Kurzmitteilung Ein methodischer Beitrag zur Porengrößen-Messung bei Böden

A methodic contribution for the measuring of volume of pores in soils An apparatus for determination of the soil pores in the pF-range 0–2,5, partially produced in home-work, is described. Thereby are used ceramic plates 50 × 35 cm with a thickness of 5–8 mm. The ceramic plates are sticked on 63 × 50 cm gum plates with Teroson-Cement-BE and packed in correspondingly great wooden boxes. The soil samples are dehydrated in an over-pressure chamber.     

Kalium-Dynamik und Kalium-Fixierung nordwestiranischer Böden

Dynamics and fixation of potassium in soils of North-West-Iran The following results were obtained from experiments conducted on two calcareous soils (A-horizon) and on two soil samples from fertilizer experimental plots (K₀ = control plot, K₅ = 1000 kg K₂O/ha) to study the dynamics and fixation of potassium in these soils: The K-exchange curve of K₅ sample when compared with K₀ sample showed that, as a consequence of high fertilizer dose, most of the specific adsorption sites for cations (particularly on illites and weathering products of illites) were occupied by K which, thus, resulted into lower K-adsorption as well as fixation. The shape of K-exchange curves of other three samples (Alluvial soil, 16, Brown soil 26 and K₀ sample, Fig. 5 and 6) indicates a typical bend at definite activity ratios. This bend in the exchange curves exists apparently in soils containing high content of illitic clay mineral fraction. This behaviour has been interpreted as a consequence of contraction of layers of illitic minerals which were formerly expanded due to loss of potassium. The K-desorption experiment, which then followed, showed that a major part of sorbed amounts of potassium could not be desorbed and remained fixed in the soil. Similar type bend as in the exchange curve was also observed in the potassium fixation curves (Fig. 6 and 7). Illite is the dominant clay mineral in all these soils which in Brown soil and K₀-sample is expanded at edges; the expansion goes back to 10 A on treatment with K which then does not expand again on saturation with Mg.     

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.     

Schwermetallverteilung und Tongehalte in Böden

Heavy metal distribution and clay contents in soils . In soil profiles differing considerably in horizon pattern and parent material the contents of Mn, Zn, Cu and Co were correlated with those of clay (and CEC), of total Fe (and dithionite soluble Fe) and - after relation to clay - with C. The correlations with clay, CEC, Fe_t and Fe_d were in all cases positive and highly significant, though differing between the different metals and between the references. Deviations for all elements are due to lithogenic differences in soils from mesozoic sediments and for Mn also due to its lower pedogenic stability. The correlations with C were not significant, since O horizons were not yet investigated. The ‘mobility’ of the heavy metals ( = EDTA + NH₄O Ac-extractable in relation to total amount) in topsoils could be more correlated (negative) with the reserves than with other soil features. Relating the ‘immobile’ heavy metal contents to the other soil features considerably improved the correlations.     

Blei- und Cadmium-Status Berliner Böden

Lead an cadmium conditions of Berlin soils Pleistocene sediments of Berlin contain 10 mg/kg Pb and 0.1 mg/kg Cd, but debris of the city 80 mg/kg Pb. The topsoils are enriched with 60–100 mg/kg of anthropogenous Pb, near roads more than 200 mg/kg, and with 0.3–0.6 mg/kg Cd. Only low quantities of both elements were soluble in NH₄-acetate, but half of the polluted elements was extractable with AEDTA, the unextractable part being enriched in the clay fraction. Exchange experiments show very high sorption rates of soluble lead, but in case of cadmium sorption was much lower so that this element can percolate especially sandy acid soils with low humus contents in higher amounts.     

PH-Verteilung und Pufferung von Böden

PH-distribution and buffering of soils A frequency distribution of the pH values of 927 soils clearly reflects the three soil buffer ranges (carbonate, pH-dependent charge and aluminium release) by higher frequencies within these ranges and lower frequencies between them.     

Plutonium in Gemüse,Obst und Böden

Plutonium in vegetables, fruits, and soils The plutonium content of fruits and vegetables from the Karlsruhe area in the years of 1971 - 1975 was determined. In vegetables the Pu-239 and Pu-240 activities were highly different, fluctuating between 64 fCi/kg fresh weight and values below the detection limit of about 6 fCi/kg. The activity of most of the vegetables and of all fruits was not higher than 10 fCi/kg. The nuclide Pu-238 could be identified in a qualitative way only, i. e. all measuring values remained below the detection limit of about 17 fCi/kg. The total-alpha-activities which were simultaneously determined in the vegetable and fruit ashes were in the range of 0.5 -19 pCi/kg fresh weight. Soil samples taken from the same region had a mean Pu-239 and Pu-240 activity of 5.9 ± 1.4 fCi/g and a total-alpha-activity of (10 ± 1.5) · 10³ fCi/g. Samples taken from the immediate vicinity of the Karlsruhe Nuclear Research Centre did not show increased activity levels.     

Verteilungsmuster lithogener,pedogener und anthropogener Schwermetalle in Böden

Distribution of lithogeneous, pedogeneous and anthropogeneous heavy metals in soils The study in hand shows relations between lithogeneously, pedogeneously and anthropogeneously enriched heavy metals and their concentration grades. Conclusions can be drawn from the vertical and horizontal distribution pattern of heavy metals on the nature and origin of their enrichment which is determined decisively by their mobility. Heavy metals enriched lithogeneously show relatively uniform as well as stratified concentration grades in the profile. A diminution of the heavy metal contents in all surface directions takes place starting from the centre of the lithogeneous enrichment. Pedogenetic processes lead to an increase of all element concentrations in certain soil horizons. Lateral transport causes an increase of heavy metal contents in the soils of low grounds compared with summits. Heavy metals enriched anthropogeneously are mostly accumulated in topsoils. Heavy metals concentrations due to dust immissions are characterized by a remarkable diminution of the concentration within the main wind direction. Heavy metal enrichments due to direct anthropogeneous charges are following the ground borders.     

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.     

Bodenatmung,Stickstoffmineralisation und Humusabbau ostafrikanischer Böden nach Trocknung und Wiederbefeuchtung

Soil respiration, nitrogen mineralization and humus decomposition of East African soils after drying and remoistening Soil respiration and nitrogen mineralization of 51 East African cultivated, savanna and forest soils were compared after 3 and 21 weeks of air drying. The average soil respiration after 21 weeks of drying was 1.221 ± 0.106 times higher than that after 3 weeks of drying whereas the average nitrogen mineralization was not increased significantly (factor 1.132 ± 0.256). The increase in soil respiration was correlated positively with the water soluble organic matter. During air dryings of 3 days and moist incubations of 4 days at 30°C, which were repeated 20 times in 10 soils, 3–10% of the organic carbon and 8–19% of the organic nitrogen (low humus vertisol 69%) were mineralized. Changes in the amount and the extinction of humic and fulvic acids were considered to be indicative for an increased humification during the drying and remoistening of soils.     

Analytische Bestimmung und Fraktionierung von Cu,Zn, Pb,Cd, Ni und Co in Böden und Unterwasserböden

Analytical methods for determination and fractionation of Cu, Zn, Pb, Cd, Ni, and Co in soils and underwater soils Using a wet oxidation procedure with mixtures of strong acids, even samples rich in both organic carbon and carbonate could be dissolved quantitatively in platinum crucibles. Fractionation of trace elements was performed by extraction with oxalate (boiling and at room temperature), and with EDTA. Analytical problems (mainly by contamination) could be eliminated by simple preventive arrangements.     

Kurzmitteilung Einfluß der Qualität der organischen Substanz auf die Konsistenz landwirtschaftlicher Böden

Influence of organic matter quality on consistency of agricultural soils The soil organic matter of two samples similar in the texture and approximately in the organic C contents, but very differently in the consistency properties, were investigated by pyrolysis-field ionization mass spectrometry (Py-FIMS). The shifts of the values of the liquid and plastic limits towards higher moisture contents are explained by a different quality of soil organic matter, in particular by higher amounts of longchained lipids (C_8-32 alkanes, alkenes, fatty acids), N-compounds and lignin dimers.     

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.     

Der Einfluß von Niederschlag und Höhenlage auf den Humusgehalt ostafrikanischer Böden

The influence of precipitation and altitude on the humus content of East African soils Positive correlations were found between the log of the carbon and nitrogen content of the 0–15 cm soil layer, altitude and average annual precipitation of 20 grassland soils, 13 forest soils and 21 cultivated soils at altitudes of 10–2840 m and a precipitation of 380–2410 mm in Kenya, Tanzania and Uganda. For each of the soil groups equations with the two variables altitude and precipitation were derived, which accounted for 76–93 per cent of the variation of the carbon (0,42–5,62%) and nitrogen (0,04–0,71%) content. There was no correlation between altitude, precipitation and the C/N ratio of the soils.     

Die Adsorption von HCB und DDD in Böden

The Adsorption of HCB and DDD by soils A method for studying the adsorption of substances with low water solubility by soils has been set up. The method has been verified by two chemicals (HCB, DDD) and a number of different soils. The results have shown a significant correlation between the distribution ratio and the content of organic carbon.     

Protonenpuffersubstanzen in Böden

Proton buffer compounds in soils A classification of solid soil buffer substances according to the type of proton accepting sites, viz. carbonate buffer, variable charge buffer, silicate buffer and hydroxide buffer is proposed. The buffer reactions are discussed in some detail and so are formation and transformation processes of buffer. An association of pH-ranges to various buffer compounds is hampered by an insufficient knowledge of the acid strength of the different functional groups.