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One of the mechanisms for sudden particle release is a decrease in groundwater salt concentration to below the critical salt concentration (CSC), where repulsion forces between fine particles and matrix surfaces exceed binding forces. In this paper, an attempt was made to determine the CSC with both batch and column experiments. Two types of sediments were tested: (a) homogeneous quartz sand and (b)...
A high degree of soil variability over short distances and small areas is common, particularly in forest soils. This variability is sometimes, but not always, related to readily apparent variations in the environmental factors that control soil formation. This study examines the potential role of biomechanical effects of trees and of lithological variations within the parent material in explaining...
The accumulation of carbon (C), nitrogen (N) and phosphorus (P) and their vertical distribution in the soil profile in relation to site age were studied in a chronosequence of 19 sites on reclaimed spoil heaps from open-cast coal mining, near Sokolov (Czech Republic) and compared to a semi-natural alder forest in the vicinity of the mining area. The reclaimed sites were located on tertiary clay or...
Phosphorus (P) availability has generally been assumed to be the limiting or co-limiting factor for plant growth in alpine environments. To test this assumption, the biogeochemistry of phosphorus (P) along an alpine topographic/snow gradient located on Niwot Ridge, Colorado Front Range was studied in the context of P limitation for plant growth. We measured the various P pools using a selective extraction...
The objective of the study was to assess the extent and severity of heavy metal contamination of arable soils of the Damascus Ghouta, an area with intensive agricultural production. We examined the present degree and spatial distribution of heavy metal concentrations in 51 soil profiles and in 22 topsoil samples in the Damascus Ghouta. The soils were digested with aqua regia for heavy metal analysis...
Isotopic signatures of soil components are commonly used to infer past ecologic and climatic shifts in the soil record. The theory behind the fractionation of isotopes that occurs during ecosystem processes is well understood; however, few isotopic studies have explored ecosystem relationships in modern soils. We discuss relationships of stable carbon isotopic signatures in plant tissue, soil organic...
Multivariate regressions on ultraviolet (UV) absorbance (210-300 nm) data were tested as a potential tool to estimate concentrations of total dissolved organic carbon (DOC), DOC in the XAD-8-adsorbable (hydrophobic) fraction (HoDOC), and dissolved nitrate (NO 3 -N) in forest floor leachates. Partial least square (PLS) regressions were established for 20 zero-tension lysimeter solutions sampled...
The bioavailability and ultimate fate of heavy metals in the environment are controlled by chemical sorption. To assess competitive sorption of Pb and Cd, batch equilibrium experiments (generating sorption isotherms) and kinetics sorption studies were performed using single and binary metal solutions in surface samples of four soils from central Spain. For comparisons between soils, as well as, single...
Soil structure exerts important influences on the edaphic conditions and the environment. It is often expressed as the degree of stability of aggregates. Aggregation results from the rearrangement, flocculation and cementation of particles. It is mediated by soil organic carbon (SOC), biota, ionic bridging, clay and carbonates. The complex interactions of these aggregants can be synergistic or disruptive...
There exists a clear knowledge gap about the kinetics and mechanisms of desorption of metals and metalloids from soils and clays, even after repeated emphasis on its importance for a better understanding of the mobility, transport and fate of metals and metalloids in natural environments. In this study, we investigated the phosphate-induced desorption kinetics of preadsorbed selenite from montmorillonite...
As an essential indicator of soil quality, soil organic carbon (SOC) and its fractions play an important role in many soil chemical, physical, and biological properties. A 4-year field experiment was conducted to determine the effects of different nutrient and water regimes on paddy soil organic carbon quality by measuring the major SOC fractions. Four nutrient regimes were compared: (i) control;...
As a subdiscipline of soil science, pedology consists of an accepted body of laws and theories that cover a range of related ideas and concepts. We have traced the history of these concepts as they pertain to the definition of the soil; soil horizons, profiles, and pedons; soil-forming factors; pedogenic processes; soil classification; soil geography and mapping, and soil-landscape relationships....
Contents of soil organic matter (SOM) and total nitrogen (TN) in the surface soils and subsurface soils were measured in five types of floodplains classified with different flood frequencies in river marginal wetlands of Erbaifangzi, China, in 1999. Contour maps and profile maps were constructed to describe the spatial distribution of SOM and TN in order to identify the influences of flood frequency...
With respect to carbon sequestration in soil, attempts have been made to identify soil organic matter (SOM) fractions that respond more rapidly to changes in land-use than bulk SOM, which could thus serve as early indicators for the overall stock change. We used a combination of physical fractionation (size and density separation) and chemical characterisation (C-to-N ratios, CuO lignin signature,...
The evergreen Nothofagus betuloides and deciduous Nothofagus pumilio live close together in Tierra del Fuego. The fact that these two species rarely form mixed forests suggests that the soil factor can contribute to the distribution of two species on a local scale. Most of these forests are undisturbed; therefore, soil characteristics may reflect both the influence of the species and of the dominant...
In semiarid climate soils, the establishment of a plant cover is fundamental to avoid degradation and desertification processes. A better understanding of the ability of plants to promote soil microbial processes in these conditions is necessary for successful soil reclamation. Six different plant species were planted in a semiarid soil, in order to know which species are the most effective for the...
Fuzzy classification combined with spatial prediction was used to assess the state of soil pollution in Isfahan region, central Iran. Total concentrations of cadmium (Cd), lead (Pb), zinc (Zn), copper (Cu), and cobalt (Co) were determined in 255 topsoil samples (0–20 cm) collected irregularly in a study area of 6800 km 2 . Heavy metals concentrations were grouped into four classes according...
This study was carried out in a Mediterranean salt marsh from semiarid Southeastern Spain, to determine the influence of eight halophytes (Asteriscus maritimus (L.) Less., Arthrocnemum macrostachyum (Moric.) Moris, Frankenia corymbosa Desf., Halimione portulacoides (L.) Aellen, Limonium cossonianum O. Kuntze, Limonium caesium (Girard) O. Kuntze, Lygeum spartum L., and Suaeda vera Forsskål ex J.F....
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