Soils Of Different Origin Research Articles

Speciation and Complexation of Cadmium in Extracted Soil Solutions

We report the soil solution speciation of Cd in 64 field-collected contaminated soils containing between 0.1 and 38 mg Cd kg-1. The soils were analyzed for pH (3.5−8.1), soil organic matter (8.0−108 g C kg-1), total dissolved Cd (0.03−182 μg Cd L-1), dissolved organic carbon (1.5−12 mg C L-1), and free Cd2+ (10-10−2 × 10-7 M). Free Cd2+ activity in solution was determined using differential pulse anodic stripping voltammetry (DPASV), assuming DPASV is sensitive to easily dissociated inorganic ion-pairs and free Cd2+ while excluding organic complexes. The solid/liquid partition coefficient (Kd) varied over a range from 10 to 100 000, and the fraction of the dissolved Cd present in solution as the estimated free Cd2+ species varied between 0 and 60% but averaged about 20%. The dissolved concentrations of Cd and the free Cd2+ activity in the soil solutions of contaminated soils of different origins can be predicted with reasonable accuracy using a simple competitive adsorption model dependent on pH and total metal loading.

Weight and optical differences between soil humic acids fractions obtained by coupling SEC-PAGE

Humic acids (HAs) from four soils of different origin (podzoluvisol, phasozem, chernozem and ferralsol) have been fractionated by coupling size exclusion chromatography (SEC) and polyacrylamide gel electrophoresis (PAGE). Preparative quantities of HA fractions (HAFs) with different molecular sizes (MSs) and exactly defined electrophoretic mobility (EM) have been obtained from all the samples. Fractions identically marked had similar EM, independently of HA sources. The weight content, extinction coefficients (ECs), E4/E6 ratios have been studied for all HAFs. EC values and E4/E6 ratios increased as MS decreased within an individual HA sample. The weight content of high MS fraction was the highest in podzoluvisol and ferralsol and the smallest in phasozem and chernozem. On the other hand, chernozem and phasozem HAs contained considerably more of the lower MS fraction than HAs from the podzoluvisol and ferralsol. The knowledge of weight and optical differences between soil humic acids fractionated by coupling SEC-PAGE could be valued for explanation of some physico-chemical properties of soils and influence of soil genesis on humic matter properties.

Genetic characterization of naturally occurringRhizobium melilotipopulations and their potential to form effective symbioses with lucerne

Genetic characterization by Randomly Amplified Polymorphic DNA (RAPD) fingerprinting was employed to study the status of Rhizobium meliloti populations inhabiting nodules of lucerne. Rhizobium strains were isolated from nodules harvested from plants growing in inoculated or uninoculated experimental plots, uninoculated commercial fields and from lucerne grown in pots containing soils of different origin. Dry matter analyses were recorded and rhizobia were assessed for relative genetic diversity between treatments. Inoculated and uninoculated soils did not differ in terms of dry matter production, and lucerne grew, and was adequately nodulated, in soils with no history of lucerne cultivation. These findings, and the demonstration that there is a rich genetic diversity of Rh. meliloti in these soils, show that it is not always necessary to apply a standard commercial inoculant.

Red soils of different origins from southwest Nigeria: Characteristics, classification, and management considerations

Representative profiles of the Owena, Egbeda, Alagba, and Balogun series were studied. The Owena soil is formed in amphibolite whereas Egbeda and Balogun soils are formed in biotite gneiss derived parent materials. The Alagba soil is formed in sandstone parent rock. The main objectives were to characterize the soils and their clay fraction, and to classify and interpret soil properties for agricultural land use. Most soils exhibit 2.5 YR hues in subsurface horizons. A pedon formed in biotite gneiss has the highest dithionite Fe content and Fed/clay ratio. The relationships between clay content and Fed values vary according to parent material origin and, therefore, would have to be interpreted differently for soil weathering processes. Clay coatings were noticeable in some soil horizons of all pedons studied. Soils are generally medium to slightly acid with sandstone-derived soils being the most acid. The clay mineral suite in all soils is dominated by kaolinite with traces of 2:1 and 2:2 clay minerals, goethite, hematite, anatase, maghemite, and rutile. In addition, some soils contain trace amounts of gibbsite. Kandic horizons have been identified in all soils. The low charge properties of the soils reflect the intensely weathered clay mineral suite. The base status is probably influenced by the cropping system and therefore may tend to unnecessarily differentiate highly weathered soils at the order level. The Egbeda and Balogun series were classified as Rhodic Kandiudults, clayey-skeletal, oxidic and Rhodic Kandiudalfs, clayey-skeletal, oxidic, respectively. Others, Owena, and Alagba series, were classified as Typic Kanhaplohumults, clayey, oxidic and Rhodic Kanhaplustults, fine loamy or clayey, oxidic, respectively. In the FAO-Unesco legend, all soils become Rhodic Ferralsols. In addition, the Owena (with its nitic properties) is further classified as niti-rhodic Ferralsol. The two classification systems are at variance for highly weathered (variable charge property) soils and this difference will definitely influence management decisions depending on which system is used at any particular time. Soil attributes favorable for agricultural use include thick sola and favorable structures. Chemical properties suggest minimal fixation of phosphorus. Key words: Dithionite Fe, kandic, oxidic, variable charge, ferralic, exchangeable Al

Determination of arsenic in geological samples by HG AAS.

A continuous hydride generation (HG) AAS procedure for the determination of As in geological samples utilizing the SH-group containing amino-acid L-cysteine for the pre-reduction of As (V) to As (III) in HNO(3) has been optimized and compared with a method utilizing KI and ascorbic acid in HCl. The influence of some transition metals (Co, Fe, Ni) on the determination of As has been investigated. Decompositions of geological certified reference materials, sediments and soils of different origin and geochemical composition with concentrated HNO(3) have been performed in open and closed systems and the resulting As content has been compared with certified and proposed data.

Extractable chromium determination in soils by AAS

The lixiviation of trace metals from soils using selective extractants gives valuable information, especially for agricultural purposes. The two reagents validated by a group of European researchers coordinated by the Measurements and Testing Program (MAT) of the Commission of the European Community, in single extraction procedures, are EDTA 0.05 moll−1 and CH3COOH 0.43 moll−1. This paper reports the effect of these extractants upon chromium determination in extracts by AAS. Matrix effects were studied in extracts of two soils of different origin: a terra rossa soil from a Mediterranean area and a sewage amended soil. For the FAAS technique, the matrix effects were studied for air-acetylene and nitrous oxide-acetylene flames and using Cr(VI) and Cr(III) as standard solutions. The interfering effects observed are circumvented by the use of 1% 8-hydroxyquinoline as suppressor agent. For the ETAAS technique, charring and atomization curves were obtained for extracts in each reagent and after setting up the graphite furnace program, matrix effects were studied. Different matrix modifiers (Mg(NO3)2, Pd and Triton X-100) were also tested. Once the analytical method had been established, single extraction procedures were applied in the two soils, determining the percentage of extractable chromium in relation to the total content.

Anaerobic biodegradation of gasoline oxygenates in soils

ABSTRACT: This study evaluated the biodegradation of methyl tertiary butyl ether (MTBE), ethyl tertiary butyl ether (ETBE), and tertiary butyl alcohol (TBA)—three chemicals used as gasoline additives. The biodegradation under sulfate reducing, methanogenic and denitrifying conditions was measured in static soil and water microcosms using soils of different origin and varying characteristics. The results indicate that TBA was the easiest compound to biodegrade, whereas MTBE was the most recalcitrant. It is thought that cleavage of the ether bond in MTBE and ETBE is the first and rate‐limiting step in the degradation of these organics. TBA degradation was enhanced by nutrient addition in the nutrient poor soils but hindered by the presence of other easily‐degraded organic compounds. Degradation of MTBE and ETBE occurred only in the soil with the lowest organic matter content and with a pH around 5.5. No degradation of MTBE and ETBE was observed in the organic‐rich soils, and in the organically poor soil the addition of easily degradable organic compounds inhibited MTBE and ETBE degradation.

Chemical and physical characteristics of four soil types under conventional and no-tillage systems

This study was conducted to determine how soils of different origin respond to no-till practices, with emphasis on organic C accumulation and its subsequent effect on soil properties. Tillage experiments which had been running for between 5 and 15 years on four southeastern USA soils with textures of sandy loam, loam, silt, and sandy clay loam were utilized. Soil samples were collected from conventional and no-tillage treatments at depths of 0–2.5, 2.5–7.6, and 7.6–15.2 cm. No-tillage plots had higher bulk density, aggregate stability, organic C, exchangeable cations and acidity, cation exchange capacity, and extractable P, K, and Mn, but most of these properties were not significantly different ( P < 0.05) from those of conventional plots. Modulus of rupture and extractable Fe decreased in the no-till plots. Most of these changes, other than bulk density, occurred as a result of increases in organic C content, and the lack of more significant differences is attributed to inadequate residue production and/or its rapid decomposition in this relatively hot, moist climate.

Aluminium sulphate solubility in acid forest soils in Denmark

Ion leaching in 3 sandy spruce forest soils of different origin and pH was investigated in the laboratory. Zero-tension lysimeters containing undisturbed soil columns of varying soil depth were subjected to H2SO4 loadings for a period of 9 weeks. The analysis of the resulting leachate supports the hypothesis that Al-sulphate minerals may form in acidic soils when exposed to acid (H2SO4) deposition. In the B horizon of a glaciofluvial sandy soil (pH 4.2), both H+ and sulphate ions were retained to maintain 2pH + PSO4 = 11.9 in the leachate solutions. This relation between H+ and sulphate activity may be due to an adsorption mechanism or a precipitation mechanism. The precipitation mechanism is favored by the good fit of leachate composition to the conditions for jurbanite [AlOHSO4] formation from gibbsite [Al(OH)3]. In the B horizon of a sandy till at pH 3.7, the Al in soil solution (0.5 mmol L−1) was leached with sulphate. As the sulphate load was increased, some sulphate was retained. This may also be due to the dissolution and precipitation of an Al-sulphate mineral. The ion activity products of leachate solutions from the B horizon of this soil were close to the pKs reported for jurbanite. The conditions for the possible existence and/or formation of Al-sulphate minerals in acidic soils are discussed.

Extractability of Cobalt, Copper, Manganese and Zinc with Three Different Chemical Methods of Soils of Different Origin

Abstract The aqua regia extractant was more efficient than 0.5 N HNO3 or acid ammonium acetate-EDTA, pH 4.65 in extracting soils Co, Cu, Mn and Zn. The amounts of these elements extracted with 0.5 N HNO3 represented 12 to 16%, 22 to 59% and 20 to 39% of aqua regia extractable amounts in the studied groups of Egyptian, Finnish and German soils, respectively. These percentages for acid ammonium acetate-EDTA extractable amounts were for Co 5 to 9%, for Cu 15 to 43%, for Mn 11 to 26% and for Zn 4 to 29%.

Engineering Properties of Soil-Lime Mixes

The relation between sample preparation and curing procedures, and the engineering properties of compacted soil-lime mixes was investigated. Four natural Oklahoma soils of different origins were used in this study. The effects of variation of lime content, water content, and curing environment factors were evaluated on the basis of the strength, permeability, and pH of compacted specimens. It was found that the compressive strength increases with increasing lime content. Strength improvement was most conspicuous in the samples compacted at moisture contents above the optimum; the strength of samples compacted at lower moisture content could usually be improved by increasing the availability of water during curing. The soil pH appears to be an important factor controlling the soil strength, but its influence is better regulated by the lime-water ratio than by lime-soil ratio. The permeability of all soils was increased by the addition of lime, but the effect is reduced when water is sprinkled on the compacted lifts prior to curing.

Influences of textures of coherent soils of different origin on the interrelationship between physical properties and deformation characteristics : Rapoport SG In Russian. Figs. Univ. Moscow, Vestnik, Ser. Geol. V27, N1, 1972, P108–P114

Influences of textures of coherent soils of different origin on the interrelationship between physical properties and deformation characteristics : Rapoport SG In Russian. Figs. Univ. Moscow, Vestnik, Ser. Geol. V27, N1, 1972, P108–P114

Inorganic pH Dependent Cation Exchange Charge of Soils

AbstractSodium hydroxide titration curves were determined on H resin treated montmorillonite, untreated acid and neutral soils of different origins and on the same soils with an H resin treatment. The acid montmorillonite titration curve reveals four buffer ranges corresponding to hydronium ions (range I), monomelic trivalent aluminum ions Range II), and two pH dependent charge ranges. Untreated acid soils contained pH dependent buffer zones governed jointly by the organic fraction, the soil pH, the presence of monomeric trivalent aluminum, and the exchange blocking mechanisms of other cations. Following an H resin treatment, soils containing less than 2 per cent of organic matter exhibited a clearly defined third buffer range (Range III) from pH 5.5 to 7.6. The inflection points are masked in the pH dependent buffer range in soils containing more than 2 per cent organic matter. The presence of added aluminum increased the pH dependent charge in an acidified montmorillonite while added ferric iron slightly decreased it. The natural acid weathering processes in soils result in some blocking of pH dependent charge as in Dodge soil of Wisconsin (KCl pH 4.5). When greater acidity develops, a large pH dependent charge results, as in Coolville soil in Ohio (KCl pH 4.0), and the lime requirement of the soil thus increases greatly.

Antiphage activity of some actinomycetes

Of a total of 100 actinomycete strains isolated from soils of different origin, 65% contained substances with antiphage activity in their cultivation media, the effect being marked for more phage types in 12%. The results are compared with those obtained by other authors and the possibility of applying bacterial viruses as model organisms for the titration of antiviral chemotherapeutics is considered.

Investigations on Cambodian soils

Abstract Basic information on the nature of soils, their potentialities, and their limitations is necessary to evaluate Cambodian agriculture properly, and to develop a program for increasing food and other crops. Suitable information has, however, been limited, especially as there is not to be found in any report much data relating to soils of different origins over the whole country. There is, needless to say, some information on confined areas of Cambodia.

The infrared absorption spectra of soil components

Abstract In the preceding paper (1), the authors had determined the infrared absorption spectra of humic acids obtained from various soils of different origin, and concluded that they were, according to their infrared characteristics, classified into four groupes, i.e., A,B,Rp, and P types. After that, the authors conducted some experiments of the infrared spectra of soil components in order to get some information on the nature of so-called humin, and forms of soil clay and clay humus complex. The infrared spectra of silica, sesquioxides, clay minerals and humates of aluminium, iron and calcium were also determined for comparison. These experimental results will be given in this paper.

A contrast in the opal phytolith assemblages of two Victorian soils

A statistical analysis of the assemblages of opal phytoliths in two Victorian soils of different origin, occurring approximately 90 miles apart and supporting generally different plant communities, reveals that some shape types of the phytoliths are common to both soils, while significant differences occur in the amount and nature of other shape types. The general conclusion is that the phytoliths in soil from basaltic tuff on the summit of Mt. Gellibrand in the Western District derive from the local plant population; those in alluvial clay soil developed under swampy conditions at Dalmore, Koo-wee-rup Swamp, derive largely from the local swamp vegetation, with the possibility of the introduction of certain shape types from different plants supported on the southern Dandenong Ranges 18 miles to the north, and on intervening areas. Transportation into the swamp lands would have been effected by the watercourses flowing in from the north, once the phytoliths had been released from plants and shed into the soils near the watercourses. It is doubtful whether any significant proportion of the phytoliths was wind-borne into either of the soils examined.

Differentiation of the Vegetative and Sporogenous Phases of the Actinomycetes: 2. Factors affecting the Development of the Aerial Mycelium

SUMMARY: When first isolated on soil extract agar, soil actinomycetes consistently produce aerial spores in surface colonies. They retain this property when maintained in sterile soil, or when grown on washed suspensions of common soil bacteria, living or dead, in a water agar medium. In soil, when the composition, moisture content and temperature are kept constant, the initial stimulus towards the production of aerial mycelium is free access of air: the quantity and nature, vegetative or sporogenous, of the inoculum, and, within a broad range, the pH of the soil are of minor importance. Once growth is established, the next most important factor stimulating sporulation in the soil is also physical, namely dehydration. In natural and sterilized soils of different origins, and in a ‘Synthetic’ soil containing 250 p.p.m. of nitrogen as nitrate, the modes of growth of different actinomycetes strains are similar, and generally uncharacteristic of their species.

Rochas-mater da "terra roxa"

SUMMARY Physico-chemical and mineralogical studies of the of the Sao Paulo State by the Soil Division of The Agronomical Institute proved the existence of different in and its origin from basaltic rocks. The Brasilian denomination terra is already many times translated to which is inexact, because the colour roxa corresponds to violet in English. We must insist on the perfection of Brasilian expression, which gives the shortest and the best characteristic of the true soil, derived through the decomposition of basalts and diabases in the Sao Paulo State. The term originated much confusion, because there are in this state many soils of different origins, but the true soil is guite unique. The colour of this soil appears very beautifully on the clean fields above the diabase hills at the distance of some hundreds of meters. In the state of complete dryness the soil becomes coffee brown, but never gets a red colour. The soil is the best soil of South America, on the contrary the red soils, which are mostly lateriuc, are bad soils. Some exceptions, do exist, of course. The basalts produce laterites and other red of better qualities. With the purpose to contribute to the study of the and the red the present essay was made, describing the basic rocks of South-Brasil, as mother rocks of soils. The basic monograph of Djalma Guimaraes Magmatic Province of South-Brasil (5), many times mentioned in the petrographic literature, definitively established the prin­cipal types and the mineral-components of triassic basic rocks in South-Brasil. We have found some varieties of basic rocks, not yet known, but considered important for the question of and red soils. To soil science we consider of importance the discovery of acid melaphyres without labradors, which are essential for all other basaltic rocks, with exception of most basic and extreme types.