during the determination of the equilibrium activity ratios of soils at 5 < pH > 6, but that the errors may be ignored in British soils at pH > 5. Modified interpolation procedures designed to minimize errors from these causes appear to introduce larger errors than they avoid.The paper also indicates the conditions under which various approximations in the calculations may be employed.
THE CLASSIFICATION OF ARID ZONE SOILS
Authors: WESTERN S. 
Published: July 2006

SummarySoils in regions of arid and semi‐arid climates exhibit only limited pedogenetic profile development, and they might be more usefully described, classified and mapped in terms of their depositional character. The main source of understanding of their origins and practical significance is likely to be the sedimentary geomorphology of the area concerned, rather than the minimal pedogenetic features. The term ‘sedosols’ is proposed for these soils and a method of classification is outlined, based on depositional features and origins.Sub‐orders are based on mode of deposition to give four sedimentary families, viz. fluvial, littoral, aeolian, and anthropic.In lower category classification, series based on pedogenetic features cannot be defined and are replaced by the ‘depositional series’ characterized by the types of sediment (e.g. coarse textured, fine textured; saline, non‐saline).Typical phases are based on soil depth and degree of erosion. Salinity induced by irrigation is also best recognized at phase level as it is essentially an ephemeral feature.The three major differentiating characteristics of sedosols are soil texture, degree of depositional stratification and effective soil depth.
NUCLEATION, POLYMERIZATION, AND PRECIPITATION OF FeOOH1
Authors: HSU PA HO 
Published: July 2006

SummaryFresh Fe(ClO4)3 solutions, 0.01 M or 0.001 M in iron (III), were seeded with iron (III) hydroxide brown sols and the reaction processes were investigated. In two experiments, HC1O4 was added to fresh Fe(ClO4)3 solutions to lower their degrees of super saturation with respect to iron (III) hydroxide. Depending upon the quantity of seeding solution added, it was found that samples differed greatly in appearance and in the stability during ageing. With a small amount of seeding solution added and following a relatively long induction period, the sample rapidly developed to a dense, cloudy yellow suspension with FeOOH precipitate settled shortly afterwards. With an increased amount of seeding solution added, the sample gradually became more brownish and less turbid and eventually a clear brown sol was observed. Although α‐FeOOH was the major hydrolysed species in all samples, a yellow precipitate which settled under gravity was found only in those containing a small quantity of seeding solution. The above results provide experimental evidence supporting the hypothesis (Hsu and Ragone, 1972) that the initial number of nuclei relative to the concentration of mono‐meric species is the key factor governing the appearance and the stability of an hydrolysed iron (III) solution.In another experiment, varying amounts of a seeding solution were added to a fresh, pure 0.001 M Fe(ClO4)3 solution to which no HC1O4 was added. All samples rapidly hydrolysed to clear brown sols in less than 6 hours and no noticeable seeding effect was observed. It is suggested that a pure 0.001 M Fe(ClO4)3 solution is highly supersaturated with respect to iron (III) hydroxide and a large number of nuclei spontaneously form in situ shortly after preparation.
A COMPARISON OF DATA FROM AGRICULTURAL SOIL SURVEYS WITH ENGINEERING INVESTIGATIONS FOR ROADWORKS IN AYRSHIRE
Authors: McGOWN A. , ILEY P. 
Published: July 2006

SummaryRecently a number of outline soil survey maps, on a scale I: 25 000, each covering some IOO km square, have been made available by the Soil Survey of Scotland to County Advisory Officers) Planning Officers, and others who have specialist requirements. In North Central Ayrshire a number of major roadworks have been completed in recent years and the Kilmarnock and Hurlford Bypasses are at present under construction. Site investigations have been undertaken in connection with these works and construction records kept. These make possible the assessment of the usefulness of the soil survey maps for initial route and realignment planning of roads.The delineation of the various soil associations on the soil survey maps related very closely to the limits of the various engineering soils encountered. The groupings adopted by the soil surveyors for boulder clays have, however, been found to be narrower than presently required by engineers) while the groupings adopted with respect to the raised beach and alluvial deposits too wide.It is suggested that the engineering behaviour of boulder clays needs closer examination and any correlations between engineering and soil association groupings should be sought. Also if the grading, water content, and bulk density of the raised beach sands and gravels could be given by the soil survey, this information would permit engineers to make a much better judgement of the road‐bearing capacity of these materials. Alluvial deposits should be similarly tested and distinguished as either riverine or lacustrine deposits.To avoid duplication of effort in the future when geotechnical maps are produced and to gain the maximum benefit of the information so far collected, a closer liaison between engineers and the Soil Survey of Scotland is suggested.
DISTRIBUTION OF INOSITOL PHOSPHATES, PHOSPHOLIPIDS, AND NUCLEIC ACIDS AND MINERALIZATION OF INOSITOL PHOSPHATES IN SOME BANGLADESH SOILS
Authors: ISLAM A. , AHMED B. 
Published: July 2006

SummaryConcentration of inositol phosphates, phospholipids, and RNA and its derivatives of ten Bangladesh soils varied between 17.5 and 150 ppm, 0.5 and 11.0 ppm, and 0.22 and 1.30 ppm respectively. Variation in inositol phosphates was related to total phosphate and organic phosphate contents. Variation in phospholipids was associated with total phosphate, organic phosphate, and organic matter contents whereas the variation in RNA and its derivatives was related to total phosphate contents of the soils. Maximum mineralization of inositol phosphates was obtained in the first 30 days either when incubated with lime or when submerged under water. A moderate rate was observed in the subsequent 30‐day incubation periods. The mineralization was greater in soil which contained more organic matter and inositol phosphates. Mineralization also increased with pH. Liming enhanced mineralization as it induced conditions for the proliferation of phosphate transforming organisms.
INTERACTION OF BTPYRIDYLIUM HERBICIDES WITH ORGANO‐CLAY COMPLEX
Authors: KHAN S. U. 
Published: July 2006

SummaryThe adsorption of diquat (1,1′‐ethylene‐2,2′‐bipyridylium dibromide) and paraquat (1, 1′‐dimethyl‐4,4′‐dipyridylium dichloride) by an organo‐clay complex has been investigated. Paraquat was adsorbed by the organo‐clay complex in greater amounts than was diquat. Infrared studies suggest the formation of charge‐transfer complexes between diquat or paraquat and the organo‐clay complex. Organic matter upon interaction with clay may facilitate the adsorption of diquat and paraquat on clay minerals in soil.
STUDIES ON SOIL COPPER
Authors: McLAREN R. G. , CRAWFORD D. V. 
Published: July 2006

SummaryAdsorption isotherms were determined for the specific adsorption of copper by soils and soil constituents. Adsorption was found to conform to the Langmuir equation. The Langmuir constants, a (adsorption maximum) and b (bonding term), were calculated. Soils were found to have specific adsorption maxima at pH 5.5 of between 340 and 5780 μg g−1, and a multiple regression analysis revealed that organic matter and free manganese oxides were the dominant constituents contributing towards specific adsorption. Adsorption maxima for soil constituents followed the order manganese oxides > organic matter > iron oxides > clay minerals, which supported the findings for whole soils.The cation exchange capacities (non‐specific adsorption) of the test soils were found to be far greater than the specific adsorption maxima. However, evidence suggests that, for the relatively small amounts of copper normally present in soils, specific adsorption is the more important process in controlling the concentration of copper in the soil solution.
STUDIES OF SOIL ORGANO‐MINERAL FRACTIONS
Authors: WATSON J. R. , PARSONS J. W. 
Published: July 2006

SummarySand‐, silt‐, and clay‐size organo‐mineral fractions were isolated in bulk from surface horizons of five soils following ultrasonic dispersion in water. Good clay separation was achieved for all except one highly organic, calcareous clay soil. Organic‐N and ‐C were concentrated in the clay and silt fractions but for each soil the organic C : N ratio decreased in the order sand > silt > whole soil > clay. Acid hydrolysis of the silt and clay fractions revealed a slight concentration of amino acid‐N and NH4‐N in the clays but only small differences in the distribution of individual amino acids were observed. The results suggest that both silt and clay fractions may be important in the stabilization of soil organic matter.
STUDIES OF SOIL ORGANO‐MINERAL FRACTIONS
Authors: WATSON J. R. , PARSONS J. W. 
Published: July 2006

SummaryOrgan‐mineral particle‐size fractions, isolated from five soils by ultrasonic dispersion in water, were extracted with anhydrous formic acid/acetylacetone before and after treatment with aqueous HF partially to destroy silicate material. The resulting residues from two of the clay fractions, one montmorillonitic the other kaolinitic, were extracted further using the same reagents and also with 0.5M NaOH. The pattern of nitrogen extraction and nitrogen distribution data for the size fractions of four soils was similar but those of a fifth soil, with a high content of amorphous oxides, were quite different. There was evidence that the increasing nitrogen contents of successive samples of extracted material were mainly due to an increased amino acid content, especially dibasic acids. A serial extraction of clay fractions using formic acid/acetylacetone followed by HF followed by formic acid/acetylacetone and finally NaOH dissolved approximately 90 per cent of the organic‐N.
A RELATIONSHIP BETWEEN PHOSPHORUS REQUIREMENT, THE IMMOBILIZATION OF ADDED PHOSPHATE, AND THE PHOSPHATE BUFFERING CAPACITY OF COLLIERY SHALES
Authors: FITTER A. H. 
Published: July 2006

SummarySoluble phosphorus was allowed to age in contact with four colliery shales for up to 6 months. The ageing process apparently involved three stages–(i) a rapid initial drop controlled by pH; (ii) a steady‐state period; and (iii) an exponential decline whose rate was proportional to buffering capacity. Using this relation‐ship a model was derived to predict soil phosphorus requirement.
MINERALOGY AND GENESIS OF CLAYS IN RED‐BLACK SOIL TOPOSEQUENCES ON BASIC IGNEOUS ROCKS IN KENYA
Authors: KANTOR W. , SCHWERTMANN U. 
Published: July 2006

SummaryThe clay mineralogy of two red‐black soil toposequences on basic igneous rocks in Kenya has been investigated. Besides some illite and amorphous material kaolinites predominate in the slope soils (ultisols) whereas smectites are the main clay minerals in the soils of the depressions (vertisols). The kaolinites are poorly crystalline and have high surface area. According to chemical analysis, IR spectroscopy, and D.T.A. the smectites appear to be a ferriferous member of the montmorillonite‐beidellite series having approximately 0·5 Fe3+ in octahedral and 0·2 Al per O10(OH)2 in the tetrahedral position. The profile and slope distribution of kaolinites and smectites led to the conclusion that the smectites are the first weathering product and, depending on hydrological conditions governing the soil solution composition (Si, Mg, pH), either persist (depression) or are decomposed (slope) and followed by kaolinites.
GENESIS OF RED AND BLACK SOILS ON BASALT ON THE DARLING DOWNS, QUEENSLAND, AUSTRALIA
Authors: BECKMANN G. G. , THOMPSON C. H. , HUBBLE G. D. 
Published: July 2006

SummaryShallow friable red soils (euchrozems) and shallow cracking clays (black earths) occur in close proximity on basalt hills of the Darling Downs of Queensland. The euchrozems are mainly restricted to fiat hill crests and are associated with lithosols; the shallow black earths occur on upper pediment slopes, on small convex crests and on depressions on flat crests. The euchrozems are moderately leached and contain kaolin minerals and hematite with minor montmorillonite, while the black earths are dominantly montmorillonite with minor kaolin and hematite. It is proposed that the euchrozems have developed by long continued weathering under stable well‐drained conditions while the black earths have formed in sites prone to erosion and in situations with less water available for weathering. The weathering products produced in each situation have ensured continuation of the processes. The presence of two red soils in anomalous positions have been ascribed to (a) soil formation on exposed ‘bole’ (compacted red clay) layers and (b) local peculiarities of parent material controlling the course of weathering.
CHARACTERISTICS OF NUBIAN SANDSTONE‐DERIVED SOILS
Authors: SINGER A. , AMIEL A. J. 
Published: July 2006

SummaryNubian sandstone exposures in sub‐humid, semi‐arid, and arid environments have given rise to red, sandy but in other respects very different soils. Soils have a fairly well developed profile only in the sub‐humid zone, including a textural B horizon and are free of soluble salts and carbonates. In the semi‐arid and arid zones, profile differentiation is weak or non‐existent. Soils are shallow and contain carbonates, and in the arid zone also soluble salts, including gypsum. Kaolinite is the only clay mineral which is common to all the nubian sandstone parent materials. It is the major clay mineral in the sub‐humid zone soil. In the semi‐arid soils smectite is a second major clay component. In the arid zone both smectite and palygorskite, in minor amounts, accompany kaolinite. Both smectite and palygorskite are probably pedogenic neoformation products. Material of aeolian origin has probably been introduced into the silt and fine sand fractions of both the semi‐arid and arid soils. Some contamination of the clay fractions may have also occurred.
KINETICS OF ION EXCHANGE IN SOIL ORGANIC MATTER
Authors: BUNZL KURT 
Published: July 2006

SummaryThe rate of ion exchange of humic substances (humic acid and peat in the hydrogen form) with lead ions was investigated. As in processes occurring in nature, the lead solution was added in all our experiments slowly and continuously at a constant feed rate to the well‐stirred water‐suspended humic substances. Control experiments were also performed with a well‐defined synthetic ion‐ exchange resin (carboxylic acid type). The uptake of divalent lead ions by the humic substance and by the ion‐exchange resin, which is coupled with the release of an equivalent amount of hydrogen ions, proceeds as a function of time according to a characteristic sigmoidal curve. During the initial phase, the rate of ion exchange increases continuously with time, even though the humic substances become more saturated with lead ions.Theoretical calculations, based on a film diffusion process as the rate‐determining step, show that this behaviour should indeed be observed if any solution, containing exchangeable counter ions, is added continuously to an ion exchanger suspended in a solvent.The theory predicts further, in agreement with the experimental results, that in the initial phase of the ion‐exchange reaction, the uptake of the counter ions is proportional to the square of the time. If experiments are performed with different rates of addition of the counter ions, the time required to exchange a certain amount of counter ions should be proportional to α‐1/2, where α is the rate at which the ions are added. This prediction is also in accordance with the experimental results.
THE CALCAREOUS SOILS OF AZERBAIJAN.
Authors: ABEDI M. J. , TALIBUDEEN O. 
Published: July 2006

SummaryThe surface properties of soil carbonate were related to its distribution in thirteen profiles of a catenary sequence of calcareous soils from Azerbaijan.When carbonate surfaces were contaminated by Mg2+, 45Ca was used as a tracer for Mg2+ as well as Ca2+, thus enabling the carbonate surface areas to be estimated. These were shown to be inversely and curvilinearly related to soil carbonate contents, but with some abnormality for the three extremely saline/alkaline soils. Na+ does not appear to be specifically adsorbed on carbonate surfaces in the latter.The specific and the total surface areas of carbonate in the surface soils are very sensitive indices of profile development, and are combined with the content and particle‐size distribution of carbonate in the profiles to show the variation in soil development along the catenary sequence.