Marine Clay Soil Research Articles

Relation between Vertical Soil Movements and Water‐Content Changes in Cracking Clays

AbstractField studies on swelling and shrinkage in clay soils are scarce, due to the lack of sound experimental methods and suitable mathematical equations. This study was aimed at developing such methods and equations. Disks were positioned at various depths in the soil in order to measure vertical movements in undisturbed soil. Newly developed equations were applied to convert these vertical soil movements into three‐dimensional volume changes and crack volume and to relate them to water‐content changes. These equations are unique in that they are valid for water loss in the structural‐, normal‐, residual‐, and zero‐shrinkage phases, and for both isotropic and anisotropic shrinkage. Methods and equations were successfully tested in a 1‐yr field experiment in a heavy marine clay soil in the Netherlands. The use of seven rotating disks for measuring soil volume changes was about 10% more accurate than two other less laborious methods. An interesting application of this method and equations is the determination of soil water‐content changes by measuring vertical soil movements.

Effect of crop rotation, cultivar and nematicide on growth and yield of potato (Solanum tuberosum L.) in short rotations on a marine clay soil

The effects of cropping frequency on the yield of potato and on the development of soil-borne diseases was studied from 1979 to 1985 in a crop rotation experiment on a marine clay soil. Tuber yield decreased markedly with increasing cropping frequency. The yield of cv. Hertha was reduced by 27% in continuous cropping and by 15% in a wheat/potato or sugar beet/potato rotation, when compared with the rotation wheat/sugar beet/oats/potato. However, a pot experiment showed that yield depression in continuous cropping depended on the cultivar used.

Synergistic interactions betweenRhizoctonia solani Kühn,Verticillium dahliae Kleb.,Meloidogyne spp. andPratylenchus neglectus (Rensch) Chitwood & Oteifa, in potato

Samples of a sandy soil and a marine clay soil sterilized by steam were put in 55-1 containers insulated with polystyrene and placed outdoors on a brick pavement. Sandy soil was infested singly or in all possible combinations with root-knot nematodes (Meloidogyne spp.) and the fungiRhizoctonia solani andVerticillium dahliae, and the marine clay soil was infested with the root-lesion nematodePratylenchus neglectus and the same fungi to evaluate the effects of these organisms on the yield of potato. The experiments were carried out from 1983 to 1986. Tuber yield was reduced by single infestations of theMeloidogyne spp. andV. dahliae but not significantly byR. solani orP. neglectus. A three-factor interaction: nematode ×R. solani × V. dahliae was found in both experiments.R. solani andV. dahliae showed significant synergistic effects when soil was infested with theMeloidogyne spp. orP. neglectus.

Carbon and Nitrogen Levels in a Subsurface Drained Silty Clay Soil

ABSTRACT Organic carbon and nitrogen content were determined for soil samples taken annually from 1978 through 1983 from four depth increments from all plots of a shallow subsurface drainage research project. Drainage treatments were 3, 6 and 12 m spacing and no drainage. Drain tubing was 75 m diameter perforated corrugated plastic. Soil water from buried porous cups above and below the drains and from drain outflow was analyzed for nitrogen content. The objectives were to determine the long-term changes in soil carbon and nitrogen content, determine nitrogen levels in soil water and drain discharge, and to improve our understanding of nitrogen fertilizer management under intensive drainage systems for poorly drained marine and lacustrine silty clay soils. Over time, intensive cropping and drainage caused significant decreases from initial values of both soil carbon and nitrogen content for all depths measured. The difference between initial and final soil carbon and nitrogen values for the surface 0.15-m depth of soil suggests the possibility of a drainage-caused decrease in soil carbon (P = 0.08) and shows a significant drain treatment effect on soil nitrogen (P = 0.013). Drainage-caused soil nitrogen depletion in the 0.15-m soil depth occurred over the first years of the study during corn production and stopped after alfalfa was grown. Nitrogen levels in drain water exceeded 10 ppm only in July of the second year of intensive cropping.

Results of a ground-water level and nitrogen fertilizer field experiment with apple trees on a marine clay soil

This paper summarizes and reviews some of the results of a 12-year experiment which was carried out in order to examine drainage requirements of apple trees on a newly reclaimed soil. The experiment involved production of Cox's Orange Pippin and Golden Delicious apples, grafted on M9 rootstock, that were planted on 11 different ground-water regime plots which were split into three nitrogen treatment sub-plots. It was found that there was a distinct variation in amounts of shoot growth, apple production nitrogen mineralization, and fruit quality on account of variations in the ground-water regime. No optimum ground-water regime could be established. This optimum may be quantified by using the capital budgeting decision procedure. The optimum nitrogen concentration in mid-shoot leaves, however, was found to be 2.3 and 2.4 percent of dry matter for Golden Delicious and Cox's Orange Pippin respectively.

Root growth of potato crops on a marine-clay soil

In 1982 and 1983 root samples were taken by auger from potato crops grown on marine clay in the Flevo-Polder. The roots increased their penetration depth throughout the periods of measurement, and ultimately reached depths between 80 cm and 100 cm below the hills. Between 50 and 60 days after emergence, decay of roots commenced, starting in the upper horizons. In the hill mean root length densities varied between 1 and 2 cm cm−3. Below the hills root density rarely exceeded 1 cm cm−3. The random variation in root density was equivalent to a coefficient of variation of 50%. There were significant effects of the position of sampling (relative to the centre of the plant) on root density; densities were usually lowest beneath the furrow. Depending on season and sampling date, total root length varied between 3.4 and 7.1 km m−2, and root dry mass varied between 33 and 77 g m−2. Representative figures for specific root length were 100–120 m g−1 dry weight. About 90% of the root diameters were smaller than 0.44 mm; the most frequent class (35%) were roots with diameters between 0.12 and 0.20 mm.

Fertilizer regime and changes in the phosphate and potash status of a silty marine clay soil during 25 years

Changes in the soil phosphorus and potassium status on three farming systems in the Northeast Polder during 25 years are related to the fertilizer regime over this period.

ISOTOPE GEOCHEMISTRY OF CARBONATE DISSOLUTION AND REPRECIPITATION IN SOILS

The processes of dissolution and reprecipitation of carbonates in soils developed on carbonate rocks, loess-derived soils, and marine clay soils were studied with the methods of stable isotope geochemistry. Between 10 and 50 percent of the carbonates present in the upper part of soils developed on carbonate rocks are newly formed. In loess-derived soils and in marine clay soils, up to 100 percent of the carbonates present may be newly formed. The efficiency of the dissolution-reprecipitation process varies between 10 and 30 percent. In the salt marsh investigated the dissolution is caused by the action of biogenic carbon dioxide.

Soil formation in swamp soils of the coastal fringe of Surinam

This paper presents data on the sedimentation processes along the Surinam coast, the resulting deposits and soil formation in the young Holocene marine clay soils. Along the Surinam coast two types of materials were observed: fine-textured (clay) and coarse-textured materials (sand and shells). They originate from different sources, are transported along different ways and are deposited separately. Three types of coasts were distinguished: an erosional, a sand accretionary and a mud accretionary coast. Behind the erosional coast and the sand accretionary one salt pans may develop with a sparse vegetation and impervious stiff clays. Behind a mud accretionary coast a brackish water swamp generally developes, which may be nearly always inundated or periodically dry. In the wet swamps an accumulation of pyrite occurs, but little or no oxidative soil formation. In the periodically dry swamps the accumulation of the pyrite is alternated by oxidative soil formation and compaction. Ultimately four groups of soils were recognized which differ from each other in acidity and permeability and consequently have different agricultural potentialities.

Some morphological aspects of regrouping phenomena in Dutch soils

Mostly pedogenesis is the result of a combination of processes. These cause a number of macro- and micromorphological changes, a part of which are denoted as regrouping phenomena. Regrouping of soil components includes all changes in distribution and orientation patterns within the pedon, with the exception of changes caused by additions or transformations of mineral components. The phenomena may be subdivided into: 1. (1) Pedoturbations. These mixings of components can be caused by natural processes (such as activity of fauna, transfer of soil by gravity, swelling and shrinkage of clay minerals) and by human activity (mechanical soil amelioration, cultivation). Turbations may lead to granulation and a better porosity (high pore volume, more favourable types of voids) but they can result also in a higher density. 2. (2) Pedocompactions. These stress-induced phenomena are caused by i.a. burrowing animals and plant roots, swelling and shrinkage of clay minerals and fluctuation of groundwater, but also by anthropic influences such as tillage (plowpans), vibration of engines, piling of soil material, etc. The relevant changes are i.a. decrease of pore volume, less favourable types of voids, the beginning or intensification of plasmic fabric formation. 3. (3) Concentrations. These are caused by natural processes, such as mobilization and illuviation of clay or disperse humus and illuviation of coprogenous humus, or they are primarily due to anthropic factors (humidity at the moment of tillage, kind of tillage, land use, etc.). Concentrations of one or more components may be found. In the latter case concentrations of the different components may occur separately or in banded fabrics (slaking-crusts, agricutans). On the basis of the present classification two examples of pedogenesis are dealt with: 1. (1) Slaking soils. The genesis of these soils (many marine clay soils, loessloam soils, etc.) is characterized by: 1.1. (a) Sorting of components at the surface and crust formations. 1.2. (b) Sorting of components in the top soil by micro-erosion or puddling. followed by compaction; in both cases subsequently combined or separate illuviation and concentration of the sorted components (clay, silt, sand, humus): formation of agricutans. Depth and extent of illuviation and concentration are determined by the degree of development of plowpan (mecacompaction) and its type. 2. (2) “Knip” soils. The genesis of these marine soils is characterized by a very distinct combination of micromorphological changes: 2.1. (a) Sorting of components and subsequently separate illuviation and concentration of clay, silt and sand (formation of argillans, skeletans and granotubules). 2.2. (b) Transfer of top soil material by gravity to the sub-soil (gravipedoturbation: filling up of cracks). 2.3. (c) Changes caused by the swelling and shrinkage of clay minerals. These changes are separations of clay-sized material (argillipedocompaction: formation or intensification of plasmic fabrics) and distortions of fabrics (pedoturbation) underneath the top layer due to the transport of materials as mentioned under the points (a) and (b). Even argillans, skeletans and granotubules can be distorted in this way, which results i.a. in the formation of some pronounced types of plasmic fabrics, such as masepic and mosepic.

Decalcification of marine clay soils connected with decalcification during silting

The marine clay area in The Netherlands consists largely of soils which are deposited in various periods of the Subatlanticum. In the 11th century man began to protect these areas from flooding by means of dikes. A part of the soils is now decalcified to variable depths. In general, the strongest decalcification phenomena are to be found in the oldest polders. However, the length of time since enclosure cannot be considered the only or even the most important factor for these variations. Decalcification following enclosure is preceded by a more intensive decalcification during silting. During this stage both supply and leaching of CaCO 3 take place at a variable rate. The way in which they differ from place to place and the changes they are subjected to during silting are made clear by analysis. It is concluded that the variable conditions during silting are the most important cause of present-day variations in CaCO 3 content and depth of decalcification in the marine clay soils of The Netherlands.

The Soils of the Lower Eastern Slopes of the Cameroon Mountain and Their Suitability for Various Perennial Crops

On the eastern slopes of the Cameroon Mountains soils occurring below the 100- metre contour were surveyed on a scale 1:25,000. Most soils are young marine clay soils used for growing bananas, oilpalms, cocoa, rubber and tea. At some places there are lava streams from the mountains. A more general soil survey was made of the younger and older volcanic soils above the 100-metre contour line and a map, scale 1 : 100,000, was produced. The relative age of the various volcanic deposits could be estimated after completing the study of the origin, genesis and distribution of marine soils, that cover volcanic deposits in the lower part of the plain. The discovery of beach walls at different levels formed as a result of differences in sea-levels and gradual rise of the land, helped to solve various soil problems. Most soils are K-deficient, especially young volcanic soils.