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The effects of acid deposition on cation release and key properties of two forest soils collected near Guiyang and Nanchang in southern China were studied in leaching experiments. Rebuilt soil columns consisting of three soil layers were exposed to five different leaching solutions, i.e. deionized water, two solutions with pH about 3.5 and two solutions with pH about 4.3. Salts (CaSO 4 ,...
The effects of temperature, time and cycles of drying and rewetting on the extractability of Zn added to a calcareous soil were studied by three successive extractions with DTPA. The concentrations of DTPA-extractable Zn increased linearly with the concentration of added Zn. The proportion of added Zn in the DTPA-extractable fraction decreased with increasing incubation time and with increasing...
Magic angle spinning (MAS) nuclear magnetic resonance (NMR) was used to investigate the chemical environment of P in soil and soil components. 31 P and 27 Al MAS NMR spectra are presented of synthetic aluminium hydroxides (amorphous aluminium hydroxide and gibbsite), reacted with P under different conditions of P concentration, temperature and pH. The reaction product is...
A short general review of all aspects of the NMR technique, in both the spectroscopic and imaging modes, as applied to the study of soil, is presented from a mainly technical point of view. Illustrations, in the form of spectra and images, are reproduced for whole soils, solids, solid fractions, and liquid extracts from material in the authors' group. Nuclides covered are 1 H, 13...
Displacement imaging is a recent, powerful NMR method with which distributions of displacements can be acquired of e.g. fluids within a porous medium. Both motion parallel and perpendicular to the flow direction may be observed within a time window of a few milliseconds to several seconds. By combining displacement imaging with the line scan technique, one-dimensionally resolved measurements with...
Isotopes of strontium (Sr) are a useful tracer for weathering, atmospheric fluxes, cation biocycling, and pedogenesis. We present basic models for application of strontium isotopes to the soil-vegetation-atmosphere system. The mathematical formulations fall into the general categories of: (1) steady-state models, in which isotopic ratios remain constant over the time scale of interest; and (2) time-dependent...
The strontium (Sr) isotope method can be a powerful tool in studies of chemical weathering and soil genesis, cation provenance and mobility, and the chronostratigraphic correlation of marine sediments. It is a sensitive geochemical tracer, applicable to large-scale ecosystem studies as well as to centimeter-scaled examination of cation mobility within a soil profile. The 87 Sr/ 8...
The release of base cations by the weathering of soil minerals provides the primary buffer against the detrimental impact of acid deposition on the soil. The rate of release of base cations will be governed by mineral composition and the exposed surface area of mineral grains. In theory it is possible to calculate the surface area of a mixture of grains on the basis of particle size and geometry....
Several algorithms for analyzing the diversity of the world pedosphere are reviewed and employed. Special emphasis has been laid on indices based on the Theory of Information. We study the diversity and distribution of major soil groups by continents and climatic zones on the basis of data compiled by the FAO at the scale 1:5,000,000. Major soil group-distribution model relationships on a world...
A sequential extraction procedure, used to remove the heavy metals in specifically adsorbed and easily reducible manganese (Mn) oxide fractions, was used to study the transformation of heavy metals added to an alkaline soil. Most of the endogenous Cu (86%) and Pb (79%) were found in the residual fraction (RES) which was considered to be mainly highly crystalline Fe oxides and silicate minerals. The...
Electromagnetic (EM) induction and ground-penetrating radar (GPR) methods have been used extensively in areas of karst to detect and delineate major structural and solution features and to improve site assessments. These methods do not work equally well in all soils and the amount of practical information derived from surveys has varied. The choice of the most appropriate method often depends on the...
The spatial variation of soil properties within landscapes is controlled by the soil forming factors relief, parent material, climate, organisms, and time. Although this relation is a paradigm in soil survey, it is rarely considered in the analysis of spatial variability of soil properties. Homogeneous soil units are mostly mapped according to the soil properties found close to the soil surface. Nevertheless,...
Concentrations of amino acids were measured in hydrolysates of manured and unmanured soil samples collected in 1876 and 1959 from the Park Grass experiment, and in 1964 from the Broadbalk Wilderness plots, at Rothamsted, England. Discriminant analysis separated successfully the Park Grass treatment groups after the effect of absolute amino acid concentration had been removed. The same statistical...
Soil solution is the direct source of mineral nutrients to vascular plants. Soil solutions of sieved samples at water-holding capacity of a seminatural calcareous soil, never cultivated or treated by fertilizers, were collected by sequential centrifugation at 24-18,900xg relative centrifugal force (RCF), followed by ultrafiltration (0.2 μm), and analysed for Al, Ca, Fe, K, Mg, Mn, Mo, Na, P, S, Si...
We investigated the effects of changing fire regime on the stocks and isotopic composition of soil organic carbon (SOC) in a tropical savanna ecosystem at Matopos, Zimbabwe. Vegetation plots from both sandy and clay-rich soil types at this location have been subjected to fire frequencies ranging from annual burn to complete protection for the last 50 years. Gross variations in 0-5 cm SOC stocks and...
The relationship between the known water content and that determined using Magnetic Resonance (MR) methods was studied for samples of two soils packed to various dry bulk densities; four basic MR protocols were employed (single 90 o pulse, inversion-recovery, Carr-Purcell-Meiboom-Gill (CPMG), and spin-echo (SE) pulse sequences). The soil types were chosen from a previously studied range of...
The distribution of soil organic substances at five topographic sites was evaluated in the undisturbed mountainous forest of the Yuanyang lake ecosystem, northeastern Taiwan. The high annual rainfall there (>4000 mm) contributes to extreme acidity of the soil, which has a thick organic layer. The soil organic substances are classified as water soluble organic carbon (WSOC), microbial biomass carbon...
A promising technique for dating paleosols is reported based on radiocarbon ( 14 C) dating of asexual spores from vesicular-arbuscular mycorrizae (VAM). The soils are dispersed in water and some 6000-8000 spores separated by hand picking under a low power microscope. The dried spores are then dated by accelerator mass spectroscopy (AMS). A chronosequense of closely superimposed paleosols...
A typical geostatistical analysis of soil data proceeds on the assumption that the properties of interest are the outcomes of random processes. Is the assumption reasonable? Many factors have contributed to the soil as we see it, both in the parent material and during its formation. Each has a physical cause, each must obey the laws of physics, and each is in principle deterministic except at the...
Because of their high content in heavy metals, Fe-Mn concretions present in soils can be a source of release of trace metals in the environment. Metal-rich concretions were isolated from a top horizon of a Rendzic Lithosol developed on limestones in France. The distribution of metallic elements (Cr, Co, Ni, Cu, Zn, Pb) was studied at different scales: field sampling, isolated concretions, and individual...
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