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1.
我国主要变性土的微形态研究   总被引:3,自引:1,他引:2  
本文研究了变性土三大土类黑粘土、浊粘土,艳粘土的微形态特征。通过大形态、微形态、超微形态观察和膨胀收缩试验揭示了变性土的孔隙、结构、粘粒的就地重新排列以及土壤垒结与土壤粘粒含量、粘粒种类以及土壤膨胀势之间的关系,其中福建浊粘土的微形态特征发育最明显。  相似文献   

2.
福建红壤和砖红壤性红壤的发生和分类的探讨   总被引:4,自引:0,他引:4  
王果  林景亮  庄卫民 《土壤学报》1987,24(4):352-360
本文研究了发育于福建中亚热带和南亚热带13个土壤剖面的理化性质、微形态性质和粘粒矿物性质,讨论了这些土壤的富铝化程度、红壤和砖红壤性红壤土类划分指标的选择及分类问题,结果表明,供试土壤均处于中度脱硅富铝化阶段,但在程度上有差别。以B层粘粒高岭石的平均含量为主要指标,平均硅铝率为辅助指标,将供试土壤分为两个土类:第一类是砖红壤性红壤,其B层粘粒高岭石平均含量大于70%,或介于60—70%之间,但硅铝率小于2.10;第二类为红壤,其B层粘粒高岭石平均含量小于60%,或介于60—70%之间,但硅铝率大于2.10,这里红壤和砖红壤性红壤的概念不完全等同于地带性土壤的概念。  相似文献   

3.
中国变性土的分布、特性和分类   总被引:6,自引:2,他引:4  
张民  龚子同 《土壤学报》1992,29(1):1-17
本文研究了我国主要变性土的区域分布、某些发生学特性和分类问题。研究结果表明:我国变性土及变性土型土壤有广泛分布,从热带、亚热带到暖温带。其共同的成土条件是:有一定干湿交替的气候、低平的地势、富含盐基的母质和粘重的质地。据估计,此类土壤约占全国总土地面积的1%左右。变性土是在特殊的地球化学环境和干湿交替的条件下形成的,深受地域性因素的影响,其成土年龄古老而发育程度较弱。一般变性土带有某些水成土的特征,而钙质变性土兼有水成土和钙层土但又不完全与它们相同的成土地球化学特点。所研究的11个剖面中,有8个属于中国土壤系统分类(首次方案)中的变性土土纲,其余3个则属于潮湿土土纲。  相似文献   

4.
试论中国淋溶土的成土过程与基本特性   总被引:4,自引:2,他引:2  
肖笃宁  谢志霄 《土壤学报》1994,31(4):403-412
淋溶土是我国的一类重要土壤,总面积约12.5万km^2。在我国现行的土壤分类系统中,有几个土类-暗棕壤、棕壤、酸性棕壤、白浆土以及部分褐土可归属于淋溶土^1)。这些土壤大都是温带针阔叶混交林下的森林土壤,生物地球化学循环别具特征。据30个剖面的统计分析,其B/A层粘粒含量比值,从暗中壤-棕壤-黄棕壤,为1.47-1.88-2.53,经统计土壤发育过程中粘粒的生成量(或损失量)相差七倍。上述几种土壤  相似文献   

5.
利用X射线衍射法估算了福建省221个土壤样品中粘粒云母含量并讨论了与粘粒云母含量变化有关的因素。结果表明母质是影响粘粒云母含量的主要因素。海积物、河积物及页岩上发育的土壤粘粒云母含量一般较高;基性岩上发育的土壤粘粒云母含量一般较低。风化度较高的赤红壤、红壤、黄红壤和黄壤等土类的粘粒云母含量一般较低。风化度较低的C层的粘粒云母含量一般较B层和A层高,但异源母质的堆积可以使A层粘粒云母含量高于B层和C层。  相似文献   

6.
玄武岩发育的几种红壤的矿物特征   总被引:5,自引:0,他引:5       下载免费PDF全文
蒋梅茵  杨德湧 《土壤学报》1991,28(3):268-275
本文主要研究不同生物气候条件下由玄武岩母质发育的红壤、赤红壤和砖红壤的理化性质及矿物组成。粘粒中氧化铁的含量都很高,为16.98±0.83%。砖红壤与赤红壤粘粒中高岭石与非晶物质的含量相近,它们之间的差异是赤红壤中没有三水铝石,而含有7—11%蒙皂石。红壤粘粒中高岭石和非晶物质的含量都低于砖红壤和赤红壤,而水云母和蒙皂石的含量较高,也没有三水铝石。粘粒含量、阳离子交换量、硅铝率、硅铁铝率、铁的游离度和风化淋溶系数等都反映了土壤风化程度上的差异,它与水热条件特别是年均温和积温有关,进一步说明生物气候因素引起的土壤性质及矿物组成变化比其它因素强烈。砖红壤与砖红壤性水稻土的差异是在氧化铁形态上;红壤与红壤性水稻土相比,后者粘粒中蒙皂石含量略高,水云母含量略低。  相似文献   

7.
汪建中 《土壤》1992,24(1):29-32,40
本文根据赣东地区第2次土壤普查资料,论述了该区水稻土、潮土、红壤、黄壤、山地草甸土和紫色土6种主要土壤类型和由不同母质发育形成的红壤的土壤颗粒组成特点及其粘粒含量的变化等。  相似文献   

8.
母质和微地形条件对变性土形成的影响   总被引:3,自引:1,他引:2  
福建南亚热带的地带性土壤为砖红壤性红壤。在本地带沿海漳浦、龙海等县的低丘、台地玄武岩风化物上发育的一种暗色粘质土壤,历史上归属于砖红壤性红壤,经研究其性状明显区别于砖红壤性红壤,我们确定它为典型艳色湿润变性土。这种变性土与砖红壤性红壤呈复区分布。  相似文献   

9.
福建省变性土特性的研究   总被引:10,自引:4,他引:6  
在福建沿海低丘、台地玄武岩风化物上发育一种暗色粘质土壤,历史上归属于砖红壤性红壤。本研究证明,它明显区别于砖红壤性红壤,主要表现于:风化--淋溶作用和脱硅富铝化作用较弱,通体暗色,层次分异不明显,粘粒含量高,粘土矿物以蒙脱石占优势,有明显膨胀收缩性,干季出现一定深度的开裂,阳离子交换量大,盐基饱和度和pH值较高。据此,这种土壤有必要从砖红壤性红壤中划分出来。按美国土壤系统分类,本土壤定名为细质、蒙脱石型、高热、典型艳色湿润变性土。可以认为,变性土在我国也应作为一个独立的分类单元。  相似文献   

10.
安战士  徐明岗 《土壤》1988,20(6):310-313
本文用多元回归方法确定了陕西关中和陕北的(土娄)土、黑垆土和黄绵土中有机质和粘粒的交换量及它们对土壤总交换量的相对贡献。(土娄)土、黑垆土和黄绵土粘粒的交换量平均值分别为43、33、28me/100g。三类土壤有机质的交换量平均值分别为154、307、204me/100g,它们对土壤交换量贡献平均为24%。粘粒对土壤交换量的贡献3倍于有机质,但有机质的吸收性能约为粘粒的6倍,因此,该三类土壤中,粘粒是交换量的主要来源物,而有机质则是交换量的主要贡献因子。若欲改善土壤的吸收性能,必须施用有机肥料,提高土壤有机质含量。  相似文献   

11.
Five variants of the distribution of clay (<0.001 mm) and physical clay (<0.01 mm) fractions along the vertical profiles of Vertisols (slitozems) and vertic soils (slitic subtypes of different soil types) from the European part of Russia are distinguished: (1) accumulative, (2) even, (3) regressive, (4) with a maximum in the middle-profile horizon and with their approximately equal contents in the upper and the lower horizons, and (5) eluvial–illuvial. These distribution patterns are related to the lithological specificity of sedimentation and formation of parent materials composed of swelling clays of different geneses and ages. Solonetzic, eluvial- gley, and solodic processes contribute to the development of the eluvial–illuvial and, partly, regressive variants of clay distribution. All the five variants with a predominance of the even distribution pattern can be found in Vertisols. Most of Vertisols in the European part of Russia have a medium clayey or a heavy clayey texture in the entire profile. The regressive distribution pattern is typical of the group of vertic soils. In the upper horizons of Vertisols, where slickensides do not form, the texture is usually heavier than that in the analogous horizons of vertic soils. The middle-profile and lower horizons with slickensides have similar statistical distributions of particle-size fractions in Vertisols proper and in vertic soils. However, in Vertisols, a tendency for a more frequent occurrence of the soils with a higher content of the clay fraction and with a higher portion of this fraction in the physical clay fraction is observed (as compared with the vertic soils).  相似文献   

12.
The ages of organic matter of some dark-colored horizons and calcareous concretions in some Vertisols from tropical,subtropical and warm-temperate zones of China were studied using radiocarbon dating method.The relationship between soil age and genesis of Vertisols was also expounded based on the study of their genetic characteristics and micromorphological features.The results show that although Vertisols have developed for a relatively long time,their weathering and soil forming process are weak and young with little horizonation.This is closely related to their special grochemical soil forming environment.Low-lying terrain,heavy texture,clay minerals dominated by montmorillonites and alternative drying-wetting climate give rise to the vertic features expressed in intense swelling-shrinking and cracking-closing in soils.As a result,the soil development and soil leaching process are resisted,and the climatic effect on the horizonation is impeded.Moreover,pedoturbation eliminates the horizonation in the upper part of soil profile,and postpones their evolution into zonal soils.So vertisols show certain pedogenic inertia and stay at relatively young developmental stage.Therefore,Vertisols are intrazonal soils dominated by local soil forming factors such as the relief and parent materials.  相似文献   

13.
Studies on Vertisols of Southwest China show that the distribution of organic matter, mechanical composition, carbonates and spore-pollen in their profiles exhibits a definite differentiation and the radiocarbon age has a functional variation with soil depth, which suggests that pedoturbation model is a kind of incomplete model for genetic study and that the disturbance and inversion of solums of Vertisol are not as rapid and absolute as expected. In further consideration of the characters of swelling pressure and shear strength of Vertisol, vertic soil and other zonal soils, it is speculated that soil mechanics model is more adaptable for interpreting the morphogenesis of Vertisols without any contradiction with soil properties.  相似文献   

14.
Moralistic 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 soil water regime.  相似文献   

15.
On the basis of soil studies along routes and on key plots, 35 new areas of soils with definite features of vertigenesis have been identified in Belgorod and Voronezh oblasts and in the northern part of Volgograd oblast (in the Don River basin). Earlier, vertic soils were not noted for these areas. In the studied region, their portion in the soil cover is much less than 1%. All the delineated areas of vertic soils are confined to the outcrops of swelling clay materials of different origins (marine, lacustrine, glacial, and colluvial sediments) and ages (Quaternary or Tertiary) that may be found in four landscape positions: (1) in the deep closed depressions within vast flat watersheds; (2) in the bottoms of wide hollows on interfluvial slopes and, sometimes, on steeper slopes of local ravines; (3) in the hydromorphic solonetzic soil complexes, and (4) on step-like interfluvial surfaces with the outcrops of Tertiary clays. Within the studied areas, soils with different degrees of expression (six grades) of vertic properties are present. These soils belong to the type of dark vertic soils proper and to vertic subtypes of different soil types according to the Russian soil classification system; according to the WRB system, they belong to Vertisols proper and to reference soil units with a Vertic prefix in the groups of Chernozems, Phaeozems, and Solonetzes. Statistical data on the morphometric indices of the vertic properties (the depth and thickness of the soil horizons with slickensides, a wedge-shaped structure, and cracks filled with material from the upper horizons) and the depth and thickness of the Vertic horizon are analyzed.  相似文献   

16.
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   

17.
Soil organic matter (SOM) was studied in relation to vertic processes (i.e., shrinking/swelling, cracking, vertical turbation, lateral shearing, gilgai formation) in Vertisols and vertic soils of the North Caucasus in Russia, and Texas and Louisiana in the USA. Their impact on SOM properties and distribution was analyzed according to various levels of soil organization, such as soil cover, profile, horizon, and aggregate structure using chemical methods, micromorphology, isotopic analyses, and physical fractionation. The greatest variations both in the distribution and properties of SOM were found in mature Vertisols at the level of soil cover including Ctot, organic carbon stocks, stable carbon isotopic composition, and SOM 14C-age, chemical composition. The distribution of SOM at the profile and horizon levels was related to the functioning of Vertisols during wet-dry cycles. The isotopic and chemical study of densi-granulometric fractions at the aggregate level reflected the minor role of vertic processes.  相似文献   

18.
Studies on Vertisols of Southwes China show that the distribution of organic matter,mechanical compositon,carbonates and spore-pollen in their profiles exhibits a definite differentiation and the radiocarbon age has a functional variation with soil depth,which sugests that pedoturbation model is a kind of incomplete model for genetic study and that the distubance and inversion of solums of Vertisol are not as rapid and absolute as expected.In further consideration of the characters of swelling pressure and shear strength of Vertisol,vertic soil and other zonal soils.it is speculated that soil mechanics model is more adaptable for interpreting the morphogenesis of vertisols without any contradiction with soil properties.  相似文献   

19.
《CATENA》2005,59(1):93-116
In the Senegal valley, it is commonly considered that the Acid Sulfate Soils of the delta are fossil soils overlain by more recent sediments, and that the Vertisols, which abruptly overlie a thick sandy horizon, result from a change in the sedimentation mode of the river. However, we show that both soils belong to the same pedological system extending from the delta to the limit of the last marine transgression. This conclusion is based on (1) the study of soil profiles intermediate between Acid Sulfate Soils and Vertisols along a 100-m sequence in the delta, (2) the mineralogy of the clay fraction (<2 μm) in a 200-km transect along the river, and (3) the similarity of the sand size distribution across the textural discontinuity between the horizons. The following processes are involved in the pedological transformations: (1) development of acidity by oxidation of pyrite, (2) neutralization of acidity initially by the carbonate in shell beds, and later by the hydrolysis of easily weatherable silicate clays. The slightly alkaline river water precipitates kaolinite and later smectite at the contact between the strongly acidic and slightly alkaline environments. This results in the formation of a superficial vertic clay horizon surmounting a sandy horizon. Therefore, we emphasize that the soil morphology results from development and control of acidity and not from changes in past climates.  相似文献   

20.
Data on clayey swelling soils with gilgai microtopography are systematized. Classifications of gilgai microtopography representing regularly alternating microhighs and microlows are discussed, and its geometric parameters under different landscape conditions are considered. Gilgai microtopography is developed within flat or slightly inclined elements of the mesorelief composed of swelling clays of different geneses. These materials are characterized by the high swelling–shrinking capacity upon wetting–drying cycles owing to the predominance of clay minerals of smectitic group. These processes are especially pronounced under conditions of the impeded surface drainage and contrasting of the wet seasons with strong soil moistening by atmospheric precipitation or surface water and the seasons with deep soil drying under the impact of physical evaporation and transpiration. The areas with gilgai microtopography have complex soil cover patterns composed of Vertisols and vertic soils. Their formation is related to lateral movements of solid material in the soil profiles and along the curved soil surface. The morphological types of soil complexes in such area are systematized.  相似文献   

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