bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE DETERMINATION OF THE SURFACE AREA OF SEPIOLITE FROM CARBON DIOXIDE ADSORPTION ISOTHERMS
Authors: DANDY A. J. 
Published: July 2006

SummarySepiolite has a microporous structure the pores of which may be penetrated to differing extents by molecules of different gases. A study has been made of the adsorption of CO2 on outgassed sepiolite (from Amboseli, Tanzania) at 193°, 209·7°, 273·2°, and 298·2 °K using a gravimetric method. Values of the surface area of sepiolite were calculated from BET (Brunauer, Emmett, and Teller) and Kaganer plots of results, assuming molecular areas for CO2 based on extrapolated liquid densities. There were only relatively small deviations from a mean value of 279 m2/g. However, the values were much lower than those previously determined by adsorption of N2 and of other gases.It is suggested that CO2 adsorbed at these temperatures should be assumed to be in the liquid state, but that the usual method of calculating the molecular areas of adsorbed CO2 from the liquid densities at these temperatures yields values which are too low. Molecular areas of 20·8 Å2 at 193 °K and 23·4 Å2 at 209·7 °K are preferred.Isosteric heats of adsorption at different coverages were calculated from the isotherms. The results indicated heterogeneity of the surface, with decreases in the values of the heat of adsorption occurring at low coverages and in the‘monolayer region’. They compare well with values calculated from the BET equation.
TRACE‐ELEMENT CONTAMINATION OF PARKLANDS IN URBAN AREAS
Authors: PURVES D. , MACKENZIE E. JEAN 
Published: July 2006

SummaryEvidence is presented that soils in urban parklands are markedly contaminated with Cu, B, Pb, and Zn. Herbage from the same areas contains significantly higher levels of Pb and Zn than herbage from permanent pastures in rural areas.
SEPARATION OF THE LIGHT FRACTION FROM SOILS BY ULTRASONIC DISPERSION IN HALOGENATED HYDROCARBONS CONTAINING A SURFACTANT
Authors: FORD G. W. , GREENLAND D. J. , OADES J. M. 
Published: July 2006

SummaryPartially humified material can be separated from other soil material by flotation on a bromoform‐petroleum spirit mixture of density 2·0 g cm‐3. Maximum recovery of partially humified material requires ultrasonic dispersion and the addition of a surfactant to the suspension. For large‐scale work‘Nemagon’ may be used in place of the bromoform‐petroleum spirit mixture.
PHOSPHORUS TRANSFORMATIONS IN A CHRONOSEQUENCE OF SOILS DEVELOPED ON WIND‐BLOWN SAND IN NEW ZEALAND
Authors: SYERS J. K. , WALKER T. W. 
Published: July 2006

SummaryThe rate of transformation of inorganic phosphorus fractions and forms was investigated in a chronosequence of weakly weathered soils developed on windblown sand. The net decline of acid‐extractable Ca‐P during 104 years of soil development was approximately 2600 kg/ha m profile. This fraction was progressively removed from surface horizons and had virtually disappeared from the oldest soil. Residual inorganic P, considered to be included apatite which is not extracted by 0·5 and 1N HC1, was relatively constant in profiles of the chronosequence but decreased in the oldest soil. In the younger soils, the NH4F‐P fraction was low but, with increasing time, the weight of this fraction increased, initially in surface horizons. The net accumulation of non‐occluded secondary inorganic P during 104 years was 360 kg/ha m profile and this was largely due to an increase in the NH4F‐P, rather than the 1st NaOH‐P fraction. There was no net shift from non‐occluded to occluded secondary inorganic P. Although apatite is initially present as inclusions within primary minerals in the wind‐blown sand, an extensive loss of P has occurred during 104 years.
A RAPID METHOD FOR DETERMINING THE SURFACE AREA OF ALUMINOSILICATES FROM THE ADSORPTION DYNAMICS OF ETHYLENE GLYCOL VAPOUR
Authors: RAWSON R. A. G. 
Published: July 2006

SummaryA new method is described for determining the surface area of soils and clays by adsorbing ethylene glycol vapour under continuous evacuation at c. 10‐2 cm of mercury. The adsorption of a monolayer of ethylene glycol is inferred from the dynamics of pressure changes in the adsorption chamber. The time at which monolayer adsorption is evaluated is proportional to the total weight of ethylene glycol required to form a monolayer on all samples in the adsorption chamber. This period ranged from 30 to 75 minutes when from 0·39 to 1·56 g of glycol was adsorbed in the experiments. A single 0·75 g sample of Wyoming bentonite required 0·195 & glycol.
ACIDIC PROPERTIES OF PLANT LIGNINS AND HUMIC MATERIALS OF SOILS
Authors: THOMPSON S. O. , CHESTERS G. 
Published: July 2006

SummaryThe acidic properties of lignins from the native vegetation of a virgin Ella loamy sand and the humic acids, the 1, 4‐dioxane extractable humic fraction and residual humic acids from the virgin and cultivated soils were investigated by determining solid‐state cation exchange capacities for Cu and Ca and by non‐aqueous potentiometric titration, using potassium methoxide in a benzene‐methanol mixture as titrant. The lignins and soil dioxane extracts were titrated in pyridine; the humic acids in dimethylformamide. Platinized Pt and CH3OH modified calomel electrodes formed the electrode combination.The CEC of the humic acids were much higher than the CEC of lignins with both cations but the Cu: Ca absorption ratios were less for humic acids than for lignins. Titration curves of lignins showed two potential breaks with total acidities of 960 to 1,190 me/100 g. Titration curves of the humic acids showed three to six potential breaks while curves of the soil dioxane extracts showed three and four. The total acidities of the two types of humic isolates were 1,100‐1,200 me/100 g. The equivalent weights of most lignins and humic materials were very similar although the acid groups might be different with respect to types and acid strength. Lignins from other plant materials and humic isolates from other soils were also investigated by non‐aqueous titration to determine the general applicability of the results obtained with isolates from the Ella soils.
THE MEASUREMENT AND MECHANISM OF ION DIFFUSION IN SOILS
Authors: VAIDYANATHAN L. V. , NYE P. H. 
Published: July 2006

SummaryDiffusion coefficients of soil phosphate calculated from flux to chloride form of anion‐exchange resin‐paper, assuming total depletion of the labile pool at the boundary, were too small and unrealistic. Thus not all the phosphate in the labile pool contributed to the diffusion process while being desorbed at constant pH in the presence of an indifferent anion—Cl—from the resin‐paper. Desorption relationships under these conditions, using CaCl2 at atmospheric CO2 pressure, were markedly different from the relationship between the long‐term 32P‐exchangeable phosphate and the corresponding pore‐solution concentrations. In the same soil containing different amounts of labile phosphate, a different desorption relationship was found for each phosphate level.The constant proportionality between amount of phosphate diffusing into resin‐paper and square root of time was indicative of a constant concentration at the boundary. The resin‐paper: soil system was therefore considered as an infinite composite medium in which diffusion through both resin‐paper and soil were rate‐limiting. The constant boundary concentrations were estimated by the use of the diffusion coefficients in the resin‐paper, the phosphate adsorption isotherm for the resin‐paper and the desorption relationship for each phosphate level in the soil.Diffusion coefficients, calculated using the boundary concentration appropriate to each phosphate level, were related to the slopes of the corresponding desorption relationships, resulting in values of the impedance factor similar to those found for K diffusion under similar conditions.The resin‐paper method, however, does not provide an accurate enough measure of the diffusion coefficient of soil phosphate to be of any practical use. Until better and simpler methods are found, the diffusion coefficient may be calculated using the slopes of the desorption relationship and the separately determined value of the impedance factor.
THERMODYNAMICS AND THERMOCHEMISTRY OF THE EXCHANGE REACTION BETWEEN NH4+ AND Mn2+ IN A MONTMORILLONITE CLAY
Authors: GILBERT M. , VAN BLADEL R. 
Published: July 2006

SummaryThe exchange reaction between NH4+ and Mn3+ was studied on a montmorillonite clay at several temperatures and different ionic strengths.Manganese was preferred to ammonium; this preference increased with the temperature and dilution of the dialysate. Comparison with published data concerning exchanges involving NH4+ and the alkaline‐earths showed that in the sequence of increasing selectivity: Mg2+ < Ca2+ < Sr2+ < Ba2+, Mn2+ lies between Mg2+ and Ca2+. The enthalpy change was measured calorimetrically and calculated by application of the van't Hoff law to the temperature coefficient of the equilibrium constants. Both values were in good agreement. The excellent recoveries of Mn2+ at the end of the exchange reaction and the constancy of the cation exchange capacity over the whole range of surface composition ruled out the possibility of significant adsorption in the MnOH+ form. The behaviour of manganese was very similar to that of the alkaline‐earth cations.
SEASONAL PATTERN OF WATER‐SOLUBLE CONSTITUENTS FROM LEAVES OF POPULUS×‘NORTHWEST’ (HORT.)
Authors: DORMAAR J. F. 
Published: July 2006

SummaryAqueous leaf extracts were obtained at regular intervals during the 1967 growing season from Populus×‘Northwest’ (Hort.). After lyophilization the samples were analysed for acidity and ash, sugar, phenol, and N contents. They were examined with thin‐layer chromatography and infra‐red spectroscopy.Simple phenolic compounds, present earlier in the growing season, made way for more complex phenols as the season progressed, and the extracted material became more acid. The increased loss of phenolic compounds and acids from the leaves toward the end of the summer continued during their first autumn on the ground. The polysaccharide content decreased during the season. The infra‐red spectra of the lyophilized material were useful in making comparisons. It was concluded that, for percolation and transformation studies of Chemozemic soils, aqueous leaf extracts obtained during late summer or autumn should be the most relevant.
THE ASSOCIATION OF VANADIUM AND MOLYBDENUM WITH IRON OXIDES IN SOILS
Authors: TAYLOR R. M. , GILES J. B. 
Published: July 2006

SummaryHigh concentrations of V and Mo in ironstone gravels have previously been reported. Examination of soils in which ironstone concretions have formed during pedogenesis indicates that Mo/Fe ratios are in fact higher in the finer fractions than in these gravels, whereas the V/Fe ratios tend to be independent of particle size. In the lateritic podzolic soils examined, the observed association between V and Fe in the iron oxides of the fine earth fraction (< 2 mm) is maintained during any solution of this fraction and any subsequent transportation and precipitation involved in the development of the gravels.Differences in the degree of association with Fe shown by Mo and V are considered to be due to different modes of transport of these elements through the soil. It is suggested that V moves as a vanadyl cation whereas Mo is transported as a complex anion.
QUANTITATIVE PEDOLOGICAL STUDIES ON SOILS DERIVED FROM SILURIAN MUDSTONES
Authors: STEWART V. I. , ADAMS W. A. , ABDULLA H. H. 
Published: July 2006

SummaryThe soils in Cwmcadian, Merionethshire, have developed in uniform Silurian mudstones. This rock consists of fundamental primary particles of silt and clay size. These are released on weathering in the same ratio as they occur in the rock. Because of the simple mode of weathering, silt may be used as an internal standard against which to assess gains and losses of mobile soil constituents during pedogenesis.
A SEMI‐QUANTITATIVE HYDROLOGICAL CLASSIFICATION OF SOILS IN NORTH‐EAST ENGLAND
Authors: EDMONDS D. T. , PAINTER R. B. , ASHLEY G. D. 
Published: July 2006

SummaryMultiple regression equations relating the times‐to‐peak of flood hydrographs on twenty‐six rivers in NE. England with the characteristics of causative rainfall and those of the relevant river basin, showed flood‐wave formation to be largely dependent on storm duration and the average, minimum, infiltration rate of the soil. Other significant factors were the initial flow in the river, temporal variation of rainfall during a storm, and main river channel length and slope.
THE ORIGIN AND DISTRIBUTION OF HYDROCARBONS IN AN UPLAND MOORLAND SOIL AND UNDERLYING SHALE
Authors: JONES J. G. 
Published: July 2006

SummaryInvestigations of plant and soil lipids at an upland moorland site revealed certain similarities in composition. In all lipid samples the polar compound fraction was the largest and the paraffinic the smallest. The range (C16–36) and pattern of alkanes in the soil were also similar to those of the surface vegetation, both demonstrating a definite predominance of Codd components. A slight peak in the alkanes identified was seen in the region C27–C30. The pattern of alkanes in the water running into the soil was quite different, and was not seen to influence the spectrum detected in the soil. Incubation of soil samples with and without added succinate, although causing a drop in lipid content, did not produce many significant changes in the soil alkanes. Plant‐derived alkanes in the soil appeared to be resistant to microbial alteration under the experimental conditions employed. The origin of alkanes in an ancient sediment, the underlying shale, was not so clear since the carbon preference index was around unity. It seemed possible that microbial activity might have altered the spectrum of alkanes in the sediment during ageing.
A COMPARATIVE STUDY OF NUMERICAL CLASSIFICATION AND ORDINATION OF SOIL PROFILES IN A LOCALITY NEAR OXFORD
Authors: DE LA C. H. E. CUANALO , WEBSTER R. 
Published: July 2006

SummaryData for 85 soil profiles, located at random within 17 physiographic units in a 1,000 km2 area near Oxford, and each characterized by 37 properties, were analysed by two sets of multivariate techniques. Principal component analysis yielded two components accounting for 44 per cent of the total variation, and the distribution of the profiles along these components is plotted as a scatter diagram (ordination). Similarity analysis and hierarchical grouping (classification) were performed using three different similarity indices, two different standardization techniques, and three different sorting strategies. Before analysis the profiles were classified by two pedologists, independently using their judgement.For the Brown Earths there was moderately good agreement between the results of the two prior classifications and between them and those produced by the several numerical procedures. The degree of clustering was slight and much less than imagined prior to analysis. For the Gleys there was no evident clustering. Different numerical procedures gave different results, as also did the two prior classifications. Pedologists faced with difficult classificatory decisions cannot look to any hierarchical clustering strategy as arbiter, though they should get guidance from a principal component plot.
AGEING OF PHOSPHATE ADDED TO SOIL
Authors: LARSEN S. , WIDDOWSON A. E. 
Published: July 2006

SummaryThe ageing of phosphate added to suspensions of a calcareous soil was measured in terms of the solubility of the phosphate and the amount of isotopically exchangeable phosphate (E value). These both showed a decrease in reactivity of the added phosphate during a period of 5 months. A constant ratio of E values after 24 and 500 hours showed that no redistribution within different fractions of labile phosphate occurred.
THE MOBILIZATION OF IRON BY EXTRACTS OF EUCALYPTUS LEAF LITTER
Authors: ELLIS R. C. 
Published: July 2006

SummaryWhen aqueous extracts of leaf litter from four closely related Eucalyptus species were reacted with soil material under aerobic conditions their iron mobilizing activity was found to be inversely related to the productivity of the sites on which the species grew. The activity of litter extracts of the four species grown in similar soils in the field was found to increase in the order E. regnans, E. obliqua, E. radiata, E. sieberiana. The results indicate that species‐soil interactions could be as important as inherent species characteristics in determining whether or not a species is a ‘podzol former’.The effect on the activity of the extracts of altering their pH before reaction with either soil or with prepared iron oxides suggests that, whereas organic acids could be mainly responsible for mobilizing iron from soil and from anhydrous ferric oxide, polyphenols could be more important than organic acids in mobilizing iron from hydrous ferric oxide.The pH and Eh curves obtained when litter extracts were titrated with a ferric chloride solution showed that iron from this source was strongly reduced by the extracts at low pH.
THE APPLICATION OF MULTIVARIATE ANALYSIS TO SOIL STUDIES
Authors: NORRIS J. M. 
Published: July 2006

SummaryThe assumption that the variation of soil can be characterized by the variation of a set of relatively few soil properties is examined. Different sets of properties describing the same soil profiles, in particular those measured in the field, and those measured in the laboratory, are used to group these profiles by principal components analysis. This numerical method is used so that each set is grouped by exactly the same procedure. Data from the Riverina plains of New South Wales and some Cotswold (Gloucestershire) beechwoods are examined in this way and a close correspondence found between grouping based on field and laboratory data separately. The results cannot be generalized, though the method is suitable for any area. In particular, the results are unlikely to hold if comparisons are made between single properties.
EFFECTS OF TEMPERATURE ON THE MEASURED CATION‐EXCHANGE CAPACITIES OF ANDO SOILS
Authors: WADA KOJI , HARADA YASUO 
Published: July 2006

SummaryThe CEC was measured by a method which eliminates washing for removal of excess saturating salt. The effect of temperature on the CEC of soils and clays varied and depended on their major cation‐exchange materials; the ratio of the CEC measured at 10–20 °C to that measured at 50–60 °C was 0.36 to 0.59 for allophane, imogolite, and/or humus, 0.62 to 0.75 for kaolin minerals, and 0.90 to 0.99 for montmorillonites. The CEC, increased at higher temperature in a neutral n acetate solution, was only partly reduced by lowering the temperature again. There was no evidence for an acceleration of cation diffusion with increasing temperature. A structural alteration in which some ‘bound’ functional groups are set free for ionization is proposed as a major cause of the large CEC increase observed for Ando soils at higher temperature.
SOME EFFECTS OF PARTIAL STERILIZATION ON MINERAL NITROGEN IN A LIGHT SOIL
Authors: DRAYCOTT A. P. , LAST P. J. 
Published: July 2006

SummaryField plots on loamy sand with and without the soil fumigant ‘D‐D’ (dichloropropane‐dichloropropene mixture) were sampled at 0–12, 12–24, and 24–64 cm depths during May 1966–8. All plots received 125 kg/ha nitrogen fertilizer early in March each year and were cropped with sugar beet. Fumigation increased the total amount of mineral (NH4++ NO3−) nitrogen to a depth of 64 cm by 67 kg/ha on average, largely by increasing NH4+‐nitrogen. In unfumigated plots some mineral nitrogen leached below 12 cm every year but there was at least 125 kg/ha in the surface 64 cm in 1966 and 1968; during the wet spring of 1967 much leached below 64 cm. Sequential sampling in 1968 confirmed that some of the fertilizer nitrogen moved down the profile during spring.Plots partially sterilized either one or two years previously and not again, contained the same quantity of mineral nitrogen as plots that had never been fumigated. Fumigation increased the mineral nitrogen in plots by a similar amount whether or not they had been fumigated previously. Thus, on this soil, partial sterilization with ‘D‐D’ seemed to have little residual effect on mineral nitrogen.
A STATISTICAL EVALUATION OF THE INTER‐RELATIONSHIPS BETWEEN PARTICLE‐SIZE FRACTIONS, FREE IRON OXIDE, AND TRACE ELEMENTS1
Authors: PRABHAKARAN NAIR K. P. , COTTENIE A. 
Published: July 2006

SummaryA statistical approach was adopted to study the association between particle‐size fractions and trace elements in soil, because conventional studies on the subject usually involve chemical methods of fractionation, which may lead to loss and upsets in natural distribution patterns. The results showed that both total and extractable contents of Zn, Al, Cu, Mn, Pb, and Fe are bound up either in clay or silt fractions, although variations as to the particular particle‐size diameter range did occur among the different elements. An attempt to resolve these relationships fitting a linear mathematical function, y=a+bx, based on the statistical association of individual particle‐size fractions with particular trace elements, gave satisfactory results. There was no evidence to indicate that certain size fractions could mobilize trace elements by virtue of their abundance in these soils. There was convincing statistical proof to show that amorphous Fe2O2, possibly by way of surface coating of finer particles, may retain a large proportion of the trace elements investigated.
THE ORIGIN OF THE PENTOSE FRACTION OF SOIL POLYSACCHARIDE
Authors: CHESHIRE M. V. , MUNDIE C. M. , SHEPHERD H. 
Published: July 2006

SummaryIncubation of soil with monosaccharide for 224 days resulted in the evolution of about 80 per cent of the substrate carbon as CO2 and the transformation of 3 per cent to soil sugars whether the substrate was 14C‐glucose or xylose and whether the soil was pH 7.4 or pH 5.0. There was no detectable change in the total amounts of individual sugars in the soil during incubation. 14C‐glucose and xylose gave the same distribution of radioactivity among the soil sugars : hexoses and 6‐deoxy‐hexoses were initially well labelled, with glucose having twice the specific activity of the other sugars. As the incubation progressed some activity appeared in the pentoses (the activity in xylose became very low within the first 14 days of the 14C‐xylose incubation) and that in the hexoses slowly declined, with glucose no longer predominant. Nevertheless after 448 days the hexoses were still 3–4 times more radioactive than the pentoses. The activity in rhamnose did not decline with time so that eventually it became the most strongly labelled sugar.Incubation of soil with glucose and 14C‐acetate showed very little transformation of the acetate to sugars indicating that glucose is not metabolized to C2 compounds before it is transformed to other sugars.Ammo‐acids in soil incubated for 7 days with 14C‐glucose had much lower levels of radioactivity than hexoses or 6‐deoxy‐hexoses.It is concluded that if soil pentose originates by microbial synthesis it must accumulate slowly by a long process of selective decomposition of a mixture of polysaccharides.
PHOSPHATE SOLUBILITY IN DANISH SOILS EQUILIBRATED WITH SOLUTIONS OF DIFFERING PHOSPHATE CONCENTRATIONS
Authors: JENSEN H. E. 
Published: July 2006

SummaryIn four out of ten Danish soils, varying in texture, pH, and forms of inorganic phosphate, phosphate solubility in dilute CaCl2 solution corresponded to the solubility of one or other of six phosphate minerals presumed to exist in soils. On adding moderate rates of phosphate, only one of the soils sustained phosphate activities corresponding to such a mineral (octocalcium phosphate). Consequently, removal of added phosphate from solution, as in the determination of the differential phosphate potential buffering capacity was the result of an adsorption type of mechanism rather than precipitation of crystalline phosphate compounds.