摘要:

SummarySeveral mixed hydroxides obtained by co‐precipitation of FeCl2or FeCl2with Na2SiO2followed by ageing and purification were studied by X‐ray diffraction, infra‐red spectroscopy, and surface‐area measurements.The compounds with molecular ratios SiO2/Fe2O3ranging from 0·1 to 1·17 are essentially amorphous.Silica, which is not to be considered as an integral part of the gel, is chemi‐sorbed on the ferric or‘ferrosic’ phase.The good agreement between IR, DTA, and surface‐area measurements with increasing molecular ratios permits the distinction between two ranges of silica contents. In the first range, MR0·1 range, silica polymerizes as a separate phase growing upon the‘ferro

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1969.tb01569.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SummaryThe investigation attempts to ascertain rates and amounts of soil erosion from a small unvegetated area (120m×15m). Measurements from markers embedded in the soil indicate a removal of 10 mm per annum on 5°C slopes, 32 mm per annum on 45°C slopes, and 43 mm per annum on 62°C slopes. A sediment trap indicated that in a week when there was 56·8 mm rain, approximately 60 g/sq m was eroded. Results of the work are used in an explanation of the eroded soils of a much larger area, known as the Lower Swansea Va

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1969.tb01570.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SummarySodium molybdate, at the rate of 10 ppm Mo, was added to the surface of seven acidic soils which were then stored moist for 3 to 10 months. After storage, less than 4 per cent of the added Mo was leached through any of the soils by the equivalent of a 250 mm rain. Between 36 and 91 per cent of the added Mo could be extracted with 0·1M NaOH, this proportion decreasing with longer incubation. Up to 40 per cent resisted treatment with both H2O2and NaOH, and most of this was extracted with dithionite plus citrate. It is concluded that Mo is not lost by leaching from acidic soils other than sands, but is adsorbed on sesquioxide surfaces and slowly changed into less soluble forms

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1969.tb01571.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SummarySimilar relative effects were obtained for plastic limits, percentage stable aggregates, and hydraulic conductivities when a tropical red earth, consisting predominantly of kaolin and iron oxide, and a tropical black earth consisting predominantly of montmorillonite, were saturated with Ca, Mg, K, or Na ions or combinations of these. Plastic limits were independent of the nature of the saturation cations, but were significantly dependent upon clay type. Percentage stable aggregates of artificially prepared aggregates and hydraulic conductivity were affected by the four cations in the order Ca = Mg>K Na and were also significantly affected by clay type. Combinations of the four cations generally gave intermediate effects with Ca‐saturated soils more susceptible to deterioration by K or Na than Mg‐saturated soils. The results confirm the generally deleterious effect of Na ions and show that K ions have effects similar to Na on the properties investigated. They suggest that heavy potash fertilization without liming may lead to structural deterioration of these so

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1969.tb01572.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SummaryIn an earlier investigation three different methods had to be used for the treatment of laboratory‐compacted clay soils prior to the preparation of thin sections for use in fabric studies. The three methods, viz., the Carbowax method, the Araldite‐resin impregnation method, and the Aquax method, had limited application depending on the degree of saturation and the clay‐mineral composition of the soil. A new method has been developed which can be applied to all clay soils irrespective of their mineralogy and degree of saturation. In this method, the pore water of the soil specimen is first replaced with monostyrene using a two‐step diffusion process. Then the specimen is impregnated with an Araldite‐resin mixture which can be cured at a temperature of 55°C. The method has yielded better thin sections than those obtained by any of the three previous methods. Pure montmorillonite soils can be treated with a greater degree of success than hithert

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1969.tb01573.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SummaryApparent and partial molal volumes of K‐kaolin and K2SO4, Mg‐kaolin and MgSO4, and Ca‐kaolin and CaCl2as a function of electrolyte and particle concentration were determined from density measurements at 30°C. The apparent (ø) and partial molal volumes (V) of the kaolin or the salts studied increase with concentration and are larger in salt‐clay mixtures. Kaolin saturated with electro‐strictive cations has lower volumes than that saturated with less str

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1969.tb01574.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SummarySepiolite has a microporous structure the pores of which may be penetrated to differing extents by molecules of different gases. A study has been made of the adsorption of CO2on outgassed sepiolite (from Amboseli, Tanzania) at 193°, 209·7°, 273·2°, and 298·2 °K using a gravimetric method. Values of the surface area of sepiolite were calculated from BET (Brunauer, Emmett, and Teller) and Kaganer plots of results, assuming molecular areas for CO2based on extrapolated liquid densities. There were only relatively small deviations from a mean value of 279 m2/g. However, the values were much lower than those previously determined by adsorption of N2and of other gases.It is suggested that CO2adsorbed at these temperatures should be assumed to be in the liquid state, but that the usual method of calculating the molecular areas of adsorbed CO2from the liquid densities at these temperatures yields values which are too low. Molecular areas of 20·8 Å2at 193 °K and 23·4 Å2at 209·7 °K are preferred.Isosteric heats of adsorption at different coverages were calculated from the isotherms. The results indicated heterogeneity of the surface, with decreases in the values of the heat of adsorption occurring at low coverages and in the‘monolayer region’. They compare well with values calculated from

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1969.tb01575.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SummaryEvidence is presented that soils in urban parklands are markedly contaminated with Cu, B, Pb, and Zn. Herbage from the same areas contains significantly higher levels of Pb and Zn than herbage from permanent pastures in rural areas.

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1969.tb01576.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SummaryPartially humified material can be separated from other soil material by flotation on a bromoform‐petroleum spirit mixture of density 2·0 g cm‐3. Maximum recovery of partially humified material requires ultrasonic dispersion and the addition of a surfactant to the suspension. For large‐scale work‘Nemagon’ may be used in place of the bromoform‐petroleum sp

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1969.tb01577.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

SummaryDirect and indirect methods of determining cation ratios of natural soil solutions are reviewed. The problems of comparing their results are discussed. K activity ratios derived from measurements on ethyl alcohol‐displaced soil solutions and values determined for the same soils by theQ/Iequilibration procedure were in excellent agreement. An approximate rapidQ/Iprocedure using two K‐Ca solutions whilst less precise in its determination of activity ratio would be useful for routine purposes. The use of a proportionality constant to calculate activity ratios is accepta

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1969.tb01578.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY