摘要:

SummarySeven soil regions, each of which is dominated by soils belonging to one or two great soil groups, are defined and mapped. The outstanding feature is the presence of a variety of soils with widely differing characteristics. The soils are deeper, have more profile differentiation and are finer‐extured than those in most‐arid regions and are frequently overlain by currently‐forming deposits of wind‐transported materials. Because the vegetative cover is better developed and there are only small areas of rocky hills and bare rock pediments, water erosion and deposition are not as prominent as in other ari

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1960.tb02206.x

出版商:Blackwell Publishing Ltd    

年代:1960

数据来源: WILEY

摘要:

SummaryRemnants occur in arid Australia of a formerly extensive land surface on which deep lateritic soils were developed. The lateritic profile, which contained silicified layers in the upper portion of the pallid zone, was subsequently truncated and water‐transported deposits containing lateritic detritus were laid down over the exposed mottled or pallid zones. Silicification of the upper portions of these deposits resulted in the formation of surface silcretes (the duricrust).The silcrete capping on the lateritic plateaux is overlain by either younger soils formed on deposits of wind‐transported materials, or by deposits of wind‐blown gypsite. Gypsum, leached from the latter, has accumulated in the mottled and pallid zones of the lateritic pr

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1960.tb02207.x

出版商:Blackwell Publishing Ltd    

年代:1960

数据来源: WILEY

摘要:

SummaryThe Kirkuk Plain has undergone partial salinization, followed by weak leaching. The areas irrigated in the past are the worst affected. Quality and quantity of irrigation water are most important factors in controlling the degree of salinization, while minor factors include deep gullies and the presence of a gypsum bed near the surface. The salts originate from the Fars Beds and the gypseous alluvium. Saline soils were encountered in areas with water tables much deeper than 2 m.

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1960.tb02208.x

出版商:Blackwell Publishing Ltd    

年代:1960

数据来源: WILEY

摘要:

SummaryA geological reconnaissance of the northernmost group of islands of the Canadian Arctic (Queen Elizabeth Islands) afforded an opportunity to study the nature of the soils. Profile development is rare, and the nature of the soil surface mainly depends on the slope of the ground and the type of bedrock. Chemical weathering and plant action are almost negligible in the arctic environment. Three profiles were examined in detail, two in well‐drained positions and one probably water‐logged for most of the thaw period.It is concluded that soils of this area should properly be regarded as polar equivalents of lithosols and regosols and that they should not be classed with the Tundra Great Soil Group. The name Rawmark Great Soil Group is suggested to encompass such soils of polar environment both in the northern and southern hemisphe

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1960.tb02209.x

出版商:Blackwell Publishing Ltd    

年代:1960

数据来源: WILEY

摘要:

SummaryAssuming a simple ferro‐ferric redox system in a waterlogged soil containing active organic matter, the equationEh= (1.28±0.03) − is derived and some evidence is brought to support it.The term is three times greater than that commonly used when adjusting soil Ehmeasurements for pH change.The author recommends that both Eh and pH values should be invariably quoted as measured, and a third term included for the adjusted Ehif necessary.The equation is also used to suggest the importance of pH changes when considering the movement and precipitation of iron in aerated s

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1960.tb02210.x

出版商:Blackwell Publishing Ltd    

年代:1960

数据来源: WILEY

摘要:

SummaryThe clay‐clay attractive forces were greater in crumbs from acid soils than crumbs from similar soils but Containing free CaCO3. This has two causes: (a) positive charges on the edge faces of the clay crystals; (b) exchangeable trivalent cations on the clay. Using the improved sodium‐saturation method these two causes were distinguished by measuring the reduction in the strength of the crumbs by (a) raising the pH of the percolating NaCl to 7.4 with para‐nitrophenol buffer, and (b) preliminary NaCl‐HCl leaching. The effect of trivalent cations was dominant in very acid soils where Al+++can exist in the soil solution. The soil conditioner‘Flotal’strengthens soil crumbs, initially at least, by substituting Fe+++ions on the exchange complex. No evidence was found for cementing by precipitated Al(OH)3, or Fe(OH)3.The same concentration of CaCl26 × 10−3M was required to flocculate suspensions of moderately acid surface soils both at the natural pH of the soil and after buffering the suspensions to pH 7×4. However a Callite and an acid subsoil (no organic matter) flocculated at a CaCl2, concentration of 3 × 10−4M at pH 5. Thus there appears to be sufficient organic matter present in normal cultivated acid soils to neutralize the positive charges on the edges of any clay particles dispersed from the crumbs.It is suggested that, although liming an acid soil decreases the attractive forces between clay particles within soil crumbs, the presence of free CaCO3, in the soil helps to maintain a sufficiently high concentration of electrolyte in the soil solution to reflocculate dispersed clay and so keep dra

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1960.tb02211.x

出版商:Blackwell Publishing Ltd    

年代:1960

数据来源: WILEY

摘要:

SummaryA detailed investigation of soil anisotropy on a small test area is reported. Measurements were made with piezometers of various diameters. The method employed involves two measurements of hydraulic conductivity in a single piezometer. In addition, transmission rates were determined on horizontal and vertical undisturbed core samples.The results show the vertical hydraulic conductivity to be highly variable and dependent on the depth below the soil surface. The horizontal hydraulic conductivity is less variable. Results of anisotropy calculations from piezometer measurements show a dependence on the dimensions of the cavity below the piezometer, the large piezometers gave anistropy ratios1.The dependence of test results on cavity dimensions is explained by the dependence of the vertical hydraulic conductivity on depth below the soil surface. Taking account of the inhomogeneous nature‐of the soil in the conventional analysis of anisotropy yields a similar dependence on cavity dimensions as was found from the field data. It is concluded that anisotropy calculations may lead to erroneous conclusions when applied to conditions in which the assumptions implicit in the theory are not approximately fulfilled.The usefulness of the methods employed in this investigation is that valuable data regarding soil variability have been obtained. This variability was not apparent in a previous study with the augerhole metho

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1960.tb02212.x

出版商:Blackwell Publishing Ltd    

年代:1960

数据来源: WILEY

摘要:

SummaryDefinitions of structure, fabric, and texture, as used in pedology and geology, are proposed in which structure conforms to the broader concept of the soil physicist, fabric conforms to the concept as used in pedology by Kubiena (1938) and in sedimentary petrology (Pettijohn, 1949), and texture conforms to the broad concept as used in petrology (Rice, 1954). Fabric is a part of structure, and structure a part of texture. The term pedality is proposed for the study of what has been called structure in the field, and field grading for field texture. Kubiena's (1938) concepts of skeleton and plasma are defined more specifically, and the concepts of pedological features, and basic, elementary, primary, secondary, and tertiary structure introduced. Descriptive terms for structure are suggested and a descriptive system for soil materials proposed. Nomenclature of pedological features and the various levels of structure and fabric are discussed.

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1960.tb02213.x

出版商:Blackwell Publishing Ltd    

年代:1960

数据来源: WILEY