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1.
The potassium (K) content of soils developed from Pleistocene calcareous till, glacial sand and loess in NW Germany was investigated in order to characterize stores of K in feldspars (Kfeldspar) and mica/illite (Kmica/illite) as well as changes as a function of soil depth. From each horizon, up to seven sand, six silt and three clay fractions were separated. Kfeldspar and Kmica/illite were quantified by means of chemical composition and estimation by IR‐spectroscopy. On account of distinct differences in mineralogical composition between different particle size fractions, K‐content of the bulk soil < 2000 μm and the proportion of Kmica/illite and Kfeldspar are clearly related to grain size distribution of the sample. Generally, the K‐content of particle size fractions of a soil derived from calcareous till is significantly higher than that of a soil from glacial sands. Kmica/illite of clay and silt fractions increases with depth, reflecting greater mica/illite weathering at the soil surface, whereas Kfeldspar shows no noticeable change. Illite accumulates by lessivage in Bt horizons. On a whole‐soil basis, the Bt horizons of Luvisols derived from loess and calcareous till contain more Kmica/illite than either the A or the C horizons. By comparing the K‐content in the different particle size fractions with soil depth, the highest rate of change is found for soils derived from glacial sand. Gains in K in the silt fractions of soils from calcareous till and glacial sand result from weathering of feldspar sand grains. Additionally, decomposition of feldspar‐containing rock fragments of gravel size, and aeolian sedimentation, may also have contributed to these gains.  相似文献   

2.
在贵阳市乌当区采集了白云岩、石灰岩、钙质紫色砂页岩等9种母质(岩)上发育的土壤样品763个,分别进行了土壤主要理化性质的测定和差异性分析。结果表明不同母质(岩)发育的土壤理化性质具有很大的差异:红色粘土、老风化壳和页岩上发育的土壤pH值均为酸性至强酸性,有机质和CEC含量中等,土壤质地较粘重;石灰岩、白云岩和钙质紫色砂页岩上发育的土壤pH值为中性至微碱性,有机质和CEC含量较高,质地较为适中;砂页岩和河流冲积物上发育的土壤pH值为酸性至中性,其余理化性质为中等水平;砂岩发育的土壤pH值为强酸性,其余理化性质均较差。  相似文献   

3.
The iron oxide and clay minerals in some typical red and yellow podzolic soils from New South Wales have been investigated by X-ray diffraction and infra-red spectroscopy. The dominant iron oxide mineral is goethite containing about 13–14 mol % AlOOH, this being the mineral which gives the yellow soils their characteristic colour. The red soils also contain finely divided hematite which masks the colour of the goethite. Lepidocrocite was not detected in any of the soils examined. The dominant clay minerals are kaolinite and dioctahedral interstratified illite-smectite, the latter being more concentrated in the finer clay fractions, especially in soils developed on calcareous greywacke. In the red podzolic soil developed on Ashfield shale, illite-smectite is strongly interlayered with well-ordered aluminous material. Dickite occurs in this soil.  相似文献   

4.
Availability of applied potassium (K) as a fertilizer to plants is influenced by soil mineralogy, environmental factors, and rates of K application. The objective of this research was to study the effects of clay minerals and K application on K supply characteristics of calcareous soils in Iran. Surface and subsurface horizons of six sites with different ranges of clay content and exchangeable K were selected. The soils were treated with potassium chloride (KCl) solution with different K concentrations. Four wet–dry cycles were sequentially applied. Illites, vermiculites, and chlorites were present in all soils. Smectites were present in larger amounts in one soil. The increase in soluble and exchangeable K was expressed by linear equations in which the slops influenced by the dominant clay minerals. Potassium fixation was much higher in soils with more illites and vermiculites. Results revealed that different forms of K were affected by the dominant clay minerals but were independent from the rate of applied K.  相似文献   

5.
台湾红壤及森林土壤中之氧化铁   总被引:3,自引:0,他引:3       下载免费PDF全文
本文综合汇整近年来在台湾,应用高梯度磁场分离技术,配合一般化学分析,X-射线衍射法,磁测分析,电子显微镜观察与电子衍射鉴定,以及铁-57穆期堡尔谱学分析等方法,研究红壤与森林土壤中,氧化铁的分布及其结构性质之成果回顾;关于氧化铁之分布情形,其研究结果显示:台湾红壤中普遍存在有赤铁矿与针铁矿等氧化铁矿物,而在化育自大屯山更新世纪安山岩母质与澎湖列岛更新世纪玄武岩母质的红壤中,以及兰屿绿岛海边之银白色  相似文献   

6.
Thirty two soil samples from China were analyzed for exchangeable K before and after drying. Most soil samples were higher in exchangeable K after air-drying and ovendrying (60°C) than when wet. Soil clay minerals, especially clay-size mica, affected K released in air-dry and oven-dry samples. According to composition of clay minerals of air-dried samples, five classes were recognized. Soil samples with high mica and montmorillonite have the highest exchangeable K. Samples that contained higher kaolinite than mica had lower exchangeable K. Samples with higher kaolinite than quartz and mica had still lower exchangeable K. Samples of sandy soils contained very low exchangeable K. When quartz was the main mineral, the samples that had kaolinite and gibbsite as the main clay minerals had very low exchangeable K. The degree of weathering (weathering mean) bore an inverse relationship to the amount of K released on drying in air or at 60°C. Udults and Udalfs (Red Earths) of southeastern China, because of their high K release on being dried, are inferred to have received fine mica from the Western Desert dust rainout, reported to Liu et al. (1981).  相似文献   

7.
Characteristics of Clay Minerals in Podzols and Podzolic Soils   总被引:1,自引:0,他引:1  
The clay minerals in Podzols and podzolic soils developed under coniferous forests in the Subarctic and Cool-temperate zones are characterized by the predominance of smectite and/or mica-smectite interstratified minerals in the eluvial horizons and chlorite-vermiculite intergrade in the illuvial horizons. A large amount of vermiculite is present in the eluvial horizons of some podzolic soils in the Cool-temperate zone. The illuvial horizons of these soils also contain free iron oxides such as goethite. Imogolite and allophane are present in the illuvial horizons of several soils derived from volcanic ashes. It is suggested that the critical bioclimate for the release of interlayered aluminum from the 2:1-type minerals lies between the Cool- and Warm-temperate zone. In the eluvial horizons of Podzols and podzolic soils, mica minerals and chlorite, as primary minerals, have been transformed to smectite through the pedogenic process. Based on previous studies on the structure and degradation of the dioctahedral mica minerals, it is considered that smectite is transformed from 1M-type mica minerals directly, and from 2M-type mica minerals via mica-smectite interstratifled minerals. The formation of a smectite lattice in the eluvial horizon should be a clay-mineralogical indicator of podzolization.  相似文献   

8.
在贵阳市乌当区采集了9种母质(岩)上发育的土壤样品763个,分别测定了土壤的主要理化性质和主要重金属元素含量,通过对比分析表明不同母质(岩)发育的土壤理化性质和重金属含量都具有很大的差异。土壤理化性质的差异性主要表现为:石灰岩、红色粘土、老风化壳和页岩发育的土壤质地粘重。砂岩发育的土壤质地较轻,钙质紫色砂页岩、白云岩、砂页岩和河流冲积物发育的土壤质地适中;石灰岩、白云岩和钙质紫色砂页岩发育的土壤pH值为中性至微碱性。河流冲积物发育的土壤pH值为中性,其余5种母质(岩)发育的土壤pH值为酸性至强酸性;白云岩、钙质紫色砂页岩和河流冲积物发育的土壤有机质含量较高,而砂岩发育的土壤有机质含量较低,其余5种母质(岩)发育的土壤有机质含量介于二者之间;河流冲积物、石灰岩、白云岩和钙质紫色砂页岩等发育的土壤CEC较高,而砂岩发育的土壤CEC较低,其余4种母质(岩)发育的土壤CEC介于它们之间。土壤重金属含量差异性表现为:钙质紫色砂页岩、石灰岩、河流冲积物等发育的土壤中锅、铬、汞的含量较高。而红色粘土、河流冲积物和石灰岩等发育的土壤中铅和砷含量较高,砂岩发育的土壤中5种重金属元素的含量均为最低,其余母质(岩)发育的土壤中5种重金属元素的含量均介于上述之间。通过相关性分析结果表明:研究区域内土壤重金属镉、铬、汞、铅、砷的含量差异主要是由于成土母质(岩)的差异性所致,土壤理化性质的变化则是影响土壤重金属含量的次要因素。  相似文献   

9.
The release of non-exchangeable potassium from 24 calcareous soils of divergent mineralogy, from southern Iran, was examined. Sand, silt and clay particles were fractionated after dispersion with an ultrasonic probe. Samples were extracted with 0.01 M CaCl2 for 30 successive 2-h periods. The clay fraction released the largest amount of K in each soil. Cumulative K released ranged from 175 to 723, 35 to 128, and 71 to 146 mg kg?1 contributing 20–90, 4–39 and 2–54% for clay, silt and sand fractions, respectively. The lower proportion of K released from sand and silt fractions can be explained by the presence of a high content of CaCO3 and quartz in these fractions. The release kinetics for the non-exchangeable K data showed that parabolic diffusion and power function were the best fitting kinetic models. This indicated that slow diffusion of K from the mica interlayer positions is the main rate-controlling process. Cumulative K released and constant b values of parabolic diffusion model correlated significantly with the mica content of the clay fraction.  相似文献   

10.
《Journal of plant nutrition》2013,36(7):1513-1526
Abstract

Many tropical plant species originated in areas with acidic soils and do not grow well in calcareous (high pH) soils. It is impossible to acidify soils that have high contents of calcium carbonate in south Florida. Replacing calcareous soils with acidic soils obtained from distant regions is an alternative. Unfortunately, such introduced acidic soils may eventually be neutralized by irrigation and ground water that is saturated with calcium carbonate. The objective of this investigation was to examine the acidity changes and buffering capacities of three types of acidic soils (silica sand soil, red loamy sand soil, and a mixed soil) used to establish tropical plants in a rainforest exhibition at Fairchild Tropical Garden, Miami, FL. The three areas were excavated to remove native calcareous soil, limestone bedrock, and filled with acidic soils. Various rainforest plants were planted. Soil samples were collected in contiguous 10 cm‐deep segments from the soil surface to the bedrock shortly after deposition of the soils and one year later. Soil pH, EC, particle distribution, buffering capacity were determined. Results showed that both silica sand and mixed soils had been neutralized and the soil pH values had risen over 7 in all soil depths after one year. However, less than 10 cm of the surface and bottom soil layers of red loamy sand had been neutralized and the soil pH in the middle of soil profile remained unchanged due to its higher buffering capacity. A column leaching study showed that the acidity in the red loamy sand soil would be neutralized by irrigation water and by capillary movement of groundwater with a high concentration of calcium bicarbonate. Buffering curves indicate that it is easier to maintain acidity in sandy soil than of loamy sand and mixed soils with acidified irrigation water. Indeed it is difficult to acidify the mixed soils with high organic matter content after these soils have been neutralized.  相似文献   

11.
白云星  周运超  周鑫伟  张春来 《土壤》2020,52(2):414-420
当前喀斯特石漠化治理研究中出现了一个新词汇即喀斯特土壤。通过对喀斯特土壤已发表文献的研究并结合后寨河小流域内2 755个土壤剖面信息,探讨了喀斯特区域内土壤类型及其差异,对喀斯特土壤进行了定义并辨析了在纯碳酸盐岩地区喀斯特土壤与喀斯特区域土壤的区别。结果表明:后寨河流域共有石灰土、水稻土和黄壤3大土类,石灰土主要分布在海拔1 250 m以上的区域,且随着海拔的升高,分布相应增多,水稻土和黄壤主要分布于海拔1 350 m以下的区域;石灰土主要分布在流域东部峰丛洼地及中、西部山峦上,水稻土主要分布在流域东部洼地及中部河流西侧,黄壤分布无明显规律;不同土类剖面形态特征差异较大,石灰土平均土壤厚度(49.68 cm)低于水稻土(84.33 cm)和黄壤(85.54 cm),但石灰土平均石砾含量(7.94 g/kg)却远高于水稻土(4.28 g/kg)和黄壤(4.54 g/kg);石灰土、水稻土和黄壤的土壤厚度与坡度均呈负相关关系,平均坡度分别为18.92°、1.52°和3.23°。根据喀斯特的定义,喀斯特土壤应是喀斯特岩石发育形成的石灰土,而不应理解为分布在喀斯特区域的土壤,但大量文献中存在着对喀斯特土壤定义混淆的现象,辨别二者对石漠化治理具有重要意义。普定后寨河小流域土壤剖面信息也证明纯碳酸盐岩区域不仅仅有石灰土,还存在其他土壤类型,因此喀斯特区域土壤包含喀斯特土壤和非喀斯特土壤,而喀斯特土壤应特指由碳酸盐岩发育形成的石灰土。正确认知土壤的基本属性、土壤与植被的关系和土壤与母岩的关系,可以更好地辨别二者。  相似文献   

12.
Soil particle size distribution (PSD), particularly the active clay fraction, mediates soil engineering, agronomic and environmental functions. The tedious and costly nature of traditional methods of determining PSD prompted the development of water sorption‐based models for determining the clay fraction. The applicability of such models to semi‐arid soils with significant amounts of calcium carbonate and/or gypsum is unknown. The objective of this study was to validate three water sorption‐based clay prediction models for 30 calcareous soils from Iran and identify the effect of CaCO3 on prediction accuracy. The soils had clay content ranging from 9 to 61% and CaCO3 from 24 to 97%. The three water sorption models considered showed a reasonably fair prediction of the clay content from water sorption at 28% relative humidity (RMSE and ME values ranging from 10.6 to 12.1 and −8.1 to −4.2, respectively). The model that considers hysteresis had better prediction accuracy than the other two that do not. Moreover, the prediction errors of all three models arose from under‐prediction of the clay content. The amount of hygroscopic water scaled by clay content decreased with increasing CaCO3 content. The low organic carbon content of the soils and the low fraction of low‐activity clay minerals like kaolinite suggested that the clay content under‐predictions were due to large CaCO3 contents. Thus, for such water‐sorption based models to work accurately for calcareous soils, a correction factor that considers the reduction of water content due to large CaCO3 content should be included.  相似文献   

13.
Red-Yellow soils are widely developed on terraces and hilly lands in the south-western half of Japan. They do not show any evidence of bleaching in the lower part of the A horizon, and are characterized by an extremely strong acid reaction, and a very low base-status9). There are few studies on clay mineralogy of Red-Yellow soils in Japan. Egawa et al4). have reported on clay mineralogy of soils derived from the Pleistocene and the Tertiary sediments most of which may be regarded as Red-Yellow soils. Matsui and Katô10) have described clay minerals of Red-Yellow soils derived from the Pleistocene sediment in the environs of Shinjobara, Shizuoka Prefecture. These investigations indicated that clay minerals of Red-Yellow soils derived from the Pleistocene sediments consisted mainly of kaolin minerals, whereas those of Red-Yell ow soils derived from the Tertiary sediments were of the kaolin-illite association.  相似文献   

14.
Yu  Zhan  Zhang  Yangzhu  Sheng  Hao  Zhang  Liang  Zhou  Qing  Yan  Xiong 《Journal of Soils and Sediments》2020,20(3):1558-1570
Purpose

The aims of this study were to investigate the composition of clay minerals in soils derived from different parent materials and to elucidate how parent materials and pedogenic environment affect the distribution of clay minerals and reveal the implications for pedogenetics and taxonomy in Stagnic Anthrosols.

Materials and methods

Clay mineralogy and physicochemical properties of the Hydragric horizon of Stagnic Anthrosols derived from granite (GR), plate shale (PS), quaternary red clays (QRC), limestone (LS), purple sandy shale (PSS) and fluvial-lacustrine deposit (FLD) located in Hunan Province of China were analysed to explore the relationships between the conditions influencing the formation of the soil and the composition of clay minerals.

Results and discussion

Results indicated that the composition of clay minerals is closely related to both parent material and type of Stagnic Anthrosols: the soils derived from GR, PS and QRC, which are mostly classified as Fe-accumulic-Stagnic Anthrosols, are dominantly 1:1 type kaolinite and vermiculite and illite/vermiculite mixed layer minerals of widespread distribution. However, soils derived from LS, PSS and FLD were mainly classified as Hapli-Stagnic Anthrosols and are mainly composed of 2:1 type illite/smectite mixed layer minerals, where chlorite is commonly found. Illite is widely distributed and its content varies the least among different parent materials. An extremely significant relationship between pH and kaolinite, chlorite and mixed layer minerals was noted, and the two kinds of mixed layer minerals showed highly significant negative correlation.

Conclusions

This study revealed that the types and quantities of clay minerals in the soil are closely related to the types of parent material. This reflected better direction and degree of development in Stagnic Anthrosols, which is related to the physicochemical properties of parent material and can be used as one of the bases for the classification of soil groups and subgroups within the soil family for Stagnic Anthrosols in Chinese Soil Taxonomy.

  相似文献   

15.
The morphology is described of eight surface-water gley soils developed in til in Wales and central and northern England. Physical and chemical analyses as well as micromorphological observations are used to investigate processes affecting the genesis of the soils. The characteristic property of surface-water gley soils, namely slowly permeable subsurface horizons, causes a degree of periodie waterlogging within the profile. Effects of gleying and shrink/swell processes are described. Three main aspects of weathering are shown to be operating: decalcification in two of the three calcareous profiles, the breakdown of coarse into finer particles and the alteration of the clay fraction, chiefly the formation of mixed-layer minerals from mica. Argillic B horizons are present in some soils. In profiles developed in calcareous till the degree of decalcification relates strongly to the amounts of recognizable clay concentrations as seen in thin section. Of the other five profiles three clearly have argillic B horizons. Problems associated with the identification of argillic B horizons in surface-water gley soils in till are discussed.  相似文献   

16.
The clay minerals of more than 200 soil samples collected from various sites of Fujian Province were studied by the X-ray diffraction method and transmission electron microscopy to study their distribution and evolution.Montmorillonite was found in coastal solonchak,paddy soils derived from marine deposit,lacustrine deposit and river deposit,and some lateritic red soil,red soil and yellow soil with a low weathering degree.Chlorite existed mainly in coastal solonchak and paddy soil developed from marine deposit.1.4nm intergradient mineral appeared frequently in yellow soil,red soil and lateritic red soil.The content of 1.4nm intergradient mineral increased with the decrease of weathering degree from lateritic red soil to red soil to yellow soil.Hydrous micas were more in coastal solonchak,paddy soils derived from marine deposit,lacustrine deposit and river deposit.and puple soil from purple shale than in other soils.Kaolinte was the most important clay mineral in the soils iun this province.The higher the soil weathering degree,the more the kaolinite existed.From yellow soil to red soil to lateritic red soil,kaolinite increased gradually,Kaolinite was the predominant clay mineral accompanied by few other minerals in typical lateritic red soil. Tubular halloysite was a widespread clay mineral in soils of Fujian Province with varying quantities.The soil derived from the paent rocks rich in feldspar contained more tubular halloysite.Spheroidal halloysite was found in a red soil and a paddy soil developed from olivine basalt gibbsite in the soils in this district was largely“primary gibbsite” which formed in the early weathering stage.Gibbsite decreased with the increase of weathering degree from yellow soil to red soil to lateritic red soil.Goethite also decreased in the same sequence while hematite increased.  相似文献   

17.
On calcareous micaschists in the northern Adula Region, Switzerland, brown soils are formed under grasses and herbs at altitudes below 2000 m. Podzols occur below Ericaceae below 2000 m and are formed irrespective of vegetation above this altitude. Calcimorphic soils are not found. Brown soils have a stable clay mineral association of chlorite and mica, while in the A horizons of podzols and in initial podzols alteration of chlorites to smectites occurs.  相似文献   

18.
我国土壤放射性碳年龄   总被引:2,自引:0,他引:2       下载免费PDF全文
刘良梧  茅昂江 《土壤学报》2001,38(4):506-513
我国地域辽阔 ,土壤类型众多。土壤中不仅含有有机质和腐殖质 ,而且许多土壤中还含有丰富的钙质结核、分散碳酸盐以及贝壳、珊瑚等可供放射性碳断代的良好对象。土壤有机和无机1 4 C年龄研究表明 ,我国大多数土壤是全新世时期的产物。其中又以全新世中期和晚期的土壤占绝对优势。人为土纲中的土壤年龄与六千余年来我国悠久的农业耕种历史密切相关。相比之下 ,只有少数土壤形成于晚更新世晚期。而另一些土壤有数个形成、发育阶段 ,它们的年龄自然亦就跨越不同的地质时期 ,具有多元化的特点。  相似文献   

19.
中国南方富铁铝化土壤土系建立进展   总被引:1,自引:0,他引:1  
欧阳宁相  张杨珠  盛浩  周清 《土壤》2021,53(5):907-915
土壤基层分类单元划分,特别是土系建设是土壤系统分类的基础,也能直接为农业生产提供更详细的科学指导。富铁铝化土壤(砖红壤、赤红壤和红壤)在我国南方广泛分布,为了解其在中国土壤系统分类中归属以及土系建设情况,本文综述了自2008年以来土系研究的相关成果,系统分析了富铁铝化土壤诊断层和诊断特性检索、高级分类单元归属以及基层分类单元建设现状,并展望了土系建设的发展方向:进一步细化土系划分和描述标准,加强新土系建设,加强新技术和新方法在土系建设中的应用,加大和扩展土系建设成果的运用,旨在为我国南方富铁铝化土壤系统分类研究提供参考。  相似文献   

20.
顾新运  许冀泉 《土壤学报》1963,11(4):411-416
石灰岩在我国的分布相当广泛。由石灰岩所发育的土壤在不同成土条件下产生不同的特性。欲阐明此类土壤的特性,必须依靠细致的野外调查和精密的室内分析。广西是著名的喀斯特地区,石灰岩出露面占总面积的60%左右;云南东南部的石灰岩地区也占总面积的50%以上。对于这些地区的土壤发生、特性和利用等问题,已有不少研究,但在粘土矿物组成及其演变规律方面还缺乏资料,故由滇桂地区石灰岩发育的土壤中挑选少数土壤标本,分析其粘土矿物组成,借以阐明不同成土条件对石灰岩发育土壤的影响。  相似文献   

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