摘要:

SummaryA method is described to measure the magnetic susceptibility of soils and clays using an analytical balance and a small magnet. Small amounts of ferromagnetic iron oxide occur in most soils and are concentrated in the clay fractions of surface horizons. Ignition of soil samples is shown to cause large increases in the magnetic susceptibility.

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1963.tb00943.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

SummarySelf‐diffusion coefficients for Rb+, K+, and Sr++have been measured in homoionic soils by determining the quantities of radioactive tracers crossing from labelled to initially unlabelled soil sections through ion‐exchange membrane barriers. Diffusion coefficients were considerably lower than in aqueous solution, and the value for Sr++was approximately one‐tenth of those for the monovalentions. The diffusion of Rb+in soils containing both Rb+and Ca++was also studied using various compactions and soil solution compositions. The results suggest that cations are able to diffuse along the charged surfaces of soil particles, but at a lower rate than in the free pore solution. Experiments on the effects of temperature suggest that the activation energy for the diffusion of Rb+in the heteroionic soil was greater at low than at high bulk densities, a result which is interpreted in terms of surface mov

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1963.tb00944.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

SummarySelf‐diffusion coefficients for I‐and H2PO‐4in soils have been measured by determining the movement of radioactive tracers of these ions from a cylindrical section of labelled soil to a similar section initially without tracer. DIvaried with the composition of the equilibrium soil solution used, both concentration and nature of cation affecting the value. These results may be explained by variations in the extent of negative adsorption of diffusing anions in the presence of negatively charged soil particles, and the consequent variation in the size of pore from which the anions are excluded.Phosphate diffusion was measured in the natural soil. The low values of DH2PO4are attributed to adsorption and fixation of phosphate ions. Results obtained using different methods of phosphorus extraction and treatments designed to investigate effects of microbial activity are disc

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1963.tb00945.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

SummaryFurther studies have been made of the alkaline nitrobenzene oxidation of soil organic matter and certain fractions thereof, as well as of some plant materials, on the lines of a previous investigation. By using dichloromethane in place of diethyl ether as an extractant the recovery of aromatic aldehydes, especially syringaldehyde, has been greatly improved. Methods have been developed for the identification and determination of the related acids: syringic, vanillic,p‐hydroxybenzoic, ferulic, andp‐coumaric acids. Some minor aromatic products of the oxidation have also been identified. Application of the improved methods to samples of soils and peats has, in many instances, resulted in an increased proportion of the total carbon accounted for as aromatic products. The results are, however, only about 20 per cent higher than those previously obtained, and the outcome of the investigation has been to confirm and extend the results previously obtained. Whereas the proportion of carbon in the organic matter of peats which can be recovered as aromatic products is commonly about 5 per cent, in aerobic soils it remains low, generally less than 1 per cent, and it seems likely that this represents only a small fraction of the total aromatic material present in such so

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1963.tb00946.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

SummaryCalculations are presented of the fraction of charge compensated by cations for some clay systems. Surface charge density, electrolyte type, concentration and composition are studied in their relation to positive adsorption and exchange of cations in some clay systems. It is calculated that the negative adsorption due to mono‐valent anions is about one‐third that due to divalent ones present at the same concentrat

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1963.tb00947.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

SummaryA method is described for dividing soils into iron oxide, sand, silt, and clay fractions suitable for trace‐element analysis. The oxides are extracted under ultra‐violet light by ammonium oxalate (pH 3·3), which dissolves goethite and other iron oxides but not gibbsite or boehmite; it also extracts some soil organic matter and, probably, trace elements associated with it.Two horizons of two brown earths were analysed spectrochemically for Ba, Co, Cr, Cu, Ga, Mn, Ni, Pb, Sr, Ti, V, and Zr. The extracted oxides were the fractions richest in trace elements and contained large proportions of the total Co, Cu, Mn, Pb, and V. Except for Sr, Ti, and Zr, the amounts of trace elements in the sands were small and were distributed between the silicate‐mineral fractions in the order: sand>silt>clay. About half of the total Zr was in the sand fractions but appreciable amounts were in the extracts and clays. Increases of iron oxide and clay in the illuvial B horizons were paralleled by increases in the amounts of Ba, Cr, Co, Ga, Ni,

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1963.tb00948.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

SummaryThe decomposition of silicate minerals and related substances by fungi has been investigated using two techniques: (a) the incorporation of the mineral material in agar medium, when its breakdown is indicated by the formation of clear zones round the fungal growth; (b) the determination of the metal and silicate ions, derived from the insoluble materials and brought into solution as a result of fungal activity in liquid medium. Strains of fungi which produced citric and/or oxalic acid proved to be effective in decomposing certain natural silicates, while an oxalic acid‐producing strain also released metallic ions and silica from rocks and soils. A possible role of fungi in biological weathering is discusse

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1963.tb00949.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

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 moist

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1963.tb00950.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

SummaryThe concept of chemical potential was applied in studying the form of soil phosphate present in some Manitoba soils. Generally for all the soils studied, the soil phosphates were more soluble than hydroxyapatite but less soluble than dicalcium phosphate dihydrate. Evidence was obtained for the existence of octocalcium phosphate in most of these soils. The effect of phosphate fertilization and per cent calcium carbonate on the form of native soil phosphate was also evaluated.

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1963.tb00951.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

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 effect

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1963.tb00952.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY