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Soils on a sequence of well drained Neoglacial moraines up to 240 years-old, plus an older soil, were sampled to investigate soil development through the initial stages of podzolization. Pebbles and cobbles in the moraines are about 75 to 80% granitic rock. Computations based on minerals observed optically and on chemical analyses indicate that plagioclase and quartz are the predominant minerals...
The molecular composition of soil organic matter (SOM) in Pleistocene moraines of different ages in the Bolivian Andes was investigated by elemental analyses (C, N) and by off-line pyrolysis under nitrogen at atmospheric pressure and on-line pyrolysis-field ionization mass spectrometry (Py-FIMS) in vacuum. Moraine ages of 9,000, 16,000, 20,000 and > 20,000 years were derived from 14 ...
Soils on Holocene-age moraines of the Mendenhall Glacier in southeast Alaska range from morphologically undeveloped to soils having field-identified spodic horizons that are more strongly expressed with increasing soil age. A soil chronosequence was sampled to study development of spodic features and to compare the expression of these features with chemical and micromorphological properties. Organic...
As part of a land-ecological survey of the middle Caqueta basin in Colombian Amazonia, a total of 41 well drained upland soil profiles under primary rain forest was studied. Two soil groups were recognised on the basis of principal components analysis (PCA). Soils pertaining to the first group cover about 45-60% of the well drained uplands and classify as Alisols and Acrisols. They are characterised...
Land evaluation is the process of predicting the use potential of land on the basis of its attributes. A variety of analytical models can be used in these predictions, ranging from qualitative to quantitative, functional to mechanistic, and specific to general. This paper classifies land evaluation models by how they take time and space into account, and whether they use land qualities as an intermediate...
Concentrations of amino acids were measured in hydrolysates of manured and unmanured soils collected in 1881 and 1980 from the Broadbalk continuous wheat experiment at Rothamsted (England). Discriminant analysis successfully separated the treatment groups after the effect of absolute amino acid concentration had been removed. This suggests that it may be possible to identify an amino acid fingerprint...
The aim of this work was to analyse the influence of soil structure on water movement in different ploughed soil layers. The structure of soil layers was accurately defined and described. The water content and the oxygen-18 content of the water, taken as an environmental tracer, were measured taking into account the internal structure of clods: clods showing a very low macroporosity (called Δ clods)...
Image analysis of photographs made from 5 cm 10 cm soil thin sections from a Vertisol profile (0 - 175 cm depth) in southern Italy demonstrates the existence of two types of pore networks: a network of pores of continuously decreasing porosity and irregularly abundant macropores. These pore networks change in a regular manner from one depth to another. Certain macropores occur in the range of the...
The δ 18 O values of smectite (+ 14.2 to +20.5‰) from soils and sediments along the coastal plain of Ariake Bay, northern Kyushu, Japan, suggest that the smectites are detrital in origin. Samples of detrital smectite from the catchment of major rivers entering Ariake Bay have similar δ 18 O values (+18.2 to +22.8‰). The oxygen-isotope data rule out neoformation at low temperatures...
The current soil dynamics of a podzol-oxisol climosequence located in Tahiti on basaltic and pyroclastic parent rocks has been investigated using the test-mineral technique. The test-mineral, a vermiculite with a high exchange capacity (161 meq/100 g) was placed in recoverable bags in the A and B horizons of three members of the sequence, for periods of 1 to 3.5 years.Changes in the chemistry...
Geomorphic distribution and petrological differentiation patterns of ferricretes widespread on landsurfaces were studied in the Dembia-Zemio area, southeastern Central African Republic. Four types of ferricretes are distributed on high plateaux, hillslopes and low plateaux. The main contrast corresponds to the differentiation between ferricretes of high plateaux rich in poorly hydrated minerals,...
The connectivity of pore space is an important topological property of soil. Together with the porosity and the pore-size distribution, it governs the transport of water, solutes and gases.This paper describes the Euler-Poincare characteristic (EPC) as an index of connectivity of soil pore space in three dimensions, and shows how the EPC can be estimated by analysing pairs of parallel images, so-called...
Knowledge of rates of release of base cations from mineral dissolution (weathering) is essential to understand ecosystem elemental cycling. Although much studied, rates remain enigmatic. We compared the results of four methods to determine cation (Ca + Mg + K) release rates at five forested soils/sites in the northcentral U.S.A. Our premise was that multiple approaches, each with their own specific...
Soil chronosequences were examined on flights of tectonically uplifted marine terraces near Cape Blanco and Cape Arago, southwestern Oregon. All of the soils contain abundant organic C and are strongly acidic (pH in H 2 O < 4.7) with < 10% base saturation and > 30% of the exchange sites saturated with Al. The soils in the two areas show a progression in development from Spodosols...
Weathering rates of silicates obtained from laboratory experiments are generally one or two orders of magnitude higher than field weathering rates. To obtain more information on this gap in weathering rates a large undisturbed soil column (length 30 cm and a surface area of 113 cm 2 ) was percolated with a HClH 2 SO 4 solution. Percolation rates during the experiment were...
Batch and column experiments were conducted to study the effect of pore water velocity on the adsorption of cadmium (Cd) onto a homogeneous nonaggregated porous medium under controlled environmental conditions. A wide range (5-214 cm/hr) of pore water velocities was imposed to observe adsorption effects. The results of batch experiments showed that adsorption coefficients are affected by the solid-to-liquid...
A grid sampling pattern of 108 sample locations at distances ranging from 15 to 122 m was used to develop a baseline characterization of soil physical and hydrological properties in a 40 ha field. Statistical distributions of silt and sand were not normal. Coefficients of variation of sand, silt and clay contents were 59%, 18% and 25%. Pedotransfer functions (PTFs) were developed using indicator...
The adsorption of sulfate at different pH in the presence of different concentrations of sodium perchlorate, sodium nitrate or sodium chloride by two variable charge soils with contrasting surface charge properties was studied. The adsorption decreased with the increase in pH. For the Ferralsol carrying net positive surface charge at natural pH increasing the concentration of NaClO 4 or...
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