Zur Genese der Marschböden. I. Der Einfluß von Sediment- und Bodengefüge

On the genesis of tidal marsh soils I. The influence of sediment- and soil-structure The significance of sediment structure for soil structure has often been disregarded when discussing the properties and genesis of tidal marsh soils. After defening several terms that are often misinterpreted, three types of tidal-marsh-soils with different structure are described: 1 . the typical clayey tidal-marsh-soils with very various aggregate structures: The well aired and permeable “SEEMARSCH” (marine-tidal-marsh-soil) with polyhedral and prismatic structure, which is formed from the flaky “card-house” structure of marine sediments rich on salt; the densely paked “BRACKMARSCH” (brackish-tidal-marsh-soil), whose moisture is due to perched water, which coarse prismatic to columnar structure, which is formed from the mainly horizontally orientet structure of brackish sediments due to dispersion; the moderately permeable “FLUSSMARSCH” (tidal-river-marsh-soil), whose wetness is often due to groundwater, with medium to coarse prismatic structure, which is formed from the finely aggregated structure of perimarine tidal-river sediments; 2 . the tidal marsh soils poor in clay, rich in silt and very fine sand with coherent structure and low air porosity, due to a strong tendency towards puddling of the top soil by raindrops, causes the formation of “HAFTNÄSSEMARSCH” (marsh soil whose moisture is due to capillar water); 3 . the tidal-marsh-soils rich in plant remains, clay and with a high level of groundwater often extremly acid, with coherent structure, which formed the generally highly permeable “ORGANOMARSCH”. The conditions of formation of these soils and the soil parameters are discussed also.     

Periodische und aperiodische Veränderungen in den Eigenschaften junger Marschböden im Deichvorland

Periodical and aperiodical changes of properties of young marshland soils seawards the dike The changes of properties of young marshland soils searwards the dike were investigated (1.) throughout the year, (2.) after storm tides, long drought periods and intensive rainfalls, and (3.) in the course of the low-high tide cycle. - In each case the relative cation distribution of the saturation extract remained constant. The relative distribution of the mobile cations remained also constant within the low-high tide cycle, white it shows fluctuations with a deviation of up to 16 % from the mean Na-content within the oneyear investigation and up to 28 % after extreme climatic or storm tide conditions. The annual salt fluctuations were determined to be at least 60–80 %. The deviations from the mean salt content were at least 100 % after storm tides and long drought periods (extreme deviation of 370 % within the first 1–3 cm soil) and partly also after heavy rain. The redox conditions remained constant within the low-high tide cycle, whereas they differed to a small extent following extreme climatic or storm tide conditions. With values of 0.4–0.9 the soils showed a small spectrum of different Ca/Mg ratios. Moreover, the determined annual fluctuation of the Ca/Mg ratios showed that the Ca/Mg ratio is not a suitable classification criterion.     

Rekonstruktion des Paläomilieus und der Geo‐Pedogenese kalkfreier Marschböden Niedersachsens

Reconstruction of the paleo‐environment and geopedogenesis of non‐calcarous marshland soils (Eutric Gleysols) of Lower Saxony The genesis of non‐calcarous marshland soils is still controversially. For clarification, the paleo‐environments of two Eutric Gleysols were reconstructed by using X‐ray fluorescence spectroscopy, light microscopy, and scanning electron microscopy. Profile 1 shows seven facies. The diatom composition reveals paleo‐environments variable in time with lacustrine, brackish, and marine conditions. Pyrite was found at the transition of clastic material and peat and within the peat, indicating together with frequently found small Zr:Al and Si:Al ratios and small Ca:Sr ratios calm, brackish, and lagoonal sedimentation conditions with reed‐peat formation. Profile 2 shows two facies; their transition is very sharp and characterized by a sudden change in diatom composition, geochemical quality, and carbonate contents. The diatom flora and Ca:Sr ratios of the lower facies reveal a tidal creek habitat with a connection to the sea and exceptional small Si:Al and Zr:Al ratios. The results, particularly for many facies of profile 1, suggest a decalcification during geopedogenesis. Two genetic phases of this decalcification are therefore likely for today non‐calcarous marshland soils, either during early geopedogenesis or during later terrestrial development.     

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.     

Zur Pedogenese und Klassifikation von Marschböden des Unterweserraumes. I. Gesamtnährstoffe,Carbonatgehalt, Kationenbelag und Diatomeenflora als Indikatoren für Sedimentations-Bedingungen und Bodenentwicklung

Development and Classification of Marsh Soils from the Unterweser Region, West Germany. I. Total Nutrients, Carbonate Content, Exchangeable Cations and Diatom Flora as Indicators of the Role of Sedimentation Conditions in Soil Development This study was carried out to see how much sedimentation conditions determine the properties– in particular the Ca/Mg ratio – of marsh soils (fluvaquents of coastel areas). The following results show, that the marsh soils properties are not determined by different sedimentation conditions: – The vertic fluvaquents don't have a higher clay content than the mollic and aeric fluvaquents – The total (t) contents of P, Ca, Mg, K and Na varied because of different soil development – The Ca_t/Mg_t ratio in soils with CaCO₃ was higher than in soils without CaCO₃, and – related to the Ca_a/Mg_a ratio – it can also be used as a classification characteristic (a = exchangeable) – The Ca_a/Mg_a ratio varied greatly because of differences in exchangeable Ca content. Vertic fluvaquents sometimes, but not often, have a higher content of exchangeable Mg than the mollic and aeric fluvaquents. Comparing maps of the Weser area as it appeared at various times in the Holocene with the soil map, shows that the sedimentation pattern is invariably brackish-marine. This is further confirmed by the diotom flora of the soils tested. Thus the properties of marsh soils, long believed to be dependent on sedimentation conditions, are the product of different continuance and intensity of soil development.     

Zur Pedogenese und Klassifikation von Marschböden des Unterweserraumes. II. Die Bedeutung von Schwefelmetabolismus,Methanproduktion und Ca/Mg-Verhältnis für die Marschen-Klassifikation

Development and Classification of Marsh Soils from the Unterweser Region, West Germany. II. Importance of Sulfur Metabolism, Methane Production and Ca/Mg Ratio for Classifying Marsh Soils The importance of sulfur metabolism in each step of marsh soil development (Brümmer, 1968) is also confirmed for the marsh soils of the Unterweser region. Sulfur contents and sulfur fractions indicate that soil development has advanced further in brackish marshes than in marine and river marshes. The results give additional evidence that the various properties of marsh soils are only partly caused by sedimentation conditions. – The sedimentation areas (Müller, 1954) apply only to small regions. Thus, methane production predominates in the freshwater area, while sulfate reduction predominates in the marine area. Both processes occur at high rates in the brackish area. Classifying soils on the basis of the Ca/Mg ratio gives the same soil groups as Brümmers classification. Consequently, classifying the marsh soils of Niedersachsen on the basis of Ca/Mg ratio is a suitable method, if the idea that sedimentation conditions cause soil properties – especially the contents of exchangeable Ca and Mg – and the present designations of the soil groups are rejected.     

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.     

Zur Genese der Marschböden. II. Kalksedimentation,Entkalkung

On the genesis of tidal marsh soils II. Carbonate sedimentation, decalcification A central problem of the tidal-marsh soils is the calcareous deposit of the parent material. On the basis of small-scale, systematic investigations it has been demonstrated in two “key areas” in the Weser tidal flats, that fluviatile and brackish soils are descended from calcareous or not-calcareous sediments. Soils buildet from calcareous sediments shows a low depth and a low rate of decalcification because of a high content of clay and bases as well a permanent high level of groundwater during the development of the soils.     

Die Bedeutung der Umsetzung von Weizenstroh im Hinblick auf den C- und N-Haushalt von Löß-Ackerböden

The significance of wheat straw decomposition with regard to the C- and N-cycle of a cultivated loess soil In 1984/85, a microplot experiment with ¹⁵N-enriched fertilizer was carried out on a field of the Calenberg loess area near Hannover (surface area of the plots: 1 ± 2 m; experimental soil: stagnigleyic cambisol from loess). On the one hand, the extent of immobilization as well as remobilization of native soil- and fertilizer-N associated with straw incorporation (± 8 t/ha) was quantified. On the other hand, the turnover as well as the alteration of C- and N-masses in the decomposing straw material was studied. About 70% of the initial dry organic matter of straw was mineralized within one year. An enrichment of fertilizer-N as well as native soil-N in the residues of up to 20 kg/ha was observed as compared to the initial N-mass. On a microplot cropped with winter-wheat, microbial N-immobilization of about 30–40 kg/ha (native soil-N and fertilizer-N) occured in the soil after straw incorporation. The immobilization extended to march 1985. Subsequent, associated with a C/N-ratio in the straw of 43, N-remineralization as well as -extramineralization was observed with 40 kg/ha at maximum in december 1985.     

Adsorption und Desorption von Methabenzthiazuron in verschiedenen Böden

Adsorption and desorption of methabenzthiazuron in various soils A method investigating adsorption and desorption of pesticides using radioactive tracers and a computer programme is described. The adsorption and desorption of the herbicidal substance methabenzthiazuron in 7 soil samples is investigated. The adsorption of methabenzthiazuron decreases from the A_p- to the C-horizons. A good correlation exists between the adsorbed amount of the herbicidal substance and the C- and N-content of the soils. The relatively highest desorption was found with nearly humusfree soils. The amount of adsorbed herbicide residues, not desorbable by water in 5 desorption cycles, is much higher in the humic soils than in the nearly humusfree soils. From the relationship found between adsorption and corresponding herbicide concentrations proper adsorption values can be predicted for any herbicide concentration within the investigated concentration range by using one single adsorption measurement as a basis of calculation.     

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.     

Einfluß von Bodeneigenschaften,Bodennutzung und Bodentemperatur auf die N-Mobilisierung von Kulturböden

Influence of soil characteristics, agricultural use and soil temperature on the N-mobilization of cultivated soils A new N-mobilization model, which considers also the short term and seasonal N-supplying capacity of soil is presented. At a fixed time the potential mobilizable N (N-MOB) is a sum of difficultly mobilizable N (N-MOB_s) originating from the pool of difficultly mobilizable N (N_s) and the easily mobilizable N (N-MOB₁) originating from the pool of easily mobilizable N (N₁). It is possible to characterize soil according to their M₁, N-MOB_s and v (N-MOB_s per day) values. Usefulness of these parameters in N-nutrition and ground water burden from N has been discussed. Basic parameters of this model have been experimentally determined independently with the help of two different experiments i. e. laboratory incubation and column lysimeter using surface soil samples. The easily mobilizable N pool (N₁) values were found in the range of 142 to 814 kg N ha^?1 which corresponded to 1.2 to 7.4 % of organic N content of these soils. The difficultly mobilizable N per day (i. e. v = N-MOB_s per day) in an incubation experiment (35°C) were found in the range of 1.5 to 24kg N ha^?1. However, in the column lysimeter experiment, in contrast, these values at 10°C ranged between 0.05 to 0.9 kg N ha^?1. These values correspond to N-MOB_s values in the range of 11–182 kg N·ha^?1 for a period of 200 days which approximate to a vegetation period. For practical purposes, the N₁ and v values could be calculated by just measuring 3–4 points after 14 days of incubation at 35°C. The results show that N-MOB_s values strongly correlated compared to N₁ values to total N, organic carbon and clay content and non significantly to pH and silt content. The results of an laboratory incubation experiment carried out to assess the effect of temperature on N-mobilization show that even at 0°C there was N-mobilization. The results revealed that in the temperature range of 0–8°C (a range of soil temp. usually observed in winter months) and in the range of 25–40°C (range of summer months temp. for surface arable soil), a small change in the soil temperature would result in enormous increase in the quantity of mobilized N. The highest mobilized N quantity was found above 60°C.     

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.     

Tonmineral- und K-Ca-Austauscheigenschaften von Oberböden des Nährstoffpotentialversuches Hallertau

Clay mineralogy and K-Ca-exchange properties of surface soils from the nutrient potential trial Hallertau (Bavaria) In soils of four locations of the Hallertau nutrient potential trial, with a soil texture consisting of sand, silty sand, silty loam and sandy clayey loam, clay mineral properties were measured with the standardized glycerol expansion method and with n-alkylammonium (Rn_c-NH₃⁺-clay). The expandable minerals of the sandy soils consist exclusively of smectites s.s., (s.s. = sensu stricto) with 0.42 to 0.28 charge equivalents per formula unit (p.f.u.). The expandable minerals of the loams are an assemblage of smectites s.s. and vermiculites. The total layer charge of the smectites s.s. extend from 0.54 to 0.28 charge eq. p.f.u. The fine clay fractions (< 0.1 μm) do not contain vermiculites. The layer charge density of vermiculites with homogeneous charge in the coarse fractions varies between 0.60 and 0.95 charge eq. p.f.u. The immediate K-Ca-exchange was extended with the values of the continued K exchange versus Ca at low K intensity. The Q/I isotherms of sandy soils have a more pronounced curvature than the isotherms of the loams; in all cases, however, the exchange curves have a continuous form. This phenomen is discussed in terms of the clay mineralogy of the soils. After 8 years without K fertilizing, samples gave values between 168 and 497 kg smectite-K/ha for the surface soils. The constant rates of K-desorption vary between 12.8 and 28.7 kg K/ha (surface soil). The rates are better differentiated between unfertilized and fertilized soils for the loams than for the sandy soils. The constant rates of K release were found to be controlled at an AR-level between 1.6 · 10^?4 M^1/2 (unfertilized sandy soil) and 5.2 · 10^?4 M^1/2 (fertilized sandy clayey loam soil).     

Oberflächenstrukturen und Eigenschaften von Permafrostböden im nordsibirischen Lena-Delta

Patterned ground and properties of permafrost soils of the Northsiberian Lena Delta The land surface of the Lena Delta is covered by polygon structures with scattered pingos and dunes. There exist so-called aerated, swampy and open polygons (open water surface) with Gelic Gleysols and Gelic Histosols (gelundic phase). The soils show only minor signs of cryoturbation and weathering. They contain high amounts of silt and slightly decomposed organic matter down to soil depths far beyond the permafrost table during summer. The soil surface is rising due to accumulation of organic matter and periodic flooding. This leads to a continuous rise of the permafrost table and subsequently to a permafrost freeze storage of plant material. The soils are therefore effective carbon sinks. On top of an investigated pingo a Gleyi-gelic Cambisol developed due to windexposed position, good drainage and higher soil temperatures connnected with a deeper permafrost table. This soil did not show any signs of cryoturbation. It has a relatively low content of organic matter due to a higher mineralization. As a consequence of frost effected sorting and wind erosion the soil material near to the surface is rich in sand and has a reduced silt content.     

Möglichkeiten der Verwertung von Rotschlamm und Grünsalz auf Hochmoorböden

Practicable application of red sludge and melanterite (FeSO₄) on bog peat soils A new way is shown to dispose the industrial by-products red sludge and melanterite by agricultural application. The ferrous products sorbe the moveable phosphates in the acid bog peat soil, so that they are still available for plants, but will not or only a little be leached. In a field trial the amount of leached phosphorus could be reduced by about 80%. The agricultural use of red sludge and melanterite is thereby at the same time a contribution to reduce the pollution of surface waters.