bluuebunny/crossref_metadata_2025_split huggingface dataset:
SOILS AND QUATERNARY GEOLOGY IN BRITAIN
Authors: CATT J. A. 
Published: July 2006

SummaryThe succession of Quaternary deposits in Britain records only small, fragmentary parts of a very complex history of Quaternary events resulting from many climatic fluctuations. Deep sea sediments provide a more continuous record, but correlation between the oceanic and terrestrial successions is at present extremely difficult, mainly because of the lack of absolute dates for older parts of the latter. The often conflicting evidence provided by indirect methods of dating and long‐distance correlation is illustrated by reference to the chalky tills of East Anglia and the English Midlands, and the importance of soil studies in elucidating regional Quaternary stratigraphy is emphasised.The scanty history of pedogenesis in various parts of Britain is tentatively related to the provisional succession of Quaternary stages. Important changes in soil development processes occurred in mid‐Flandrian times as well as in earlier cold and temperate (inter‐glacial) stages, Many features of unburied soils are probably early Flandrian or older relicts, and difficulties consequently arise over use of the word ‘palaeosol’. Interglacial relict features in soils on pre‐Devensian deposits (paleoaigillic subgroups) are distinguished from Devensian and Flandrian soil characters, but it is difficult at present to differentiate pedogenesis of successive interglacials.More than two‐thirds of England is covered by Quaternary deposits, mainly of cold periods, and these generally provide better agricultural soils than pre‐Quaternary sediments. Some relict features of both cold and temperate Quaternary stages also seem to be significant in determining the agricultural capability of British soils, but their effects need evaluating more precisely.
DIFFUSE DOUBLE LAYER THEORY APPLIED TO Na‐Ca EXCHANGE EQUILIBRIA IN TEMPERATE AND SEMI‐ARID TROPICAL SOILS
Authors: POONIA S. R. , PAL RAJ , TALIBUDEEN O. 
Published: July 2006

SummaryA cation exchange equation based on diffuse double layer (DDL) theory was tested on 26 surface and sub‐surface soils from 6 field experiments in temperate and semi‐arid tropical regions. Sodification (the fraction of total charge on the surface neutralised by the excess of Na+ plus the deficit of Cl−), or the exchangeable Na percentage, ESP, of these soils in relation to SAR, the molar ratio (Na]/[Ca + Mg] 1/2, was evaluated from the observed data on Na:Ca exchange in two ways, using the DDL equation: (1) by multiplying the surface charge density of the soil with a mean correction factor f (based on the whole isotherm) assuming no interaction between adjacent clay platelets; this predicted the sodification of the soils satisfactorily between 0–30 ESP, though at the highest SAR values (i.e. > 60), predicted ESP values were significantly smaller than the experimental values for 23 of the 26 soils; (2) by assigning values to the extent of interaction Yd (directly related to the electric potential Ψd midway between adjacent clay platelets) over the whole isotherm; Yd was found to increase by varying degrees in different soils with SAR and ESP. Also in 12 of the 15 pairs of soils compared, the mean value, d, over the whole Ca‐Na exchange isotherm was appreciably larger for surface soils (which had higher surface charge densities) than for the subsoils from the same sites.The suggestion that the Yd parameter provides a better criterion than the f parameter for characterising and comparing Na:Ca exchange equilibria in contrasting soils is discussed in relation to the effects of soil components.
PRECIPITATION OF CARBONATES IN SOILS IN CONTACT WITH WATERS UNDERSATURATED OR OVERSATURATED IN RESPECT TO CALCITE*
Authors: LEVY RACHEL 
Published: July 2006

SummaryUnder transient conditions, the precipitation of carbonates in a calcareous and a non‐calcareous soil was influenced by calcium, magnesium and bicarbonate ions from soil sources. These sources were: the soil solution, the soil exchange complex and the dissolution of aluminosilicates. There was no significant difference between the amount of carbonates which precipitated in the two soils when in contact with the same water. It was found that for small portions of water in contact with the two soils, precipitation of carbonates took place both from under‐saturated and the over‐saturated waters. As the cumulative amounts of water in contact with the soils increased, the amount of ions contributed by the residual soil solutions and the exchange complexes decreased, and the amount of precipitating carbonates decreased also. At very large cumulative amounts of water, the precipitation of carbonates in the soils was controlled by both the water and the ions released from the soils.
THE ORIGIN OF THE RED MEDITERRANEAN SOILS IN EPIRUS, GREECE
Authors: MACLEOD D. A. 
Published: July 2006

SummaryTo determine the contribution of limestone weathering to soil formation the insoluble residues of six samples of the Pantokraton limestone were separated by treatment with 2M acetic acid at pH 3. The mean insoluble residue content is only 0.15% and to produce a soil depth of 40 cm it has been calculated that about 130 m of limestone would have to be weathered. No correspondence was found between the particle size distribution of the residues and of the overlying red soils, and the high siltrclay ratios of the soils do not indicate prolonged subtropical weathering. The particle size distribution of the soils is akin to that of aerosolic dusts. The dust loading of the atmosphere in the eastern Mediterranean is among the highest recorded, and it is proposed that the soils have developed on dust blown by sirocco winds from the deserts of N. Africa.
SOME CONTRASTS IN SOIL DEVELOPMENT BETWEEN GRASSLAND AND DECIDUOUS WOODLAND SITES
Authors: GRIEVE I. C. 
Published: July 2006

SummarySoil profile and structural development were compared under two land‐use types on acid and calcareous soils. The grassland soils were found to have better developed and more stable structures in the A horizon, but unchanged bulk density and infiltration capacity. In the B horizons the direction of difference was reversed. Profile development was deeper under woodland on the softer parent materials. The differences were primarily related to root density, penetration and more intimate incorportion of organic matter under grass.
A NEW HAND‐HELD RECORDING PENETROMETER FOR SOIL STUDIES
Authors: ANDERSON G. , PIDGEON J. D. , SPENCER H. B. , PARKS R. 
Published: July 2006

SummaryThis paper describes and evaluates a new solid‐state recording hand‐held cone penetrometer developed for in‐situ soil studies. Force is measured by a strain‐gauged transducer, and depth by an accurate optical system. Data for up to 20 penetrations per plot are stored and processed within the instrument in the field.The new penetrometer has been evaluated in field and soil tank experiments in comparison with three widely contrasting existing penetrometers ranging from a simple hand‐held penetrometer to a trailer‐mounted power‐driven instrument.The results indicated that the simple hand‐held penetrometer gave appreciably different cone resistance profiles from the other instruments. In particular, spurious ‘treatment effects’ obtained from the tillage experiment were shown to be due to inadequate instrument performance. The new solid‐state recording hand‐held penetrometer gave results comparable with those obtained from the more complex trailer‐mounted instrument and another hand‐held recording penetrometer.
OPTIMAL INTERPOLATION AND ISARITHMIC MAPPING OF SOIL PROPERTIES
Authors: BURGESS T. M. , WEBSTER R. 
Published: July 2006

SummaryKriging is a means of spatial prediction that can be used for soil properties. It is a form of weighted local averaging. It is optimal in the sense that it provides estimates of values at unrecorded places without bias and with minimum and known variance. Isarithmic maps made by kriging are alternatives to conventional soil maps where properties can be measured at close spacings.Kriging depends on first computing an accurate semi‐variogram, which measures the nature of spatial dependence for the property. Estimates of semi‐variance are then used to determine the weights applied to the data when computing the averages, and are presented in the kriging equations.The method is applied to three sets of data from detailed soil surveys in Central Wales and Norfolk. Sodium content at Plas Gogerddan was shown to vary isotropically with a linear semi‐variogram. Simple punctual kriging produced a map with intricate isarithms and fairly large estimation variance, attributed to a large nugget effect. Sloniness on the same land varied anisotropically with a linear semi‐variogram. and again the estimation error of punctual kriging was fairly large. At Hole Farm. Norfolk, the thickness of cover loam varied isotropically, but with a spherical semi‐variogram. Its parameters were estimated and used to krige point values and produce a map showing substantial short‐range variation.
HILL LAND STUDIES IN THE GRAMPIAN REGION OF SCOTLAND
Authors: JONES R. J. A. , TINSLEY J. 
Published: July 2006

SummaryFactors affecting the growth of mixed grass swards in the Upper Don Basin were studied in two phases: in 1967–68 within the altitude range 260–440 m and in 1969–70 in the range 330–550 m O.D. In the first phase the interaction effects of altitude, aspect and soil parent material on herbage yields and mineral element contents were studied using 24 sites in a 3 × 2 × 2 factorial design, without fertilizer in 1967 and with nil, N. P and NP treatments in 1968. Total yields from 3 cuts at 2 monthly intervals averaged 4.84 tonnes D.M. ha−1 in 1968 with no overall significant altitudinal differences. Application of 75 kg N ha−1 as Nitrochalk raised the yield by over 40 per cent, slightly more in the presence of P on soils derived from mineralogically acidic parent materials. Overall, yields from soils on ‘basic’ materials were at least 25 per cent greater than from the ‘acidic’ ones. Sites with southern aspects mostly oulyielded the northern ones but not significantly so. In the second.phase 3 pairs of ‘acidic’ sites only were used, with an NPK treatment added to the 1968 treatments, and lime for the most acid soils at 550 m O.D. On these highest sites the yields were much reduced by the adverse climatic conditions.Samples of the dry matter from each treatment, replicate and cut at each site were analysed and the offtakes of N, P, K, Ca and Mg determined as well as the apparent recoveries of N, P, K and Ca from the fertilizers. The constraints of altitude on yield and composition were strongly correlated with the prevailing air and soil temperatures. The practical implications of the findings for upland livestock production are discussed but the detailed correlation and factor analyses of the data are presented in another paper.
RELATIONSHIPS BETWEEN NET REDISTRIBUTION OF Al AND Fe AND EXTRACTABLE LEVELS IN PODZOLIC SOILS DERIVED FROM LOWER PALAEOZOIC SEDIMENTARY ROCKS
Authors: ADAMS W. A. , RAZA M. A. , EVANS L. J. 
Published: July 2006

SummaryExamination of the translocation and net redistribution of Al and Fe in podzolic soils on Lower Palaeozoic sedimentary rocks has shown marked differences in behaviour between the two elements. Iron exhibits the classical pattern of eluviation and illuviation, the consequences of which are closely correlated with amounts of ‘active’ Fe extracted with pyrophosphate. On the other hand Al rarely accumulates in B horizons enriched in Fe. In addition pyrophosphate‐extractable Al is unrelated to its net redistribution pattern. Stagnopodzols on Lower Palaeozoic sediments are strongly acidic throughout and show a characteristic trend in oxidation/reduction conditions with depth. It is the differential response of Al and Fe to the combination of these properties, particularly in relation to their effect on illuviation, which accounts for the observations.
A REAPPRAISAL OF SOIL MAPPING IN AN AREA OF SOUTHERN SCOTLAND. PART I THE RELIABILITY OF FOUR SOIL MAPPING UNITS AND THE MORPHOLOCICAL VARIABILITY OF THEIR DOMINANT TAXA
Authors: RAGG J. M. , HENDERSON R. 
Published: July 2006

SummaryA two stage random sample survey was made to study the composition of four common soil mapping units already mapped in the Central Lowlands of Scotland. The four mapping units were sampled at densities proportional to their mapped area. In terms of their A horizon textures, the mapping units had percentage reliabilities of 84, 96, 93 and 97 and drainage class reliability scores of 70, 80, 72 and 70. On the basis of taxonomic units within the mapping units, percentage reliabilities ranged from 43–66 but no minor constituent soil exceeded 16 per cent in any of the units studied. Although complex according to currently accepted guidelines, such mapping units should be named according to the dominant taxonomic unit. Errors of identification due to inadequate definitions of taxonomic units have contributed to some of the low levels of reliability of taxonomic units within mapping units and soil taxa should be defined more precisely in Scotland.Means and variances of the taxonomic units, upon which the above named mapping units are based, indicate that the four taxonomic units (and hence also mapping units) under study are not equally variable in the area of investigation.
A REAPPRAISAL OF SOIL MAPPING IN AN AREA OF SOUTHERN SCOTLAND. PART II THE USEFULNESS OF SOME MORPHOLOGICAL PROPERTIES AND OF A DISCRIMINANT ANALYSIS IN DISTINGUISHING BETWEEN THE DOMINANT TAXA OF FOUR MAPPING UNITS
Authors: HENDERSON R. , RAGG J. M. 
Published: July 2006

SummaryResults of a two‐stage random sample survey were used to give information about the usefulness of some soil morphological properties for distinguishing between the four taxonomic units, all gley or gleyed soils.A multivariate logistic method of discriminant analysis was used. The classifications by soil surveyors and by the statistical analysis were mainly in good agreement, but many generally accepted B horizon criteria used for assessing hydromorphism were of little value in discriminating between the soils under study. Depth to gleying and secondary lithology, were valuable distinguishing properties while the matrix colour value, texture and structure of the B horizons were useful in some instances.Serious consideration of the role of statistical techniques, such as discriminant analysis, is advocated both as a guide to those who design soil taxonomies and as an aid to field identification.
THEORY OF TIME RESPONSE OF TENSIOMETERS
Authors: TOWNER G. D. 
Published: July 2006

SummaryThe time taken for a tensiometer to reach equilibrium with the soil‐water pressure is a function not only of the tensiometer characteristics but also of the soil‐water transport properties. When. in an appropriate system of units. the numerical value of the conductance of the tensiometer cup is small compared with that of the hydraulic conductivity of the soil, and the sensitivity of the pressure ‘gauge’ is large compared with the differential water capacity of the soil. then the precision of the measurements is such that the observed response may be indistinguishable from that of a tensiometer in bulk water. referred to as ‘tensiometer limited’.The theory developed in this paper for a hemispherical tensiometer cup shows that tensiometer‐limited conditions can be achieved in practice. Moreover. such conditions would often correspond to a rapid response system. It is suggested that it might be advantageous in the design of a field recording system to choose a tensiometer‐limited system even if it is not the fastest realisable one in order that its response is completely predictable from the known tensiometer characteristics. independent of the unknown soil properties. which may be changing.
PHYTOTOXINS IN PERIODICALLY WATERLOGGED FOREST SOILS
Authors: SANDERSON P. L. , ARMSTRONG W. 
Published: July 2006

SummaryThe concentration of iron(II), manganese(II), ethylene, volatile fatty acids (VFAs) and hydrogen sulphid have been determined in peaty forest soils subject to waterlogging. Although VFAs would merit further investigation, iron(II) seems to be the only toxin likely to accumulate in sufficiently large quantities to cause root damage.The use of the ion selective electrode for sulphide measurements is criticized.
A METHOD FOR STUDYING MICROBIAL ACTIVITY IN INTACT SOIL CORES
Authors: OSBORNE G. J. , POOLE N. J. , DREW ELIZABETH A. 
Published: July 2006

SummaryCarbon dioxide evolution from soil is generally considered to be an indication of actively metabolising biomass. This paper describes a method for studying carbon dioxide evolution from intact soil cores. It also introduces the possibility of using the method in studies of biomass using fumigation techniques.
WATER FLOW IN SOIL MACROPORES III. A STATISTICAL APPROACH
Authors: GERMANN P. , BEVEN K. 
Published: July 2006

SummaryTwo regression equations describing water movement in saturated macropores in the field are compared with a theoretical expresion of the form Qmaα e2ma where Qma is the saturated volume flux density through a macropore system of porosity ema. The theoretical exponent of 2 agrees fairly well with the analyses of two very different sets of field experiments by Burger (1922–1940) and Ehlers (1975). It is suggested that the relationship Qma= Q*e2ma may be a useful first approximation to predict macropore flow, where Q* is an empirical coefficient that is expected to depend on the hydraulic connectivity, geometrical structure, tortuosity, roughness and other properties of the macropore system.
A METHOD OF PREDICTING BULK DENSITY CHANGES IN FIELD SOILS RESULTING FROM COMPACTION BY AGRICULTURAL TRAFFIC
Authors: BLACKWELL P. S. , SOANE B. D. 
Published: July 2006

SummaryA simplified soil mechanical model was constructed to predict compaction beneath agricultural wheels when running on soils of certain characteristics. Soil strength functions were developed from in situ measurements of field soils and some laboratory measurements. Soil strain was measured by surface sinkage and changes of dry bulk density by gamma‐ray transmission methods. Soil stresses were measured by deformable spherical transducers and compared to predicted stresses using equations developed by Söhne. A method of analysis was devised to identify a form of the virgin compression line from field data. Changes of the slope and intercept of this line were monitored over a range of moisture contents for two soils and used in the prediction model.The prediction model was tested against compaction measured during independent experiments at different sites. Good prediction was found for soils of initial dry bulk density greater than 1.1 g cm−3 and cone resistance greater than 500 kPa, using a 30°, 12.9mm diameter cone. On looser and weaker soils the predicted compaction was often less than measured values.Using the model for simulation of compaction beneath a range of wheels revealed that contact pressure alone can be a misleading guide to compaction. Increases of bulk density below 10cm are considerably influenced by wheel load. The most effective way of reducing compaction requires the use of both a minimum load and a maximum contact area.
SOME NEW EQUATIONS TO DESCRIBE PHOSPHATE SORPTION BY SOILS
Authors: SIBBESEN E. 
Published: July 2006

SummaryPhosphate sorption was studied on surface and subsurface soils sampled from the old field experiments at Askov, Denmark. Two empirical three‐parameter equations, an extended Freundlich and an extended Langmuir equation are proposed and compared with the Langmuir, the Freundlich, the ‘double’ Langmuir, the Gunary, and the Fitter‐Sutton equations.In the proposed equations the affinity parameter of the Langmuir equation and the exponent of the Freundlich equation are replaced by the term Bc −D the value of which decreases with increasing phosphate concentration, c. On average the Freundlich equation thus modified yielded the closest fit to the sorption data. This was followed by the Fitter‐Sutton, the modified Langmuir, the ‘double’ Langmuir, the Gunary, the Freundlich, and finally the Langmuir equation. Out of the three equations that yielded the closest fit to the sorption data the correlation between the parameters within the equations, furthermore, was least for the proposed extended Freundlich equation. Therefore, this equation may be generally suitable for describing phosphate sorption by soils.
TITRATIONS OF FULVIC ACID FRACTIONS I: INTERACTIONS INFLUENCING THE DISSOCIATION/REPROTONATION EQUILIBRIA
Authors: DAVIS H. , MOTT C. J. B. 
Published: July 2006

SummaryPotentiometric titrations were performed on solutions of a polysaccharide fraction and a polycarboxylic acid fraction of fulvic acid. Accurate titration end points were determined by the application of Gran's equivalence point techniques.Reverse titrations did not follow identical paths to the forward ones because hydroxyl ions were consumed after the end points of the titrations against alkali had been reached. Analyses of the dissociation and reprotonation data demonstrate that electrostatic interactions alone cannot account for the calculated equilibria. The anomalous dissociation/reprotonation equilibria can be explained by the existence of inter‐ and intramolecular hydrogen bonds among functional groups on the fractions.
TITRATIONS OF FULVIC ACID FRACTIONS II: CHEMICAL CHANGES AT HIGH PH
Authors: DAVIS H. , MOTT C. J. B. 
Published: July 2006

SummaryThe stability in solution of a polycarboxylic acid fraction and a polysaccharide fraction of fulvic acid was investigated by pH stat titrations. At pH 8.0 alkali‐consuming reactions occurred on the polycarboxylic acid fraction. At pH 10.0, these alkali consuming reactions were continuing steadily after 22 days. It is suggested that hydroxylation of bound Al may contribute significantly to the consumption of alkali by the fraction. The data indicated that alkali consuming reactions occurred on the polysaccharide fraction at pH 10.0, but not at pH 9.0 and below. Evidence is discussed which indicates that a ‘peeling process’, by which end reducing sugars are stripped off polysaccharide chains and transformed to saccharinic acids, could account for the alkali consumption on this fraction.
TRANSFORMATION OF 15N‐LABELLED AMMONIUM IN TWO SOILS DIFFERING IN NH+4‐FIXING CAPACITY
Authors: FISCHER W. R. , PFANNEBERG T. , NIEDERBUDDE E.‐A. , MEDINA R. 
Published: July 2006

SummaryTwo soils differing in ammonium fixation capacity were incubated for 127 days with 15N‐ammonium sulphate. In a gley soil with high NH+4‐fixing capacity caused by smectites with a charge up to 0.8 per formula unit, the major part of the added ammonium was first fixed by minerals and then released slowly during incubation. The proportion of labelled N in the nitrate fraction increased during the first weeks and then decreased permanently. In contrast, in a histosol with low NH+4‐fixing capacity, the exchangeable fraction contained most of the labelled NH+4, this being highly available to microorganisms and therefore subject to nitrification. About 50% of the added 15NH4 was lost from the histosol in 127 days, but only about 20 per cent was lost from the gley soil.
NITRATE LOSSES IN SOIL DRAINAGE WATERS IN RELATION TO WATER FLOW RATE ON A DECIDUOUS WOODLAND SITE
Authors: TRUDGILL S. T. , PICKLES A. M. , BURT T. P. , CRABTREE R. W. 
Published: July 2006

SummaryThe nitrate load in drainage water from a freely‐draining calcareous soil under deciduous woodland increased consistently as the rate of water flow increased, suggesting that nitrate was rapidly available and not readily exhausted.