Extraction de l'adenosine triphosphate dans les sols: Une nouvelle methode de calcul des pertes en ATP

Adenosine triphosphate (ATP) was extracted from 6 soils and 3 ATP supplemented clays with a sulfuric acid reagent previously shown to minimize ATP losses. Results indicated that ATP losses were due to adsorption phenomena. The amount of adsorbed ATP was related to soil composition, soil weight and to the actual ATP content of the analysed soil sample. A mathematical formula was developed to determine the adsorption coefficient of ATP and consequently the ATP content of soils, using, for each soil, two experimentally determined soil ATP contents based on analysis using two different soil weights.The adsorption coefficient was constant in each soil, independent of soil ATP content and soil moisture content. Freeze-drying reduced the adsorption coefficient on 4 of the 6 soils but did not affect soil ATP content. In practice this method permits accurate correction for ATP losses, it simplifies the experimental procedure and reduces the number of analyses if multiple ATP measurements are required for a given soil under different conditions.     

Transformations des carbonates dans une sequence de sols developpees sur marnes dans Le Bassin Aquitain,France

Soils of a toposequence formed chiefly in Tertiary marls in the south-eastern part of the “Bassin Aquitain” have been studied by field and micromorphological methods. Profiles were examined in detail in the field and oriented samples taken of horizons for observations of micromorphology. From the upper to the lower part of the toposequence, the four profiles also form a chronosequence, viz., a recent calcareous brown soil (sol brun calcaire), an old calcic brown soil (sol brun calcique), a still older leached brown soil (sol brun lessivé) and a hydromorphic leached soil (sol lessivé hydromorphe).The profile distribution and forms of calcite can be related to the morphology, ages and parent materials of the soils. Calcite is found as relics in the upper horizons of the calcareous brown soil and in the form of accumulations in the Bca and Cca horizons of the calcareous brown soil, the calcic brown soil and the leached brown soil. Where accumulations are limited, calcite forms pseudomycelia associated with roots, first as calcitans in tabular pores or craze planes and second as coalescing pseudomycelia. Finally, the calcite invades the S-matrix by epigenesis and results in crumbly masses. These masses have the shapes of the structural voids originally present in the parent materials. The common voids in the marl are vertical craze planes, the widths of which differ with the moisture regime of a soil. In the sandstones, the craze planes are horizontal and very small. The distribution of the calcitans and the presence of the crumbly masses indicate that the processes of accumulation of calcite are in part biodependent, i.e., related to root distribution, and in part lithodependent, i.e., related to structure of the parent rock.Finally, the presence in the calcareous brown soil of calcite as relics in the upper horizons and as successions of cutans from outsides to insides of pores (calcitan, argillan, calcitan) in the Bca horizon shows that the profile has a polycyclic origin.     

Activite biologique des sols,modalités et lithodépendance

Summary In the first part of this paper, the qualitative and quantitative role of brown pigments in leaf litter is emphasized. In general, these products contain mainly nitrogen and are relatively resistant to mineralization. Earthworms and white rot fungi are considered the primary metabolizers of these complex compounds, whereas bacteria, enchytraeids and microarthropods seem to play a minor role in biodegradation of these compounds. The biodynamic behaviour of these compounds may account for the formation of mull, which is usually linked to high activity of earthworms and white rot fungi. On the other hand, moder formation is mainly carried out by activities of enchytraeids and different microarthropods in another type of litter with other properties, both in quantity as well as in quality. In the second part of this review, some examples are given which stress the role of the inorganic composition of the parent material (for example, the percentage of Fe in the C horizon derived from Rhetian sandstone) for biological activity in the corresponding soil. The effect of mineral nutrients applied by man are also discussed. In general the presence and activities of the various organisms and their biocoenoses depend largely upon the environmental conditions, the type and amount of organic litter and the productivity of the entire ecosystem.

Dedicated to the late Prof. Dr. M.S. Ghilarov     

Decomposition de corps microbiens dans des sols fumiges au chloroforme: Effets du type de sol et de microorganisme

Five microbial species (Aspergillus flavus, Trichoderma viride, Streptomyces sp., Arthrobacter sp., Achromobacter liquefaciens) were cultivated in liquid media containing ¹⁴C-labelled glucose. The decomposition of these microorganisms was recorded in four different soils after chloroform fumigation by a technique related to that proposed by Jenkinson and Powlson, to determine the mineralization rate of microbial organic matter (K_c coefficient). Three treatments were used: untreated soil, fumigated soil alone and fumigated soil supplied with ¹⁴C-labelled cells. Total evolved CO₂ and ¹⁴CO₂ were measured after 7 and 14 days at 28°C.The labelled microorganisms enabled the calculation of mineralization rate K_c (K_c = mineralized microbial carbon/supplied microbial carbon). The extent of mineralization of labelled microbial carbon depended on the type of soil and on the microbial species. Statistical analysis of results at 7 days showed that 58% of the variance is taken in account by the soil effect and 32% by the microorganism effect. Between 35 and 49% of the supplied microbial C was mineralized in 7 days according to the soil type and the species of microorganism. Our results confirmed that the average value for K_c = 0.41 is acceptable, but K_c variability according to soil type must be considered.The priming effect on organic C and native microbial biomass mineralization, due to microbial carbon addition was obtained by comparison between the amount of non-labelled CO₂-C produced by fumigated soils with or without added labelled microorganisms: this priming effect was generally negligible.These results indicate that the major portion of the error of microbial biomass measurement comes from the K_c estimation.     

Etude integree de sols a pseudo-gley sous vegetation naturelle du plateau des Hautes Fagnes (Belgique): Partie I le milieu de pedogenese, la morphologie et le fonctionnement actuel des profils

This work is an attempt to establish the morphogenesis of four hydromorphic profiles (Plateau des Fagnes, Eastern part of the Belgian Ardennes). Various scientifical approaches were used, namely geomorphology, mineralogy and palynology.The aim was to show that very sharp discordances may appear between “inherited” profile morphology and the present state of hydromorphy characterized by vegetation, humus forms, and physico-chemical measurements, such as redox potential and oxygen diffusion flux intensity (see partie II)     

Relations entre la fertilisation et la concentration des nitrates et du potassium dans les feuilles et le rendement et la qualite du mais de table

Abstract

Twenty sweet corn tissue samplings were made from ten field trials during 1974–76. Fertilization had little effect on yields, but a good relationship was found between yields and leaf tissue nitrate and potassium concentrations, in the leaves 40–50 percent developed at the F‐9, F‐13 and F‐14 vegetative stages. The lower and upper tissue nitrate and potassium concentration limits (deficiency and excess) were found to range between 2000 and 3000 ppm nitrate, and 1.5 and 4.2 percent, or 2.0 and 3.25 percent potassium, according to their vegetative development. Excessive nitrogen and phosphorus application decreased kernel tenderness and total solids (sugar) content, but potassium fertilization enhanced total sugar accumulation.     

Laccases de Polyporus versicolor dans le sol et la litiere

Laecases of Polyporus versicolor in soil and litter. The laccases forms A and B, prepared from Polyporus versicolor, were compared with the laccases liberated from soil and litter by means ofchromatography on G100 Sephadex and DEAE DE 52 Cellulose. It appears that the soil and litter enzymes were of the form A that is strongly electronegative. These results suggest that because of their negative charges, laccases A, were weakly adsorbed onto humic colloids. Consequently, protection might be given to the active sites of the enzymes without preventing the formation of “humo-laccases” complexes in soil and litter.     

Caracterisation micromorphologique et hydrodynamique des niveaux structures par le gel Quaternaire dans les formations superficielles du bassin-versant de la Fecht (Vosges, France)

Detritic superficial formations, covering most of the slope in Fecht basin (Vosges, France), are deposited in the course of Quaternary cold periods. A detailed study on these deposits give evidence of structures directly or indirectly associated with the action of deep freezing and thawing: laminated structure, compact laminated structure with silt caps, stratified displaced granitic regolith, gelifluction deposits, etc. The cryogenic structures are generally well conserved, unless they are submitted to actual pedogenesis. Their influence on the hydrodynamic properties of the slope deposits is noteworthy: according to discriminant analysis, hydric comportment in this porous medium is largely influenced by the herited cryogenic structures. These structures, conserved under the actual soil, present high bulk density, weak water retention and low saturated hydraulic conductivity which are clearly contrasted to the values obtained in the upper part of the profile submitted to the destruction by pedogenesis. Particularly displaced granit regoliths, because of the included few permeable bands of fine material, react as a zone that hinders hydric transfers and induces lateral flows in slope deposits. This fact plays an important role in stationnal hydric budget.     

Effets des engrais N,P et K sur le rendement et la qualite de l'ensilage ue mais

Abstract

Thirteen fertility trials were made throughout Quebec's corn growing region during 1972–74. These included eleven fertilizer combinations with corn silage as the test crop and were carried out on nine soils. Total dry matter and digestible nutrients (TDN) varied greatly from year to year, though, mean yields increased by 23 and 30 percent respectively with the 50 kg N/ha treatment, compared to control receiving no nitrogen fertilization. However, 150 kg N/ha was required to attain a maximum yield of 1250 kg/ha crude protein. Despite a 0.2 percent nitrate content found in the silage grown on the most northerly site, a 120 kg P/ha combined with 100 kg N and K gave the highest mean TDN production (9580 kg/ha).

Potassium fertilization affected plant K content of corn grown at the most northerly site only, where a 0.5 percent was found with the control on a suit containing low potassium levels. Further, striking increases in Ca and Mg concentrations were observed with corn grown on that soil. However, magnesium concentration ranging from 0.11 to 0.14 percent were found with nine field trials out of twelve. Also, low K:(Ca + Mg) ratios were found on three trials, which were increased with potassium fertilization levels of 150 kg K/ha. Accordingly, it is suggested that uptakes of 200, 48, 200, 30 and 30 kg/ha of N, P, K, Ca and Mg are required for good corn silage crops.     

Influence de la roche-mère et du climat sur les propriétés andiques des sols en région montagnarde tempérée (Vosges, France)

La diversité des conditions d’environnement (roche-mère, climat, végétation) prévalant dans un massif de moyenne montagne (Vosges, France) nous a permis d’établir leur rôle dans la manifestation à des degrés divers des propriétés andiques dans le sol. Nous avons examiné un lot de 13 profils sélectionnés à partir de critères lithologiques, climatiques et morphologiques présumés favorables à l’expression de ces propriétés andiques: roches-mères basiques d’origine volcanique ou non, climat montagnard très humide, abondance de matière organique sur une grande profondeur. Ces profils se subdivisent en deux populations. Quatre d’entre eux peuvent être classés comme des Andisols (Alic Fulvudands) alors que les autres ont des propriétés andiques trop faiblement exprimées pour appartenir à cet ordre et doivent être classés comme des Andic Haplumbrepts. Tous ces sols sont dépourvus d’allophanes. Dans cet environnement de moyenne montagne, les facteurs favorables à la manifestation de propriétés andiques sont d’une part, les altitudes et les expositions qui induisent de faibles températures et de fortes précipitations et d’autre part, l’altérabilité des roches-mères déterminée par leur composition chimique et minéralogique. Comme les vieux matériaux volcaniques sur lesquels se développent la plupart des sols étudiés sont pauvres en verres, voire complètement dévitrifiés, les Andisols vosgiens présentent beaucoup d’analogies avec les Andisols non-allophaniques non-volcaniques identifiés dans d’autres environnements. Leurs propriétés andiques sont faiblement exprimées et elles sont dues à la présence de complexes organo-métalliques associée à des teneurs élevées en carbone organique. The diverse environmental conditions (parent material, climate, vegetation) in the Vosges Mountains (France) allow us to investigate their role in the development of soils with varying degrees of andic properties. We studied 13 profiles selected on the basis of lithological, ecological and morphological criteria assumed to favour the formation of andic properties, i.e. basic parent materials of volcanic and other origins, wet montane climates and accumulation of thick layers of organic matter. The profiles belong to two classes: four are Andisols, more precisely Alic Fulvudands, and the others are Andic Haplumbrepts with only weakly expressed andic properties. In this montane environment the factors favouring the andic properties seem to be on the one hand height and exposure inducing cold and humid microclimates, and on the other the chemical and mineralogical composition controlling the weatherability of the soil’s parent materials. For example, the old volcanic rocks on which most of the soils occur are poor in glassy material or are even completely devitrified. Accordingly, Andisols in the Vosges are like those of non-volcanic, non-allophanic Andisols elsewhere in the world: their andic properties are weakly expressed and are caused by organo-metallic complexes associated with their upper organic-rich horizons rather than by allophanes.     

Influences stationnelles sur l'alteration chimique des sols derives de till (Sherbrooke, Que., Canada)

In a small watershed of the canadian Appalachians, five trenches were studied in two catenas facing each other, one forested, the other under recent prairie vegetation (100 years of age), to investigate the character of chemical weathering in these sites. On the top of the forested catena there was a humo-ferric fragic podzol, and further down, and orthic gleysol. The other catena had a humo-ferric fragic podzol, then, downwards, a grey gleyified luvisol and a luvic fragic gleysol. Percolating waters near these trenches were sampled regularly, at various depth. The distribution of the ions on the meadow side indicated on one hand that H₄SiO₄, Na⁺ and Mg²⁺ in percolating waters are related to the total volume of soil through wich waters percolate, that the dissolution of aluminium is accelerated in acid sites (upslope) and that the solubility of iron reaches a maximum in the zone influenced by the water table. On the other hand, calcium, which is easily liberated in the high sections, is in part fixed when the solutions get concentrated, iron and aluminium are soon traped, silicium is less mobile than the basic cations. The constituants of primary minerals organize as follows: concentration of Al₂O₃ and Fe₂O₃ upslope, when the contrary is for the basic oxydes and SiO₂; this trend stands out more clearly in the top 30 cm. Thus on top of the forested catena, chemical weathering is intense, the aluminium and iron oxydes are highly evacuated in this podzol. At the same altitude, in the prairie podzol, which probaly had 100 years ago a less acidifying vegetation (hardwoods) than in the first case, feldspars and micas are degraded and we find mostly transformed minerals (montmorillonite — Al). Minerals are very much less degraded downslope because of their confined position and the high ionic content of the percolating waters.