Eigenschaften von Böden unterschiedlicher Nutzung im Stadtgebiet von Rostock

Qualitative properties of soils in the urban area of Rostock different in use With the purpose of mapping urban soils in Rostock, Northern Germany. extensive investigations determining the presence, the genesis and the properties of natural and man-influenced soils were realized. In the following article selected chemical and physical properties of soils different in use situated on garden-, park-, graveyard-sites and living areas were shown and discussed. The positive influence on the pH-value in living areas of the city centre, deep enrichment of humus under garden use and the tendencies to soil acidification in sandy soils of park sites were emphasized.     

Die Verwendung von Antimon-Elektroden zur pH-Messung in Böden

The application of antimony electrodes for soil pH measurements Glass electrodes are unsuitable for long-term, micro-volume pH measurements in soils because of their form, size and drying of the glass membrane. Sb-electrodes are suited for pH measurements in soils whose oxygen saturation does not vary excessively. pH values determined with Sb electrodes decrease with increasing water tension or decreasing moisture. Colour changes of pH indicators confirm this trend.     

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.     

Die Messung der Katalaseaktivität von Böden

The determination of Catalase Activity in Soils by Dr. Beck 1. The elaboration of a method for the determination of the activity of catalase in soils is described. The method envolves the gasvolumetric determination of oxygen released by decomposition of a H₂O₂-solution by soils, suspended in buffers in the presence and absence of the catalase inhibitor NaN₃. 2. The influences of the following factors on catalase activity were studied: Methods for the determination of developed oxygen, enzyme- and substrate concentration, inhibition of catalase by NaN₃, pH- and temperature-optima of catalase and the presence of plant residues in soils. 3. It was found, that there was only a little decrease in catalase activity when fresh or dried samples of soils were stored over a periode of 4 months under laboratory conditions. The catalase activity of different soils showed very good correspondence to the dehydrogenase activity of the soils and less correspondence to the amount of soil respiration and the amylase activity. No relation could be found to the number of microorganisms in soil.     

Kurzfristige pH-Pufferung von Böden

Short-time pH buffering of soils Changes in pH of 60 soils after HCl addition were related to reaction time and soil characteristis. Between 80 and 100% of the added protons were taken up by the soils within a few seconds, resulting in the release of exchangeable Ca, Mg and Al in strongly acid soils. The decrease of proton activity between 0.25 and 30-70 h can be formally described as a diffusion process. pH buffering depended on soil pH and organic C content but not on clay content. Buffering decreased from pH 3.5 to about 6 and increased again up to pH 7. Increase of C_org increased buffering mainly from pH 6-7.     

Stickstoffdynamik von Böden mit Abwasserverrieselung

Nitrogen dynamic of soils with wastewater irrigation The nitrogen status of a Sandy Cambisol and a Loamy Luvisol of Berlin, which were flooded with wastewater over a period of 100 years were studied. The two-year examination of the water, redox and nitrogen dynamics showed great differences in nitrogen leaching and the intensity of nitrification and denitrification processes.     

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.     

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.     

Die Böden von Wallhecken in Schleswig-Holstein I. Klassifikation und Genese

Soils of Mound Hedges in Schleswig-Holstein I. Classification and Genesis In typical landscapes of Schleswig-Holstein soils of mound hedges were investigated (FAO (1989): Cumulic Anthrosol). New soils have been developed from the deposit of the mound hedge in less than 250 years. A classification with regard to the German classification of natural soils is suggested. The soil genesis from sandy deposits has reached the step of Dystric Regosols, groundwater has induced gleyic features. Soil genesis could be described chronologically, if time of deposition of these mound hedges is known. Some of the natural soils are conserved below the deposit. Pedogenesis in an area, changed by man, could be reconstructed. This is why systematic, scientific soil investigations of mound hedges may be very interesting.     

Zur Bestimmung von Gips in Böden

On the determination of gypsum in soils The (020) X-ray reflection of gypsum at 7,56 Å is nearly specific and may be used for detection and quantitative measurement of the mineral in soil samples. By X-ray powder diffractometry gypsum can be detected as far down as 0,5% by weight. This limit may be extended down to 0,005% by concentration in the density fraction 2,1–2,5 g/cm³. For quantitative measurements references may be prepared from sample parts by dehydration of the original gypsum and adding known quantities of this mineral. So it is possible to compare samples of nearly identical grain size distribution, and mineral contents. This is important in the powder-diffractometrical quantitative measurement of a mineral with low hardness and good cleavage where mechanical stress during homogenisation lowers the intensities of X-ray reflections. Under comparable conditions for sample and reference, gypsum contents can be determined in the range of 0,5 to 20% by weight with an accuracy of ± 3% (relative).     

Kolorimetrische Bestimmung von Dicyandiamid in Böden

A colorimetric method for the determination of dicyandiamide in soils A colorimetric method derived from the diacetyl reaction for the determination of creatine has been developed for the determination of dicyandiamide in soil extracts. Dicyandiamide reacts with 1-naphtol and diacetyl forming a red colour complex with maximum absorption between 535 and 540 nm. The detection limit ranges between 0.1 and 0.3 mg dicyanidiamide-N/100 g soil. In soil extracts neither naturally occurring substances nor metabolites of dicyandiamide influenced this colour reaction. After addition of 1, 5, 10, 20 mg dicyandiamide-N to 100 g soil and immediate extraction by water an average recovery rate of 95% was found. The relative standard deviation amounted to ± 1.60%.     

Abbau von Monolinuron in verschiedenen Böden

Degradation of monolinuron in different soil types The degradation of ¹⁴C-methyl, -ureido- and -phenyl-labelled monolinuron was studied in laboratory experiments with different soil types. Mineralization of the ureido-group was followed by two methods. It was found, that the mineralization rate depends on the soil. For the herbicide monolinuron there was a definite degradation characteristic. The release of ¹⁴CO₂ from the methyl- and ureido-group was faster than from the phenylring. In soil extracts monolinuron was found together with one or two radioactive substances not yet identified. Soil respiration was unchanged after the application of monolinuron. In a sterile soil no degradation occurred.     

Verhalten von Dünger-NH4 in Böden unterschiedlicher tonmineralischer Zusammensetzung im Inkubationsversuch

Fate of fertilizer ammonium in soils with different composition of clay minerals in an incubation experiment In an incubation experiment with three different soils (gray brown podsolic soil from loess, alluvial gley, and brown earth, derived from basalt) the specific adsorption (fixation) and release of fertilizer NH₄⁺ was investigated. In one treatment 120 mg NH₄–N/kg soil was added, while the other treatment (control) received no nitrogen. Soils samples were taken every ten days and analyzed for nonexchangeable and exchangeable NH₄⁺ and NO₃^?. The experimental results are showing that the specific adsorption of applied NH₄⁺ was related to the type of clay minerals. While the loess soil, rich in illite, and the alluvial soil, rich in expansible clay minerals, bound about 40% of the added NH₄⁺ specifically, the soil derived from basalt with mainly kaolinite bound only about 10 %. From the recently “fixed” fertilizer NH₄⁺ about a half was nitrified during the incubation period of about 9 weeks. In the control there was no significant release of specifically bound NH₄⁺. Obviously this NH₄⁺ is located more deeply in the interlayers of the clay minerals and not available to microorganisms.     

Die Nitrifikation in Böden (Sammelreferat)

Nitrification in soils A literature review is given on the biology of nitrifying organisms, the nitrification process in soil and factors influencing nitrification in soil with special reference to the following aspects:

• 1 Importance of nitrification in the nitrogen cycle.
• 2 Biology of nitrifying micro-organisms.
• 2.1 Chemolithotrophic bacteria and heterotrophic micro-organisms.
• 2.2 Physiology and biochemistry of nitrifying micro-organisms: gain of energy, specifity and concentration of substrate, influence of soil reaction.
• 3. Methods for the measuring nitrification in soil.
• 3.1 Experiments for the determination of nitrification.
• 3.2 Calculation of the nitrification process.
• 4. The course of nitrification in different soils.
• 4.1 Rate of nitrification.
• 4.2 Influence of various environments: soil reaction, temperature, oxygen and water content.
• 4.3 Effect of soil organic matter and vegetation.