bluuebunny/crossref_metadata_2025_split huggingface dataset:
EVIDENCE OF THE UPWARD MOVEMENT OF NITRATE DURING THE DRY SEASON IN THE KIKUYU RED LOAM COFFEE SOIL
Authors: ROBINSON J. B. D. , GACOKA P. 
Published: July 2006

SummaryEvidence is presented to show that an upward movement of nitrate takes place in the Kikuyu red loam coffee topsoil during the hot, dry season following the main rain periods. This upward movement contributes towards the build‐up of nitrate which is observed to take place in the topsoil as it dries out.
THE ORIGIN OF THE INDURATED B3, HORIZON OF PODZOLIC SOILS IN NORTH‐EAST SCOTLAND
Authors: ROMANS J. C. C. 
Published: July 2006

SummaryMorphological examination of podzol profiles in the Eastern Grampians and lowland Strathmore, together with pollen analyses of hill peat and podzol A horizons, suggest that the podzols of Strathmore have been developed since the post‐glacial climatic optimum, whilst those of the Grampians are much older.On morphological grounds it seems improbable that the indurated B3 horizon now found in these podzolic soils could have been present in the high base status brown forest soil profiles which appear to have existed in Strathmore prior to the development of the present‐day podzolic soils.A comparison of the stage of development of the podzol profile with indurated B3, horizon found buried beneath the earth bank around the Roman marching camp at Kirkbuddo in Angus, with the present‐day soil profile, confirms that the development of the indurated B3, horizon is related to the development of the podzol profile. Its origin must be ascribed, therefore, to pedological rather than to periglacial processes.
PHOSPHATE EQUILIBRIA IN AN ACID SOIL
Authors: TAYLOR A. WORMALD , GURNEY E. L. 
Published: July 2006

SummaryA detailed study of the aluminium phosphate ion products in solutions equilibrated with an acid, phosphate‐deficient soil showed that the phosphate status of the undisturbed soil is compatible with the existence of variscite (AIPO4·2H2O) in the soil but produced no evidence that this phase has any effect in controlling the composition of dilute solutions equilibrated with the soil for periods of less than 32 days.When the soil is acidified, subsequent changes in the composition of the solution reflect the dissolution of aluminium hydroxide and decay of the clay minerals. Phosphate additions to the acidified soil are rapidly precipitated, and the final phosphate concentration is less than would be supported by variscite under these more acid conditions.
A PUNCHED‐CARD SYSTEM FOR SOIL PROFILES
Authors: MUIR J. W. , HARDIE H. G. M. 
Published: July 2006

SummaryA punched‐card system, designed to make data on a large number of profiles readily available, is described. The problems of converting the data to a form suitable for punching on the card are fully discussed. A numerical code is used to group the profiles according to soil series, major soil group, or geographical location. Analytical results of various kinds are also coded for each major horizon. A feature of the system is that information on a complete profile is coded on one card so that the profile remains the basic unit.
A NOTE ON THE CHEMICAL ANALYSIS OF A SOIL BURIED SINCE ROMAN TIMES
Authors: MATTINGLY G. E. G. , WILLIAMS R. J. B. 
Published: July 2006

SummaryThe chemical composition of a soil buried beneath a Roman amphitheatre was compared with soil from the surrounding field and with the materials from which the amphitheatre was constructed. The calcium carbonate and total potassium contents of the buried soil and the cultivated surface soil were similar. The buried soil contained 0·78 per cent. carbon, 0·126 per cent. nitrogen, and 0·044 per cent. organic phosphorus and the surface soil 2·42 per cent. carbon, 0·318 per cent. nitrogen, and 0·097 per cent. organic phosphorus. Much more phosphorus, soluble in 0·5 M sodium bicarbonate, was present in the buried soil (12·8 mg. P/100 g.) than in the surface soil (1·3 mg. P/100 g.). Losses of nitrogen since the soil was buried in Roman times were estimated to be about 70 per cent.
SOME EFFECTS OF RAINFALL, RADIANT DRYING, AND SOIL FACTORS ON INFILTRATION UNDER RAINFALL INTO SOILS
Authors: ROSE C. W. 
Published: July 2006

SummaryThe effect of the structural condition of a soil on infiltration under laboratory simulated rainfall was investigated. Infiltration was greater with better structural condition for both undisturbed and disturbed samples. The infiltration rate of a soil surface damaged by intense rainfall decreases as rainfall continues. After equal periods of exposure there was little difference, for any of three soils examined, between total infiltration of rainfall at a rate of 6 in. per hour and at 4 in. per hour. The application of a pressure less than atmospheric to the underside of 2‐in.‐deep samples, simulating the moisture tension observed in the transmission zone on infiltration into deep soil columns, did not increase infiltration under rainfall as would be expected. For a clay soil previously exposed to rainfall, infiltration rate after radiant drying for 24 hr. and rewetting was only half that of replicates which were dried in shade.The nature of the cation with which a soil may be saturated markedly affects the permeability of the soil to water; and this effect persisted when water was applied with the added mechanical action of falling drops. Artificial crumbs of pure clays and a clay mixture were brought to moisture equilibrium with saturated water vapour, and their stability under rainfall examined. Calcium‐saturated kaolin crumbs were rapidly broken down and dispersed under rainfall, in marked contrast to their stability on immersion in water without the mechanical effect of falling drops. Calcium‐saturated illite and montmorillonite experienced no visible breakdown of the crumbs and no dispersion for the same rainfall exposure.
AN ESTIMATION OF MICROFAUNAL POPULATIONS IN SOILS AND FOREST LITTER
Authors: STOUT J.D. 
Published: July 2006

SummaryIn mineral soils the microfaunal population consists principally of nematodes and protozoa. The ciliate protozoa tend to be more numerous than the rhizopods. In beech‐litter rotifers and copepods are also very numerous. There is a significant difference between the litter populations of summer and winter.
PEDOTUBULES: THEIR DEFINITION, CLASSIFICATION, AND INTERPRETATION
Authors: BREWER R. , SLEEMAN J. R. 
Published: July 2006

SummaryThe term pedotubules is proposed for a group of pedological features which have a tubular external form and which are distinguished from cutans (Brewer, 1960a) by their complex internal composition and fabric. Pedotubules are classified according to their internal fabric and composition, details of external form, distinctness, and by a comparison of their fabric and composition with that of the horizons of the soil profile. Their general morphology suggests their origin as voids caused by faunal and floral (root) activity which have been filled, or partially filled, with soil material. Since little is known of the details of the effects of faunal activity on soil materials, such interpretations are tentative.
THE INFLUENCE OF SOIL TYPE ON THE RESPONSE OF MAIZE TO UREA IN GLASSHOUSE EXPERIMENTS
Authors: COURT M. N. , DICKINS J. C. , STEPHEN R. C. , WAID J. S. 
Published: July 2006

SummaryA greenhouse experiment compared the effects of ammonium nitrate and urea (1 per cent biuret), applied to forty‐two soils, on the growth and yield of maize foliage.Dry‐matter yields of maize in most soils were similar when both sources supplied 0·15 g or 0·30 g N per pot. At 0·45 and 0·60 g N per pot plants in soils with urea yielded less than with ammonium nitrate in sixteen and nineteen soils respectively. Urea adversely affected plant development to a greater extent in light soils than in heavy soils and peats. A partial correlation analysis indicated that responses to urea at the two higher rates of application were positively correlated with ammonia absorption capacity and a correlation with clay content was indicated. No significant partial correlations were obtained with organic matter content, pH, exchangeable‐hydrogen, cation‐exchange capacity, and moisture content.
SOIL PROFILES FOR DISPLAY PURPOSES
Authors: BEATER B. E. 
Published: July 2006

SummaryA technique for the preparation and preservation of soil profiles is described. Constructional details of the metal frame, methods for procuring the monolith in the field and the subsequent facing of it are presented in some detail. The preservation or hardening of the soil monolith in its frame with plasticized poly‐vinyl acetate emulsion, stabilized with poly‐vinyl alcohol, was found to be extremely effective.
CUTANS (CLAY FILMS) AND POTASSIUM AVAILABILITY TO PLANTS1
Authors: SOILEAU J. M. , JACKSON W. A. , McCRACKEN R. J. 
Published: July 2006

SummaryThe influences of iron‐kaolinite cutans enveloping soil aggregates on the availability of K within these aggregates were studied. Synthetic iron‐kaolinite clay coatings on illite aggregates were prepared. Macroscopic and microscopic observations of the synthetically prepared aggregates indicated the formation of almost continuous, partially orientated crystalline iron‐kaolinite cutans around the perimeter. There were indications that the presence of the coating tended to stabilize the aggregates. Photomicrographs of wheat root‐aggregate associations revealed intimate surface contact between the two with some penetration and disruption by the wheat roots, both in the coated and uncoated aggregates.Plant growth and potassium uptake were restricted in the presence of iron‐kaolinite coatings on K‐rich illite aggregates compared with plants grown on aggregates without coatings. Moreover, the presence of the coatings resulted in appreciable increases in Ca and Mg accumulation by the plants.Results of this investigation suggest that cutans may modify significantly ion availability and accumulation by plants growing in highly weathered, iron‐rich soils.
THE MOBILIZATION OF IRON BY AQUEOUS EXTRACTS OF PLANTS
Authors: MUIR J. W. , LOGAN J. , BOWN C. J. 
Published: July 2006

SummaryThe organic‐acid fraction maintains iron in solution from pH 4 to at least pH 9.5, with a maximum of 15 mg iron per gram of dried pine needles at pH 8; the amino‐acid fraction is inactive above pH 4.5. The constituents of the organic‐acid fraction are examined individually and their effectiveness com‐pared. Of the active acids, all except phosphoric acid are α‐hydroxy carboxylic acids. A synthetic solution, with a composition that corresponds to the analysis of the organic‐acid fraction, is used to demonstrate that all the major active constituents have been identified. The activity of the individual acids and the organic‐acid fraction is due to their ability to form water‐soluble complexes with iron and to stabilize ferric hydroxide sols. The water‐soluble complexes are formed over a wide range of pH and in the presence of calcium ions. The formation of ferric hydroxide sols, however, is greatly influenced by pH and by the presence of calcium ions. These findings are related to soil processes and to the morphological character of the soils on which Scots Pine trees normally grow.
SOME FACTORS AFFECTING LOSSES OF AMMONIA FROM UREA AND AMMONIUM SULPHATE APPLIED TO SOILS
Authors: GASSER J. K. R. 
Published: July 2006

SummaryUrea supplying 100 1b of N/acre was either broadcast on the surface or mixed with four soils (two clay‐loams, two sandy‐loams) and losses of ammonia were measured when the soils were maintained at 40, 50, or 60 per cent water‐holding capacity (WHC) and incubated at 5°or 25°C. Urea and ammonium sulphate were similarly applied to two calcareous soils at 40 per cent WHC and 5°or 25°C. Losses varied most among soils, from 2 per cent of the N applied from an unmanured clay‐loam to 13 per cent from an unmanured sandy‐loam. Changing temperature and water content affected losses little on average, but their effects differed with different soils. Losses of ammonia were similar from urea and from ammonium sulphate applied to the calcareous soils. Analyses at the end of the experiments showed that: (i) nitrite tended to accumulate in the sandy and calcareous soils, accumulation being favoured by lower temperature and wetter soil; (ii) ammonia was lost at 25° C from calcareous soils until all the ammonium‐ N had been nitrified, from the slightly alkaline clay soils until nine‐tenths had been nitrified, and from the neutral sandy soils until half had been nitrified.
CATION EXCHANGE REACTIONS
Authors: SALMON R. C. 
Published: July 2006

SummaryWyoming bentonite, Blisworth illite, and a fen peat were saturated with different proportions of calcium, magnesium, and potassium, and exchange between these cations was studied by measuring their activity ratios in dilute equilibrium solutions. With both clays the activity ratio aMg/aCa in solution was linearly related to the ratio of adsorbed Mg/Ca, the former being 1.22 times larger than the latter ratio. Peat held magnesium much less strongly than calcium, and the difference increased with increasing magnesium saturation. With all three materials the activity ratio aMg/aCa+Mg in solution was curvilinearly related to the percentage magnesium saturation. Peat adsorbed potassium less strongly relative to the divalent cations than did the clays, and bentonite adsorbed potassium less strongly than illite. Decreasing the Ca:Mg ratio increased the strength with which peat adsorbed potassium, but had no effect on potassium adsorption by the clays. Exchange between magnesium and calcium in forty British soils was studied by measuring the concentration ratio [Mg]/[Ca+Mg] in equilibrium soil solutions. The relation between [Mg]/[Ca+Mg] in solution and the ratio of exchangeable Mg/(Ca+Mg) in different soils varied within the range covered by peat and bentonite or illite, suggesting that differences between soils might be due to different organic‐matter contents. The extent to which [Mg]/[Ca + Mg] in solution was altered by changes in the exchangeable magnesium content differed considerably between soils. These differences were not all explained by variations in exchange capacity, showing that different soils adsorb magnesium with differing strengths relative to calcium.
STUDIES OF FUNGI IN A PODZOL
Authors: WILLIAMS S. T. , PARKINSON D. 
Published: July 2006

SummaryA study of fungal populations in the mineral horizons of a podzol was conducted using a soil‐washing technique. The mycoflora of various microhabitats was studied and compared. Results indicated that the position of the substrates in the profile largely determined which species were able to colonize them. Investigation of seasonal fluctuations of the fungal populations revealed no significant qualitative or quantitative changes throughout the year, variations observed reflecting the heterogenous spatial distribution of fungi in the soil.
A CLASSIFICATION OF HUMUS FORMS AND MICRO‐FABRICS OF TEMPERATE GRASSLANDS
Authors: BARRATT BERYL C. 
Published: July 2006

SummaryThe humus form is recognized in a soil profile as the group of A horizons in which organic matter is concentrated, and it is thus the upper part only of the genetic humus type, the true measure of which is the complete organic profile extending into B and C horizons. Grassland humus forms are subdivided on a basis of field morphology into two groups: mull, in which the organic residues are largely incorporated as an intimate clay‐humus mixture, and mor, in which organic residues in varying stages of decomposition overlie the mineral soil with a sharp boundary but may show weak mechanical admixture of mineral grains. A mor‐like mull intergrade is recognized where the mull is very high in intimately incorporated organic matter.According to variation in horizon thickness, structure, and consistence, sixteen humus forms are recognized: strongly granular, weakly granular, massive or blocky, fine, matted, laminated, and lenticular mulls, strongly granular, weakly granular, and laminated mor‐like mulls, and granular, massive, matted, laminated, banded, and mullized mors. Where mineral grains are very abundant in mor a sandy phase is recognized.Each layer or horizon of a humus form may have one or more distinct micro‐structures or fabrics. Twelve fabrics have so far been recognized under grassland: weak mull humus, strong mull humus, mull‐like moder, mull‐like rendzina moder, leached mull‐like rendzina moder, silica moder, swollen moder, rendzina moder, leached rendzina moder, raw soil humus, sclerotial humus, and raw humus.
A SEASONAL STUDY OF OXYGEN UPTAKE OF SOME PASTURE SOILS AND ACTIVITIES OF ENZYMES HYDROLYSING SUCROSE AND STARCH
Authors: ROSS D. J. 
Published: July 2006

SummaryRates of oxygen uptake and activities of enzymes hydrolysing sucrose and starch were determined in soils under pastures of grasses and clovers at bimonthly intervals at eight sites in New Zealand with different climates. Differences between sampling periods were significant in most soils. Values of oxygen uptake and enzyme activities were not generally significantly correlated between themselves nor with the moisture contents of the soils nor their prior rainfall history. It has not been possible to suggest an optimal sampling period for different soils. The oxygen uptakes of all soils increased two‐ to threefold in the presence of glucose. Mean annual values of oxygen uptake of the eight soils were significantly correlated with their contents of organic carbon, reducing sugars produced on incubation in buffer, and rates of hydrolysis of starch, but not of sucrose. Climatic factors and the composition of the pastures probably influence the activities of carbohydrase enzymes in soil. The ratios of the activities of enzymes hydrolysing sucrose to those hydrolysing starch were greatest in the driest soils under predominantly grass pastures at sites with the lowest mean annual temperatures.
STUDIES ON THE DECOMPOSITION OF CONIFEROUS LEAF LITTER1
Authors: HAYES A. J. 
Published: July 2006

SummaryAn investigation of some aspects of the rate and type of decomposition of leaf litter of Abies grandis Lindley, Picea sitchensis (Bongard) Carrière, and Pinus sylvestris L. in a mixed coniferous plantation near Bangor was carried out. Leaf litter was exposed on the surface of the litter layer and at the humus/mineral soil interface, at different distances from the base of selected trees, each type of litter being laid out only under its own tree species. Seasonal changes in the rate and type of decomposition were investigated by exposing litter in June 1959, October 1959, and April 1960. The moisture content of the experimental litter showed a good correlation with rainfall. In all three tree species there was a high positive correlation between leaf length and dry weight, and this was used to determine the progressive losses in dry weight of the litter. There was a rapid initial loss in dry weight, and thereafter Abies continued to lose weight most rapidly, and Pinus more slowly, whereas Picea showed little change. There was usually little change in N content, although in one case this decreased by about 50 per cent in the first two months after exposure. The C content either decreased for the first six months after exposure or showed little change. The C/N ratio generally showed either a consistent slow decrease or little variation, although in the June 1959 exposure there was a very rapid decrease in C/N ratio during the first two months. The quantity of extractable polyphenols decreased very rapidly after the litter had been exposed, and thereafter there was usually little change. There was some evidence that addition of polyphenol from external sources could occur.
STUDIES ON THE DECOMPOSITION OF CONIFEROUS LEAF LITTER
Authors: HAYES A. J. 
Published: July 2006

SummaryIn a study of some aspects of the rate and type of decomposition of leaf litter of Abies grandis Lindley, Picea sitchensis (Bongard) Carrière, and Pinus sylvestris L., the external features of the needles at different stages of decay have been recorded, together with the micro‐fungi appearing on the needles and cultured from them. A regular sequence of colour changes was demonstrated, from the original green to grey‐green, brown, grey to black. Unless conditions were very favourable, the litter of Picea sitchensis changed colour much more slowly than that of the other species. The proportion of collapsed leaves increased progressively with time, although in the earlier stages of decay reversion to the non‐sunken condition could occur by water uptake. A definite succession of fungi was recorded as the litter decomposed. Needles remaining affixed to the tree were commonly colonized by Fusicoccum bacillare, accompanied on needles of Pinus by Lophodermium pinastri. On freshly fallen needles, Haplographium penicilloides, Aspergillus fumigatus, and Penicillium frequentans occurred frequently, together with white hyphal ‘cushions’ in the stomatal apertures, and a sterile net‐forming surface mycelium. Older litter was colonized by Trichoderma viride, Oidiodendron fuscum, and Verticicladium trifidum. Mucor hiemalis and Aposphaeria sp. were present throughout the period of decay, together with a number of less common species.
BLOCKED CHARGES ON CLAY MINERALS IN SUB‐TROPICAL SOILS
Authors: DAVIDTZ J. C. , SUMNER M. E. 
Published: July 2006

SummaryHypothetical mechanisms for charge blocking on the surfaces of kaolinitic minerals are presented to account for the anomalous behaviour of ferrallitic soils on deferrification. On iron oxide removal, the following situations can arise where positive and negative charges (i) both increase, or (ii) both decrease, or (iii) increase and decrease concomitantly. These variations in charge after deferrification can adequately be explained on the basis of blocking which affects both the basal planes and edges of the clay minerals.
CHARACTERISTICS OF SOME SOLONETZIC SOILS IN THE GLACIAL LAKE EDMONTON BASIN OF ALBERTA
Authors: ARSHAD M. A. , PAWLUK S. 
Published: July 2006

SummaryPhysical and chemical analyses of five geographically associated Solonetzic and Chernozemic Black soil profiles from the glacial Lake Edmonton basin were conducted to investigate the mechanisms operative in their genesis. Soils, classified as Black Solonetz and Black Solodized Solonetz, satisfied both morphological and chemical criteria as set forth by the National Soil Survey Committee of Canada for soils of the Solonetzic Order. The lack of pronounced solodization in the Bnt horizons of these soils was attributable to the proximity of bedrock to the surface which prevented the removal of Na salts from the profile. A high content of exchangeable Na in the Bnt horizons appeared to have assisted the comminution of coarse clay particles to fine clay particles. The soil, classified as Saline Black, had the chemical properties but lacked the morphology of Solonetzic soils. Two Eluviated Black profiles were genetically different from each other. While the Eluviated Black profile in one case was completely solodized and appeared to be regrading towards the normal soil type, the soil at the other site had features that reflected the influence of weak solonetzic processes.
THE SOLUBILITY OF PHOSPHATE IN A CALCAREOUS SOIL
Authors: LARSEN SIGURD 
Published: July 2006

SummaryThe concept of chemical potentials was used to study the solubility of phosphate in a calcareous soil when equilibrium was approached by precipitation.By comparison with results obtained by dissolution of soil phosphate it was demonstrated that precipitation resulted in a considerably greater solubility than did dissolution.The relationship between the monocalcium phosphate potential and lime potential could be reconciled with the presence of hydroxyapatite in the soil. Ion activity products near to those of pure hydroxyapatite in the presence of calcium carbonate were also obtained.