Range Of Parent Materials Research Articles

Allochthonous material originating from saprolite as a marker of termite activity in Ferralsols

Ferralsols, which are estimated to cover 7.5 millions km2 worldwide, are deeply weathered red or yellow soils found in the humid tropics. They are considered as the end of a geochemical sequence of weathering and are dominated by low-activity clay and sesquioxides. Their physical properties are closely related to their strong submillimetric granular structure. We aimed to characterize the 2:1 clay minerals identified in many Ferralsols and to discuss them as a marker of soil-feeding termite activity in Ferralsols. We present results recorded with Brazilian Ferralsols developed under Cerrado native vegetation on a range of parent materials. It was found that the 2:1 minerals vary from weakly weathered muscovite to hydroxy-Al interlayered vermiculite, sometimes associated to a fine material with a chemical composition highly different from that of the groundmass of the surrounding submillimetric granular aggregates. Results show that both 2:1 minerals and the associated fine material have to be considered as allochthonous material originating from the saprolite and were brought to the Ferralsol by soil-feeding termite activity. This confirms the major role of termites in the properties of Ferralsols and raises questions about the possible consequences of land use change which usually deeply affects soil biodiversity.

Use of magnetic susceptibility to assess metals concentration in soils developed on a range of parent materials

This research was conducted to evaluate the utilization of magnetic susceptibility measurements in the assessment of metal concentrations in soils developed on a range of parent materials in northwestern Iran. Eighty surface soil samples were collected from eight parent rocks including ultrabasic rocks, basalt, andesite, granite, marl, limestone, Qom formation, and shale. The collected samples were assessed to determine magnetic susceptibility at low frequency (χlf) and concentrations of some metals comprising chromium (Cr), iron (Fe), copper (Cu), nickel (Ni), zinc (Zn), cobalt (Co), and manganese (Mn). The results showed that the highest levels of metals and χlf were observed in basic and ultrabasic soils. Strong positive correlations (P < 0.01) detected between χlf and Fe (0.87), Mn (0.78), Zn (0.74), Ni (0.90), Co (0.78), and Cr (0.90) in all samples indicated a potential for using magnetic susceptibility in semi-quantitative estimation of metal concentrations in soils of natural ecosystems. Multiple linear regression between metal contents and χlf showed that Ni, Zn, Mn, and Co could explain 77% of the total variance in χlf in the study area. K-means cluster analysis categorized the studied soils into three groups based on metals and χlf variability. Clustering of soils based on their parent rocks and use of further magnetic measures, i.e., saturation isothermal remanent magnetization (SIRM), isothermal remanent magnetization (IRM100mT) and natural remanent magnetization (NRM) are expected to improve the accuracy of metal concentration predictions in natural soils of the study area.

Major Elements in Soils Along a 2.8–km Altitudinal Gradient on the Tibetan Plateau, China

There are a series of special mountain soils on the Tibetan Plateau of China in an alpine environment for the high altitude. However, very few studies have focused on major soil elements in relation to soil formation in this area. Aluminum (Al), iron (Fe), calcium (Ca), sodium (Na), potassium (K) and magnesium (Mg) contents of 237 topsoil samples covering a 2.8-km altitudinal gradient in uncultivated areas along the Qinghai-Tibet Railway of China were measured using inductively coupled plasma atomic emission spectroscopy. The spatial distribution of the elements and its relationship to the parent rocks and climatic parameters were analyzed. Soils along the gradient are derived from a range of parent materials, but most are less than 30 cm deep with little development (Cambisols). Soil Al, Fe and Mg contents showed a decreasing trend from the start station (Xining Station) to end station (Lhasa Station) of the Qinghai-Tibet Railway, whereas soil K and Na contents were relative stable from Xining Station to the Kunlun Mountains and then increased gradually. Soil Ca content was lower in the southern part of the Tanggula Mountains. The major soil element contents clearly reflected the parent rock and climatic influences. Soils with higher Ca content appeared in areas with Ca-Mg carbonate rocks, soils with higher Al were found in areas with silicate-rich and high-Al silicate clastic rocks and silicate-rich aluminosilicate loose sediments. Soils with higher K and Na contents appeared in areas with high-K, high-Na and silicate-rich aluminosilicate rocks. Soil Na and K contents were affected by temperature, whereas the contents of Mg, Fe, Ca and Al were more affected by precipitation. Soil Na and K contents increased with increasing temperatures, whereas the contents of Mg, Fe, Ca and Al decreased with increasing precipitation. This analysis provides a relationship between soil properties and rapidly changing environmental conditions. The data can be used to investigate the effect of the climate or land use change on soil properties.

Mineralogy and ion exchange properties of the particle size fractions of some Brazilian soils in tropical humid areas

The inorganic fractions of 25 samples from 12 representative Brazilian soils were separated into six subfractions (clay, silt, very fine sand, fine sand, medium sand, coarse+very coarse sand) and their effective cation and effective anion exchange capacity (ECEC and EAEC, respectively) evaluated by the compulsive exchange method using unbuffered BaCl 2 solution. The soils had developed from a range of parent material, such as sandstones, Tertiary unconsolidated sediments, siltstones, silty shales, basalts, metapelites and mica schists. The silt fraction of sandstone-derived soils had an ECEC of at most 2 mmol c kg −1 while the silt fraction of basaltic soils had ECEC which reached 106 mmol c kg −1. The silt fraction of the soil derived from mica schists had an EAEC of 9 mmol c kg −1, which was the highest of all the soils analyzed. The highest ECEC recorded was close to 300 mmol c kg −1 for the fine sand fraction of soil derived from silty shales. Sand fractions from Tertiary unconsolidated sediments were practically inert, while those from sandstones made only a small contribution to the effective exchange capacity. The origin of these differences may lie in the characteristics of the parent materials of the soils. Primary micas, illite and feldspars together with inactive quartz were the major components of the coarse fractions of the soils. We attributed the high ECEC of the coarse fractions to several factors, including feldspars and mica being subjected to intense weathering, accelerated cation release from the mineral structure, and silt and sand-sized clay mineral pseudo-aggregates. In highly weathered tropical soils, the coarse fractions can play an important role in active soil fertility because they are not chemically inert and in potential fertility because of their importance as reservoirs of nutrients.

Lithological factors affecting magnetic susceptibility of subtropical soils, Zhejiang Province, China

Magnetic susceptibility ( χ) was measured on subtropical soils formed on a range of parent materials in Zhejiang Province, China, to demonstrate the influence of parent material lithologies on the amount and vertical distribution of χ in the soils. We found that the χ values of soils vary by up to two orders of magnitude with their parent material lithologies. Soils formed on igneous rocks with high χ values showed high absolute χ and distinctly decreased χ compared with χ values of parent materials. The χ values of soils formed on basalt, andesite and granodiorite were >250×10 −8 m 3 kg −1. The χ values of soils formed on granite, and other neutral and acid igneous rocks ranged from 50×10 −8 to 120×10 −8 m 3 kg −1. In most of the soils formed on sedimentary rocks, χ enhancement in upper horizons of soils was found compared with parent material χ. This enhancement was believed to be pedogenic formation of superparamagnetic (SP)–stable single domain (SSD) magnetic grains, which are characterized by high values of frequency dependent susceptibility ( χ fd) and anhysteretic remanent magnetization (ARM). Soils formed on sedimentary rocks with a very low initial χ and iron content showed a low χ value throughout the profile. It was found that there is a highly significant relationship between the χ values of soils and their dithionite–citrate–bicarbonate solution (DCB) soluble iron contents (Fe d). The χ values of soils in chronosequences formed on alluvium and two marine deposits increased as soils became older. It is suggested that the χ values can be used as a tool for determining the relative age in chronosequence studies.

Origin of quartz in selected soils and sediments, North Island, New Zealand

Abstract Quartz from two marine shales has δ18O values indicative of low-temperature crystallisation. In a Mangakahia Group shale, the lowtemperature quartz is confined to the silt fraction and is a result of diagenesis; in the Whangai Shale, it occurs as clastic chert in a range of grain sizes. Quartz in soils formed from andesitic and basaltic parent materials is of eolian rather than pedogenic origin. However, quartz in the sand fractions of soils formed from a range of parent materials, including volcanic, has a δI8O value indicative of high-temperature formation and was probably a component of rhyolitic tephras from central North Island. Similar δ18O values for quartz in beach sands from the west coast of Northland indicate a predominantly rhyolitic source, and higher δ18O values of quartz in east coast beach sands indicates the presence of additional locally derived sediment. Only one example of low-temperature quartz was found in the soils investigated but this was found to be of eolian origin. Qua...

Characteristics of soil and productivity of Pinus radiata (D Don) in New South Wales .II. Pedogenesis on a range of parent materials

Soil profile descriptions were made at a series of 11-year-old unfertilized Pinus radiata stands in the Lithgow district of New South Wales. Catenas within three soil parent materials were selected to compare variation in soil physical and morphological properties with growth of P. radiata. These parent materials were a Silurian siltstone, a Permian conglomerate and a Silurian-Devonian rhyolite. Basal area growth of the P. radiata stands increased down catenas on the Silurian siltstone as soil depth to a root impeding layer increased. Plateau soils on the Permian conglomerate had hardsetting surfaces and high gravel contents, and were associated with very poor pine growth. By way of contrast, lower slope, colluvial gradational earths were deep, fine-textured soils and supported more productive pine stands. The Silurian-Devonian rhyolite parent material produced highly leached soils, commonly with conspicuously bleached A2 horizons and poor sandy textures of surface soil. Both physical and chemical features of the rhyolite interacted with pedological processes to affect adversely soil physical conditions and trace element availability, in particular boron. The poorer P. radiata growth on lower or concave slope in comparison with upper slope position was a result of increased soil leaching and horizon differentiation. This pattern contrasted with improved pine growth on the deeper soils on lower slopes on the two sedimentary parent materials. These case studies emphasize the importance of geology and pedological processes when evaluating the applicability of specific soil physical factors to site classification for P. radiata plantations.

MINERALOGY OF SURFACE SOIL SAMPLES OF SOME QUEBEC SOILS WITH REFERENCE TO K STATUS

Surface samples of five Quebec soils (St. Bernard, Ormstown, Howick, Dalhousie and Bearbrook) were selected to represent typical agricultural soils with a range of parent material. Soil minerals were fractionated by size into five separates and examined using X-ray diffraction (XRD) techniques and chemical analyses. In nearly all cases the non-clay separates (250–2.0 μm) contained feldspars, amphiboles and quartz as dominant minerals with only small amounts of layer silicates. Feldspars, amphiboles and quartz were also relatively abundant in the clay separates. The layer silicates in the clay separates consisted mainly of mica, chlorite and vermiculite. The soils had similar mineral suites, considered indicative of a low degree of weathering. Considering the mineral composition and the low degree of weathering, it is proposed that primary K-bearing minerals, including K-feldspars, are important sources of K in these soils. Key words: K release, particle size, soil mineralogy

Forms of phosphorus in some Greek forest soils

Abstract The concentration and distribution of organic P and of the inorganic P fractions of Al, Fe and Ca were determined in forest soils derived from a range of parent materials and developed in different bioclimatic zones. Organic P was significantly correlated (r=0.61) with soil organic matter, and in the top soil, it constituted between 7 and 63% of total P, depending on the origin of soil parent material. Similarly, the concentrations of Al‐, Fe‐ and Ca‐P, ranged from 20 to 60% of total P, and in the topsoil increased from locations on the Mediterranean to the Pseudoalpine zone i.e. with increasing precipitation. The concentration of Al‐P was always lower than Fe‐ and Ca‐P. The concentration of Fe‐P increased and the corresponding cocentration of Ca‐P decreased with decreasing soil pH and increasing age of the geological formations from which soil parent materials are presumed to have been produced by weathering.

Chemical composition of soil vermiculite clays as related to their genesis

Chemical and mineralogical analyses of the clay fraction of eleven soils containing a large amount of vermiculite clay and representing a wide range of parent materials revealed that two types of vermiculite clays exist: (1) An aluminous type in which Al3+ substitutes for Si4+ in tetrahedral positions in the same order of magnitude as in the coarse grained vermiculites and micas, and with Al3+ as the dominant octahedral ion. (2) A silicious type in which only Si4+ occupies the tetrahedral positions, and with Fe3+ and Mg2+ as the dominant octahedral ions. The aluminous vermiculite clay was found to occur in soils derived from acid igneous rocks and is usally associated with mica, whereas the silicious type was found to occur in soils derived from basic igneous rocks which do not contain mica. Because of this close association of these two types to their parent material, it was concluded that the aluminous vermiculite is a product of alteration of mica whereas the silicious type is a product of synthesis from primary oxides of silica, alumina, iron, and magnesium. Both types of vermiculite clays tend to be dioctahedral in contrast to the trioctahedral nature of the coarse-grained vermiculite.

Population Regulation of Eschscholzia Californica by Competition and Edaphic Conditions

Eschscholzia californica Cham., the California poppy, occurs naturally in western North America from the Columbia River south to Baja California and from the coast of California eastward into the Great Basin. Within this extensive region it grows in open sites, frequently associated with grasses. Both the poppy and the grasses require ample light for optimal development and begin growth contemporaneously after the advent of winter rains. In dry years, when grass develops poorly, poppies apparently do well; in wet years the reverse is true. The poppy grows on well-drained soils of dunes, alluvial fans, river terraces, steep banks, and rocky places. These soils may be derived from a wide range of parent materials, including serpentine. It has also been observed to colonize burned-over areas and endure on them for a number of years (Bowerman 1944). The poppy has behaved as a benign weed under conditions created by man. Small populations arise atop gravel piles, in gravelly ballast of railroads, or on road cuts and other areas where the established vegetation has been destroyed by excavation. Occasionally poppies may be seen in grain fields, where their growth is apparently favoured by mowing the overtopping grain. Although the plants themselves are cut back, new shoots emerge from ground level and flower from mid-summer to autumn. These observations suggested the following hypotheses: (1) Genetic adaptation to specific soil type is involved in the poppy's adaptation to a broad range of soil types. Such response has been reported for other herbaceous species (Kruckeberg 1951; Jowett 1958, 1959; Bradshaw & Snaydon 1959; Bradshaw 1960). (2) Growth of associated grass is antagonistic to Eschscholzia. (3) Eschscholzia cannot tolerate soils with high water content but can become established on porous soils high above the water table. These hypotheses were tested experimentally at the Botanical Garden of the University of California at Berkeley during 1959 and 1960.