bluuebunny/crossref_metadata_2025_split huggingface dataset:
NON‐EXCHANGEABLE AMMONIUM IN SOILS OF ISRAEL AND ITS RELATION TO CLAY AND PARENT MATERIALS
Authors: FEIGIN A. , YAALON D. H. 
Published: July 2006

SummaryThe occurrence of non‐exchangeable ammonium in the main soil groups of Israel and its relation to various factors were determined in 129 samples from thirty‐one profiles. In arid and semiarid soils the level ranged from 0·18‐0·53 me/100 g, with most values falling between 0·25 and 0·40 me/100 g. In the sub‐humid Mediterranean region the values ranged between 0·04 and 1·0 me/100 g, with most of them falling between 0·14 and 0·65 me/100 g. In most cases the percentage of non‐exchangeable ammonium‐N in the total soil nitrogen was in the range of 2–25 per cent.The clay fraction is a significant factor influencing the amount of non‐exchangeable ammonium in the soils tested. The relatively low amounts of non‐exchangeable ammonium found are consistent with the predominant clay mineral in most of the soils being montmorillonite. A good correlation was obtained with the content of illite, which is the main carrier of the non‐exchangeable ammonium. The mean non‐exchangeable K/non‐exchangeable NH, ratio in the Israeli soil clays was 17. In soils derived from or affected by aeolian dust, the level of non‐exchangeable ammonium calculated for the clay fraction spans that of aeolian dust and is, in general, higher than in soils developed from limestone, dolomite, marl, tuff, or basalt.
SOIL PHYSICS: TWENTY‐FIVE YEARS ON1
Authors: CHILDS E. C. , YOUNGS E. G. 
Published: July 2006

SummaryIn comparison with the situation twenty‐five years ago, the analysis of soil‐water hysteresis has been transformed by the concepts of independent and non‐independent domains, and the analysis of the diffusion‐like movement of water in unsaturated soil has led to a theory of the development of water content profiles which was only vestigial at the time of the founding of the British Society of Soil Science. The theory of the control of ground water has greatly developed, mostly along established lines, as also have field methods of determining the hydraulic conductivity necessary for the application of this theory. In striking contrast, the debate about the assessment of soil texture pursues its course unchanged.
FULVIC ACID: I. PARTIAL FRACTIONATION1
Authors: MacCARTHY PATRICK , O'CINNEIDE S. 
Published: July 2006

SummaryFulvic acid extracted from peat was partially fractionated on anion and cation exchange resins. In the latter case the fractionation is attributed to the presence in fulvic acid of components possessing amine groups; this was confirmed by chemical means and by infrared spectroscopic evidence. The infrared and ultraviolet spectra of fulvic acid and its various fractions are discussed and the occurrence of carboxyl, phenolic, and amine groups in fulvic acid and the fractions obtained is considered. It was further established that nitrous acid can destroy the amine groups present in fulvic acid.
KINETICS OF ISOTOPIC EXCHANGE OF PHOSPHATE ADSORBED ON GIBBSITE
Authors: KYLE J. H. , POSNER A. M. , QUIRK J. P. 
Published: July 2006

SummaryAn Elovich‐type equation has been used to describe the kinetics of isotopic exchange of phosphate adsorbed on the surface of gibbsite. The equation is
image
where A and B are parameters; θ=bF/[b+a(I‐F]; a and b are the molar concentrations of the phosphate on the crystal surface and in solution respectively and F is the fraction exchange of the radio‐isotope at time t. First‐order rate constants were obtained from the equation. The reference state for the first‐order rate constants, and the distribution of activation energies, for exchange can be related to the Elovich equation parameters. The kinetic results are consistent with SN1 dissociation or SN2 bimolecular solvolysis for the phosphate ligand. The eschange reaction is subject to an acid‐base catalysis the exact nature of which could not be determined from the available data.
COMPARISON OF DIFFERENT FORMS OF PHOSPHATIC FERTILIZERS PART I: RAPE AND SWEDES
Authors: JONES EDRYD 
Published: July 2006

SummaryEighteen experiments were carried out in Wales and the West Midland Region, between 1966 and 1971 to compare granular basic slag with powdered basic slag and superphosphate (or triple superphosphate) as phosphatic fertilizers for rape and swede crops. At the swede sites additional comparisons involving ground mineral phosphates were also made.The fertilizer treatments were applied at sowing time and at rates supplying 28 and 56 kg P/ha for rape and 28 and 56, or 44 and 88 kg P/ha for swedes. Large increases in yield of rape and swedes to the lower rate of phosphate application were recorded at most sites but, in general, only very small additional responses were obtained to the higher dressing.For both rape and swede crops, the relative effectiveness of the different phosphatic fertilizers varied somewhat between sites. Comparisons of the superphosphate and basic slag treatments show that the former gave slightly higher yields at most sites. Granular basic slag was marginally inferior to powdered slag for swedes but in general the differences between the effects of superphosphate (or triple superphosphate) and the two forms of slag were small.The effects of the Gafsa phosphate treatments for swedes were variable, being as effective as superphosphate or basic slag at some sites and much less so at others. This inconsistency detracts from their over‐all usefulness. There was no definite advantage in the finely‐ground (80 per cent through 300 mesh (50 μm)) material over the relatively coarser (60 per cent through 100 mesh (150 μm)) product.Moroccan mineral phosphate was inferior to the Gafsa phosphates for swedes, particularly at the most responsive sites.
DENSIMETRIC FRACTIONATION OF SOIL ORGANO‐MINERAL COMPLEXES
Authors: RICHTER MARTIN , MIZUNO ICHIRO , ARANGUEZ SANTIAGO , URIARTE SUSANA 
Published: July 2006

SummaryA rapid, simple, and precise density fractionation of soil mineral‐organic complexes, suitable for routine work, is described. Special features of the method are: low sample weight, use of glass‐fibre paper to collect the lighter fractions, and use of a modified Walkley‐Black procedure to determine the carbon content of the light fraction in test tubes. Density‐distribution curves of organo‐mineral soil complexes are shown to yield useful basic information on degradation processes of soil organic matter caused by cultivation. The results suggest that complexes between clay and organic matter tend to build up preferentially with a certain proportion between the components.
AN ASSESSMENT OF THE RELATIONSHIP BETWEEN THE SURFACE PROPERTIES OF CHALK SOILS AND SLOPE FORM USING PRINCIPAL COMPONENTS ANALYSIS
Authors: ANDERSON K. E. , FURLEY P. A. 
Published: July 2006

SummaryFive line transects were sited over grass‐covered, convex‐concave slopes in the Berkshire and Wiltshire chalk downs, with the object of describing and interpreting the variation in selected surface soil properties. Previous work had concentrated upon the correlation between single variables and slope gradient and slope length, whereas the emphasis of the present paper lies in examining the interrelationships amongst the variables through the use of principal components analysis.A consistent pattern of variation was established between the five sites. The first component derived from the analysis was interpreted as a combined organic matter and soluble constituents factor, which accounted for between 50 and 60 per cent of the total variance. The second component was identified as particle‐size variation and accounted for a further 13 to 18 per cent of the total variance.Whereas the distribution of the component scores for the second component supported the original idea of a sharp junction effect in the pattern of soil properties on the slope, the first and most important component indicated a more diffuse transition from net erosion to net deposition conditions.
RECONNAISSANCE FOR SOIL SURVEY
Authors: BECKETT P. H. T. , BIE S. W. 
Published: July 2006

SummaryThe total length of soil boundary on a map can be measured by counting the number of intercepts between boundaries and a randomly distributed array of sampling lines. It is thus also possible to estimate the length of the same boundaries before survey by means of a similar array of field traverses. The per cent sampling error of estimates of boundary density (boundary per unit area), is approximately the reciprocal of the square root of the number of intercepts.
SOIL TRANSECT CORRELOGRAMS OF NORTH OXFORDSHIRE AND THEIR INTERPRETATION
Authors: WEBSTER R. , DE LA C H. E. CUANALO 
Published: July 2006

SummaryIn almost all soil surveys some attempt is made in the early stages to assess the scale on which the soil changes, and the information required is often obtained from transects. By recording soil properties at a constant close spacing on such transects methods of analysis, especially those devised for time series, data can be applied to reveal patterns of variation, and hence lead to rational mapping strategy. Correlograms, which show on average the relation of soil at one point to that at another, seem especially promising.The potential of time series analysis in soil survey was explored by measuring soil properties in three horizons in profiles at 10 m intervals along a transect across the Lower Jurassic outcrop in north Oxfordshire. Correlograms were computed for clay, silt, pH, CaCO3, colour value, and stoniness in each horizon. They showed that, for all the properties, the relation between sampling points weakened steadily over distances from 10 m to about 230 m. The average spacing between geological boundaries on the transect was also about 230 m, and outcrop lithology was inferred as one of the main sources of soil variation. The effect of rock type was eliminated by computing deviations of the original values from the means of the outcrops in which they occurred. Correlograms of these showed almost no relation between points more than 10 m apart; i.e. the only other major source of variation occurred within 10 m.In this instance mappable soil boundaries are likely to occur on average every 230 m, and sampling at a spacing closer than I15 m would be needed to detect them from profile inspection alone. Alternatively a map of the geological boundaries with descriptions of the soil for each map unit would constitute almost the best soil map that could be achieved in this area.
THE EFFECT OF PHOSPHATE APPLICATIONS ON THE DIFFUSION COEFFICIENTS AND AVAILABLE PHOSPHATE IN AN ACID SOIL
Authors: KUNISHI H. M. , TAYLOR A. W. 
Published: July 2006

SummaryThe apparent bulk phosphate self‐diffusion coefficient, resin extractable and isotopically exchangeable phosphate were measured on an acid Cecil sandy loam soil pre‐treated with calcium carbonate and monocalcium phosphate. Apparent diffusion coefficients increased four‐fold with a five‐fold increase in phosphate addition, but were not increased by liming. Resin extractable phosphate was greater than isotopically exchangeable after large phosphate additions. Calculated porous self‐diffusion coefficients did not change as a result of phosphate additions. The contribution of solid‐phase phosphate to diffusion was small and close to the limits of measurement.
THE OCCURRENCE AND PREDICTION OF CLODS IN POTATO RIDGES IN RELATION TO SOIL PHYSICAL PROPERTIES
Authors: CAMPBELL D. J. 
Published: July 2006

SummaryClod crushing resistance, bulk density, moisture content, and size distribution, together with fifteen bulk soil physical properties, were determined at thirty sites. Regression analyses indicated that the plasticity index of the soil is the principal property affecting both the clod crushing resistance and the yield of clods. Other less closely related properties are not always consistent in their effect between clod size ranges. A‘clod factor’ was derived from the product of the clod crushing resistance and the weight of clods in the ridge for each soil. The clod factor is linearly correlated with plasticity index (r= 0·587, P= 0·002) and a clod factor > 1000 was found for soils with a plasticity index greater than about 5. Harvest observations suggest that where the clod factor exceeded 1000, the efficiency of a mechanical potato harvester was reduced.
THERMODYNAMICS OF THE EXCHANGE OF NICOTINE ON ALUMINIUM‐MONTMORILLONITE
Authors: SINGHAL J. P. , SINGH R. P. , SINGH C. P. , GUPTA G. K. 
Published: July 2006

SummaryThe ion exchange equilibria involving the interaction of nicotine with Almontmorillonite was studied thermodynamically. The exchange isotherms at 30° and 60°C indicated a preference for Al ions by montmorillonite as compared with nicotinium ions. A separation factor supported the conclusion. The enthalpy gain indicated tighter binding of Al. The entropy gain indicated a diffused and disordered arrangement of nicotinium ions in the Goüy layer with Al forming a more ordered arrangement in the Stern layer.
A PYROLYSIS‐GAS CHROMATOGRAPHY METHOD FOR DISCRIMINATION OF SOIL HUMUS TYPES
Authors: BRACEWELL J. M. , ROBERTSON G. W. 
Published: July 2006

SummaryPrinciples governing the choice of a pyrolysis‐gas chromatography method for work on soils and organic macromolecules are reviewed, and the method is applied to the discrimination of mull and mor humus in freely drained soils. Relatively undecomposed surface humus shorizons yield pyrolysis products characteristic of lignin, but these are not present in mineral horizons apart from traces persisting in some podzol A horizons. Mor humus incorporated in A horizons is characterized by a high pyrolysate content of furfurals and phenols whilst mull humus yields proportionately more pyrrole. Humus in B horizons yields a low furfural content with respect to pyrrole and a low content of polar heteroatomic molecules with respect to benzene, toluene, and light molecules of low polarity.
CHANGES IN THE CHEMICAL NATURE OF SOIL ORGANIC PHOSPHATE DURING PEDOGENESIS
Authors: BAKER R. T. 
Published: July 2006

SummaryIn two chronosequences of soils, total organic phosphate (P0) accumulated rapidly during the first 50 years of soil development, when organic matter increased and pH decreased. The rate of P0 accumulation then declined with age of soil until a ‘steady state’ was reached. The amounts of phospholipid, inositol phosphates and humic acid—P0 followed the same trends as the total P0.Parent materials and very young soils contained largely citric acid‐soluble P0, but after less than 50 years, surface horizons accumulated sufficient organic matter to complex a considerable proportion of the P0. An upper limit of 20–5 per cent citric acid‐soluble P0 and 70–80 per cent NaOH‐soluble P0 was attained within 50 years of soil formation in the surface layers, and this slowly extended down the profile so that, after 10000 years, the soil had 20 per cent citric acid soluble‐P0 and 70 per cent NaOH‐soluble P0 to a depth of 1 m.
COMPUTED EFFECTS OF ADSORPTION KINETICS ON PESTICIDE MOVEMENT IN SOILS
Authors: LEISTRA M. , DEKKERS W. A. 
Published: July 2006

SummaryFor a model at high water fluxes, the inclusion of first‐order adsorption‐desorption rate constants leads to slower leaching of pesticide and increased spread than predicted using instantaneous equilibrium. The initial condition of the substance near the soil surface is also found to be important.A model with simultaneous fast and slow adsorption‐desorption equilibria describes and explains published experimental data comparatively well. Under a pattern of intermittent rainfall, the effect of adsorption‐desorption kinetics on pesticide movement is comparatively small.
AMORPHOUS CONSTITUENTS OF SOME HIGH ALTITUDE SOILS OF THE SOUTH ISLAND OF NEW ZEALAND
Authors: MILESTONE N. B. , WILSON A. T. 
Published: July 2006

SummarySoils developed at high altitudes in the South Island, New Zealand have several pedological properties similar to the volcanic allophane soils of the North Island. Their clay fractions consist of finely divided parent material with some degree of ordering and some oxidation of ferrous to ferric iron, but because they are so finely divided they give no X‐ray diffraction patterns, and their IR spectra are typical of amorphous aluminosilicates. They are shown to have structure by electron microscopy and thermal analysis. It is suggested that the clays have been produced by the grinding together of stonesby frost action, and that similar material probably exists in other alpine areas and in polar regions where frost action is common.
TIME‐DEPENDENT SORPTION OF PHOSPHATE BY SOILS AND HYDROUS FERRIC OXIDES
Authors: RYDEN J. C. , McLAUGHLIN J. R. , SYERS J. K. 
Published: July 2006

SummaryThe sorption of inorganic phosphate (P) by soils and hydrous ferric oxides was studied at times up to 192h. An initially rapid decrease in solution P concentration was followed by a much slower decrease between 48 and 192h with soils, Fe gel. and natural goethite, whereas synthetic goethite gave a well‐defined equilibrium condition after only 48h. Resolution of the sorption isotherms showed that the increase in P sorption with time involved an appreciable shift of P from a more‐physically sorbed form to a chemisorbed form. This was supported by chemical fractionation which showed that NaOH‐extractable P was fairly constant with increasing sorption time, whereas the additional sorbed P was extracted by citrate‐dithionite‐bicarbonate from soils, and by HC1 from Fe gel and natural goethite. These sorbents contained short‐range (amorphous) material, whereas synthetic goethite, from which all sorbed P was NaOH –extractable. did not. It is proposed that the time‐dependent sorption of P and the associated shift of P to chemisorbed forms, involves the diffusion of P into “structurally porous”, short‐range order material.
EFFECTS OF IONIC STRENGTH ON CHEMISORPTION AND POTENTIAL‐DETERMINING SORPTION OF PHOSPHATE BY SOILS
Authors: RYDEN J. C. , SYERS J. K. , McLAUGHLIN J. R. 
Published: July 2006

SummaryAmounts of inorganic phosphate (P) sorbed by two unfertilized soils, during times less than required to reach equilibrium, were affected by the ionic strength and cation species of the matrix solution. For non‐equilibrium conditions the amounts of P sorbed increased with increasing ionic strength and were greater with Ca2+ than Na+. For higher P additions, resulting in equilibrium solution P concentrations greater than 30 to 40μrnole 1−1, the effects of the matrix solution on P sorption were maintained at equilibrium, whereas at lower P additions the dependence of sorption on matrix solution composition was eliminated at equilibrium.Equilibrium sorption isotherms for each soil and matrix solution were described by three Langmuir equations, which corresponded to distinct concentration ranges or regions (I, II, and III) on the overall isotherm. The free energies of sorption (ΔG) for each region, were essentially independent of the soil matrix solution. The sorption maxima for regions I and II of the isotherm for a particular soil were also virtually independent of the matrix solution used. The sorption maximum for region III, however, was markedly dependent on the matrix solution, implying a potential‐determining (p.d.) sorption mechanism.
THE MORPHOLOGICAL, PHYSICAL AND CHEMICAL PROPERTIES OF TWO MOUNDS OF MACROTERMES BELLICOSUS (SMEATHMAN) COMPARED WITH SURROUNDING SOILS IN SIERRA LEONE
Authors: MIEDEM A R. , VAN VUURE W. 
Published: July 2006

SummaryThe mounds are situated in the Makeni Area, Northern Province, Sierra Leone. Seventy five percent of this area consists of clayey upland soils that belong to the Makeni series (Typic Paleudult), which contain about 80 per cent of gravel‐sized hardened plinthite glaebules. The upland is dissected by numerous streams along which gravel‐free fine‐loamy terrace soils occur that belong to the Masuba series (‘Plin thic’Udoxic Dystropept) occupying about 15 per cent of the area. Mound 1 is a young inhabited mound on a Masuba soil, whilst mound II is an old abandoned mound on a Makeni soil.A trench was dug from the centre of the mounds into the surrounding soils. Profiles were described and samples were analyzed for organic carbon, CEC, exchangeable Ca, Mg, K, Na, and pH, and for particle size analysis with 5 sand fractions.The material used to build the mounds is derived from the subsoil (between 30 and 100 cm depth). Termite channels extended laterally for at least 10 m for mound I, but could not be traced so clearly for mound II.Mound I and the nest of mound II contain a higher percentage of particles less than 250 μm than the surrounding subsoil. Material over 2 mm is not carried by termites.Both mounds show a higher base saturation and higher values of exchangeable Ca, Mg and K, compared to the surrounding subsoil. Increased CEC and pH are noted in mound I and the nest part of mound II, the latter also showing increased values of exchangeable Na. Organic carbon values are equal to those of the surrounding subsoil.Accumulation of mineral elements from organic matter collected as food, including small contributions from the fungus combs and termite bodies, is primarily responsible for the observed differences. In view of the water analyses no contribution is expected from the fluctuating groundwater table.
CHEMICAL DEGRADATION OF HUMIC AND FULVIC ACIDS EXTRACTED FROM MEDITERRANEAN SOILS
Authors: CHEN Y. , SENESI N. , SCHNITZER M. 
Published: July 2006

SummaryHumic and fulvic acids were extracted from two Israeli and tour Italian soils and oxidized with alkaline permanganate solution after methylation. Following oxidation, the degradation products were separated by solvent extraction and chromatographic methods and identified by gas chromatography‐mass spectrometry.Major oxidation products were aliphatic, phenolic and benzenecarboxylic acids. In toto, 33 oxidation products were identified. These were essentially the same compounds as those produced by the permanganate oxidation of methylated humic and fulvic acids extracted from soils formed under widely differing climatic and geologic conditions, except that yields of phenolic acids from Mediterranean humic and fulvic acids were lower than those produced under similar conditions from humic materials extracted from other soils. The information provided by chemical degradation suggests that humic and fulvic acids from widely differing soils have similar chemical structures.
POLYCARBOXVLIC ACIDS EXTRACTED BY WATER AND BY ALKALI FROM AGRICULATURAL TOP SOILS OF DIFFERENT DRAINAGE STATUS
Authors: LINEHAN D.J. 
Published: July 2006

SummaryWater‐ex tractable poly carboxy lie acids and alkali‐extractable humic acids and fulvic acids, were isolated from agricultural top‐soils of two soil associations. Samples from four soil series from each association were selected with drainage status varying from well‐drained to very poorly‐drained. The amounts of atkali‐extractable humic acid and water‐ex tractable polycarboxylic acids were highest in the very poorly‐drained soils whilst the amounts of alkali‐extractable fulvic acid were generally similar in all the soils, although the fulvic acid accounted for a lower proportion of the total organic matter in the poorly‐drained soils. Oxalate‐extractable aluminium decreased with increased drainage impedance, whilst no such trend was observed for oxalate‐extractable iron. It is suggested that the fulvic acid‐like polycarboxylic acids are removed from the soil solution by adsorption onto sesquioxides; so that the lower content of aluminium oxides in the very poorly‐drained soils results in depressed levels of fulvic acid and increased concentrations of water‐extractable polycarboxylic acids.