摘要:

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 groundw

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1977.tb02300.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

SummaryIron, Al, and Mn were extracted by oxalate and dithionite from two Brown Mediterranean Soils, two Red Mediterranean Soils, one Vertisol and one Gley soil, all derived from basalt or scoria in the sub‐humid and humid Mediterranean regions of the Golan Heights.Ratios of oxalate: dithionite extracted iron (Feo:Fed) were low in all soils, indicating that the predominant form of free iron is crystalline. Feoaccumulates in the argillic B horizons of the Mediterranean soils, while Fedaccumulates in the surface horizons. A large part of the free iron oxide in the surface horizons of Mediterranean soils is associated with non‐clay fractions. While manganese behaves in a manner somewhat similar to that of iron, no definite trends could be discerned in the vertical distribution of free aluminium.In the Vertisol, Feoand Mnoaccumulate in the subsoil. Fedand Mndincrease slightly with soil depth. In the Gley soil, amorphous iron accumulates in the surface horizon, total free iron in the bottom horizon. Both amorphous and total free Mn had been depleted from the upper horizons of the Gley s

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1977.tb02301.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

SummaryUsing optical and scanning electron microscopy various forms of gibbsite are described in some tropical soils. In a lateritic soil from Zaire gibbsite occurs on argillans, in randomly oriented crystal sheets, as nodular aggregates infilling vughs and on ped faces. The mineral also surrounds quartz grains and kaolinite pseudomorphs after biotite. In other soils gibbsite occurs as silt‐size particles disseminated through the matrix, as large nodular aggregates, and as anatomizing sheets associated with crystal chambers. It is clear from these observations that alumina must be a mobile constituent and was probably translocated through the soil in solutio

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1977.tb02302.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

SummaryThe mineralogy of 14 chloritic soils of various drainage classes developed on different parent materials from the Loch Awe area of Argyllshire, Caithness, and the Southern Uplands reveals only minor variations'in clay mineralogy with profile depth, the frequent presence of primary minerals indicating that all the soils are immature, and that weathering is at an early stage. Iron‐rich chlorite generally persists throughout the profiles, varying little in amount or chemical composition between horizons; where identifiable, the polytype is II b. Oxidation of iron modifies the thermal characteristics of the chlorite in all the freely‐drained soils but usually only in the surface horizons of gleys. Irrespective of soil type or drainage class, in most profiles chlorite weathers only slightly, probably by vermiculitization around the edges of fla

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1977.tb02303.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

SummaryMoralistic soils (vertic and non‐vertic black clays) were sampled along a 200 m top sequence in the Transvaal Highveld, South Africa. The Milk wood soil on the upper part of the margalitic top sequence has an Al horizon which lacks both slickensides and self‐mulching properties but has strong blocky structure, the others are all self‐mulching (i.e. Vertisols). The Vertisols differ in some morphological properties such as the absence (Mngazi series) and presence (Arcadia series) of pedogenic calcite accumulation, both overlying decomposed dolerite, whereas the third member from a red‐black centenary sequence is calcareous with a gleyed subsoil horizon.Chemical and XRD analysis suggest that the clays of the Vertisols comprise mainly a partly chloritized iron‐rich smectite with Ie>Mg + Al in the octahedral layer (and interlayer positions), while in the upland Milkwood soil intergradient halloysitic clay occurs in addition to a more‘open’structured chloritized iron smectite. The mineralo‐chemical results and the geomorphic data suggest that the genesis of these soils is controlled primarily by the internal so

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1977.tb02304.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

SummaryData from a chemical determination of 21 elements plus seven Soil Survey routine laboratory measurements for three horizons of 30 soil profiles have been treated by multivariate techniques to find relationships and grouping of soil properties in soils mapped as Denchworth series.The samples profiles were developed in parent materials of Oxford, Kimmeridge and Gault clay origin. The Oxford clay grouping was confirmed, but the Kimmeridge and Gault clay soils were better represented by three rather than two classes.

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1977.tb02305.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

SummaryCanonical correlation is an analytical technique for relating one multivariate set of measurements on a population to another in terms of linear functions of the two sets. It can express quantitatively the relation between the soil, described by one set of variates, and its environment, described by another, and attempt statistical prediction of the one from a knowledge of the other. The method is described briefly, and applied to soil and environmental data from soil surveys in Britain (the Dee catchment of North Wales) and Australia (Ginninderra in the Australian Capital Territory and the Wungong Brook catchment near Perth, Western Australia).The technique is judged to be a useful exploratory tool for seeking relations in situations that are little known or understood.

ISSN:0022-4588    

DOI:10.1111/j.1365-2389.1977.tb02306.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY