Geoderma
Soil structure has been destroyed over large areas of arid and semi-arid regions by soil degradation processes. This study was conducted to investigate the effects of two organic amendments, urban refuse and peat, on the improvement of soil structure and to analyse correlations between organic carbon content, fungal and bacteria populations and aggregate stability. Two series of five plots were...
Parent material relations in loess-influenced soils of west-central Kentucky were studied to better understand the nature of the loess and its impact on the soils of that area. Twenty-one stable landscape positions were sampled on two adjoining transects trending northwest to southeast from the Ohio River to the Tennessee border. Profiles were described in the field, and samples were collected for...
A deterministic model was applied to simulate soil water chemistry data, collected during an 18-year period in an acid forest soil in Solling, Germany. In this paper, the hydrochemistry of Cl, NO 3 and SO 4 is discussed. Seasonal and long-term variations of Cl concentrations in soil solution were successfully simulated as a result of atmospheric deposition and hydrological processes...
Accurate in situ determination of unsaturated soil hydraulic properties is often not feasible because of natural variability of most field soils, and because of instrumental limitations. Therefore the soil hydraulic properties are often measured in the laboratory, or derived by computer models using simple standard laboratory methods.This paper analyses problems in describing field hydraulic properties...
This study examines the mineralogy of salt crusts developed on the irrigated paddy soils in the Soudano-Sahelian region of Niger. It involved field observations supplemented by laboratory determinations: powder XRD, SEM-EDAX, IR spectral analyses. The salt crusts were found in the concave zones near to the dike along the Niger River. They consisted of white mamillated konyaite crystals supported...
Vegetation and soil of mangrove swamps were studied with the aim of understanding the interrelationships of the mangrove ecosystem. Principal components analysis (PCA) was used to generate a hypothesis that the distribution patterns of mangrove vegetation were influenced by variation in soil properties. The hypothesis, tested by simple correlations of vegetation components and soil variables, revealed...
An irrigated agricultural area of 2350 ha in the San Joaquin Valley of California was used for assessing regional-scale vertical flow and solute transport. The study area was sufficiently large to show variability in salt-loading to the groundwater due to cropping and irrigation efficiency. A geographic information system (GIS) was used to store and manipulate a variety of data required for vertical...
An analytical expression describing the moisture retention characteristic was tested using multiple regression on 105 horizons in 34 representative soils from Greece, with textures from loamy sand to heavy clay. All samples were analyzed for particle size distribution, organic carbon content, carbonates content and dry bulk density. It was found that soil moisture retention by the studied soils...
Relationships between topographic position and soil water, soil nitrogen (N), and tree growth were examined on two regional landforms in Minnesota, USA. The study was conducted in northern pin oak stands (Quercus ellipsoidalis E.J. Hill) on an outwash plain, and in aspen stands (Populus tremuloides Michx.) on a ground moraine complex. Three slope positions (upper, middle, lower), four aspects (NE,...
The biodegradation of pure eicosane (nC 2 0 ) in rendzina soil samples was studied in a laboratory experiment at 20°C. After 8 weeks, 25% of eicosane was mineralized. Terminal oxidation led to C 2 0 : 0 acid, with eicosan-1-ol as probable intermediate. An interesting dehydrogenation process occurred, leading to eicos-9-ene which was oxidized into eicos-9-enoic and...
Hydrologic characteristics of soils are of general significance for many land use activities because of their relationship to water and solute flow. Water plays important roles in soil genesis, agricultural productivity, and transport of potential contaminants to groundwater. Sandy soils in portions of the Lower Wisconsin River Valley (LWRV), dominated by Sparta sand (uncoated, mesic Typic Quartzipsamments),...
Quantitative assessments of the impact of agricultural practises on soil quality have been hindered by the lack of basic spatial units for designing landscape-scale research projects. This paper builds on the relationship which has been demonstrated to exist between small (5 m by 5 m) slope segments and soil distribution in order to define larger landform element complexes in till landscapes of southern...
The adsorption isotherm of zinc and the kinetics of the adsorption and desorption of zinc by the short-range ordered oxide of iron, which was formed both in the absence and presence of citric acid, were studied. The results showed that the presence of citric acid, one of the most common organic ligands in soil, during the precipitation of Fe oxide substantially modified the characteristics of surface...
Pedogenesis was investigated on soils which were rehabilitated following mining of Late Pleistocene sand dunes at Tomago, on the east coast of Australia. The soils were rehabilitated by spreading stockpiled A1 horizon material over mixed A2 and B horizon materials from the original humus podzols. A four stage chronosequence of 1, 5, 11, and 17 years since soil rehabilitation was established and changes...
Soils with plinthite and ironstone concretions are extensive in Maranha˜o State, northeastern Brazil. They formed from the Fe-rich Itapecuru sandstone in a tropical subhumid climate with distinct wet and dry seasons. Most plinthic soils in Brazil have properties associated with low-activity clays, but these soils were reported to have properties associated with high-activity clays.The main objectives...
The degree of weathering was investigated in four sandy soils at Hjelm Hede in northwest Jutland, Denmark. Previous studies showed that the degree of podzolisation was influenced by vegetation as follows: Quercus robur (oak) < Calluna uulgaris (heather) < Picea sitchensis (spruce). This study shows that the soil under grass is the least podzolized. The data show that the particle size and mineralogy...
The Hedley fractionation recognizes plant-available forms (Resin Pi, Bicarb Pi, and Bicarb Po) and refractory forms (NaOH Pi, NaOH Po, sonic Pi, sonic Po, HCl Pi, Residual P) of soil phosphorus. This updated survey of the recent literature shows that the sequential fractionation proposed by Hedley et al. can also be used to separate forms of organically bound soil phosphorus from the geochemically...
Neoformation of allophane, imogolite, and gibbsite has been studied extensively in soils in humid climates, but little is known about their micro distribution patterns. such information may provide insight about the conditions at the micro-site scale, responsible for their formation and disappearance.Our study describes amorphous and crystalline coatings in a Melanudand on a 18,000 yr old andesitic...
This article presents a review of applications of computed tomography (CT) in soil science and petroleum engineering. We discuss the use of CT images to obtain quantitative expressions for soil structure. We elucidate this approach with a case study of an infiltration experiment in an undisturbed clay soil. The clay sample was scanned in initially dry condition and after infiltration of water with...