Quantitative Mineralbestimmung in der Schlufffraktion von Böden auf der Grundlage der chemischen Analyse und unter Anwendung der Karl-Fischer-Titration. I. Verfahren

Quantitative estimation of the mineralogical composition of silt fractions of soils based on both, chemical analysis and application of Karl-Fischer-titration. I. Method This paper describes a method for calculating the mineralogical composition of the silt fractions of soils. The chemical analysis and the temperature dependence of water release are used for determining micas and feldspars, each in three components in a relatively short procedure. The release of water was measured by Karl-Fischer-titration at controlled temperatures. At temperatures above 550°C the water release of the particle size fractions correlates with their content of micas. The quantity of micas can be obtained from the amount of released water and the results of the chemical analysis. The influence of kaolinite, amphibole and the fluoride content on the calculation is described. By considering the potassium content of the mica fraction results of the chemical analysis are used to quantify feldspars.     

Mineralselektive K-Freisetzung aus Böden mit Oktodecylammonium-Ionen (nc = 18)

Mineral-selective K release from soils by octodecylammonium- ions (n_c = 18) n_c18-releasable potassium was determined on soils of five different areas. n_c18-releasable K is the potassium which is displaced by octodecylammonium ions (ODA). Because the main sources of this potassium are trioctahedral micas, it is called briefly biotite-K. The investigated soils are from different areas in Bavaria (loess and clay stone derived soils, alluvial soils); partly the locations are K fertilizer trials. Soils of known age are locations from the Niederrhein terraces (Holocene soils). In the 0.2–2 μm (coarse clay) and 2–6 μm (fine silt) fractions the biotite-K content lies between 12 and 40% of total K. At given fractionation the highest amounts of K were released from the coarse clay of the soils. In the loess soils rich in silt the biotite-K pool in the medium and coarse silt fractions was also considerable. Clay soils showing poor K supplying power (K fertilizer trials) in the field are characterized by very low biotite-K quantities in all silt fractions. In the Holocene soils the age of which varies between 4 000 and 8 000 years the ODA releaseable values are greater than in the loess soils. In all fractions of the young Holocene soils the released K is greater than in the same fractions of the old Holocene soils. Calculated to a soil depth of 60 cm the K release in kg/ha reaches from 25 000 (young soil form) to 17 000 (old soil form).     

Effects of silicate weathering and lessivage on K‐content in forest soils derived from Pleistocene sediments

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 (K_feldspar) and mica/illite (K_mica/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. K_feldspar and K_mica/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 K_mica/illite and K_feldspar 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. K_mica/illite of clay and silt fractions increases with depth, reflecting greater mica/illite weathering at the soil surface, whereas K_feldspar 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 K_mica/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.     

Zur Interpretation erhöhter Schluffgehalte in Böden des Bayerischen und des Oberpfälzer Waldes

On the interpretation of raised silt contents in soils of the Bavarian and Upper Palatinate Forest For the Bavarian and Upper Palatinate Forest (Bavaria), 41 representative pedons were examined for aeolian components using grain‐size analysis. Soils derived from loess (three pedons) are only available in the foreland of the Bavarian Forest near to the river Danube. Soils with aeolian fractions (one pedon) also exist in the adjacent part of the Bavarian Forest. No indication for loess components (37 pedons) were found in all other parts of this mountain range: these soils are missing a coarse‐silt maximum in their upper layer as should be expected for loess‐influenced soils. However, 17 of these pedons have a medium‐silt maximum in their upper layer interpreted as a result of intense physical weathering. Therefore, the widely occurrence of soils with aeolian components cannot be confirmed for this low‐mountain range of E Bavaria.     

Methodenvergleich zur pH-Bestimmung von Böden

Comparison of methods for determining of soil-pH Comparative studies are being described of pH-determinations in suspensions with m-KCl, 0.1 m-KCl, 0.01 m-CaCl₂ and water of soils derived from loess and sand. For a standard the pH-values in 0.01 m-CaCl₂-suspensions were chosen, considering, that such CaCl₂-solution reflects best conditions in natural soil solution. Mean differences of pH(H₂O)-, m-KCl- and 0.1 m-KCl-values as compared to pH(CaCl₂)-values were + 0.56, — 0.27 and — 0.02 for the soils derived from loess, and + 0.63, — 0.11 and + 0.18 for those from sand. Taking into account the pH-dependence of the difference pH(CaCl₂)-values were + 0.56 – 0.11, — 0.27 – 0.26 and — 0.02 – 0.21, for the soils derived from loess, and + 0.63 – 0.21, — 0.11 – 0.14 and + 0.18 – 0.10 for those from sand. Taking into account the pH-dependence of the difference of pH(H₂O)-values of sandy soils, and its dependence on the present electrolyte content with all soils, further the unequal differences of the pH(KCl)-values with soils from loess as compared to sand, and their particular large variability with soils from loess, it is being argued that the CaCl₂-method may only insufficiently be substitued by any one of these methods. pH-values obtained at a soil-to-liquid-ratio of 1:2.5 were only slightly different from those with a ratio of 1:1. A suspension effect could not be observed with the application of a glasselectrode.     

Characterization of clay and fine silt fractions of forest soils by standardized K/Ca sorption isotherms

For better comparison of selectivity characteristics of clay and fine silt fractions sorption isotherms standardized on the cation exchange capacity (CEC) are useful. Due to the effect of the CEC on the sorption isotherms, it is necessary to characterize the exchanging substance with regard to different ion selectivities with standardized potassium/calcium‐(K/Ca) sorption isotherms. This procedure helps to complete the knowledge about the mineralogical composition, which is obtained by X‐ray powder diffractometry. A Haplic Luvisol from boulder marl shows distinct differences in its K selectivity both between different particle size fractions and different horizons. This is partly due to the presence of smectites and vermiculites which are differently distributed within the particle size fractions. The increase of K selectivity with increasing particle diameter in the calcareous C horizon can be attributed to the marginal expansion of mica/illite by Ca²⁺ ions. The K selectivity of individual particle size fractions in different horizons of a Gleyic Cambisol from glacial sand shows major similarities. If pedogenic chlorite is formed, no changes in selectivity characteristics can be observed.     

Rekonstruktion des Ausgangszustandes und Bilanzierung von Böden einer Moränenlandschaft

Reconstruction of the original composition and balancing of soils developed on glacial till In this paper a method for the reconstruction of the original composition of soils formed on heterogeneous glacial till is described. As an exampel the original contents of carbonates, iron and clay were calculated in two soils. The soils investigated are “Rostbraunerde” under forest and ?Braunerde”? under meadow. The “Braunerde” has been regularly irrigated with waste water for the last 70 years. The heterogenity of the fine earth of the parent material is caused by the successive deposition of materials with varying particle size distribution as well as in situ cryoclastic weathering of the different rock fragments. The reconstruction was calculated from the relation between the above mentioned weatherable components and less weatherable components in the pleistocenic sediments of Berlin. The sorting grade (So, Muller, 1962), median (Md) of the particle size distribution in the 2–600 γ fraction and the contents of coarse sand, Zr and Ti in the fraction 2-2000 pm were considered as unweatherable. The calculations were performed using multi regression analysis. The influence of the pedogenetic processes of decarbonatisation, acidification, clay formation and clay migration as well as the pedological changes resulting from the waste water irrigation were quantified through the comparison between the calculated original and the measured actual contents of the weatherable components.     

Mineral Composition of Selected Soils in Saudi Arabia

Ten soil profiles from the agricultural areas in Saudi Arabia were investigated for their mineralogical properties and some general characteristics. It was found that the soils of the eastern region were Torrifluvents and Gypsiorthids, coarse in texture with high salt, gypsum and carbonate contents. Soils of the central region were found to be Torriorthents, Torrifluvents and Torripsamments, medium to coarse in texture with smaller amounts of gypsum and salt than soils in the east. Soils of the western region were Haplargids with minor amounts of carbonate and salt. Carbonate, quartz and gypsum were found to be the main constituents of the sand and silt fractions in soils of the eastern region, while quartz, carbonate and feldspars dominated the sand and silt in the central region. The sand and silt fractions of soils in the west contained mainly quartz, feldspars, hornblende and mica. Palygorskite dominated the clay fractions of soils in the east, while kaolinite was found to be dominant in the central region, and kaolinite, smectite and mica in the west. The mineral composition of the soils was affected by the rocks from which they were derived. Igneous and metamorphic rocks of the Arabian Shield affected the soils in the west, while sedimentary rocks had great influence on soils of the central and eastern regions.     

Beziehungen zwischen Zink- und Kupfergehalt in Haferpflanzen und Böden

Relationship between Zn and Cu Contents in Oat Plants and Soils The Zn concentration in oatplants at the stage of appearing panicles from agricultural fields were higher and more varying on soils of sandy texture than on soils of loess. With the former Zn in plants correlated with n-MgCl₂ extractable Zn in the soil (r = 0.745), and also with 0,5 n-HNO₃ extractable Zn if the pH dependance was taken into account. Zn in plants from soils of loess correlated with HNO₃ extractable Zn only. Cu concentrations in plants were lower on soils of sandy texture. A correlation to 0.5 n-HNO₃ extractable Cu in the soil existed in the group of loess derived soils only (r = 0.474), a negative correlation between Cu in plants and soil pH only with sandy soils (r = —0.500). Zn and Cu concentrations of plants were based on total N contents of plants instead of on dry matter, with the aim of mitigating growth dependent differences in Zn and Cu originating from unequal stage of plant development at harvesting.     

豫北第四纪沉积物的矿物特征

豫北平原属于黄淮海平原的一部分,位于太行山洪积-冲积扇以东的黄河、漳河之间,是河南新乡和安阳两地区的主要粮棉产地。豫北平原除部分地区是黄土缓丘和山前洪积冲积物外,大部分由黄河、漳河、沁河等现代河流沉积物所组成,其中沁河沉积物、黄土、次生黄土分布在豫北平原西部,漳河沉积物分布在豫北平原北部,而中部和东部则为大面积的黄河河流沉积物。为配合黄淮海平原中豫北平原的治理及南水北调工程中线的选线间题,我们曾对豫北地区各种沉积物上所发育的土壤进行分析,有关华北平原的土壤已有详细专著(熊毅等1965),本文仅就豫北平原地区土壤的矿物性质作简要讨论。     

Mineralogical composition of silt fractions and its transformation under the impact of different cenoses in model lysimeters

A lysimetric experiment has made it possible to trace changes in the fine and medium silt fractions of soils developing from the noncalcareous mantle loam under typical phytocenoses of the southern taiga zone during a 33-year-long period. The silt fractions were separated by the Gorbunov method, and their mineralogical composition was analyzed by X-ray diffractometry. The fine silt fraction consists of quartz, kaolinite, chlorite, hydromica, smectite, and feldspars. The medium silt fraction consists of quartz, kaolinite, mica, and feldspars. In both fractions, the content of feldspars in the upper horizons has increased in comparison with the initial parent material due to the physical disintegration of coarser fractions. The chemical decomposition of mica has been registered in the layer of 10–30 cm. In lysimeters under artificially planted mixed forest cenoses, acidic hydrolysis may take place at this depth. Cryogenic processes play an important role in the soil formation at the early stages.     

Morphologie und Alter von Böden der Südlichen Frankenalb und der nichtkarbonatische Mineralbestand der Kalksteine

Morphology and age of soils in the ‘Südliche Frankenalb’ and the noncarbonate mineral composition of the limestones Soils in the ‘Südliche Frankenalb’ are described according to their local particle size and color characteristics, and their typical situation in the landscape. ‘Solifluction’ (mixing of limestone fragments with terra fusca solum) and sedimentation of aeolian material were the important processes which complicate the reconstruction of soil formation. The quantities of carbonate-free residues of limestones vary in a wide range between 0.7 and 25.4%. With this property, a grain size- and a mineralogical property, the limestone samples are separated by discriminant analysis in three groups. In contrast, the clay mineral composition of all the limestone residues is very homogeneous. In the fine clay fraction (< 0.2 μm) and coarse clay fraction (2-0.2 μm) illite and illite/smectite mixed layer minerals are the predominant minerals with proportions of 90% and 80–85%, respectively. The time necessary for soil formation is calculated to be 1.6 (20 cm depth, IIT-horizon) and 2.7 million years (36 cm depth, IIT + Bv₂-horizon), respectively. This calculation is based on a Malm Delta limestone (0.7% residue). The carbonate output is calculated from CaCO₃ solution rates in the CO₂-H₂O system and actual leaching rates derived from local climate data. The period of soil formation from other limestones was not as long.     

Erodibilität repräsentativer Böden der Hallertau

Erodibility of representative soils of the Hallertau (South Bavaria) Differences between the USA and the Federal Republic of Germany in geology, soil types, and climate necessitate to verify the erodibility of the soils estimated according to Wischmeier and Smith (1978), when using the Universal Soil Loss Equation under local conditions. The erodibility of 5 representative soils of the region Hallertau within the so-called “Unterbayerisches Hügelland” was checked by measuring soil losses using a laboratory rainfall simulator. The estimated and measured erodibilities for two Aquic Hapludalfs from loess and one Ruptic-Alfic Eutrochrept from Tertiary sand compared very well as shown by coefficients of regression of 1. The estimated erodibilities for a Typic Eutrochrept and an Aquic Chromudert, both from Tertiary materials, however, underestimated the soil losses by a factor of 1.5. For all regressions the coefficients of correlation were 0.90. Due to the small number of soils checked, it is only possible to suggest causes for the observed deviations, particularly since the aggregate stability could not be the only property, as demonstrated by measurements.     

Dicyandiamidabbau in Quarzsand und Böden

Breakdown of Dicyandiamide in quartz sand and soils Under different moisture conditions the breakdown of dicyandiamide (DCD) was investigated in quartz sand with metal oxides and in soils. 1. In quartz sand without metal oxides DCD did not change over 100 days. 2. In the presence of amorphous Fe(III)-hydroxide DCD was transformed to guanylurea after 5 days to 50% and after 40 days to 90%. The transformation rate depended on the kind of metal oxides and increased with low humidity. Other metabolites were not detected in quartz sand medium. 3. In two soils (pH 6.5, 6.3; sandy silty loam and sand) the breakdown of DCD to guanylurea followed the same pattern, but continued to ammonium. About 20–70% of the added amount was transformed within 100 days. 4. With increasing soil moisture the transformation of DCD to guanylurea was slower, but the further breakdown to ammonium increased. 5. As long as DCD was present the formation of nitrate was blocked.     

Beziehungen zwischen Klimafaktoren und C-, N-Pools in Partikelgrößen-Fraktionen zonaler Steppenböden Rußlands

Relationships between climatic factors and C, N pools in particle-size fractions of steppe soils, Russia Many soils of the Russian steppe are characterized by high soil organic matter contents and similar parent material. Thus, they are suitable for investigations of a climatic impact on C and N pools. We sampled 10 topsoils of the zonal Russian steppe at 0–10 and about 50–60 cm depth intervals. After particle-size fractionation into clay (<2 μm), silt (2–20 μm), fine sand (20–250 μm) organic C and N concentrations were determined in bulk soils and fractions. The results suggest that especially the older organic matter of the subsoil (in the silt fraction) is correlated with climatic factors. Topsoils show less evidence for climatic influences on C and N pools. As the ratio of mean annual precipitation to potential evaporation (=N/V) increases, C/N ratios decrease in all fractions and, thus, in the bulk subsoil. Obviously the degree of soil organic matter alteration was more pronounced in the order Greyzem (N/V = 1.0) > Chernozem, Phaeozem (N/V = 0.89) > Haplic Kastanozem (N/V = 0.6) > Calcic (N/V = 0.34), and Gypsic Kastanozem (N/V = 0.32). The organic carbon contents of the bulk subsoil are highest in the subsoil of the Chernozem and Phaeozem, and decrease with increasing N/V ratio (i.e., increasing heat input and dryness) to the Calcic Kastanozem. This is accompanied by an increasing enrichment of organic carbon in the silt fractions (r = ?0.99 for the correlation of the C enrichment in silt with N/V).     

Beziehungen zwischen Mangan-Gehalten in Haferpflanzen und Böden

Relationship between Mn in Oat Plants and Soils The Mn concentration of oat plants in the stage of appearing panicles from agricultural fields were put in relationship to extractable Mn. With soils of sandy texture (clay < 4%, pH 4,7–6,6) a correlation existed between Mn in plants and n-MgCl₂ extractable Mn, however, no additional relationship with the easyly reducible Mn. A negative correlation between pH and Mn in plants was traced to the pH dependence of exchangeable Mn. With soils of loess (clay 5–28%, pH 6,6–7,7) a significant correlation existed between Mn in plants and easyly reducible Mn fractions (methods by Schachtschabel: extracting solutions containing Na₂SO₃, pH 8,0, or Na₂SO₃ + NaHSO₃, pH 5,5), however, only if an interrelationship with the pH of the soil was allowed for. The higher the pH of the soil the lower its level of extractable Mn might be, to reach a certain concentration of Mn in plants. This relationship seems to be caused through a modifying influence of the soil pH on the reducing power of the extracting solutions.     

LOESS IN THE SOILS OF NORTH NORFOLK

Thin silty deposits cover large areas of north-east Norfolk, occurring mainly on gently sloping and flat plateau sites and on the floors of valleys cut in the glacial deposits. Particle size and geographic distribution of the deposits suggest that the silt is windblown. The mineralogical composition of the silt fraction resembles that of the silt of Hunstanton Till, suggesting that most of the deposit was derived as loess from outwash of the Weichselian glacier. However, at some localities the sand and clay components of the deposits were derived, at least partly, from subjacent glacial sediments of pre-Weichselian age. The distribution of the silty deposits strongly affects the pattern of soil types and sometimes the growth of crops.     

Einflußgrößen der Schwermetallöslichkeit und -bindung in Böden

Solubility and retention of heavy metals in soils Model experiments were carried out under oxidizing conditions with soil samples from surface and subsurface horizons of different composition in order to investigate the solubility and retention of Cu, Zn, Cd, and Pb in soils. The solubility of heavy metals is mainly determined by ad- and desorption processes and complexation reactions of organic and inorganic ligands. Precipitation and dissolution of definite heavy metal compounds do not seem to govern the solution concentration in soils. An exception may probably be the formation of lead phosphate and zinc silicate under specific reaction conditions. The main factors which determine solubility and retention of heavy metals are total amount (except the proportion incorporated in the silicate structure) of the different metals, soil reaction, content of mobilizing and immobilizing organic substances, content of pedogenic oxides and clay minerals, and kind and concentration of salts and inorganic ligands. The results of the model experiments are used together with the results of other authors and general physico-chemical data to give an interpretation of the solubility behaviour of heavy metals in soils. The relations between heavy metal solubility, availability and mobility and possible procedures for melioration of soils contaminated with heavy metals are discussed.     

Zum Einfluß landwirtschaftlicher und forstlicher Nutzung auf die Wasser- und Luftverhältnisse typischer Böden aus Löß Nordwürttembergs

Soil water and air regime under forest and agriculture in loess soils in South-West Germany . Investigations on loess soils of South-West Germany showed distinct differences in the water and air regime under forest and agriculture. The water content was higher and the air content lower under cultivation and grassland as compared to forest. These results are caused by less transpiration of agriculture crops on cultivated plots and also by a higher bulk density of this soil due to tillage.     

Mineralogy of two red soil (Alfisol) profiles of mysore state,India

Quantitative mineralogical composition of the clay fractions of two red soil (Alfisol) profiles developed on gneissic rocks in Mysore, India, is discussed in relation to the genesis of these soils. Data on the mineralogy of their silt and sand fractions are also presented. Both the silt and clay fractions are kaolinitic and contain considerable amorphous material. A possible weathering sequence of transformation of the minerals, with probable mechanisms involved, is suggested.