Parent material and chemical weathering in alpine soils on Mt. Mansfield,Vermont, USA

We compared the elemental composition of soil and bedrock samples to determine the extent of chemical weathering and the nature of the soil parent material in alpine soils on Vermont's highest summit. Previously it was unclear whether these soils formed through weathering of bedrock, glacial till, or eolian sediment, or solely through the accumulation of organic matter. In eighteen profiles, no evidence was found to indicate that soils have developed in glacial till, despite evidence that the mountain was completely inundated by the Laurentide Ice Sheet. In contrast, results strongly support the theory that pedogenesis in this environment involves in situ bedrock weathering under a thickening blanket of acidic organic litter. Weathering indices reveal an increase in weathering intensity upwards from the bedrock, and trends of normalized rare earth elements demonstrate a strong similarity between bedrock and soil samples. Leaching has concentrated less mobile elements such as Al, Cr, La, P, Pb, and Ti in soil horizons and removed mobile elements such as Co, Fe, K, Mg, Mn, Si, and Zn. X-ray diffraction reveals that chlorite, which is present in all bedrock samples and some saprolites, has weathered completely from upper soil horizons, and that hydrobiotite, vermiculite, kaolinite, gibbsite, and goethite have formed in the soil. Ratios of immobile elements (Ce, Cr, Nb, Ta, Ti, Y, and Zr) in soil and bedrock samples are, however, notably different. Furthermore, the moderately mobile trace elements Cu, Mo, and Sr are actually more abundant in soil than in bedrock, and soil concentrations of Zr are up to an order-of-magnitude greater than in bedrock samples. Together these data argue for at least a modest eolian influx, which may have arrived during the regression of Lake Vermont during the latest Pleistocene or from an outwash source in the immediate post-glacial period. Similarly, increased Ca and Na concentrations in soil samples may signify modern deposition of dust bearing Ca (from agricultural fields) and Na (from roads).     

Geochemical assessment,distribution, and dynamics of trace elements in urban agricultural soils under long‐term wastewater irrigation in Kano,northern Nigeria

A study was conducted to evaluate the distribution and origin of trace elements (Ti, Fe, Nb, Pb, Rb, Sr, Y, and Zr) in five representative long‐term wastewater‐irrigated urban vegetable gardens of Kano, Nigeria. Surface‐soil concentrations (0–15 cm) of Ti (4600–14 300 mg kg^–1), Fe (4000–31 800 mg kg^–1), Pb (96–355 mg kg^–1), and Y (33–98 mg kg^–1) were high compared to mean concentrations in comparable soils elsewhere. However, soil‐pollution assessment yielded no evidence of anthropogenic input of the trace elements studied. Indices such as the enrichment factor, the contamination factor, and the geoaccumulation index (I_geo) revealed little to no contamination with trace elements. The I_geo calculated for these metals varied across locations between 0.00 and 0.12 with Nb having the highest I_geo value. Similarly, the contamination factor was low for all metals with the exception of Fe reaching a contamination factor of 4.2 at one location. Geochemical‐balance evaluations showed depletion of all trace elements except for Fe which was 176% higher than in a natural uncultivated and unirrigated reference soil. Correlation and factor analyses showed that all determined trace elements likely originated from the same natural sources, which probably are the soil parent material and atmospheric depositions.     

Assessing parent material uniformity of a red and black soil complex in the landscapes

The distribution of red and black soil (Xeralfs–Xerolls) associations in the Monarto area (South Australia) is complex and their genesis either being derived from a uniform parent material or a lithologic discontinuity is not known. The objectives of this study were (i) to assess Zr- and Ti-bearing grains as minerals resistant to chemical weathering prior to employing Zr and Ti in determining parent material uniformity, and (ii) to confirm whether pedological processes or a lithologic discontinuity may be responsible for the textural contrast within the red and black soil profiles. Scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX) were used to study chemical weathering and elemental composition of surfaces of Zr- and Ti-bearing grains. X-ray fluorescence (XRF) analysis was used to determine elemental concentrations in various soil fractions. Results showed that Zr-bearing grains consisted of only zircon having smooth clean surfaces, which are characteristic of a mineral resistant to chemical weathering. EDAX spectra confirmed that Zr was a specific element to represent zircon, suggesting its reliability to be used in assessing parent material uniformity. On the other hand, Ti derived not only from minerals (rutile/anatase) resistant but also from minerals (ilmenite/pseudorutile, biotite) susceptible to chemical weathering. This limited the usefulness of Ti as an index mineral for soil development studies. Except for Zr:Ti ratio, all other indicators of parent material uniformity, i.e., depth distribution curves of Zr and Y in various fractions and Y:Zr ratio showed no considerable inflection and variation with depth in a Xeralf (red soil). This indicated the Xeralf derived from a uniform parent material (mica schists), thereby texture contrast within a profile is due to pedological processes. On the other hand, depth distribution curves showed clear inflection and variation in Xerolls (black soils), indicating soils developed from lithologic discontinuities, so different trends in particle size fractions between 0–48 cm for MA5 and 0–59 cm for MA3 profiles compared to the underlying layers are due to parent material differences and not pedogenesis. The presence of complex red and black soil association in the landscape is attributed to the difference in parent materials, where the red soil developed from mica schist and the black soils from calcareous deposits.     

Characteristics of non-allophanic Andisols derived from low-activity clay regoliths in the Nilgiri Hills (Southern India)

Low‐activity clay soils on old planation surfaces of the tropics are generally considered as stable end points of soil formation. It is therefore surprising to find Andisols on them. We characterized the properties of six profiles representative of these soils in the western part of the Nilgiri Hills (2000–2500 m above mean sea level), Southern India, where the present climatic conditions are cool (mean annual temperature 15°C) and humid (mean annual rainfall 2500 mm). Thick (50–80 cm) dark‐reddish brown topsoil overlies strongly desilicated yellowish‐red materials. This horizon has andic properties to a sufficient depth and the carbon content requirement of the melanic epipedon to place these soils in the Andisol order. Our data as well as the history of the Nilgiri Hills suggest that the formation of these non‐allophanic Andisols resulted from the succession of two main steps. First, a ‘lateritic’ weathering cycle led to the relative accumulation of secondary Al and Fe oxides. Later, the accumulation of organic matter favoured by a more recent climatic change induced complexation by organic acids of Al and Fe oxides, and the production of enough metal–humus complexes to give rise to andic properties. Such soils, in which secondary Al and Fe oxides, generally considered as indicators of an advanced weathering stage, are involved in a new cycle of soil formation, are original Andisols.     

南极Fildes半岛成土过程中主要元素的行为

Nine horizon samples of three soil profiles representative of Dystri-gelic Cambisol, Fibri-gelic Histosol and Relic Ornithosol were taken from Fildes Peninsula of King George Island, South Shetland Islands to quantitatively demonstrate the enrichment, migration and loss of the elements (Si, Al, Fe, Ca, Mg, Mn, K, Na and P) in soil horizons and their behaviour within profiles by application of the enrichment coefficient calculated in terms of the abundance of Ti. Six horizon samples of 4 other profiles randomly taken from the studied area were examined for calculation of the redistributing enrichment coefficient, which was applied for a better understanding of the element redistribution between soil and clay fraction along with soil development. The results showed that the enrichment, migration and redistribution of the elements varied strongly among the investigated soils and horizons, due to the differences of weathering degrees and moisture status, influences of sea bird activities, etc.     

Effects of cement production on the elemental composition of soils in the neighborhood of two cement factories

The effects of cement production on the elemental composition of soils in the neighborhood of two cement factories in Nigeria have been investigated using the XRF and PIXE/RBS techniques. The concentration of 21 elements viz:-Mg, Al, Si, P, S, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Sr, Pb, As, Zr, Rb and Br, were determined in about 30 samples. Calcium, P, S, Cr, Ni, Cu and Zn, were found to be relatively enriched in the soils of the cement factory premises. Calcium, a cement marker element, was found to be well correlated with Mg, S, Fe, Ni and Cu in the soils, and inversely proportional to the Si and Ti concentrations. From Ca/Si ratios and enrichment factors of the marker elements, it was found that soil contamination due to cement drops sharply with distance from the factories, and with increasing depth from the surface.     

湖南张家界典型植烟土壤地球化学特征研究

为了研究张家界山地植烟区域土壤的成土环境及地球化学元素的丰缺状况和迁移富集规律,为烟区优质特色烟叶的生产和布局提供科学依据,本文采集23个长期耕种的典型植烟土壤剖面样品,测定分析了25种地球化学元素(氧化物)的含量,并对土壤的风化发育状况和元素(氧化物)的迁移富集特征进行了研究。结果表明,张家界烟区主要成土母质如石灰岩、板页岩、紫色砂页岩风化物均受到了较强的风化作用,化学风化指数(CIA)介于73.19～88.03之间,总体上土壤具有Ca、Na贫乏而Fe、Al相对富集的化学组成特征。其中紫色砂页岩风化物发育形成的紫色土的风化作用较强,土壤的淋溶作用较强;石灰岩风化物发育形成的土壤富铝化程度较低。黄壤、水稻土、紫色土中地球化学元素多数表现出一定的富集特征,大量有益营养元素的富集对于提高烟叶产量具有重要作用。土壤剖面淋溶层中元素(氧化物)P、B、Se、Mn、Zn、Cu、Ni、Y、Sc、La、Fe2O3、SiO2的含量均高于中国或世界土壤元素(氧化物)中值(均值),而N、S、Cl、Mo、Co、Sr、Br、I、CaO、MgO、K2O、Na2O、Al2O3的含量偏低,其中元素(氧化物)N、P、S、Mo、Se、Mn、Zn、Br、I、CaO、MgO在土壤剖面中的含量变化较大。通过对元素(氧化物)富集系数的聚类分析,将元素(氧化物)分为3类:呈较强富集特征的元素N、P、S、Se;呈较强迁移特征的元素(氧化物)Br、I、Mn、CaO;变化较稳定的其他元素。微量元素B、Zn、Cu和稀土元素Y、Sc、La含量较丰富且变化相对稳定,表明除了常量元素N、P、S以外,微量元素Se、B、Zn、Cu和稀土元素Y、Sc、La可能是影响张家界烟区烤烟品质的重要特征元素。     

Surface Soil Geochemistry for Environmental Assessment in Kavala Area, Northern Greece

The aim of the present study was to estimate the geochemical background and anomaly threshold values of the surface soils in Kavala, northern Greece. In order to reach this goal, a simple and practical procedure was applied. This procedure included the extraction of 42 major and trace elements by analytical grade HNO₃ from 65 surface soil samples, analysis by inductively coupled plasma?Coptical emission spectrometry and inductively coupled plasma?Cmass spectrometry, the distribution of the elemental data displayed on probability graphs (Q-Q plots), and the visualization of the results spatially by GIS software. The results indicated that natural factors mostly influence the elevated concentrations of Al, Ca, Fe, K, Mg, Si, B, Ba, Ce, Ga, Ge, La, Li, Mn Rb, Sb, Se, Sn, Sr, Y, and Zr, while anthropogenic activities mostly influence the elevated concentrations of Ag, As, Cd, Co, Cr, Cs, Cu, Hg, Mo, Ni, Pb, Th, Ti, U, V, W, and Zn. Nevertheless, almost all the elements determined showed their elevated concentrations inside the industrial part of Kavala area, which implies that the anthropogenic activities taking place in the study area, influence importantly the spatial distribution of the elements. The methodology followed in this research seems to be an adequate alternative for soil environmental studies.     

海南岛北部玄武岩区土壤母质均一性及相对年龄判定

【目的】时间序列法是定量研究土壤发生过程、演变速率及其变化阈值的重要手段,构建可靠的土壤时间序列需对土壤母质均一性和相对年龄进行判定。【方法】以海南岛北部不同喷发期玄武岩发育土壤所构成的成土时间序列（0.09、0.146、0.64、1.12、1.81、2.30 Ma B. P.）为对象,利用各种土壤属性参数（包括剖面形态、颗粒组成、稳定元素含量、风化发育指数和元素变化率等）对该时间序列母质均一性和土壤相对年龄进行判定。【结果】各剖面颜色、质地、结构等形态总体呈均一、渐变的特征,去除黏粒后的粗粉粒含量、稳定元素Ti/Zr比值在剖面内和剖面间变化均较小,表明时间序列土壤的起源母质相同。随着成土年龄的增加,黏粒含量和剖面发育指数呈线性增加的趋势,土壤风化强度指标（B指数、CIW指数、CIA指数和ba值）服从对数函数变化规律,在土壤相对年龄的判定中具有较好的指示意义。【结论】研究区土壤母质来源相同,土壤相对年龄可通过相关土壤属性体现出来,为定量研究土壤发生阈值奠定了基础。     

Element enrichment and migration within some soils on Fildes Peninsula (King George Island), the maritime Antarctic

Three soil profiles (Dystri‐gelic Cambisol, Fibri‐gelic Histosol, Relic Ornithosol) sampled from Fildes Peninsula of King George Island, Antarctica, were involved in this study to quantitatively demonstrate the enrichment, migration, loss of the elements Si, Al, Fe, Ca, Mg, Mn, K, Na, and P in soil horizons and their behaviors within profiles by introduction and application of the enrichment coefficient (calculated in relation to the abundance of Ti). Additionally, six other soil horizon samples taken randomly from the study area were examined for calculation of the redistributing enrichment coefficient: These coefficients were applied here for a better understanding of the element redistribution between soil and clay fraction along with soil development. The results show that the enrichment, migration and redistribution of the elements vary strongly amongst the investigated soils and horizons, due to the differences of weathering degrees, moisture status, and influences of sea bird activities etc.     

Effect of Long-term Fertilizer Application on the Concentration and Solubility of Major and Trace Elements in a Cultivated Andisol

The concentrations and solubility of major and trace elements in soils collected from a field for long-term experiments maintained for more than 60 years and the neighboring area were investigated in order to reveal the influence of soil management on their behavior in soils. No obvious differences in the element concentrations in soils were observed except for P and U, whose concentrations were elevated in the surface soils of the experimented field because of the long-term application of phosphate fertilizers. Soil acidification associated with the successive applications of potentially acid fertilizers had changed the solubility of many elements as follows: the solubility of Li, Be, Al, Mn, Co, Zn, Y, Cd, Ba and rare earth elements increased, while the solubility of P, As, Se, Nb, Sb, Mo and V increased by liming. In the uncultivated soils, the concentrations of Fe, Zr, Nb, Hf and Th in the water extracts were relatively high, and a certain amount of these elements in the water extracts may occur in colloidal forms.     

Genetic features of soils on sorted sand deposits of different origins in the Kola Peninsula

Differences in the chemical composition of soils developed from sorted sands of different origins are revealed. The iron-illuvial podzols on rich glaciofluvial and marine sands are characterized by well-pronounced Al-Fe-humus differentiation of the Si, Al, and Fe in the soil profile. These soils are relatively similar in their bulk elemental composition. The difference between them is seen in the degree of differentiation of the soil profiles; it is stronger in the soils developed from glaciofluvial deposits. This is particularly true with respect to the oxalate-soluble iron and aluminum hydroxides. The deposits derived from the red-colored Tersk sandstone and processed by the sea (in the coastal zone of the White Sea) have the poorest chemical composition. In the soils developed from them, the differentiation of oxalate-soluble compounds is slightly pronounced (for Fe) or completely absent (for Si and Al). These soils can be classified as podzolized ferruginous red-colored psammozems (within the order of poorly developed soils) with the following horizons: O-Ce-Cf-C. The Ce horizon has the features of podzolization, and the Cf horizon has some features attesting to the illuvial accumulation of Fe. The profile of these soils inherits a reddish tint from the parent material.     

Changes in element concentrations during Andosol formation on tephra in Japan

Andosol formation involves the rapid, abundant and in situ formation of non‐crystalline materials from tephra deposits. A large amount of humus complexed with Al also accumulates in the A horizons. As these materials are rich in Al or Fe compared to the parent tephra, the concentrations of the major and minor elements change significantly during Andosol formation. The objectives of this study were to examine how the rock type of the tephra and its weight loss during the formation process affect the changes in the element concentrations of Andosols. A total of 95 samples with different rock types from 18 pedons of Andosols in Japan were used to determine the total concentrations of 54 elements. Principal component analysis suggested that the degree of weathering and the rock types of parent tephra are the important factors in the variation of the element concentrations in Andosols. Three rock types, dacitic, andesitic and basaltic‐andesitic, were identified from the V and Zn contents of ferromagnetic minerals separated from the Andosol samples. Basaltic Andosols were identified from the abundant coloured volcanic glass and olivine in the sand fraction. Regarding concentrations of 41 elements, at least one group based on rock type was significantly different from one to three other groups at the P= 0.05 level. The content of oxalate‐extractable Si (Si_o), Al (Al_o) and Fe (Fe_o) was used as an index to show the extent of Andosol development. Relatively strong correlations between the element concentrations and Si_o, Al_o and Fe_o as well as other weathering indices were found in the andesitic samples. Among these elements, at least 27 (Be, Al, Ti, Fe, Y, Zr, Nb, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, Tl, Pb, Th and U) were enriched in the Andosols and the increases in these concentrations were related to total weight loss due to soil formation processes.     

Genesis and dynamics of an oxic dystrochrept and a typic haploperox from ultrabasic rock in the tropical rain forest climate of south-east Brazil

Oxisols are a product of long and intense weathering. Their actual characteristics can neither be traced back to a certain climatic period, nor do they reveal the present soil-forming factors. In this paper, therefore, a reconstruction of the soil genesis of a strongly weathered Oxisol is attempted by comparing the present mineralogical status and the recent dynamics of selected elements with a nearby Inceptisol from the same catena. The parent rock of both soils is serpentinized dunite with nepheline-syenitic veins; the soil moisture regime is udic. Chemical and mineralogical parameters, as well as the concentration of elements in the soil solution of a Typic Haploperox and an Oxic Dystrochrept from the same catena were analyzed for one year. The dynamics of Si and Mg strongly depended on the state of weathering. In the saprolite of the Dystrochrept, Si is partially removed and partially fixed by the formation of quartz and mixed layer minerals. Mg is first fixed in mixed layer minerals, but is during consecutive weathering leached from the transition zone from saprolite to the oxic horizon. Due to the high redox potential, Fe is not soluble, forming goethite in the upper part of the saprolite. Al is also not removed and is finally fixed in kaolinite. In the weathered upper part of both profiles the concentration of Al, Si, Mg and Fe in the soil solution is too low to perceive a further weathering. The present dynamics of Fe, Al, Mg and Si and the mineralogical status of the Dystrochrept indicate that these processes are similar to those that have led to the formation of the Haploperox. The soils, therefore, developed exclusively by the relative enrichment of Al and Fe, the partial loss of Si and the almost complete loss of Mg. Desilification and ‘laterisation’ are hence processes occurring also presently under a tropical rain forest climate.     

Some properties of a chrono-toposequence of soils from granite in New Zealand, 1. profile weights and general composition

A chrono-toposequence of five soils formed in strongly weathered granite in the South Island of New Zealand was described on the basis of soil profile morphology, landscape position, and the degree of weathering of the underlying granite. The sequence contains five progressively younger soils on increasing slopes from crest to backslope formed in a Parent Material of originally uniform mineralogical and chemical composition as Parent Rock under a uniform climate and vegetation. All profiles of the sequence are strongly weathered and leached with the final member of the sequence being considered to represent a terminal steady-state system.Changes in a number of chemical and physical soil properties were described with the increasing soil development (i.e. increasing weathering and leaching) represented in the sequence profiles. Profile soil weights (< 2mm) remained approximately constant, once weathering of stone material (> 2 mm) to fines was completed. An initial increase in profile silt and clay content was followed by a decline in both fractions with a corresponding increase in the sand fraction. Proportions of kaolin/metahalloysite initially increased and 2:1–2:2 Al intergrades decreased, but the final three sequence profiles had similar clay mineralogies with kaolin/metahalloysite being the main component. Profile weights of oxidisable carbon and total nitrogen followed an exponential decline after an initial increase between the first two sequence profiles. Profile cation-exchange capacity, total exchangeable bases, percent base saturation, and exchangeable cations showed no trends with increasing soil development. Depth-gradients of these parameters together with oxidisable carbon and total nitrogen became less pronounced, with the apparent tendency towards a steady-state system in the final sequence profile. Multiple regression analysis indicated that oxidisable carbon was the main contributing factor to cation-exchange capacity followed by clay content.Profile weights of total calcium and potassium were closely correlated and showed an approximately exponential decline with increasing soil development, whereas total magnesium showed a relatively linear decline. Total aluminium and iron both showed an initial increase and then declined. The relative rates of loss of the five total elements studied were in the order: Ca > Mg > K, Fe > Al.     

典型土垫旱耕人为土主要常量元素的迁移富集特征、成因及其意义

土壤中元素含量的分布特征反映了多个成土因素综合作用下土壤演变过程的结果。研究在黄土高原区关中平原西部地区采集两个典型的土垫旱耕人为土剖面,研究常量元素K、Na、Ca、Mg、P、Fe、Al、Ti的分布特征及其成因。结果表明,土垫旱耕人为土剖面中,K、Fe、Al、Ti呈中高型分布,Ca、P、Na、Mg呈中低型分布。各元素的迁移能力表现为:Ca最强,P、Na、Mg、K次之,Fe、Al、Ti比较稳定。Ca、P、Na、Mg在剖面上的中低型分布主要是由自然环境下元素自身的淋溶迁移引起;稳定元素Fe、Al、Ti和弱迁移元素K在黏化B层(2Bt1层、2Bt2层)和干润淋溶土表层(2A层)的峰值则主要是由于暖湿气候条件下碳酸盐的强烈淋溶而呈现的相对富集。研究表明,关中地区典型土垫旱耕人为土元素地球化学特征的形成主要受控于气候的变化,人为作用的影响主要体现在有机碳和磷等养分元素在表层的富集上。     

Baseline element concentrations in soils and plants,Wattenmeer National Park,North and East Frisian Islands,Federal Republic of Germany

Baseline element concentrations are given for dune grass (Ammophilia arenaria), willow (Salix repens), moss (Hylocomium splendens) and associated surface soils. Baseline and variability data for pH, ash, Al, As, Ba, C, Ca, Cd, Ce, Co, Cr, Cu, Fe, Hg, K, La, Li, Mg, Mn, Na, Nb, Nd, Ni, P, Pb, S, Sc, Se, Sr, Th, Ti, V, Y, Yb, and Zn are reported; however, not all variables are reported for all media because, in some media, certain elements were below the analytical detection limit. Spatial variation in element concentration between five Frisian Islands are given for each of the sample media. In general, only a few elements in each media showed statistically significant differences between the islands sampled. The measured concentrations in all sample media exhibited ranges that cannot be attributed to anthropogenic additions of trace elements, with the possible exception of Hg and Pb in surface soils.     

辽东山地冰缘地貌上覆土壤粒度及元素地球化学

对辽东山地典型冰缘地貌上覆土壤的粒度、常微量化学元素进行测试分析,结果表明:土壤颗粒组成包括黏粒20.79%、粉粒69.54%和砂粒9.67%,平均粒径整体偏细,约为6.45Ф,不同土壤类型、地貌类型及坡向的粒度分布存在一定差异。土壤元素化学组成以SiO₂（45.60%）,Al₂ O₃（12.90%）,Fe₂O₃（3.90%）,K₂O （2.17%）为主,最大比例可达73.36%。元素Ca,Na,P,Sr显著淋溶,而Mn,Ti,Cu,Zn则相对富集,其他元素迁移不甚明显。少数元素还表现出与粒度分布存在显著关联,其中K,Na,Sr,Ba多存在于砂质土壤中,而元素Ti则容易在粒度更细致的黏土颗粒中留存。化学风化指数CIA均值约为65.50,Rb/Sr约为0.70,反映风化程度较低,且长期经历干冷气候,A—CN—K三角模型表明,研究区土壤风化以脱钙钠、富铝为主,风化水平尚处于低等风化阶段中后期。