bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE SPECIFIC ADSORPTION OF DIVALENT Cd, Co, Cu, Pb, AND Zn ON GOETHITE
Authors: FORBES E. A. , POSNER A. M. , QUIRK J. P. 
Published: July 2006

SummaryThe specific adsorption of divalent Cd, Co, Cu, Pb, and Zn on goethite is measured as a function of pH. For each mole of heavy metal adsorbed approximately two moles of H+ ions are displaced from the interface. Using these results the heavy metal adsorption data are expressed as functions of the solution concentrations of both H+ and metal ions, and the interfacial reaction is described by the equation, 2SH+M2+= S2M+2H+.The adsorption data are consistent with an electrochemical model of the simultaneous adsorption of H+ ions and divalent metal ions on to the oxide. The intrinsic affinities of the metal ions for the oxide surface increase in the order, Cd < Co < Zn < Pb < Cu. However, besides the affinity of the metal ion for the surface, the adsorption curves are considered to be influenced by surface charge, the adsorption density of the metal ions and their size.The analysis of the data in terms of H+ and M2+ ion adsorption is considered to be complementary to the hydrolysis model for heavy metal adsorption.
INTERNAL STRUCTURE OF TILLED SOIL
Authors: DEXTER A. R. 
Published: July 2006

SummarySamples of tilled soil were impregnated with paraffin wax and were sectioned by sawing. The distribution of angles of incidence between voids and aggregates on the sections were investigated using random lines in three orientations. The angular distributions were found to be isotropic. Incidence angles near to normal were found to be more probable than in idealized beds of spherical aggregates.Distributions of aggregates and voids were examined along horizontal lines on the soil sections using an approach developed in communications theory. Soil structures in the size range from I to 5 mm were defined exactly by sets of sixteen transition probabilities. Differences were observed in the tilths produced by a mouldboard plough, a tine cultivator, and a rotary cultivator. The soil structures were different at different depths and changed with time after tillage.Transition probabilities measured in this way can be used in stochastic processes to simulate large tilths in a computer. The techniques described here could be adapted to the study of the distribution of soil structural features at any scale.
PLASTIC LIMIT DETERMINATION 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, was used to determine the moisture content/cone penetration curve in the region of the plastic limit for eighteen soils.The moisture content corresponding to the minimum of the curve is shown to be always numerically less than, but to correlate closely with, the plastic limit. It is suggested that the plastic limit be redefined as the moisture content corresponding to the minimum of the moisture content/cone penetration curve, with the advantages that the test is more closely related to soil behaviour, less subjective, at least as reproducible as the Casagrande test and may be carried out simultaneously with the liquid limit test.
ADSORPTION OF PHOSPHATE BY GIBBSITE
Authors: HELYAR K. R. , MUNNS D. N. , BURAU R. G. 
Published: July 2006

SummaryThe effects of the salts were studied using I per cent suspensions of gibbsite at pH 5.5 and 26°C. At 480μM phosphate and I mM calcium, the kinetic pattern was an initial rapid adsorption reaction, which approached equilibrium in 24 h, revealing a slower reaction. Adsorption isotherms determined at 24 h, with a range of final phosphate concentrations from 0.1 to 1000 μ in solution, were not affected by 20 mM sodium or potassium chloride or 10 mM magnesium chloride. Increasing calcium chloride from o to 20 TIM increased the adsorption of phosphate over the range from 1 to 100 μM final phosphate concentration. At lower (0.1 μM) and higher (1000 μM) phosphate, the effect of calcium was smaller.These results help to explain several effects of the various cations on the adsorption of phosphate by clays and soils, when effects of neutral salts on pH are also considered.
SODIUM‐CALCIUM EXCHANGE EQUILIBRIA IN SALT‐AFFECTED AND NORMAL SOILS
Authors: POONIA S. R. , TALIBUDEEN O. 
Published: July 2006

SummarySodium‐calcium exchange equilibria in soils with a range of cation exchange capacity (CEC) and surface charge density (SCD), showed calcium preference whether the results were interpreted by a thermodynamic treatment, by an electric diffuse double layer equation, or by an empirical approach. Surface soils preferred Ca more than the corresponding sub‐soils, which was mainly attributed to their higher SCDs and organic carbon contents (OC). Significant correlations between OC and (ΔGo)ca→Na, and OC and SCD, suggest the effect of OC on Ca preference to be mainly through increased SCD rather than to specific ion exchange sites.Significant correlations between ΔGo and SCD, ΔGo and KG (the Capon constant), and between corrected SCD and KG, suggest that all three approaches can be used to describe Na:Ca exchange equilibria in these soils, and that the equilibria are related to intrinsic soil properties.
LIME‐INDUCED CHLOROSIS
Authors: SCHINAS S. , ROWELL D. L. 
Published: July 2006

SummaryThe following properties were measured on 22 soil samples from seven sites in the south east of England: total CaCO3, active CaCO3 apparent solubility product, particle size distribution of the CaCO3, and pH. Active CaCO3 was between one quarter and one half of the total for all sites except one. Apparent solubility products varied for each parent material, and increased with depth in each profile and ranged from 0.93 to 4.87 × 10−9. Soil pH was directly related to apparent solubility product. Active CaCO3 was closely related to the surface area.pH measured in 0.01 M CaCl2 was the best index of yield of cauliflower, tomato, sweet white lupin and bitter blue lupin, with chlorotic symptoms increasing and yield decreasing as pH increased. The apparent solubility product of the soil carbonates and pH measured in water were also closely correlated with yield. Total and active CaCO3 were only related to yield above limits of 20 and 10 per cent respectively and even then were poor indices of yield.
EFFECT OF ORGANIC CONSTITUENTS AND COMPLEXED METAL IONS ON AGGREGATE STABILITY OF SOME EAST ANGLIAN SOILS
Authors: HAMBLIN A. P. , GREENLAND D. J. 
Published: July 2006

SummaryPaired soils of high and low organic matter content from the East Anglian silts were used to determine the role of different organic constituents and complexed metal ions in relation to aggregate stability. Although leaching with periodate and borate caused some loss of stability for most of the soils, the changes were much less than those due to extraction of the soils with pyrophosphate or acetylacetone which were more effective in removing organic materials complexed with iron and aluminium. Amounts of iron and aluminium extracted were not well correlated with changes in stability. The results indicate that in these soils polysaccharides are less important to aggregate stability than organic matter bonded to the clay particles through association with aluminium or iron.
THE MEASUREMENT AND CHARACTERISATION OF VOIDS IN SOIL THIN SECTIONS BY IMAGE ANALYSIS. PART I. PRINCIPLES AND TECHNIQUES
Authors: MURPHY C. P. , BULLOCK P. , TURNER R. H. 
Published: July 2006

SummaryThe introduction of the image analysing computer (Quantimet 720) makes possible the rapid and accurate measurement of components in thin sections and extends the range of measurements possible. Two techniques for presenting material for analysis are outlined. Models are used to demonstrate the measurement of size, irregularity and orientation of components and their discrimination according to shape.
CATION EXCHANGE PROPERTIES OF SPHAGNUM PEAT: EXCHANGE BETWEEN TWO CATIONS AND PROTONS.
Authors: ANDRÉ J. P. , PIJAROWSKI L. 
Published: July 2006

SummaryParameters of the exchange equilibria for three pairs of cations of agricultural interest (K/NH4 – Ca/Mg – K/Ca) were experimentally determined. The selectivity coefficient of the two homovalent pairs was found to be constant, whereas that of the mono‐divalent pair depended on the total concentration of cations in the solution and on the exchange capacity. Equations are given which describe the exchange equilibria in peat, which take into account its pH‐dependent exchange capacity.
PROTON‐DECOUPLED PULSE FOURIER‐TRANSFORM 13C MAGNETIC RESONANCE OF SOIL ORGANIC MATTER
Authors: WILSON M. A. , GOH K. M. 
Published: July 2006

SummaryThe structure of some humic acids, fulvic acids and lipid fractions of soil organic matter have been investigated by 13C‐n.m.r. spectroscopy. Signals from aromatic groupings were normally absent in humic and fulvic acids. There were differences in spectra from extracts prepared from different sources or by different techniques. 1 3C‐n.m.r. spectra of lipid fractions were generally similar to each other but there were some distinct differences that may be used to a ‘fingerprint’ the lipids.
INFLUENCE OF ORGANIC MATTER ON THE PHYSICAL PROPERTIES OF SOME EAST ANGLIAN SOILS OF HIGH SILT CONTENT
Authors: HAMBLIN A. P. , DAVIES D. B. 
Published: July 2006

SummaryA comparison was made of the physical properties of pairs of silt soils differing only in organic matter content. Within the textural group studied, the member of the pair with more organic matter had better physical properties relating to both plant growth and soil management. Increased organic matter give higher water holding capacities and porosities, and decreased compaction, breaking strength and bulk densities. Organic matter content alone was not sufficient to explain differences in aggregate stability to water.
ADSORPTION ON HYDROUS OXIDES I. OXALATE AND BENZOATE ON GOETHITE
Authors: PARFITT R. L. , FARMER V. C. , RUSSELL J. D. 
Published: July 2006

SummaryThe adsorption of oxalic acid on synthetic goethite (α‐FeOOH) was studied using adsorption isotherms. Infrared spectra were obtained for goethite‐oxalate complexes at several points on the isotherms. On a goethite preparation with a phosphate sorption capacity of 200|μmolg−1 the amounts of oxalate strongly adsorbed varied from near zero at pH 8 to about l00μmolg−1 at pH 4 and below. At pH 3.4, the first l00μmolg−1 of oxalic acid added was strongly adsorbed as a binuclear complex (FeOOC–COOFe), replacing two singly‐coordinated OH groups by ligand exchange. At higher concentrations a further 200 μrnol g−1 of oxalic acid formed a monodentate complex (FeOOC–COOH) so that more oxalate could be accommodated.Benzoic acid was weakly adsorbed on goethite with one benzoate oxygen replacing one singly‐coordinated OH. The other oxygen of the COO group fitted into the goethite surface so that the benzene ring was at a high angle to the (100) face.
MECHANISMS OF PHOSPHATE SORPTION BY SOILS AND HYDROUS FERRIC OXIDE GEL
Authors: RYDEN J. C. , McLAUGHLIN J. R. , SYERS J. K. 
Published: July 2006

SummaryData for the sorption of added inorganic phosphate (P) by contrasting soils and iron oxide gel were resolved by a method of successive approximation of the Langmuir sorption constants. Three distinct Langmuir equations described the overall isotherm irrespective of the experimental conditions used. Free energies of sorption (ΔG) for a particular region were similar for each soil and for iron oxide gel under all experimental conditions. In contrast, the sorption maximum for each region was influenced by the sorbent and experimental conditions.Because of the pronounced similarities in their P sorption characteristics iron oxide gel was used as a model surface for P sorption by soils. Three mechanisms for P sorption by iron oxide gel and by soils are proposed: (i) chemisorption at protonated surface sites, (ii) chemisorption by replacement of surface hydroxyls, and (iii) a more‐physical sorption of P as a potential‐determining ion.
ADSORPTION OF HERBICIDE‐DERIVED p‐CHLOROANILINE RESIDUES IN SOILS: A PREDICTIVE EQUATION
Authors: VAN BLADEL R. , MOREALE A. 
Published: July 2006

SummaryRelationships between the adsorption of p‐chloroaniline and the original adsorbate concentration were investigated for five soils ranging in organic matter content from 1.7 to 8.1 per cent and in clay content from 0.5 to 21 per cent. Adsorption data were analyzed applying the linear form of the Freundlich equation. To evaluate the general relationship between adsorption of p‐chloroaniline by soils and the solution concentration (C0), values of partition coefficient (Kp), reflecting the magnitude of distribution of chemical at equilibrium between soil colloids and solution were calculated.The experiments showed that the regression parameters were significantly correlated with the soil organic matter content. A comparison of the experimental results obtained with other soils and the calculated values gave satisfactory agreement.
SHRINKAGE IN CLAYEY SUBSOILS OF CONTRASTING STRUCTURE
Authors: REEVE M. J. , HALL D. G. M. 
Published: July 2006

SummaryShrinkage was measured on subsoil samples from two clayey alluvial soils of contrasting structural development and two boulder clay soils also of contrasting structure. Of the four phases of shrinkage recognized, the proportion of shrinkage attributable to the structural shrinkage phase is shown to be dependent on structural development and organic carbon levels in the subsoil. The importance of structural shrinkage to the maintenance of good structure in clay soils under intensive cultivation is briefly discussed.
ORGANO‐MINERAL FRACTIONS OF A CLIMOSEQUENCE OF SOILS IN NEW ZEALAND TUSSOCK GRASSLANDS
Authors: TATE K. R. , CHURCHMAN G. J. 
Published: July 2006

SummaryThe organo‐mineral fractions of seven New Zealand topsoils, which are members of a climosequence, were isolated by ultrasonic dispersion in water and separated into sand‐, silt‐ and clay‐size fractions. Several soils contained stable aggregates of mainly silt‐size, comprising cemented clay‐size particles. The tendency of one soil (McKerrow) to form larger aggregates of sand‐size was explained by its distinctive mineralogy.Total organic carbon and total nitrogen were used to indicate the amounts of organic matter in the organo‐mineral fractions. The degree of humification of the organic matter was assessed by a pyrolysis‐gas chromatography technique, which proved superior to the more conventional C/N method.In the sand‐size fractions the climate, and especially annual precipitation, strongly influenced the amounts of organic matter, whereas in the clay‐ and silt‐size fractions it was the composition of the organic matter that was influenced.
SOIL VARIABILITY AND RECONNAISSANCE SOIL MAPPING. A STATISTICAL STUDY IN NORFOLK
Authors: NORTCLIFF S. 
Published: July 2006

SummaryThe incorporation of measures of soil variability at the reconnaissance stage of soil survey is considered as a possible alternative to, or additional feature of, present procedures. A straightforward hierarchical sampling design based upon the major parent materials of the upland section of the study area and associated analysis of variance model are described. This allowed the estimation of scale components for five levels of the sampling design at separation distances from over two kilometers down to five meters. Principal components analysis is used to economise on the number of variables for further analysis. Analysis of the pattern of principal component scores shows the first six components to have distinctive variability patterns both within and between strata. It is concluded that present soil survey procedures take too little account of soil variability patterns, and that inclusions of such information at the reconnaissance stage would greatly improve the detailed survey.
MINERALOGY, GENESIS AND CLASSIFICATION OF FERRUGINOUS SOILS OF THE EASTERN MYSORE PLATEAU, INDIA
Authors: RENGASAMY P. , SARMA V. A. K. , MURTHY R. S. , MURTI G. S. R. KRISHNA 
Published: July 2006

SummaryThe relationship of geomorphic and climatic history and formation of the ferruginous soils, formed on the acidic Peninsular Gneiss, of the Mysore Plateau, India, is discussed. The profiles studied are found on two different land systems. The soils of the older, fairly smooth landscape are composed of colluvium over truncated laterite profiles, with a gravel layer and a prominent kaolin layer over the weathered rock. These soils show an accumulation of pedogenic haematite grains in the sand fraction and have considerable kaolinite and amorphous ferri‐aluminosilicate minerals in the clays.The soils of the younger, rugged landscape have similar clay mineralogy, but do not have a gravel layer, or haematite grains. The influence of the coarse‐grained parent rock is seen in the large amounts of quartz gravel. The absence of granulation is attributed to lack of accumulation of iron.The soils have been formed in an earlier, more humid climate than prevails today. The original laterite profiles were formed on a plane surface, and subsequent change in climate has led to change in the land forms and dissection. Truncation of the profiles was followed by deposition of red colluvium over the resistant ferruginous layer.These ancient soils do not fit the criteria for Oxisols in the U.S. classification, but fit well in the French system as ‘Sols Ferrallitiques’, subclass ‘fiablement désatures en (B)’. The soil from a low lying area, formed from colluvium under hydromorphic conditions. is classified as‘Vertisols et Paravertisols'.
LEAD POLLUTION IN AGRICULTURAL SOILS
Authors: COLBOURN P. , THORNTON I. 
Published: July 2006

SummaryHigh concentrations of lead, copper, zinc and cadmium, are reported in agricultural soils of the southern Peak District in association with mining and smelting sites. A reliable background range of lead concentrations in non‐contaminated soil was established and the relative topsoil enhancement (RTE) ratio was found to be a useful index of pollution. A wide range of amounts of lead was extracted from soils by dilute nitric acid; the higher end of the range may result from free lead oxides being present in some polluted soils. The amount of lead extracted also depended on the composition of the soil, a soil containing vermiculitic clay minerals maintained a very low lead concentration in solution. The effects of site history, weathering and redistributive processes are discussed.
THE IMPREGNATION OF WET PEAT FOR THE PRODUCTION OF THIN SECTIONS
Authors: FITZPATRICK E. A. , GUDMUNDSSON T. 
Published: July 2006

SummaryA technique is described to replace the water in peat by acetone prior to impregnation with resin. The peat is exposed to the vapour of aqueous acetone of increasing concentration up to 100 per cent acetone. After impregnation with resin, high quality thin sections can be obtained.
THE SURFACE TENSION OF SOIL WATER
Authors: TSCHAPEK M. , SCOPPA C. O. , WASOWSKI C. 
Published: July 2006

SummaryBecause of their organic matter content, the surface tension of water of soils is about 8 to 9 erg cm ‐2 (8 to 9 × 10 ‐7 J cm ‐2) less than that of pure water. It is estimated that the surface tension of soil solution is 63–64 erg cm ‐2 in the surface soils studied.
TOWARDS AN OBJECTIVE CLASSIFICATION OF SOIL STRUCTURE
Authors: THOMASSON A. J. 
Published: July 2006

SummaryA classification of structural condition in surface soils is proposed, based on the volumes of two categories of pore size, termed air capacity (pores greater than 60 μm diameter) and available water (pores of 60 to 0.2 μm diameter.Relationships of pore volumes to particle size class, organic carbon content and soil water regime are examined. Soil structural conditions are mainly affected by water regime and organic carbon and, apart from the extremes of sandy or clayey textures, less influenced by particle size distribution.
INTERACTION OF SOIL AND MANKIND IN BRITAIN
Authors: BRIDGES E. M. 
Published: July 2006

SummaryMan's initial occupation of the British landscape was subject to broad physical constraints which are still apparent from archaeological evidence and place‐name interpretation. The influence of soils in initial settlement establishment is seen to be difficult to interpret several thousand years later as environmental conditions, including soils, have changed. Conversely, man's effect on the soils surrounding his settlements is evident through agricultural and other activities. These activities have increased in their impact with the passage of time. A combination of historical geography and soil studies shows man's interaction with the country's most basic resource.
YTTRIUM AND ZIRCONIUM AS GEOCHEMICAL GUIDE ELEMENTS IN SOIL AND STREAM SEDIMENT SEQUENCES
Authors: MURAD ENVER 
Published: July 2006

SummaryYttrium and zirconium concentrations, taken as representative for the abundances of the heavy minerals xenotime and zircon in soils and stream sediments of the Schwarzach valley in eastern Bavaria, were found to be closely correlated, the Zr/Y ratio averaging 9.7 (r = 0.90 for 73 samples). The uniformity of this ratio ‐ despite considerable local variations of the individual concentrations—indicates its suitability for tracing back soils and sediments to the parent rocks.
SOIL LAYERS IN MIRES: FUNCTION AND TERMINOLOGY
Authors: INGRAM H. A. P. 
Published: July 2006

SummaryTwo recent North American soil classification schemes embodying criteria for distinguishing layers in mire soils are criticised as being artificial and unrelated to function. In these soils, the most important functional processes are hydrological. The two‐layer hypothesis of K. E. Ivanov, involving a set of hydrological differences and associated biological characteristics, is accordingly advocated as a basis for a natural scheme of layering, in which a surface layer, the ‘active layer’, is distinguished from the ‘inert layer’ below. Since both expressions are deemed inadmissible, it is suggested that the upper layer be termed the acrotelm and the lower layer the catotelm. A two‐layered mire soil should be termed diplotelmic and one without an acrotelm, haplotelmic. Basic definitions for all 4 terms are provided. Possible applications to eroded or reclaimed mires are briefly discussed.
THE EFFECT OF MOLECULAR SIZE ON DIFFUSION CHARACTERISTICS IN SOIL
Authors: BARRACLOUGH D. , NYE P. H. 
Published: July 2006

SummaryMeasurements of the apparent self‐diffusion coefficients of, poly(vinyl pyrrolidone) mol. wt. 40 000, polyethylene glycol) mol. wt. 4000, and chloride ion, were used to determine the effect of molecular size on diffusion characteristics in soil. The measurements were carried out on the same soil, at a range of moisture contents, and indicated that the mobility of large molecules in soils depends, to a large degree, on the inter‐aggregate pores. Any drop in moisture content which caused these pores to drain, produced a sharp decrease in the apparent self‐diffusion coefficient of the poly(viny) pyrrolidone) 40 000. Neither poly(ethylene glycol) 4000 nor chloride, which exhibited similar diffusion characteristics, were as sensitive to variation in moisture content. The results are interpreted in terms of certain parts of the pore volume being inaccessible to the diffusing molecule. Possible reasons are outlined.
PALEOsolS DEVELOPED ON CHALKY BOULDER CLAY IN ESSEX
Authors: STURDY R. G. , ALLEN R. H. , BULLOCK P. , CATT J. A. , GREENFIELD S. 
Published: July 2006

SummarySoils with paleosol features occur at the surface on the Chalky Boulder Clay in the Chelmsford area, Essex. Their particle size distribution, micromorphology and sand, silt and clay mineralogy indicate periods of weathering, clay illuviation and hydromorphism before deposition of loess in the Late Devensian. These periods are provisionally related to the Ipswichian and/or Hoxnian Interglacials.