Danish Soils Research Articles

Sulphur mineralisation in five Danish soils as measured by plant uptake in a pot experiment

Reductions in atmospheric S deposition have created S deficiency in some agricultural soils. In such soils the release of S from organic matter may be important for the supply of S to plants. In this study net mineralisation of S was measured during two successive growth seasons as S removed by plant material and leachates. Pots were subjected to natural conditions and cropped with either Italian rye grass ( Lolium multiflorum Lam.) both years or spring oilseed rape ( Brassica napus L.) followed by spring barley ( Hordeum vulgare L.) Sulphur was the limiting factor for dry matter yield in the pots. Sulphur concentrations in Italian rye grass, rape and barley varied from 0.055 to 0.21, 0.06 to 0.078 to 0.17%, respectively. Net mineralisation was 3.3–6.7 μg S per g soil year −1 (1.7 to 3.1% of total organic S), and could not prevent S deficiency in the crops; differences among soils developed early in the experiment. Net mineralisation of S was not significantly correlated with total organic S, C-bonded S or sulphate-ester S content of the soils but with microbial activity in the soils ( r = 0.90). Net mineralisation was significantly affected by the type of cropping system but differences between systems were small compared to differences in net mineralisation among soils. It may be concluded that reductions in atmospheric deposition of S must, at least partly, be replaced by S fertilisation to maintain crop yield and quality.

Adsorption and ED50 values of five soil‐applied herbicides

AbstractThe soil partition coefficients (Kd values) and ED50 values of carbetamide, isoproturon, propyzamide, trifluralin and pendimethalin were determined on various soil types. Adsorption increased in the order carbetamide < isoproturon < propyzamide < trifluralin < pendimethalin, whereas the influence of soil types on herbicide efficacy increased in the order isoproturon < carbetamide < pendimethalin < trifluralin < propyzamide. The relationship between adsorption and ED50 values of the herbicides was examined by estimating the herbicide concentration in soil water solution. Adsorption and ED50 values on common Danish soil types (0.6% carbon and 12% clay to 2.3% carbon and 4.4% clay) differed by factors of up to three and four, respectively, indicating a possibility of adjusting the herbicide dose according to soil factors.

N-Balance for Mineral N on Spring Barley Cropped Sandy Loam and Coarse Sandy Soil with Mineral and Organic Fertilizers

Abstract N-balance for mineral N was calculated for growing season and autumn-winter periods during a three-year field experiment on two Danish soils, a sandy loam and a coarse sand. Both soils were grown with spring barley and on the coarse sandy soil a catch crop was undersown in one treatment. The soils were fertilized with inorganic N (NPK) and organic N (pig slurry) applied in the spring and also in autumn (on the coarse sand). On the sandy loam soil the differences in N-leaching, N-uptake and net N-mineralization between the fertilized treatments were small. On the coarse sandy soil the autumn-applied slurry caused a strongly increased N-leaching, while the undersown catch crop reduced the leaching. The unfertilized soil differed from the fertilized treatments with a lower N-uptake and a decreased N-leaching, especially on the sandy loam soil. The type of fertilization did not influence the net N-mineralization very much. The N-balances were based on the store of mineral nitrogen in spring and at harvest, as well on the N-input and N-output, which included N fertilization, net N mineralization, and N-uptake, N-leaching and N-denitrification. The deviations in N-balance were strongly influenced by the high variations found for the N-pools included in the N-balance and only to a minor extent by the climatic conditions and the type of soil.

The Mineralogical Composition and Classification of Some Soils on Bornholm, Denmark

Abstract The mineralogical composition of the sand, silt and clay fractions of four soils from the island of Bornholm has been investigated. Three of the soils are Hapludalfs and one of them is a Haplumbrept. Compared with other Danish soils the mineralogical compositions of three of the soils have a higher content of hydrous biotite in the sand and silt fractions and higher contents of vermiculite and HIM in the clay fraction than most soils from other parts of Denmark. The fourth soil is the first investigated in Denmark in which the mineralogy indicate that it has been developed in situ (partly at least) on weathered granitic material. In two of the soils the kaolinite content was twice as high in the Ap horizon as in the C horizon.

Rye Grass as a Catch Crop in Spring Barley

The effect of rye grass catch crops in spring barley growing was tested on four Danish soils. Dry matter production of under sown late perennial rye grass was on average 800 kg, and of Italian rye ...

Evaluation of the Clay Fraction in some Danish Soils, Making Use of High-Gradrent Magnetic Separation (HGMS)

Abstract After removal of the ‘free Fe-oxyhydroxides’, a high-gradient magnetic separation (HGMS) procedure was used to separate the minerals of the clay fraction in soil samples from different horizons of two Alfisols, a Mollisol, an Ultisol and a Spodosol into a magnetic and a non-magnetic fraction. The magnetic fraction constituted 12–19% of the total clay fraction in the Alfisols, 28–35% in the Mollisol, 9–10% in the Ultisol and 11–16% in the Spodosol. X-Ray diffraction (XRD), Mossbauer spectroscopy and total elemental analysis (TEA) were used for the characterization of the different fractions. The CBD-treated magnetic clay contained mainly paramagnetic 2:1 layer silicate clay minerals, including hydroxy-interlayered clay minerals (HICM) high in Fe. The nonmagnetic clay was composed of diamagnetic minerals such as quartz, feldspars, gibbsite, kaolinite and the diamagnetic 2:1 layer silicate clay minerals.

Size Distribution of Dispersed and Aggregated Particles and of Soil Pores in 12 Danish Soils

Abstract Soil texture, aggregates in different size classes and water retention at several water potentials were measured in the top layers of 12 Danish soils. Size frequency curves of dispersed and aggregated soil particles and of soil pores were calculated using numerical differentiation of sum curves, which were obtained from measured data through interpolation procedures. Soils which originated from water sediments had narrow peaks with approximately lognormal distribution of dispersed soil particles and of soil pores, reflecting the sorting action of the water. Moraine soils appeared to have broad and flat frequency curves of dispersed soil particles, some of which were bimodal or skewed. These soils exhibited a typical bimodal size distribution of soil pores. Degree of aggregation was determined primarily by the soil content of clay, 10% or more creating stable macroaggregates of 2–6 mm diameter. A comparison of the frequency curves for soil pore size to a generalized four-parameter mathematical expression relating matric potential and volumetric water content revealed that the model fitted the empirical data reasonably well for the well-sorted water-sedimented soils, while in the case of the bimodal pore size soils a deviation of differing magnitude was observed. From the investigation it is recommended that in most cases, quantities of particles and pores in soil should be related to size with frequency rather than cumulative expressions.

OBSERVATIONS ON THE MORPHOLOGY AND SEXUAL REPRODUCTION OFCOOLIA MONOTIS(DINOPHYCEAE)1

ABSTRACTThe surface morphology of the dinoflagellateCoolia monotisMeunier was compared with the surface morphologyof Ostreopsis, The apical pore ofC. monotisis similar in architecture to that ofOstreopsisbut considerably longer (12 μm) than inO. heptagona(8–9 μm) andO. ovata(6–7 μm). A ventral pore inC. monotisis located on the right ventral margin between apical plate l′ and precingular plate 6″ and is similar in appearance and location to the ventral pore ofO. ovata.The longitudinal flagellum (20 μm) inC. monotisis longer than inO. ovata(12 μ). AlthoughCooliaandOstreopsisappear to be distinctly different and should remain as two separate genera, they appear to be related.Cells ofC. monotisdivided by binary fission. Doubling time was 3–4 days in the logarithmic phase of growth at 23°C, 12:12 h L:D, 30–90 μE‐m−2·s−1, and a salinity of 36%. Cultures reached cell densities of 2.5 × 103cells·L−1after 15 days of growth.The sexual process inC. monotisoccurred in Erdschreiber's medium when Danish soil extract was substituted with mangrove sediment extract under the culture conditions described above. Gamete fusion produced large biflagellated planozygotes (70–75 μm diam). Planozygote maturation involved cytoplasmic reorganization, loss of motility, development of a spherical shape (80–90 μm diam), and two to three orange accumulation bodies. The cells at this stage appeared to be thin‐walled cysts. Further development included reorganization of cyst contents, emergence of non‐motile gametes, and development of chloroplasts, sulcus, and girdle. The nucleus of the newly formed cells occupied 50% or more of the total cell volume. Meiosis occurred in the cyst, but nuclear cyclosis was not observed. Four daughter cells were produced within 36–48 h, and motile gametes developed. The gametes exhibited sexuality for 2 months and completed the sexual life cycle by going through a thin‐walled cyst stage.

Disintegration of the clay fraction in the eluvial horizons of some Danish podzolized soils

Abstract Using sequential extractions, total elemental analysis, and X‐ray diffraction, we have investigated the impact of the podzolization process on component composition of the clay fraction in the eluvial horizons of eight more or less podzolized Danish soils. The results indicate that podzolization is highly aggressive towards all clay components in the eluvial horizons eventually leading to their disintegration. The 2:1 layer silicate clay minerals, illite and chlorite, are first transformed into other 2:1 layer silicate clay minerals. After passing through a microcrystalline phase high in Si but low in Al, Fe, Mg, and K, they finally disintegrate completely. Even gibbsite and kaolinite disintegrate under the aggressive conditions, caused among other things by the presence of dissolved complex forming organic molecules in these horizons. Application of lime and fertilizers seems to be able to reverse the process in case of the 2:1 layer silicate clay minerals.

Mapping of irrigation need based on computerized soil and climatic data

A nation-wide mapping of irrigation need based on computerized soil and climatic data has been carried out. Based on the Danish soil classification and pedological investigations approximately 36 000 profiles have been constructed, and the root zone capacities for grass and barely have been calculated. Based on an empirical model with daily values of potential evapotranspiration and precipitation as driving variables the relationship between root zone capacity and irrigation need for different climatic zones has been outlined and an irrigation map constructed.

Specific Zinc Adsorption as Related to the Composition and Properties of Clay and Silt in Some Danish Soils

Abstract The specific adsorption of Zn was determined in batch experiments for clay minerals and clay and silt particle size fractions. A Langmuir adsorption equation was found to describe the Zn adsorption. An attempt was made to relate Langmuir parameters to the mineralogical composition of samples. Particle size, content of humus and 2:1 structured clay minerals were the most important factors for the specific adsorption of Zn.

Number and Effectiveness of Pea Rhizobia in Danish Soils

Abstract Most of 44 Danish soils tested contain between 103 and 104 pea rhizobia (Rhizobium leguminosarum biovar viceae) per gram. Pea rhizobia were not detected in acid moor and forest soils. Only one case of failed nodulation in peas in the field has been noted, in spots in a reclaimed sandy heath moor at pH 4.7. Soil suspensions of nine of the soils were tested as inoculum in large outdoor pot cultures of peas grown to maturity in nitrogen free vermiculite. One soil approached the effectiveness of commercial inoculants, and four soils were quite effective. Two reclaimed soils and two of three noncultivated soils showed low effectiveness.

Constituents of some widely distributed soils in Denmark

The results presented in this paper follow from investigations of the constituents of some Danish soils during the last 5–6 years. The data are considered in the context of the geomorphological and climatic conditions in the country. The results indicate that the dominant soil group on the Saale glacial deposits (> 100,000 years) consists of Haplorthods, whereas the main group on glacifluvial deposits related to the terminal moraines of the Weichselian Glacial Stage (16,000 to 20,000 years) seems to be Haplohumods. Hapludults are commonly found on the more coarse-textured parts of these terminal moraines. Hapludalfs are dominant on the moraines and Agrudalfs are commonly found on till plains of the later phases of the Weichselian Glacial Stage. Inceptisols and Entisols are also commonly present, but due to differences in origin and age their constituents also differ substantially. Those soils are not considered in details, only average figures from the widely distributed soil groups are included in this paper. The formation of Haplorthods and Haplohumods and to a certain extent of Hapludults has resulted in relative accumulations of quartz in the upper horizons, disappearance of chlorite, reductions in kaolinite and vermiculite, formation of poorly crystalline 2:1 layer silicate clay minerals in the A and E horizons and accumulations of oxy-hydroxides of Fe and Al in the Bh and Bs horizons. In both Hapludalfs and Agrudalfs transformation of illite into vermiculite and smectite seems to have occurred in the upper horizons. Furthermore, some smectite has accumulated in the Bt horizons of soils of these two groups. The contents of quartz, feldspars, kaolinite and oxy-hydroxides of Fe and Al stay almost constant with depth in soils of the two groups.

Determining 222Rn diffusion lengths in soils and sediments.

Radon-222 diffusion length has been measured for 28 Danish soils and sediments. Samples were placed in a diffusion column connected to a 222Rn reservoir and the transport of 222Rn through the column was measured. The diffusion length was found by comparing the measured data to time-dependent diffusion theory. Dry silt, sand and gravel materials showed diffusion lengths from 160 cm to 190 cm. For wet clay materials, diffusion lengths of about 1 cm were found.

PCDDs, PCDFs, and metals in selected danish soils

Topsoil samples from five locations in Denmark were collected and analyzed for polychlorinated dibenzo- p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and selected heavy metals. The upper soil layers contained elevated concentrations of PCDDs, PCDFs, Pb, Zn, and Cu compared to the lower layers. The soil contents of PCDDs plus PCDFs were closely related to Pb contents. Higher concentrations were found near urban areas relative to strictly rural locations. From the presented data the provisional Danish background content of PCDDs plus PCDFs is estimated to be 4–7 μg m −2 in the topsoil of coniferous forests.

Petersen, P. M., The ecology of Danish soil inhabiting Pezizales with emphasis on edaphic conditions (Opera Botanica; 77). 38 pp., 15 figs. Copenhagen, 1985

Petersen, P. M., The ecology of Danish soil inhabiting Pezizales with emphasis on edaphic conditions (Opera Botanica; 77). 38 pp., 15 figs. Copenhagen, 1985

Cadmium soil sorption at low concentrations: VI. A model for zinc competition

Previously presented evidence of Zn competition for Cd soil sorption sites has been confirmed by detailed studies of two Danish soils. Cadmium distribution between soil and solute decreases for increasing Zn solute concentrations. A Langmuir model accounting for both Cd and Zn sorption onto the same sorption sites was supported by independent experimental data on Cd and Zn distribution. The competition of Zn is governed by the product of the Zn soil sorption stability constant and the actual Zn solute concentration. Cadmium distribution coefficients may be significantly influenced by Zn at Zn solute concentrations above 100 μg Zn dm−3. This may have implications for interpreting Cd plant uptake and leaching.

Cadmium soil sorption at low concentrations: V. Evidence of competition by other heavy metals

Sorption of Cd at low concentrations onto 12 Danish soils (coarse sands to sandy loams) was studied with respect to competitive effects of other heavy metals by means of laboratory batch experiments. Both a mixture of Ni, Co, and Zn and of Cr, Cu, and Pb effectively reduced the sorption of Cd onto the soils. The employed mixtures of competing heavy metals were considered to resemble moderately polluted conditions. Cadmium distribution coefficients were reduced 2 to 14 times due to competition, but at constant concentrations of competing heavy metals the shape of Cd isotherms was not affected. The effect of Ni, Co, and Zn, which like Cd is primarily governed in soil environments by sorption, was also studied individually. Apparently Zn, which is present in relatively higher concentrations than Ni and Co, accounts for most of the observed competition with Cd.

Landbrugsjordens terrænhældning

Madsen, Henrik Breuning, Kristian Aagaard Hoist og Axel Henry Nørr: Landbrugsjordens terrsnhældning. Geografisk Tidsskrift 87: 68–70. Kobenhavn, juni 1987. Slope classes from the Danish soil classification have been digitized and area statistics in relation to counties and landforms have been carried out.

Effects of acid rain on ion leaching in a danish forest soil

The mobility of major cations (H+, ammonium, Al, Ca, Na, Mg, K, Fe), heavy metals (Mn, Zn, Ni, Cd) and anions (chloride, sulphate and nitrate) was studied in the laboratory in an acidified brown soil from a Norway spruce forest. Lysimeters containing undisturbed soil columns of the A-horizon and the A- plus B-horizon were watered with 540 mm of throughfall precipitation collected in situ, either directly (pH 3.6) or adjusted to pH 3.3 or 2.8. The pH 3.3 treatment increased leaching of Mn and Cd from the B-horizon. The pH 2.8 treatment increased leaching of ammonium, Na, Ca, Mg, K, Mn, Zn and Cd from the A-horizon and ammonium, Al, Na, Ca, Mg, K, Mn, Zn and Cd from the B-horizon. Fe leaching from the A-horizon was decreased by both acidic treatments, and the pH of the leachates was not significantly affected. Sulphate retention was 138-161 meq m−2 yr−1 by all treatments. Due to experimental conditions nitrate leaching was observed in all lysimeters.