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1.
在两个红壤剖面中,粘粒部分的矿物组成变化不大,约含有50—55%的高岭石和20%左右的非晶物质和三水铝石,还含少量水云母、夹层矿物和14Å矿物。黄壤的粘粒矿物组成与红壤有明显的不同,其中含较多的14Å矿物和水云母,而高岭石较红壤要少些。在海拔较高、风化较浅的黄壤粘粒中高岭石含量竟低于15%,而海拔较低、风化较深的黄壤中高岭石含量可高达40%左右。X射线和化学分析表明,黄壤中的14Å矿物是属于蛭石晶层间夹有非交换性羟基铝等聚合物阳离子的14Å过渡矿物。花岗岩半风化体中含有较多的埃洛石,而高岭石极少,并有一定量的三水铝石。有的半风化体中还含少量蒙皂石和方解石。 相似文献
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通过粘粒矿物的定量分析,研究了我国东部花岗岩发育的红壤和黄壤的粘粒矿物组成。赤红壤、红壤和黄红壤的粘粒(<2μm)中高岭石含量分别为54%、42%和35%,这与该土壤的年均气温之间有明显的正相关(r=0.998,n=3),然而这三个土壤粘粒的风化淋溶系数与年均气温呈良好的负相关(r=1.000,n=3)。黄壤与红壤的粘粒矿物组成有明显的差异,黄壤中含有较多的三水铝石和2:1型粘土矿物,而高岭石较少;红壤中三水铝石很少,在安徽的黄红壤中虽有不少非晶质氧化铝,但未见有三水铝石存在。 相似文献
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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
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
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不同土壤对钾的选择吸附特性 总被引:3,自引:0,他引:3
用K Ca交换平衡法对砖红壤、红壤、土、黑土和水稻土K的选择吸附特性研究结果表明 :KG 和KV 系数随着K Ca平衡体系中吸附相中钾与钙比率的变化而改变 ,其曲线特征说明土壤胶体存在着对K亲和力不同的吸附点位。在低钾饱和度时 ,土壤对K的高选择吸附主要归于粘粒矿物楔形区域电荷点位吸附 ,五种土壤楔形区域相对吸附点位顺序为 :黑土 >土 >水稻土 >红壤 >砖红壤 ,该相对吸附点位顺序与土壤含有风化云母和蛭石有关。在高钾饱和度时 ,五种土壤对K的吸附主要发生于粘粒矿物的晶层表面电荷点位 ,粘粒矿物的晶层表面电荷起源也许起决定作用 ,此时KG 选择系数的大小顺序为 :砖红壤 >红壤 >黑土 >土 >水稻土 相似文献
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鄂、湘两省土地土壤粘粒矿物的研究——Ⅱ.莽山北坡土壤中的粘粒矿物 总被引:1,自引:0,他引:1
对莽山北坡不同海拔高度的5个土壤剖面15个土样的粘粒矿物进行了X射线衍射分析和粘粒氧化物的化学选择溶提测试,结果表明:(1)莽山土壤中粘粒矿物组合的垂直变化明显。海拔500m以下的红壤、黄红壤的粘土矿物以1:1型高岭为主,粘粒氧化物中有较多的晶质氧化铁和热碱溶性氧化硅。海拔850m以上的黄壤、暗黄棕壤和山地灌丛草甸土的粘土矿物以2:1型的14×10-10m过渡矿物和水云母为主,粘粒氧化物中有较多的无定形氧化铁、铝和三水铝石。(2)随海拔升高,土壤粘粒的硅铝率、氧化铁的游离度变幅不大,而氧化铁的活化度和各种氧化铝的富集明显提高。根据这些结果,结合莽山土壤的风化威土的条件与过程,讨论了莽山垂直带土壤中粘土矿物和氧化物的分布与演化过程的特点。 相似文献
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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
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应用穆斯堡尔谱和X射线法研究红壤性水稻土的氧化铁矿物 总被引:1,自引:1,他引:1
应用穆斯堡尔谱和X射线法分析研究红壤性水稻土的氧化铁矿物,研究结果表明,红壤性水稻土的氧化铁矿物组成、特性及其形成转化与起源土壤具有明显的差异。水稻土的成土条件不利于赤铁矿的形成。红壤的粘粒氧化铁矿物以赤铁矿和高铝替代(>20摩尔%)的针铁矿为主。经淹水种稻后,赤铁矿逐渐被转化为低铝替代的针铁矿或其它形态氧化铁。渗育型水稻土P层的赤铁矿含量比相应的母土低,其针铁矿铝替代量较其它水型的水稻土高。而潴育型水稻土W层和潜育型水稻土G层粘粒氧化铁矿物均以针铁矿为主,其铝同晶替代量低(<15摩尔%),且颗粒细小,结晶度较低。这些结果反映了水稻土的成土条件和发生特点,同时对水稻土发生分类具有重要的意义。 相似文献
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亚热带和热带土壤的磁化率 总被引:4,自引:1,他引:4
亚热带和热带土壤的磁化率X变化大,高的达2000—6000单位(昆明玄武岩红壤),低的只几个单位(沼泽土、强还原性水稻土、磷质石灰土)。大体上是:自型土>潮土>水稻土>沼泽土。在自型土中,砖红壤、红壤的X值大于石灰岩土和紫色土。红壤的磁性受母岩和发育度的影响大。各地的玄武岩红壤的X值为3×102—6×103单位,其他红壤多为100—40单位(中性和酸性岩浆岩,多数沉积岩),或40—10单位(一部分石灰岩、凝灰岩)。灼烧土壤而得到的X-t曲线和“转化率”E,可粗略地反映磁赤铁矿生成的相对程度,进而估计红壤化的程度,似可在红壤的诊断、鉴定中试用。 相似文献
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Tsung Ming Tsao Yue Ming Chen Hwo Shuenn Sheu Shung Yao Zhuang Ping Hua Shao Hua Wen Chen Kai Shuan Shea Ming Kuang Wang Yen Horng Shau Kai Yin Chiang 《Journal of Soils and Sediments》2012,12(7):1054-1065
Purpose
Information on the physicochemical properties, mineral species and micromorphology of lateritic soils and gravel soil layers in paleo-environmental soil profile is severely lacking. Red soil profile of the Taoyuan terrace was employed to demonstrate its different extents of lateritic weathering. The objectives of this study were to compare the physicochemical properties of lateritic soils and gravel soil layers and identify using conventional and synchrotron X-ray diffraction (XRD) analyses mineral species in nanoparticles separated by automated ultrafiltration device (AUD) apparatus.Materials and methods
Soil samples were collected from paleo-environmental lateritic soils. Soil samples were examined using elemental analysis, conventional and synchrotron XRD analyses, high gradient magnetic separation, separation and collection of nanoparticles by AUD apparatus, and transmission electron microscopy (TEM).Results and discussion
The soil pH, redness index, quantities of free Al- and Fe-oxides (Ald and Fed), and clay content of lateritic soils are higher than those of gravel soil layers. Illite, kaolinite, gibbsite, quartz, goethite, and hematite were identified in clay fractions and nanoparticles by conventional and synchrotron XRD analyses. TEM images show presence of hematite nanoparticles on the surface coating of kaolinite nanoparticles and aggregated hematite nanoparticles overlapping the edge of a kaolinite flake in a size range of 4?C7?nm. Synchrotron XRD techniques are more straightforward and powerful than conventional XRD with random powder methods for identifying nanoparticles in red soils, particularly for illite, kaolinite, goethite, and hematite nanoparticles. According to chemical compositions of clay fractions and red soil features in the Taoyuan terrace, these red soils can be taken as lateritic red earths or red earths.Conclusions
This work suggests that physicochemical properties, mineral species, and micromorphology of red soil at all depths can shed light on the extent of paleo-environmental lateritic weathering. 相似文献13.
主要运用土壤微形态学、粘土矿物学和土壤化学方法,对海南岛三个不同母质的砖红壤剖面的微形态特征和成壤过程进行研究,并将网纹红土和砖红壤进行比较.结果表明,砖红壤典型的微形态特征为易风化矿物颗粒和粘粒胶膜的缺失、均质状的b-垒结以及风化成因铁锰质结核的出现;典型的成壤过程为强烈的化学风化、红化、均质化、淋溶以及显著的脱硅富铝化过程.随着成土母质和土壤排水条件的变化,砖红壤的微形态特征亦有所差异.而我国南方的网纹红土的发育程度低于砖红壤,不宜被划分为砖红壤或氧化土,而更趋向归入老成土,在我国土壤发生学分类中大致相当于红壤. 相似文献
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Salar Rezapour A. A. Jafarzadeh Abbas Samadi Sh. Oustan 《Archives of Agronomy and Soil Science》2013,59(2):165-182
The iron oxides fractions of four major physiographic units obtained from a transect of calcareous materials were studied to assess the effects of key pedogenic processes and local hydrology conditions as well as physiographic units in controlling iron oxides forms in the north-west of Iran. Samples from different horizons belonging to six pedons were selected and analyzed for soil physicochemical properties, clay minerals, and Fe oxides forms (Fed, Feo, Fep). In general, the soils indicated some variation in the concentration of iron oxides that could be related to rate of weathering, pedogenic accumulations, geomorphologic conditions (as results of different in physiographic units), wet and dry cycle, and organic matter. A wide relative variation in mean values of Fed (6.4–9.9 g kg?1), Feo (2.9–4 g kg?1), and Fep (0.68–1.3 g kg?1) was observed among physiographic units. On the plateau unit, the presence of the most stable geomorphologic conditions and high rate in situ weathering (reflected in clay content), coupled with minor deposition of sediment suggest that the soils have more dynamic conditions than other units, reflecting in the greatest amount Fed and the lowest Feo/Fed ratio. Fed content of the soils containing less clay content (15–25%) was significantly different from those with greater clay content (25–35%). 相似文献
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Panagiota Tsaousidou Gartzos Efthimios Tsagalides Anastasios Constantina Haidouti Gasparatos Dionisios 《Archives of Agronomy and Soil Science》2013,59(2):227-235
The various iron fractions were quantified by selective dissolution (Fed, Feo, Fet) in four Red Mediterranean soils, developed on metarhyolite and metadolerite. They were similar in all profiles. A strong trend of iron removal from the surface horizon and of its subsequent illuvial translocation to the argillic horizons was observed. In all profiles, Feo was not related to the organic matter content indicating the Mediterranean xeric soil environment. The Feo/Fed ratio and the percentage of crystalline iron oxides (Fed-Feo) suggested that the pedoenvironment in which the profiles P1, P2 were formed, allowed the high crystallization of iron oxides. As indicated by the Fed/Fet values, the weathering process was more intense in the metarhyolite-developed soils. In contrast, the metadolerite-developed soils present conditions of poorly crystallized iron oxides and a lower degree of development. 相似文献
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水稻根际中铁的形态转化 总被引:16,自引:0,他引:16
本文以熟化红壤性水稻土、淀浆白土、红壤和赤红壤为样品,研究了植稻后根际中铁的形态转化.结果表明,两种水稻土根际中无定形氧化铁、游离氧化铁、络合态铁、土壤中氧化铁的活化度及两种红壤上根际中的络合态铁均低于非根际土;而两种红壤上其余各项在根际内外分布趋势均与水稻土相反.用穆斯堡尔谱仪分析表明,所有根际土与非根际土相比,四极矩分裂增大,内磁场下降,说明根际中氧化铁被活化.同时,水稻土上根际中Fe2+增多,赤红壤中根际出现新矿物磁赤铁矿.根际中铁被活化,可能会影响根际中重金属等污染物的吸附和解吸特性、植物的铁素营养及对其它养分的吸收. 相似文献
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Yu. N. Vodyanitskii 《Eurasian Soil Science》2010,43(12):1410-1417
Technogenically contaminated urban soils contain a substantial amount of magnetite Fe3O4, whereas another ferrimagnetic, i.e., maghemite αFe2O3, more often prevails in unpolluted soils. The content of magnetite may exceed the content of another iron oxide, hematite,
in contaminated soils. In the town of Chusovoi, where emissions from a single enterprise, a metallurgical plant, predominate
among pollutants, the upper soil horizons are contaminated with magnetite of one type. In the much larger city of Perm, the
polluting sources are diverse, which results in a wide variation of magnetic susceptibility of technogenic magnetite. The
difference in magnetite properties may depend on the composition and the content of heavy metals associated with this mineral.
A considerable amount of oxalate-soluble magnetite in technogenically contaminated soils produces two important consequences.
Schwertmann’s criterion Feox: Fedit as a gleying index turns out to be overestimated and, therefore, does not work in technogenically contaminated soils. The
second consequence is that Tamm’s reagent is inapplicable to extracting heavy metals bound to amorphous iron compounds from
contaminated soils. On the other hand, a high solubility (30–60%) of technogenic magnetite by oxalate favors the use of Tamm’s
reagent for the complete extraction of iron (hydr)oxides and heavy metals bound to them. 相似文献
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N. I. Belousova 《Eurasian Soil Science》2006,39(1):1-11
Original and published data on the contents of X-ray amorphous oxalate-soluble compounds of Al, Fe, and Si in mesomorphic
eluvial soils of cold, moderately cold, and moderately warm continental humid and semihumid regions are generalized. The groups
of soils developed from mafic igneous, metamorphic, and pyroclastic rocks are considered. It is shown that the content of
oxalate-soluble oxides (OSOx) in the horizons of their maximal accumulation varies from less than 1% to 20–30%; the Alox/Feox ratio varies from 1 to 6.5. The leading factor dictating the amount and quality of the OSOx in the soils is the presence
or absence of volcanic glass in the parent materials. The boundary between the soils with and without volcanic glass corresponds
to the OSOx content of 5% and the Al2O3ox/Fe2O3ox ratio equal to 2. These criteria are more reliable than the Alox/Feox ratio used by foreign soil scientists to specify Andosols (Alox/Feox > 2). The contents of oxalate-soluble oxides of Al and Fe do not depend on the total contents of these oxides in the parent
material and seem to be related to the presence of these elements in minerals with different resistance to weathering. Under
the natural conditions described in this paper, the content of OSOx shows a very weak response to zonal (temperature-controlled)
climatic changes and/or to changes in the degree of humidity and the continentality of the climate. 相似文献
20.
《Communications in Soil Science and Plant Analysis》2012,43(7-8):923-941
Abstract The content of various forms of iron (Fe) (free, reducible, and organic) were determined by selective extraction methods in three wetland profiles between 1993 and 1995 seasons. The result showed that Fe distribution was in the order: dithionite (Fed) > hydroxylamine (FeH) > pyrophosphate (Fep) iron in the three pedons. The hydroxylamine‐Fe constituted between 10–42% (1993), 20–47% (1994), and 10–12% (1995) of the total free Fe oxides. The pyrophosphate‐Fe, on the other hand, constituted between 0.2–1.0% (1993), 19–52% (1994), and 3–9% (1995) of the total free Fe oxides. Dithionite‐Fe (total free iron oxides) content increases with the increasing depth, while hydroxylamine‐Fe decreases, suggesting that larger proportions of Fe oxides are present as crystalline forms in the lower horizons. The active Fe ratios were generally high in the top soils and low in the subsoil. It ranged between 0.03 and 0.69 (1993), 0.05 and 68 (1994), 0.05 and 0.53 (1995) in all pedons. This suggests that poor drainage slowed down soil development. Highly significant correlations (0.1%) were evident between phosphorus (P) and organic carbon; ECEC and base saturation; FeH and active Fe ratio. Significant correlations (1%) were also evident between Fe2+ and organic carbon; P and FeH; ECEC and clay. Furthermore, significant correlations (5%) were also obtained between clay and Fed; pH and Fed; active Fe ratio and P; FeH and clay; active Fe ratio and Fed. 相似文献