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Jun 27, 2022
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ln the Bh horizons of podzols developed on the Vosgian sandstones, clay accumulations can be interpretated as a result of simultaneous podzolization and clay illuviation. Field experiments by lysimeters do verify the present reality of the two processes: dispersion and migration of fine clay minerals (smectites of degradation) translocated with percolating waters downward the spodic horizons, no clay particle migration in the acid brunified soil. As it is generally admitted that aluminous ions...
Topic: soil science
By pollen analysis of Vosgian podsols, it has been shown that iron-humus podsols have been developed under heather landscape while iron podsols are in steady-state equilibrium with the climax forest. While the iron-humus podsols are younger than iron podsols, the natural C-14 measurements give higher "apparent ages" in Bh horizons. The reason is that the organic matter of iron podsol Bh has a rapid breakdown and therefore "apparent ages" may be looked on as the mean turnover...
Topic: soil science
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Jun 27, 2022 Jean-François Ponge
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Soil formation of two iron-humic podzols in the Plateau Lorrain and in the hercynian Vosges is described by the pollen analysis method. The St Gorgon's iron-humic podzol (Plateau Lorrain) follows from the human degradation of an oakwood with lime, at Bronze Age. Podzolisation was started from Calluna and an iron-humus pan was developped inside an ancient clay accumulation horizon. Podzolisation is now stopped. The Barembach's iron-humic podzol in Vosges is a climacic soil which was formed under...
Topic: soil science
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Acidification is considered in the context of a specific problem in the management of a particular community (chalk heath). Chalk heath is an intimate mixture of calcicoles and calcifuges growing in a shallow loam over chalk (top soil pH 5-6). Since the virtual cessation of rabbit-grazing with myxomatosis in 1954, bushes of Calluna and Ulex have grown up and acidified the soil below them (top soil pH 3.5-5.0). When the Ulex scrub is cleared a mixture of calcifuges and indifferent species...
Topic: soil science
Journal article
Topic: soil science
Journal article
Topic: soil science
We conducted a laboratory study using soil cores to determine whether anecic earthworm (Lumbricus terrestris) burrow linings (the hydrosphere) are sites for enhanced carbon and nitrogen mineralization and increased microbial biomass and nematode abundance. We compared microbial biomass C, C mineralization rates, metabolic quotient, levels of inorganic N (NO3- and NH4+), and nematode abundance over the course of 11 weeks in soil from earthworm burrows, bulk soil away from burrows, and a control...
Topic: soil science
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This study presents a few results of physico-chemical analyses done on different oligotrophic peats from the Swiss Jura Mountains. The methods used are the following ones (fig. 1): - granulometric wet sieving at 2000, 200 and 50 µm (Results in tabl. 2) - measure of the fiber content and the pyrophosphate index (fig. 2) - micromorphological observations (tabl. 3) - alcaline extraction with NaOH at pH = 10; determination of the "fulvic acids/humic acids ratio"; summary characterization...
Topic: soil science
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The micromorphological and micromorphometrical study of a V ermic Ustorthent and a Pachic Vermustoll of the Dobruja (Rumania) illustrates the high biological activity present in these soils, and the validity of the "vermic" concept in the American classification. Micromorphology allows to distinguish several size classes of pedotubules (agro- and striotubules) and to estimate their frequency and volume in the profile. In both soils, the upper part lof the profile consists for more...
Topic: soil science
Journal article
Topic: soil science
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The authors present a set of micromorphological observations dealing with upper horizons of equatorial soils, studied under forest and under different fallow stages. The observations mainly deal with the two following points : - humification phenomena, - granulometric modifications. They confirm the importance of fauna in the bio-dynamics of equatorial soils.
Topic: soil science
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Geostatistics has been used to study the spatial variations of the functional properties of water transfer in relation to soil characteristics. An experimental approach has been applied to a 10-hectare drainage basin in Brittany where the soils are derived from loess lying on Brioverian schist. The weight percent water content, is easily and accurately measured and is the variable used in a first step to deal with the methodological aspects, i.e. the influence of the sampling scale and soil...
Topic: soil science
The present study on the physical properties of termite infected soils, shows that the specific biological behaviours of the species influence differently the structural stability (Is test) and the permeability (K test) of strata. The soil-feeding termite Thoracotermes macrothorax, through the sheer use of a material elaborated from an equilibrated texture (clays/coarse sands) and by means of its own faeces as cement, does improve deeply the structural stability of its area. Whereas the...
Topics: Macrotermes mülleri, Thoracotermes macrothorax, permeability, structural stability, termites,...
The pedological role of termites, and in particular fungus-growing species (Macrotermitinae), is briefly reviewed. Recent work on Macrotermes muelleri in the Mayombe Forest, Congo, is then discussed in detail. M. muelleri cuts leaves in the litter into small pieces (confetti) which are transported back to the nest. After a few days storage, they are ingested, passed rapidly through the gut where they are broken up physically but subjected to little chemical action, and then they are deposited...
Topic: soil science
Thoracothermes macrothorax Sjöstedt, a humivorous termite, has a positive influence on the stuctural stability of soils by including its faeces (laden with stable organo-mineral micro-aggregates) in all of its constructions (nest and underground galleries). The observation of a high contents of polysaccharides in soil humic compounds (especially in the humin fraction of organic carbon) under the influence of this species could prove one of the factors which helps to maintain that stability.
Topics: humic compounds, humivorous termites, polysaccharides, tropical soils
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Jun 24, 2022 Jean-François Ponge
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In order to fractionate the soil organic matter into its different compounds, it is necessary to previously break completely the structural units. Physical methods are generally of a limited effect when applied on strongly aggregated soils; chemical ones need too complex operations. We investigate in this work a biological method formely used by microbiologists to obtain a bacterial desorption. Hydrolases or antibiotics are mixed together with soil samples. In both cases, the cements of...
Topics: antibiotics, disaggregation, enzymes, organic matter, soil
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The substratum of the soils is either a porous system or a water-repellant level. In the first case, it is drained by fractures and by an active succion induced through the fine porosity. In the second case, the rock prevents the vertical infiltration of the water and a water-table is establishing. This water generally flows out by lateral movement. The dynamic of these flow seems to be the controlling factor of pedogenesis. We compare in this topic soils being submitted to identical conditions...
Topics: Jura, limestone, pedogenesis, rock breaking, rock porosity, soil-rock system, soils evolution
On the calcareous karstic levels of Jura, the soils of convex areas are thin, calcic, humiferous and strongly aggregated whereas dolina soils are deep, acid and sprinkled with inherited elelments such as vegetal residues or small charcoal. The first ones aggregates are not destroyed by the rain but are translated by running water. Incubated without calcic source they lose calcium and organic matter as well as their structural stability. This enables to demonstrate the possible filiation between...
Topics: Jura, catena, erosivity index, karstic erosion, lake sedimentation
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Jun 23, 2022 Jean-François Ponge
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A simple penetrometer was used in order to obtain field data of some soil characteristics; two types of probes, for light and heavy soils, are available and the spring can be adjusted according to soil resistance. Results showed that, in certain cases, the penetrometer seems to be a useful device in giving a quantitative comparison of the differences between some soil characteristics.
Topic: soil science
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Jun 23, 2022 Jean-François Ponge
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Book chapter
Topic: soil science
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Jun 23, 2022 Jean-François Ponge
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A curve-fit model of the relationship between soil pH (A horizon) and climate forms the basis of a map of predicted pH for the conterminous United States. This map was produced with the aid of a large climatic data base, a computer mapping program and subroutines to map modeled values of soil pH. Patterns of pH follow well-recognized patterns of climate, although the pH of 7 line deviates greatly from Marbut's line dividing pedalfers from pedocals. The overall accuracy of the map and model was...
Topic: soil science
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Jun 23, 2022 Jean-François Ponge
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Journal article
Topic: soil science
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It has been demonstrated that natural humic acids can be formed by polyphenols derived from oxtdized lignin decomposition products which have been used for the formation of synthetic humic acids for some time. The monomer oxidation products during the formation of synthetic humic acids from hydroquinone in alkaline solution are p-benzo-semiquinone, p-benzoquinone and hydroxy-p-benzoquinone. The red colouring at the beginning of the reaction is reduced by the formation of the anion of...
Topic: soil science
Some properties of humic substances and the turnover of soil organic matter are discussed as an introduction to the study of humus and nitrogen reserves in soils. Brief and concise comments are given on the chemistry of the humic substances. A chemical explanation of their colour is also proposed. Examples of humus content and soil fertility are given. The influence of some constituents of soil organic matter on plant growth is differentiated into two effects: direct and indirect. The uptake of...
Topic: soil science
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One way to demonstrate the participation of phenols derived from lignin degradation and from microbial synthesis, on the one hand, together with nitrogenous protein degradation products, on the other, in formation of humic substances is the oxidative or reductive cleavage, whereby different types of phenols can be identified. The difficulties in isolating humic acids are caused by the mixture of various organic compounds in soils with similar properties. The solvents have a decisive influence...
Topic: soil science
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Jun 21, 2022 Jean-François Ponge
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I have discussed some problems of chemical composition and physical properties of humic substances with regard to their phenolic and nitrogenous structure units. The analytical data show that there are essentially two sources of phenols for the formation of humic substances in nature. (1) Phenols of mainly resorcinol and phloroglucinol type which are synthesized by microorganisms, contribute to the composition of humic acids. These substances are altered by transformation to phenols which can...
Topic: soil science
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First the author explains how to isolate humic acids and then he gives their characteristics in accordance to their conditions of formation. He discusses widely their origin from lignins and phenols synthesized by microflora. Then he shows how nitrogen integrates when phenols condense with proteins of their metabolites. The classification of organic matter in the soil is also discussed. The splitting of humic acids into various under fractions is studied on synthetic as well as natural humic...
Topic: soil science
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Jun 20, 2022 Jean-François Ponge
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Journal article
Topic: soil science
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Jun 20, 2022 Jean-François Ponge
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Book chapter
Topic: soil science
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The study concerned the Ap horizon (0-20 cm) of a ferrallitic soil cultivated with sugar-cane for over 20 years. To determine the nature and the possible origin of organic matter (OM) associated with soil clayey fractions, we compare their ultrastructure (TEM) and chemical composition (C, N and sugar contents) with those of plant materials added to the soil by culture (leaves, roots and root exudates) and to other particle-size fractions. It appears that: (i) OM associated with sand and coarse...
Topic: soil science
The influence of Calamagrostis epigeios on soil humus is investigated through a comparison of some physio-chemical factors and the mineralizing activity within the A1-layer, both under stands and in their immediate vicinity. The rise in pH, resulting from an increase in bivalent cations as well as in porosity, leads toward a stimulation of the biological activity. This latter acts essentially in the field of mineralization, thus ensuring a permanent level of organic matter in spite of an...
Topic: soil science
The long-term influence of glading on the soil humus types appears related to their nature and to the herbaceous layer they may support. In the mull, with a conspicuous herb layer, a decrease in the easily decomposable substrates follows an early increase in organic matter content and biological activity. However, the in situ mineralization is still more active the C/N ratio clearly lower than under timber tree forest and the pH higher: the humus is clearly improved. In the moder, where the...
Topic: soil science
The evolution of humus is studied by comparing old forests and glades opened less than two years ago. In Mull, the organic matter content, the saturation rate and the pH increase, while the C/N ratio decreases. Respiration rate and nitrification are stimulated in vitro. In the field, the production of total mineral nitrogen (N.N03 + N.NH4) decreases, but nitrification is more active. An increase of reorganisation phenomenas may be thought of. In Moder, the content of organic matter decreases...
Topic: soil science
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In certain soils, the exchange acidity is the result of both exchangeable H+ and Al3+. Therefore, it is interesting to distinguish them. Thus, the aim of this study was to develop one extraction method for exchangeable aluminium and protons. The definition of exchangeable aluminium is complicated by the fact that aluminium can exist in soils under numerous forms, and also, a part of non exchangeable aluminium is often extracted with exchangeable aluminium (Reeves and Summer, 1971). For McLean...
Topic: soil science
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Jun 17, 2022 Jean-François Ponge
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A granular mixture of sodium hydroxide and slaked lime, was tested as a potential alternative to alkali solutions for absorbing carbon dioxide (CO2 ) as an indicator of soil respiration rates. Because soda-lime can be used as a solid, problems with freezing and spillage are eliminated. Also no titration is necessary, the only measurement needed is the dry weight of the soda-lime before and after the absorption period. A 0.2 N solution of potassium hydroxide (KOH) absorbed 38% as much CO2 as...
Topics: CO2-efflux, absorption, absorptive capacity, carbon dioxide, sodium and potassium hydroxide, soil...
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Jun 17, 2022 Jean-François Ponge
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It is generally assumed, that podzols are formed under forest, both coniferous and deciduous. In Western Europe the opinion is, that deciduous forest does not podzolise the soils, and the heather resp. coniferous forest are made responsible for the formation of podzols. Since both vegetations are anthropogeneous, the whole process of podzolization is said to be due to man (§ 1). The heath fields and their podzols are formed since the Bronze Age. This is said to be proven by comparing tumuli...
Topic: soil science
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Jun 17, 2022 Jean-François Ponge
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Nutrients in soil organic matter (SOM) are present within complex polymers and mineral-organo associations. Investigations into the chemical composition of SOM and the nutrient elements within it have only been partially successful and have not been linked to biological processes. Particle-size and density fractionation studies have provided insight into the architecture of soils and on the distribution and stability of SOM and nutrient elements. Such studies should be continued. Modern...
Topic: soil science
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The authors studied the behaviour of various humic compounds (bitumen, fulvic acids, hymatomelanic acids, crude or refined humic acids extracted from Ca-containing, peats and anmoors) under the action of heat, with the aid of differential thermal analysis, in an inert oxidizing atmosphere. The stages of pyrolysis shown by the D.T.A. curves are defined by means of infra-red absorption spectrography. The methods of extraction and refining used are expressed by modifications in the D.T.A. curve....
Topic: soil science
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Jun 16, 2022 Jean-François Ponge
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Journal article
Topic: soil science
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Jun 16, 2022 Jean-François Ponge
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Journal article
Topic: soil science
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The author places in a historical perspective the difficulties encountered by soil scientists in establishing an universally acceptable soil classification. He compares two main types of classification, effective and genetic, the latter based on pedogenetic processes. The FAO-UNESCO classification belonged originally to the first type, but was progressively modified towards the second. The definition of "diagnostic horizons" and "diagnostic properties" are linked to the main...
Topics: diagnostic horizons, effective/genetic classification, reference system, soil classification
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Jun 16, 2022 Jean-François Ponge
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Book chapter
Topic: soil science
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Journal article
Topic: soil science
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Jun 16, 2022 Jean-François Ponge
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Relations between soil and vegetation are first reviewed, at the zonal and the local scales. Then are considered, at the ecosystem level, the relations between the environment, the soil and the vegetation: they are revealed by the humus type. Lastly, the importance of interactions between plants, mineral components of the soil and edaphic organisms are pointed out.
Topics: ecosystems, edaphic organisms, humus formation, humus types, interactions, pedogenesis, pedology,...
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Firstly, the author summarises tile two important types of humification: 1° Direct, by the rapid change of fresh organic matter (especially lignin ) into humus, so-called "inherited". 2° Indirect by chelting effect with cations and insolubilising more or less soluble precursors (fulvic acids, humic acids, insolubilising humin ). Modern fractionating processes allow the composition of the humiferous horizons to be determined and divided into its different constituents as shown in the...
Topic: soil science
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This study first gives an overview of the nature of the components which comprise soil organic matter. Tyurin's method of humus fractionation is then compared to other methods which radically break down aggregates (Bruckert and Gaiffe method). The results of this comparison provide useful information as to the role of three cations (calcium, iron, and aluminum) in humification. Two experiments conducted by one of the authors show the importance of soluble calcium in the formation of both...
Topics: andosol, biomolecules, brown soil, chernozem, fulvic acids, humic acids, humification, humin,...
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Jun 15, 2022
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This collection has been created to make available to everybody old papers (journal articles and book chapters) gathered during the 50 years of my scientific career and not digitalized until now. This collection embraces a wide array of publications in the various fields of soil science, but not only, ecology and evolution being also present.
Topics: soil science, ecology, evolution
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Within the framework of an integrated study of Algerian steppe lands, the carbon and nitrogen mineralization of a soil, was studied during a year. Seasonal dynamics of these microbial activities were compared to the edapho-climatic factors in situ. In summer, a stimulation of these activities occurs owing to a thermophilic microflora. Associated to the easily mineralizable organic substances, this particular characteristic was found to influence the potential mineralization in vitro. In spite...
Topics: C and N mineralization, alfa steppe soils, soil biological activity
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Jun 14, 2022 Jean-François Ponge
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In an attempt to elucidate the course of soil genesis on land which now carries heath, over thirty sites have been investigated, many of them archaeological sites of various ages. Present-day heathland soils and the soils buried beneath earthworks have been examined by pollen analysis and recorded by colour photography and other means. It is concluded that though a few of the soils have been podzols since the Atlantic period, the majority are secondary, having arisen as a result of man's...
Topic: soil science
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An uniformally C-14 labelled litter was laid on the soil surface in grassland (Brachypodium phoenicoides) of a calcareous brown soil in southern France (humid Mediterranean climate). For a period of two years, a study was made of the decrease in litter material, the leaching of water-soluble constituants and the incorporation by earthworms. The distribution of C-14 in the soil was studied by the autoradiographic method on soil cores. The purpose of the present study was to show the advantage of...
Topic: soil science
Humus and earthworm species were sampled in 30 points of an unexploited beech forest (La Tillaie, Fontainebleau, France), according to the distribution of geomorphological, pedological and sylvogenetical features. This stand was free of management practices for three centuries. The humus form is tightly connected to the distribution of the two main ecological categories of earthworm species (epigeic and endogeic), which is a well-known result. More original is the respective influence of...
Topics: Fontainebleau, beech stand, forest dynamics, geomorphology, humus, lumbricid worms, soil,...
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The first results were comparable to those obtained from C determination by means of sulfo-chromic oxydation. Controls by differential thermal analysis and infra-red spectrography showed that all organic matter had disappeared, and that a new compound was formed during the calcination, increasing the weight of the mineral residue. Therefore, data obtained by means of low temperature ashing appeared somewhat underestimated. Further research is being organized.
Topic: soil science
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From potentiometric titration curves and chemical determinations, the authors give informations about the acidity of the organic matter extracted from an Acid Brown Soil of the Belgian Ardennes, by means of the fractionation method of Gascho and Stevenson. The average pK of the humic fractions varies between 3.4 and 6.7. As far as acidity is concerned, the humic fractions can be ranged in the following decreasing order: pyrophosphate soluble fulvic acids > sodium hydroxyde soluble fulvic...
Topic: soil science
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The authors study the validity of the sampling of holorganic layers of forest soils, in view of the determination of their weight per area unit. A systematic sampling, at the rate of 8 plots of 1 m2 in each site, gives an average weight with a standard error less than 10%. If the A0 horizons are very thick, the plot area may be of 0.5 m2, without any loss in the precision. The weight of the annual litter is very near the truth, when the dead leaves are collected on a fiberglass cloth, fixed on...
Topic: soil science
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Jun 13, 2022 Jean-François Ponge
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Journal article
Topic: soil science
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Jun 10, 2022 Jean-François Ponge
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The author presents a classification system of humus forms, based on a series of morphological features observable in the field. The defined description criteria were used to prepare a determination key of submerged, semi-terrestrial, and terrestrial humus forms.
Topic: soil science
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Jun 10, 2022 Jean-François Ponge
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The study of about thirty beechwood sites in the Belgian Ardennes, permits to select different soil factors related to the forest productivity. From mull to dysmoder humus form, the production of wood diminishes from 7.4 to 4.4 m3/ha/year. Among the soil factors, litter decomposition rate, C/N ratio, cation exchange capacity, exchange acidity, and exchangeable Al and Ca are fairly correlated to the production. However significant differences between sites appear only in the O and Ah horizons....
Topic: soil science
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Through fractionation of humic substances, a comparative study showed that samples of boreal mor are distinguishable from mull and moder of acid brown soils of Belgian Ardennes, mainly by the nitrogen distribution.
Topic: soil science
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The behaviour of iron, illustrated by mobilized iron curves, is characteristic of the evolution of humus types, from acid mull to mor, in relation to the phenomenons of organo-mineral complexing. Curves representative of homologous sites show off the importance of the geological or lithological factor.
Topic: soil science
The study of a bio-toposequence of acid brown soils, in Belgian Ardennes, showed that moder appears as a humus climax. It is characterized by the highest values of parameters such as extraction index, HA content, ratios HA/FA, HA/Humines, humic/fulvic fractions. The diminution of these parameters on both sides of this humus form can be explained by the peculiarities of humification of mull or dysmoder types.
Topic: soil science
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Journal article
Topic: soil science
The effects of a deep-burrowing earthworm species, Martiodrilus carimaguensis, on soil fertility and plant growth were assessed in two grasslands in the Eastern Plains of Colombia. This species aestivates deep in the soil during the dry season. Fibre glass netting was used to prevent colonisation of the top soil at the onset of the humid season. Effects of earthworm absence on soil properties and plant biomass were analysed with principal component analysis. Experimental manipulation succeeded...
Topics: anecic earthworms, earthworm manipulations, soil ecology, soil fertility, tropical grasslands
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Jun 10, 2022 Jean-François Ponge
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Book chapter
Topic: soil science
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Jun 10, 2022 Jean-François Ponge
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A genetic classification of sandy soils of the Belgian Campine based on field observation and micromorphology is attempted. The southern part of this region has a glauconitic parent material which has a great influence on the soil development. Analogous stages of development can be distinguished. The intensity of these stages determines the final composition of the profile. In all considered soils, a colloidal cutan is formed around the skeleton particles. This cutan can be organic or mineral,...
Topic: soil science
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Jun 10, 2022 Jean-François Ponge
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Search for a common denominator in such diverse soil phenomena as the accumulation of surface organic debris, the forrnation of humic add, and the weathering of inorganic substances, points to the role of polyphenols. These vary, in amount and kind in leaves, according to species of plant, site characters and season. In addition, polyphenols may be biosynthesized and may also be formed during soil degradation. Since beech and oak can grow on extremes of acid and of base-rich sites, comparison...
Topic: soil science
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Jun 10, 2022 Jean-François Ponge
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Journal article
Topic: soil science
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Jun 10, 2022 Jean-François Ponge
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Journal article
Topic: soil science
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Jun 9, 2022 Jean-François Ponge
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The extraction of humic soil compounds, is realized by successive treatments, - Phosphoric acid (2 M - H3PO4) extracts fulvic acids and low density organic matter; - 0.1 M Sodium Pyrophosphate (Na4P2O7); - 0,1 N Sodium Hydroxide (OH Na). Extracts humic acids and bounded fulvic acids. The reactions with the different reagents are renewed just until the solutions become colorless. The solid residue contains the insoluble fraction or "Humin". The method is applied to various tropical...
Topic: soil science
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Jun 9, 2022 Jean-François Ponge
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The results concern the effect of ant hills on various types of grassland and the part played by particular species of ants in the processes of transforming the soil. They include physicochemical changes in the soil as well as changes in the soil microfloral activity. The investigations have been conducted on clearly different grassland environments in the vicinity of Warsaw: (1) On the natural mid-forest meadows with a muck-like soil. (2) On two cultivated meadows situated on brown, gleyed...
Topic: soil science
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Jun 9, 2022 Jean-François Ponge
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Three CO2 evolution measurement techniques were compared in a 28-year old slash pine plantation (Bradford Co., Florida, U.S.A.). Total forest floor CO2 evolution was estimated using a dynamic system with CO2 measured by an infrared gas analyzer (IRGA) system and two static techniques, one using granular soda lime and the other 1.0 N KOH. CO2 evolution measured with the IRGA system was not sensitive to variation of flow rates between 1 and 8 l min-1 (4-8 cm sec-1). Coefficients of variation were...
Topics: adsorbent, carbon dioxide (CO2) evolution, comparison, infrared gas analysis (IRGA), potassium...
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Swaby claims that amino acids, present as linking molecules between quinonoid structures in humic acid, are recoverable on acid hydrolysis. Evidence is given in this paper in support of this contention, for not only are amino acids released on acid hydrolysis, but, after electrolytic reduction, phenolic substances are found in the hydrolyzates both of natural humic acid (from peats and the clay fraction of a soil) and of a model catechol-glycine oxidation polymer. The presence of sugar...
Topic: soil science
The authors have studied during two years, the evolution in situ of different biological activities such as the amylasic, saccharasic, ureasic process reducing and total sugars, under three sorts of' vegetal covers: a sward of Brachypodium ramosum, bushes of Quercus coccifera, and Quercus ilex established on same type of soil. On the one hand, they show that the seasonal dynamics. of these activities even though placed at different levels follow a remarkably parallel evolution and on the other...
Topic: soil science
Specific activities of C and atom % excess N-15 of soil microbial biomass incubated with C-14 and N-15 labelled maize leaves were determined by two different methods: fumigation method and nucleic acid bases method. During an incubation of 309 days specific activities of C were very close. In contrast, atom % excess N-15 were 3-4 times higher with fumigation method. Soil drying conditions and adding of non labelled carbon and nitrogen show an important decrease of biomass atom % excess N-15...
Topic: soil science
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Jun 9, 2022 Jean-François Ponge
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Topic: soil science
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1 Studies of ecological interactions in the soil environment require skilled usage of concepts from physics, chemistry, mathematics and biology. This volume offers numerous examples of the multi-disciplinary nature of our work. 2 In each instance - roots as primary producers, root/microbe interactions, interactions of roots, microbes and fauna, and interactions of all three groups with the sand-silt-clay-organic matter milieu (soil) - significant new information has appeared over the last 5...
Topic: soil science
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Jun 9, 2022 Jean-François Ponge
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The soil was obtained from the B21 horizon of a well-drained sandy podzol under deciduous forest with Fagus grandifolia the major component. About seventy-five per cent of the organic matter of the soil was extracted by mechanical agitation of the system soil-water-benzene-8-quinolinol while maintaining the aqueous phase at pH 6.0 to 6.5. Treatment of the organic matter of the aqueous phase with laryl-pyridinium chloride yielded four fractions; two fractions were obtained from the benzene...
Topic: soil science
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Jun 9, 2022 Jean-François Ponge
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Topic: soil science
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Some paleogeographic and geoecological aspects of the radiocarbon method of investigating the humus of paleosols are examined. Examples are the study of the transformation of organic matter of soils in time; paleogeographic reconstructions and climate forecasts; radiocarbon chronology, refinement of geochronological scales, and correlation of natural boundaries of the Pleistocene and Holocene; and chronometry and attempts to predict ecological catastrophes.
Topics: geoecology, humus of paleosols, paleogeography, radiocarbon age
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Topic: soil science
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Jun 8, 2022 Jean-François Ponge
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The use of a small cylindrical sampler with a cross-sectional area of 1 cm2 enables samples of forest litter and the underlying humus layers to be taken quickly and with very little disturbance of the habitat. The results show a surprisingly low degree of scatter considering the small weight oflitter removed, and agree well with estimates based on much larger samples. Although month-to-month inconsistencies were encountered when attempts were made to follow the changes in weight of litter after...
Topic: soil science
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In the region Atlantic Pyrenees, large areas of land covered with, gorse, ferns, heather, molinia are locally called "touyas" or "touyas heaths". The heath land which is the result of the destruction of original oak wood is always characteristic of very acid soils though they may develop on materials very different in nature. We shall limit our study to the soils developed on loams covering ancient alluvions of the "gaves" of Pau. Main features of these soils are...
Topic: soil science
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Soil root interface microstructures constitute an outstanding research that can define the nature of soil constituents directly in contact with the root system. To effect such an analysis however it is necessary to use many techniques of observation among which the stereo microscope appears to be the key-tool for an integrated tridimensional microstructural approach. It is an instrument that may be used in the field as well in laboratory and permits observation of fresh samples with undisturbed...
Topic: soil science
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Jun 7, 2022 Jean-François Ponge
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There has been considerable confusion regarding the nomenclature of the organic matter in the soil. The most commonly accepted terminology used at present is to restrict the term humus to the amorphous dark brown or black organic material as distinct from the partially decomposed plant and animal remains. Humus is further sub-divided into (a) humin, which is insoluble in sodium hydroxide; (b) humic acid, soluble in sodium hydroxide, precipitated by hydrochloric acid, and insoluble in alcohol;...
Topic: soil science
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Jun 7, 2022 Jean-François Ponge
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Book chapter
Topic: soil science
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Book chapter
Topic: soil science
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Jun 7, 2022 Jean-François Ponge
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Topic: soil science
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The formation of pseudogleys was considered to be the result of a long pedogenetic evolution that has gone through the "leached" stage: the studies described in this paper would seem to indicate that this assumption was not valid. Indeed, the authors compare 1) the permeability of geological substrates and 2) the composition of superficial formations in which brown leached soils and pseudogleys have formed. They establish that the differentiation of these two pedogeneses migh result...
Topics: brunification, pseudogleyification, soil age, soil-bedrock interaction, soils-upper materials...
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Jun 7, 2022 Jean-François Ponge
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Topic: soil science
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Jun 7, 2022 Jean-François Ponge
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Topic: soil science
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The soils distribution in the above mentioned area was analyzed for this paper. The lateral variability of soil types, between adjoining convex proeminent positions, was studied on Triassic, Liassic and Jurassic plateaus. The variability amounts to 73 or 90% depending on whether the areas are calcareous or marly-calcareous. It is usually imputed to the initial conditions, and more particularly to the juxtaposition of the rocks /and/or superficial mineral substances. These initial...
Topic: soil science
If we consider 1. the rate of clay of the most clayey layers (B or C) of the soils, 2. the difference of clay between this layer and the A layer, 3. the cationic environment and the water regime, we show that 1. the vertical leaching is a process of well-drained soils, 2. the textural differentiation of pseudogleys results from the lateral migration of clay. A terminology is given to seperate these two processes of migration.
Topic: soil science
The water and air regime of brunified soils and hydromorphic soils was studied on several sites. It is observed that the infiltration of water does not depend on the topography and the texture, specially on high clay rates (70-80%). The comparison of the soil and geological maps, clearly proves the close relation between rock fracture systems and soil moisture regime. A dense fracture system leads to frequent wetting-drying cycles that cause soil structuration and enhance porosity. In the case...
Topics: entrapped air, infiltration, perched watertable, soil air regime, soil moisture regime
The results of laboratory experiments showed the following pedogenetic mechanisms: In soils with mor humus, the organic acids remain in the litter, leach through the A horizons and penetrate into the B horizons of the podzols, but only the aliphatic acids play a major role in the complex-formation and transport of the Fe and Al cations. These same acids also facilitate the migration of polymers produced in the litter. In the spodic horizons all the acids investigated, both aliphatic and...
Topic: soil science
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The investigations presented here are concerning the formation, the movement and precipitation of organo-metallic complexes (Fe, Al) consisting of litter soluble compounds and developing under very or slightly active biological conditions (soils with a mull or a mor humus). These complexing factors a reincluding essentially simple organic acids and polymeric compounds, but, for a definite litter weight, the complexing power of the first substances is three times stronger than the power of the...
Topic: soil science
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Topic: soil science
The experimental study presented here, gives strong support to the hypothesis that the weak migration of iron in the soils characterized by a mull (sols bruns acides and sols bruns lessivés) results, not only from a physico-chemical sorption, but also from the biodegradation of the organic complexes in the upper horizons. On the contrary, in the soils characterized by a mor (podzols and podzolic soils), iron migrates down more easily, because the organic complexes are not much degraded by the...
Topic: soil science
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Jun 3, 2022 Jean-François Ponge
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The study of thin-sections of undisturbed soil horizons and artificially prepared clay-sand mixtures indicates that, in general, strongly and continuously oriented clay -films on channel walls and on primary mineral grains are the result of clay movement in the soil profile. Under special conditions, however, the same kind of fabric can be produced in the deposition of alluvia and a similar one by alternate wetting and dryings in the profile: alternatively, illuvi:ated clays may not be strongly...
Topic: soil science
The organic matter was studied in fersiallitic soils with calcium reserve (unleached mediterranean red soils), under evergreen Quercus ilex forest, under Quercus coocifera garrigue, under Brachypodium ramosum sward and last in fersiallitic soils without calcium reserve (leached mediterranean red soils) under evergreen Quercus ilex forest. The results were obtained: 1) From routine analysis made on somewhat fifty profiles organic carbon, C/N ratio, extraction ratio, humic acids, fulvic acids. 2)...
Topic: soil science
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The humic acids of a mor from an iron-humus podzol and of a mull from a brown calcareous soil were submitted to flow-electrophoresis on cellulose-paper and on glass-fiber paper. On cellulose-paper the migration of the humic compounds permits the separation of the "mobile humic acids" from the "non-mobile humic acids". The former were easily eluated; of the latter, a part was not eluable and remained fixed on the cellulose-paper. It is not a matter of precipitation, but, very...
Topic: soil science
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Jun 2, 2022 Jean-François Ponge
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Journal article
Topic: soil science