Articles de revues : « Transitional soils »

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Elkamhawy, Elsayed, Huabin Wang, Tarek N. Salem, František Vranay et Martina Zelenakova. « Soil Fabric and Transitional Behavior in Completely Decomposed Granite : An Example of Well-Graded Soil ». Journal of Marine Science and Engineering 9, n^o 10 (23 septembre 2021) : 1046. http://dx.doi.org/10.3390/jmse9101046.

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Unlike sedimentary soils, limited studies have dealt with completely decomposed granite (CDG) soils, even though they are plentiful and used extensively in several engineering applications. In this paper, a set of triaxial compression tests have been conducted on well-graded intact and disturbed CDG soils to study the impact of the fabric on soil behavior. The soil behavior was robustly affected by the soil fabric and its mineral composition. The intact soil showed multiple parallel compression lines, while a unique isotropic compression line was present in the case of disturbed soil. Both the intact and disturbed soils showed unique critical state lines (CSL) in both the e-log p′ and q-p′ spaces. The intact soil showed behavior unlike other transitional soils that have both distinct isotropic compression lines ICLs and CSLs. The gradient of the unique ICL of the disturbed soil was much more than that of the parallel compression lines of the intact soil. In the intact soil, the slope of the unique CSL (M) in the q-p′ space was higher than that of the disturbed soil. The isotropic response was present for both the intact and disturbed soils after erasing the inherited anisotropy as the stress increased with irrecoverable volumetric change. Soil fabric is considered the dominant factor in the transitional behavior and such a mode of soil behavior is no longer restricted to gap-graded soil as previously thought.

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Pan, Yii‐Wen, et Sunirmal Banerjee. « Transitional Yielding Approach for Soils under General Loading ». Journal of Engineering Mechanics 113, n^o 2 (février 1987) : 153–69. http://dx.doi.org/10.1061/(asce)0733-9399(1987)113:2(153).

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Xiao, Yang, M. R. Coop, Hong Liu, Hanlong Liu et Jingshan Jiang. « Transitional Behaviors in Well-Graded Coarse Granular Soils ». Journal of Geotechnical and Geoenvironmental Engineering 142, n^o 12 (décembre 2016) : 06016018. http://dx.doi.org/10.1061/(asce)gt.1943-5606.0001551.

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Prosyannikov, E. V., V. B. Osipov et G. V. Chekin. « Behavior of 137Cs in soils of transitional bogs ». Russian Journal of Ecology 37, n^o 6 (décembre 2006) : 408–13. http://dx.doi.org/10.1134/s1067413606060075.

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Zabielska-Adamska, Katarzyna. « Characteristics of Compacted Fly Ash as a Transitional Soil ». Materials 13, n^o 6 (19 mars 2020) : 1387. http://dx.doi.org/10.3390/ma13061387.

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Cohesive and non-cohesive soils show a number of properties typical of a given category. Cohesive soils are characterized by cohesion, and the properties of compacted soils closely depend on moisture at compaction. However, many researchers have found the existence of so-called mixed or transitional soils. Compacted transitional soils, macroscopically recognized as non-cohesive, are characterized by mechanical properties and hydraulic conductivity which are strictly dependent on the moisture content at compaction. The aim of this work is to show the influence of the content of fine particles in fly ash on the variation of California Bearing Ratio (CBR) values as a parameter strictly dependent on initial compaction. The CBR values were interpreted in terms of moisture at compaction, void ratio and intergranular void ratio. Three different research samples were selected with fine contents of 45%, 55% and 70%; all samples corresponded in terms of grading with sandy silt. Fly ash containing only non-plastic fines behaved as cohesive soils despite the lack of plasticity. The CBR values decreased with increasing moisture at compaction or void ratio. The CBR values, plotted as a function of the intergranular void ratio, have lower penetration resistance together with fine content.

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Bijak, Szymon. « Selected properties of organic soils under boreal mire spruce forest in the Romincka Forest, NE Poland ». Soil Science Annual 68, n^o 4 (1 décembre 2017) : 182–88. http://dx.doi.org/10.1515/ssa-2017-0023.

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Abstract The paper presents selected properties of the organic soils developed in boreal mire spruce forests (Sphagno girensohnii-Piceetum) in the Romincka Forest (NE Poland). Additionally, the relationship between soil fertility and forest stand productivity was investigated. Data from 12 soil profiles, differing in terms of peatland ecological type (raised bog, transitional bog and fen) was used. The significance of the differences in soil properties among peatland types was assessed with the Kruskal-Wallis test. Soil fertility was described using soil trophic index (SIGo), whereas stand productivity according to site index (SI) value. The properties of the analysed soils varied significantly in terms of peatland type. Soils from fens were more fertile (SIGo 25–31), less acidic (pH > 5.7), with lower total potential acidity (36–40 cmol(+)·kg−1), higher base saturation (77–79%), Ca2+ content (116–136 cmol(+)·kg−1) and base exchange capacity (123–145 cmol(+)·kg−1) than soils from transition or raised bogs. No significant effect of soil fertility on the site index of stands growing on analysed soils was observed (r = 0.385, p = 0.216).

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Tkach, E. P. « The content of manganese in soddy brown soils of the Transcarpathian Mountain Valleys ». Fundamental and Applied Soil Science 16, n^o 1-2 (24 mars 2015) : 60–65. http://dx.doi.org/10.15421/041506.

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The soil covering of Transcarpathia, which is used for cultivation of crops, is rather heterogeneous as to genetic features of soils. This is mostly caused by the climatic conditions of corresponding natural zones. Brown mountain soils, soddy brown soils, meadow brown soils and mountain meadow soils have originated in mountainous areas on mountain ranges and slopes of different altitude, which are different in terms of mechanical makeup and are well drained. They are characterized by high content of inaccessible humus (in which fulvic acids predominate), acid reaction of soil solution and evident diversity in provision of mobile forms of nourishing chemicals. On the average, the reaction of soil solution is 4,60 pH of a salt solution, in the case of hydrolytic acidity – 4, 28 me/100g of soil, which characterizes them as semi-acidic. The aim of our thesis is to research the level of manganese, which is one of essential and toxic elements for plants, depending on its concentration in soil, in soddy brown soils of the mountainous zone of Thranscarpathia, and also its distribution in profile of soil horizons. To carry out this aim, samples of soil were chosen by random selection. Total manganese in the soil was determined by the method of mass spectrometery. The samples were extracted by hydrogen peroxide, chlorohydric and azotic acids (ext. p.). Dissolution of the samples was carried out using microwave sample preparation system. Active forms of manganese were extracted by generally accepted extragents: water-soluble extragent – deionized water; free forms of manganese – ammonium acetate buffer solution рН 4.8 according to M. K. Krupskyi and H. М. Alexandrova. Afterwards, the samples of soil were analysed using the method of mass spectrometery. According to the results of the research, the max. total of the manganese is observed in the mineral upper humus-accumulative horizon, but if you make a transition to the parent rock, it decreases. According to the quantitative research on determining free forms of manganese, it can be observed that soddy brown soils of the researched region are provided with the mobile forms of manganese both in the upper humus horizon and in lower transitional humus horizon. Moreover, the humus horizon of the observed region has a high content of mobile forms of manganese, which constitutes >20,1, and in the transitional horizon to the parent rock the provision index is high. A considerable increase in the water-soluble manganese in the upper humus horizon was also observed. Its concentration is considerably decreased with a transition to the lower humus horizon. The research data confirms that soddy brown soils of the observed region are contaminated with manganese compounds.

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Rusakova, E. S., I. V. Ishkova, I. I. Tolpeshta et T. A. Sokolova. « Acid-base buffering of soils in transitional and transitional-accumulative positions of undisturbed southern-taiga landscapes ». Eurasian Soil Science 45, n^o 5 (mai 2012) : 503–13. http://dx.doi.org/10.1134/s1064229312050110.

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Taruna, Yulian, Salampak Salampak, Nina Yulianti, Haiki Mart Yupi, Sustiyah Sustiyah et Fahrul Indrajaya. « Pengaruh Penyiraman Air Tanah Terhadap Perubahan Sifat Kimia Tanah dan Air Gambut di Kalimantan Tengah ». soilrens 19, n^o 1 (10 août 2021) : 58. http://dx.doi.org/10.24198/soilrens.v19i1.35092.

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This study observed the changes in chemical properties of peat soil and ground water after irrigation of two peat types: inland and transition peat. The research was carried out in the Basic and Analytic Laboratory of Palangka Raya University. Inland peat and water samples were obtained from Palangka Raya City, meanwhile and transitional peatland was taken from Pulang Pisau Regency, Central Kalimantan Province. Research methods consisted of survey and experimental test with complete randomized design (CRD) consisted of groundwater irrigation treatment and was repeated 3 times. The experimental parameters are soil chemical properties such as Ash Content, Base Saturation (KB), Nitrogen (N), Phosphor (P), Exchangeable Potassium (K-dd), Interchangeable Sodium (Na-dd), Interchangeable Calcium (Ca-dd), Interchangeable Magnesium (Mg-dd), Cation Exchange Capacity (CEC), Aluminum Saturation, Iron (Fe), Sulfate (SO₄), Hydrogen Concentration (pH), and Electrical Delivery Power (EDP), and water chemical properties such as pH, EDP, cation, and anions.. The results showed that there has been an increase in the value of CEC, P, Na-dd, SO₄, pH, and decreased of Ash Content, N, K-dd, Ca-dd, and EDP on transitional peat soils. Meanwhile, the inland peat soils showed an increase of Ash Content, N, P, Mg-dd, a saturation of Al and Fe, and decreased in the value of CEC, Ka-dd, Na-dd, Ca-dd, SO₄, pH, and EDP. There were similar effect of groundwater irrigation, towards soil chemical properties, with an exeption of iron levels (Fe). Iron levels (Fe) in transitional peat increase, but decreased in inland peat.

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deBortoli, Leah A., Bradley D. Pinno, M. Derek MacKenzie et Edith H. Y. Li. « Plant community composition and tree seedling establishment in response to seeding and weeding treatments on different reclamation cover soils ». Canadian Journal of Forest Research 49, n^o 7 (juillet 2019) : 836–43. http://dx.doi.org/10.1139/cjfr-2018-0363.

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The majority of plant diversity in North American boreal forests is comprised of understory plant communities undergoing continuous interspecific competition. Anthropogenic activities, particularly surface mining, have introduced higher severity disturbances that not only remove vegetation, but also modify soil. During reclamation, soils used to cap overburden materials have inhibited native plant growth and increased weed invasion. This study aimed to examine the effectiveness of seeding and weeding treatments for promoting the establishment of native understory plant communities, as well as a common deciduous tree species, on three different reclamation cover soils (forest floor – mineral mix, peat–mineral mix, and transitional). The broadcasting of a native forb seed mix was not successful on any of the cover soils, whereas weeding affected each cover soil differently. With weeding, the forest floor – mineral mix and transitional cover soils experienced a decrease in the relative abundance of introduced forbs and an increase in the relative abundance of graminoids. The increase in graminoid cover on the forest floor – mineral mix was mostly attributed to the expansion of Calamagrostis canadensis (Michx.) P. Beauv. Overall, weeding effectively eliminated introduced plant species, allowing competitive native grasses to establish. However, weeding may have unintentionally hindered the development of a native understory plant community via the over-establishment of grass on reclamation sites.

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Mishra, R. C. « Distribution of microfungi in the transitional zone of a subtropical lake in India ». Canadian Journal of Botany 73, n^o 3 (1 mars 1995) : 512–16. http://dx.doi.org/10.1139/b95-052.

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Counts of CFU of microfungi, percent carbon, nitrogen, phosphorus, sodium, potassium, and calcium content, and pH were determined in upland, transect, and bottom soils, the transitional zone of Gujar Lake, a subtropical and eutrophic lake in India (25°58′N, 82°39′E). Microfungi in all zones were distributed in aggregate pattern, as evidenced by significant t values (P > 0.001) and F ratios (P > 0.001) of the variance–mean test and Morisita's index. A qualitative survey revealed that Alysidium sp., Arthrinium phaeospermum, Gliomastix murorum, Pythium sp., Tliermomyces sp., Thielavia terricola, Westerdykella multispora, and Varicosporium elodae were found specific to bottom soil of the lake. Key words: distribution, microfungi, transitional zone, subtropical, correlation.

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Jantsch, Adriana, João Carlos Ferreira de Melo Júnior, Maick Willian Amorim, Letícia Larcher et João Carlos Ferreira de Melo Júnior. « Wood anatomy of Laguncularia racemosa (Combretaceae) in mangrove and transitional forest, Southern Brazil ». Revista de Biología Tropical 66, n^o 2 (24 mai 2018) : 647. http://dx.doi.org/10.15517/rbt.v66i2.33397.

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Mangroves represent an environment of great heterogeneity and low diversity of plant species that have structural and physiological adaptations linked to a high salinity environment. Laguncularia racemosa is a typical tree species in mangroves and transitional zones. This study aimed to compare the wood anatomy of L. racemosa (Combretaceae) in two different forests (mangroves and transitional forests), which have different soil conditions. For this, we obtained wood and soil samples in March 2016. We analyzed soil nutritional contents in one 15 cm deep soil sample per forest type. In addition, we selected five mangrove trees in each formation for wood anatomy analysis and took one wood sample per individual, per area. We prepared histological slides and separated materials following standard methods for wood anatomy studies. Soil analysis showed that mangrove soils had higher phosphorus, potassium and calcium contents. The transitional soil had lower pore water salinity and soil pH, probably due to high aluminum levels. Anatomical attributes differed between different forest populations. In the different wood aspects evaluated, we obtained higher values in mangrove individuals when compared to the transitional forest population: vessel elements length (375.79 mm), tangential vessels diameter (75.85 mm), frequency of vessels (11.90 mm) and fiber length (889.89 mm). Moreover, parenchyma rays height was larger in the samples of the transitional forest (392.80 mm), while the mangrove population presented wider rays (29.38 mm). The structure of the secondary xylem in the studied species apparently responds to edaphic parameters and shows variations that allow it to adjust to the environmental conditions. The population of the transitional forest showed a secondary xylem that invests more in protection than the mangrove population. Rev. Biol. Trop. 66(2): 647-657. Epub 2018 June 01.

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Ananko, T. V., M. I. Gerasimova et D. E. Konyushkov. « PALE SOILS ON CARBONATE-FREE DEPOSITS IN CENTRAL SIBERIA AND THEIR TAXONOMIC POSITION IN THE SOIL CLASSIFICATION OF RUSSIA ». Dokuchaev Soil Bulletin, n^o 77 (1 mars 2015) : 29–50. http://dx.doi.org/10.19047/0136-1694-2015-77-29-50.

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Based upon a comprehensive analysis of detailed descriptions of soil profiles and analytical data obtained by I. Sokolov, V. Zolnikov, L. Yelovskaya and other researchers, as well as upon data on the soil-forming factors, an attempt is made to determine the taxonomic level of pale undifferentiated neutral and slightly acid soils derived from carbonate-free deposits in the new classification system of Russian soils (versions 2004, 2008). The above group of soils is not uniform. According to their diagnostic morphological and physical-chemical properties the loamy permafrost-affected soils with ice-rich permafrost should be placed in the order of cryometamorphic or iron-metamorphic soils. The loamy sandy soils with dry permafrost may be placed in the same order. The soils with a shallow profile (< 30 cm) on hard parent rock should be qualified as members of the order of lithozems. The specific features of these soils make it possible to suggest new elements to the soil classification. A subtype of pale-metamorphized soils is offered to recognize the types of rzhavozems and raw-humus rzhavozems as the soils transitional to the pale soils. This suggestion is aimed at harmonization of a variety of ideas on the genesis, conditions for the development and nomenclature of soils, which permits us to give a more complete and reliable perception of the soil cover in the Central Siberian plateau.

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Juliev, M., B. Matyakubov, O. Khakberdiev, X. Abdurasulov, L. Gafurova, O. Ergasheva, U. Panjiev et B. Chorikulov. « Influence of erosion on the mechanical composition and physical properties of serozems on rainfed soils, Tashkent province, Uzbekistan ». IOP Conference Series : Earth and Environmental Science 1068, n^o 1 (1 juillet 2022) : 012005. http://dx.doi.org/10.1088/1755-1315/1068/1/012005.

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Abstract The problem of soil protection from erosion is relevant for many countries in the arid zone of the world, including the territory of Uzbekistan. In the republic, the main arrays of crops are located on rainfed lands, where the crop is created only due to moisture in precipitation. The amount of porosity (duty cycle) of soils is determined mainly by specific and bulk mass, mechanical composition, and humus content. Porosity of soils decreases from unwashed soils to washed away and down the profile. In the arable horizons of unwashed rainfed soils, it is 52%, washed out - 47.49%. Deeper in the profile, in horizons transitional to soil, due to a sharp increase in density and a decrease in the humus content in all soils, regardless of erosion, Porosity sharply drops to 48-50%. Thus, with a small bulk mass, the overall porosity of rainfed typical serozems is generally satisfactory, since it provides good soil aeration and the use of precipitation, only on highly washed away soils the porosity decreases markedly and the absorption of precipitation is slightly worsened.

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Mugabe, F. T., M. G. Hodnett et A. Senzanje. « Effect of temporal rainfall distribution and soil type on soil moisture and runoff generation in semi-arid Zimbabwe ». Hydrology Research 38, n^o 3 (1 juin 2007) : 249–63. http://dx.doi.org/10.2166/nh.2007.014.

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This paper examines the effect of temporal rainfall distribution on soil moisture and runoff generation in the 5.9 km2 Mutangi catchment in semi-arid Zimbabwe. Rainfall, soil moisture and runoff were measured during the 1999/00 and 2000/01 rainy seasons during which periods 755 mm and 615 mm of rainfall were received, respectively. The percentage of rainfall totals in these periods were 58% and 69%, respectively, in February. The total catchment runoff was 102 mm and 63 mm, of which 52% and 49% were recorded over 6 and 4 d in 2000 and 2001, respectively. Baseflow was negligible. Rainfall intensities were generally low. In the 1999/00 season there were 2 and 8 h with intensities >20 mm h−1 and 10 mm h−1, respectively. Some runoff appears to be generated by Hortonian overland flow (HOF), mainly in the early wet season before ploughing creates a rougher soil surface. The dominant process of runoff in this catchment was saturated overland flow (SOF), which occurs when the soils become saturated from below. The sodic soils along the stream channels appear to generate most of the runoff because of their small capacity to store water before saturation. The ridge soils are coarse sands, with a large capacity to store rainfall. The transitional (slope) soils have an intermediate capacity to store water. If there is a sequence of daily events that completely fills the storage available in both the sodic and transitional soils, and which begins to saturate the ridge soils, there could be very large amounts of runoff (>50% of the daily rainfall). The occurrence of such runoff events depends very heavily on the distribution of rainfall. Dry spells between rain events create storage, thereby reducing the risk of runoff from the next events.

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Grogan, James, et Jurandir Galvão. « Physiographic and floristic gradients across topography in transitional seasonally dry evergreen forests of southeast Pará, Brazil ». Acta Amazonica 36, n^o 4 (décembre 2006) : 483–96. http://dx.doi.org/10.1590/s0044-59672006000400009.

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Seasonally dry evergreen forests in southeast Pará, Brazil are transitional between taller closed forests of the interior Amazon Basin and woodland savannas (cerrados) of Brazil's south-central plains. We describe abiotic and biotic gradients in this region near the frontier town of Redenção where forest structure and composition grade subtly across barely undulating topography. Annual precipitation averaged 1859 mm between 1995-2001, with nearly zero rainfall during the dry season months of June August. Annual vertical migrations of deep-soil water caused by seasonal rainfall underlie edaphic and floristic differences between high- and low-ground terrain. Low-ground soils are hydromorphic, shaped by perching water tables during the wet season, pale gray, brown, or white in color, with coarse texture, low moisture retention during the dry season, and relatively high macro-nutrient status in the surface horizons. Forest canopies on low ground are highly irregular, especially along seasonal streams, while overstory community composition differs demonstrably from that on high ground. High-ground soils are dystrophic, well-drained through the wet season, brown or red-yellow in color, with finer texture, higher moisture retention, and low macro-nutrient status in the surface horizons compared to low-ground soils. Forest canopies are, on average, taller, more regular, and more closed on high ground. Low-ground areas can be envisioned as energy and nutrient sinks, where, because of hydrologic cycles, canopy disturbance likely occurs more frequently than at high-ground positions if not necessarily at larger scales.

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Baysal, Fulya, Maria-Soledad Benitez, Matthew D. Kleinhenz, Sally A. Miller et Brian B. McSpadden Gardener. « Field Management Effects on Damping-Off and Early Season Vigor of Crops in a Transitional Organic Cropping System ». Phytopathology® 98, n^o 5 (mai 2008) : 562–70. http://dx.doi.org/10.1094/phyto-98-5-0562.

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Transitioning farmland to certified organic vegetable production can take many paths, each varying in their costs and benefits. Here, the effects of four organic transition strategies (i.e., tilled fallowing, mixed-species hay, low-intensity vegetables, and intensive vegetable production under high tunnels), each with and without annual compost applications for 3 years prior to assessment, were characterized. Although transition cropping strategies differed in soil chemistry (P < 0.05), the magnitude of the changes typically were marginal and pairwise comparisons were rarely significant. In contrast, the compost amendment had a much greater impact on soil chemistry regardless of cropping strategy. For example, percent C and total P increased by 2- to 5-fold and K increased from 6- to 12-fold. Under controlled conditions, damping-off of both edamame soybean (cv. Sayamusume) and tomato (cv. Tiny Tim) was reduced from 2 to 30% in soils from the mixed-hay transition. In the field, damping-off of both crops was also significantly lower in plots previously cropped to hay (P < 0.05). Although not always significant (P < 0.05), this pattern of suppression was observed in all four of the soybean experiments and three of the four tomato experiments independent of compost application. The compost amendments alone did not consistently suppress damping-off. However, plant height, fresh weight, and leaf area index of the surviving seedlings of both crops were greater in the compost-amended soils regardless of the transitional cropping treatment used (P < 0.05 for most comparisons). These data indicate that mixed-hay cropping during the transition periods can enhance soil suppressiveness to damping-off. In addition, although compost amendments applied during transition can improve crop vigor by significantly enhancing soil fertility, their effects on soilborne diseases are not yet predictable when transitioning to certified organic production.

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Racchetti, Salmaso, Pinardi, Quadroni, Soana, Sacchi, Severini, Celico, Viaroli et Bartoli. « Is Flood Irrigation a Potential Driver of River-Groundwater Interactions and Diffuse Nitrate Pollution in Agricultural Watersheds ? » Water 11, n^o 11 (3 novembre 2019) : 2304. http://dx.doi.org/10.3390/w11112304.

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In the Po plain, northern Italy, rivers within agricultural basins display steep summer increases in nitrate (NO3−) concentrations. Flood irrigation in overfertilized, permeable soils may drive such diffuse pollution, facilitating interactions between NO3−-rich groundwater and surface waters. We discuss multiple, indirect evidence of this mechanism in the Adda, Oglio, and Mincio rivers. These rivers drain agricultural soils with elevated nitrogen (N) surpluses, averaging 139, 193, and 136 kg ha−1 in the Adda, Oglio, and Mincio watersheds, respectively. The three rivers cross a transitional area between highly permeable and impermeable soils, where summer NO3− concentrations may increase by one order of magnitude over short distances (8–20 km). Upstream of this transitional area, a major fraction of the river flow is diverted for flood irrigation, a traditional and widespread irrigation technique for permeable soils. We speculate that diverted water solubilizes soil N excess, recharges the aquifer, and transfers soil N surplus into groundwater, resulting in NO3− pollution. Groundwater–river interactions were estimated experimentally, via water and NO3− budgets in 0.3 to 1 m3 s−1 km−1 and in 1500 to 5400 kg NO3−–N day−1. The data suggest a pronounced east–west gradient of groundwater to river diffuse water inputs among the three adjacent basins, reflecting the soil permeability and the width of the river–groundwater interaction zone. Given the large stock of NO3− in groundwater, management interventions performed at the basin scale and aimed at decreasing N excess will not produce an immediate decrease in river NO3− pollution.

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Pankiv, Zenoviy, et Taras Yamelynets. « Ferrum concretions forms in the mollic gley soils of Low (Male) Polissya ». Polish Journal of Soil Science 53, n^o 1 (22 juin 2020) : 137. http://dx.doi.org/10.17951/pjss.2020.53.1.137.

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<p>In the humid conditions, the most common ground forms are the ferruginous ones: ferrum concretions, marsh ore, ocher spots, etc. Mollic gley soils are widely spread along the periphery of marshes and are formed under the influence of mollic and gley processes on various soil-forming rocks under conditions of sporadically pulsating water regime and excessive moisture under the meadow and swamp biocenoses. The ferrum concretions are characteristic of all genetic horizons of mollic gley soils, except for the soil-forming rock, and their content ranges from 3.3% in the mollic to 47.1% in the lower transitional horizon. The gross iron content in the fine mollic gley soils, as well as in the ferrum concretions forms, increases with depth, and the maximum values are characteristic of the lower transition horizon. The lowest values of the gross iron content are characteristic of the fine soil-forming rock (16.0 mg / 100 g soil) and the mollic soil (66.4 mg / 100 g soil). It was established that the gross chemical content of the ferrum concretions forms is dominated by the iron oxides with the highest content in the ferrum concretions of the mollic soils (48.75%). Also the ferrum concretions forms of iron are characterized by a rather high content of aluminum oxides (5.59–7.92%). The highest values of the accumulation coefficient are characteristic of the iron oxide (Kx = 7.21–2.58), which confirms the hypothesis of the dominant role of its compounds in the formation of the ferrum concretions forms.</p>

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Karmazinenko, S. P. « Pleistocene soils of the Azov Lowland, Ukraine ». Journal of Geology, Geography and Geoecology 28, n^o 2 (6 juillet 2019) : 313–26. http://dx.doi.org/10.15421/111931.

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With the aim to reconstruct the Pleistocene soils in Azov Lowland (geological sections near the villages of Bezimenne and Melekinе Donetsk region), we carried out palaeopedological research. The Paleopedological method was used, which consisted with a detailed analysis of the morphological (color, structure, granulometric composition, humidity, composition, neoplasms, inclusion, transition between horizons, border) and micromorphological (skeleton, plasma, color, aggregation, porosity, organic and clay parts, mineral skeleton, tumors, microstructure) features. Paleopedological studies of Pleistocene soils have allowed to determine the types of these deposits and to follow the dynamics of changes in soil conditions: - warm-temperate with signs and close to subtropical, when formed reddish cinnamon (krb1), reddish brown (krb2), cinnamonish-brown (shb1), reddish cinnamon (shb2), dark-colour (meadow reddish cinnamon) merged (mrb2 + mrb1), reddish cinnamon, brownish, fused saline soils (mr3) Kryzhanivka, Shyrokyno and Martonosha soils, which are distinguished by reddish shades of coloring of the profiles, are the most ferruginous, clay, with a large number of nodules witch concentration of organo-iron-clay material; - moderately-warm transition to subtropical – red-brown saline (lbb2), dark-colour (brownish-cinnamonic) fused (lbb2 + lbb1) heavy loam Lubny soils, with are less clayed, ferruginous and formed in meadow-steppe and steppe conditions (brownish-gray with cinnamonish shades of coloring profiles,the presence of moleholes, complex microaggregation); - moderately variable – humid close to subtropical – cinnamon and cinnamonsaline (zvb1), reddish-cinnamon saline (zvb2), heavy loam Zavadivka soils, which are a transitional variant to temperate climates, although some of the features of the lower Pleistocene soil formation are retained (ferrugination, presence of segregated clusters organo-clay and clay materials, microortshteins); - moderately-warm equally humid – cinnamon-brown (kdb1), ordinary chernozems (kdb2), cinnamonish-gray saline (plb1), chernozem saline (plb2), brown steppe (plc), heavy and medium loam Kaydaky and Pryluky soils, characterized by the grayish shades of coloring of profiles, the presence of moleholes, carbonates, complex microaggregates, pores and are closest to modern soils; - moderately-warm subarid – cinnamonish-brown (vtb2) heavy loam Vytachiv soils formed under the influence of turf (the presence of crust, carbonate, complex microaggregates) and brown-liked (cinnamonish-brown color of the profile,spatial structure of clays) of soil formation processes and have no analogues in modern soil cover; - moderately-continental and more arid (dry) – chernozems saline (dfb2), brown saline (dfc), desert-steppe fulvous (dfc), medium loam Dofinivka soils, with clear features of xeromorphism (low profile power, its carbonate, lack of signs of organo-mineral materials) replacing.

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Zheng, Jianqiu, Taniya RoyChowdhury, Ziming Yang, Baohua Gu, Stan D. Wullschleger et David E. Graham. « Impacts of temperature and soil characteristics on methane production and oxidation in Arctic tundra ». Biogeosciences 15, n^o 21 (8 novembre 2018) : 6621–35. http://dx.doi.org/10.5194/bg-15-6621-2018.

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Abstract. Rapid warming of Arctic ecosystems accelerates microbial decomposition of soil organic matter and leads to increased production of carbon dioxide (CO2) and methane (CH4). CH4 oxidation potentially mitigates CH4 emissions from permafrost regions, but it is still highly uncertain whether soils in high-latitude ecosystems will function as a net source or sink for CH4 in response to rising temperature and associated hydrological changes. We investigated CH4 production and oxidation potential in permafrost-affected soils from degraded ice-wedge polygons on the Barrow Environmental Observatory, Utqiaġvik (Barrow), Alaska, USA. Frozen soil cores from flat and high-centered polygons were sectioned into organic, transitional, and permafrost layers, and incubated at −2, +4 and +8 ∘C to determine potential CH4 production and oxidation rates. Significant CH4 production was only observed from the suboxic transition layer and permafrost of flat-centered polygon soil. These two soil sections also exhibited highest CH4 oxidation potentials. Organic soils from relatively dry surface layers had the lowest CH4 oxidation potential compared to saturated transition layer and permafrost, contradicting our original assumptions. Low methanogenesis rates are due to low overall microbial activities measured as total anaerobic respiration and the competing iron-reduction process. Our results suggest that CH4 oxidation could offset CH4 production and limit surface CH4 emissions, in response to elevated temperature, and thus must be considered in model predictions of net CH4 fluxes in Arctic polygonal tundra. Future changes in temperature and soil saturation conditions are likely to divert electron flow to alternative electron acceptors and significantly alter CH4 production, which should also be considered in CH4 models.

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Elkamhawy, Elsayed, Bo Zhou et Huabin Wang. « Transitional behavior in well-graded soils : An example of completely decomposed granite ». Engineering Geology 253 (avril 2019) : 240–50. http://dx.doi.org/10.1016/j.enggeo.2019.02.027.

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Hrabovský, Andrej, Pavel Dlapa, Artemi Cerdà et Jozef Kollár. « The Impacts of Vineyard Afforestation on Soil Properties, Water Repellency and Near-Saturated Infiltration in the Little Carpathians Mountains ». Water 12, n^o 9 (12 septembre 2020) : 2550. http://dx.doi.org/10.3390/w12092550.

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Vineyards are a 7000-year-old land-use tradition and both management and abandonment have result in altered soil properties. These have a great effect on water resources and soil services, and this inspired our investigation into the effects of land-use and land-use change on soils in the Modra wine-growing region in South-western Slovakia. Ten topsoil samples were taken at each of the seven research sites (n = 70) on granite parent material in cultivated and afforested vineyards and original forest soils. Laboratory analyses included determination of soil texture, organic carbon content, soil pH, and water repellency. This was supplemented by infiltration measurements under near-saturated conditions at the vineyard and afforested study sites. Studied soils have a low clay content and a high proportion of sand. The vineyard soils have significantly higher pH than the forest and afforested soils because the naturally acidic soils have been limed. The forest and afforested soils have similar properties, with higher organic carbon content. This makes them strongly to extremely water repellent and contrasts sharply with the wettability of cultivated vineyard soils. One afforested site, however, was less acidic and therefore was considered transitional between forest and vineyard soils. Our infiltration measurements established the influence of soil water repellency on the infiltration process, and our results highlighted that the infiltration rate in the vineyard soils was significantly higher than in afforested soils. The infiltration rate also gradually increased over time in afforested soils due to decreasing water repellency. Physically impossible negative sorptivity values in afforested soils were noted because of changes in water repellency during the infiltration process. Finally, we conclude that soil afforestation results in increased soil water repellency and a subsequent reduction in the infiltration rate at the matrix scale.

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Kõlli, Raimo, Endla Asi, Lech Szajdak, Tõnu Tõnutare, Alar Astover et Kadri Krebstein. « Accumulation of metallic elements into the superficial peat layer of mires and wet mineral soils of Estonian forest land / Akumulacja metali w powierzchniowej warstwie gleb torfowych i wilgotnych glebach mineralnych ekosystemów leśnych Estonii ». Ochrona Srodowiska i Zasobów Naturalnych 26, n^o 4 (1 décembre 2015) : 6–9. http://dx.doi.org/10.1515/oszn-2015-0021.

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Abstract This article studied the extent of accumulation of aqua regia extractable metallic elements (Al, Mg, Pb, Zn, Hg, Cd) into peaty (histic) epipedon (EP) of fen soils, transitional bog soils, peaty gley soils and peaty podzols. The accumulation coefficients (Kac) of the elements in EP were estimated in relation of forest floor (FF, as an input) as a comparison to deeper levels (SS, as a past background). The study revealed that the extent of accumulation and its order depend on soil (peat) type or pedo-ecological conditions of peatification. In the forming of EP from FF, the concentrations of Al and Pb were increased on an average 2.5-5.0 times, but that of Hg increased significantly only in peaty soils (on an average 1.5-1.6 times). The contents of Zn were significantly decreased (Kac 0.1-0.5) in all soil groups. The comparison of EP peats concentrations with SS data demonstrated a considerable accumulation of Pb, Cd, Zn and Hg into thin (~20 cm) superficial peat layer.

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Jayawardane, NS, et EL Greacen. « The nature of swelling in soils ». Soil Research 25, n^o 1 (1987) : 107. http://dx.doi.org/10.1071/sr9870107.

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While existing swelling models adequately describe the swelling in extensively-swelling soils, their applicability to moderately-swelling soils has not been previously tested. The swelling of different layers of a transitional red-brown earth measured in situ using swelling gauges could not be described using existing swelling models. Values of �, defined as the ratio of change in bulk volume of the soil to change in gravimetric moisture content, were less than 0.33 over the whole of the measured moisture range in all layers of this soil, except the 0.25-0.55 m depth. This indicates that the extent of swelling was less than the normal, three-dimensional swelling described by existing models. Modifications to these existing models are proposed to describe the swelling in soils with moderate swelling characteristics. The compressibility factor (�), defined as the ratio of the change in void ratio to the change in moisture ratio, measures the same soil property as the values. Values of � determined in previous field studies and on soil cores of several clay soils are also less than the 0.33 specified for normal swelling, in keeping with the expectations of the modified swelling model. However, the need for further field testing of this model for moderately-swelling soils is emphasized. The limitations of existing methods for determining swelling characteristics of soils using core samples are discussed and several alternative procedures for in situ measurements are suggested.

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Kim, Sang Yeob, Jong-Sub Lee et Junghee Park. « Response of Transitional Mixtures Retaining Memory of In-Situ Overburden Pressure Monitored Using Electromagnetic and Piezo Crystal Sensors ». Sensors 21, n^o 7 (6 avril 2021) : 2570. http://dx.doi.org/10.3390/s21072570.

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The major and minor components in granular soil materials determine their properties and behavior. This study explores the transitional behavior within threshold fines fraction of soil mixtures based on the data from the literature and experiments. From the literature survey, the void ratio, shear wave velocity, compression index, and friction angle capture the transitional turning point between the low and data-adjusted high threshold fines fractions. In particular, there is a dramatic change in hydraulic conductivity below the low threshold fines fraction that highlights the critical role of small amounts of fines in the fluid flow (e.g., clogging). From an experimental study, the engineering properties of natural soil samples identified using deformation and elastic wave sensors show transitional trends within the Revised Soil Classification System framework. The evolution of compressibility and shear wave velocity indicate that either coarse, fine, or both particles are likely to contribute to large and small strain stiffnesses when the effective stress is below 400 kPa. Thereafter, both engineering properties indicate that the soil sample retains a memory of in-situ overburden pressure when the effective stress is around 400 kPa. There is a critical role of fines that are slightly higher than low threshold fines fraction on engineering properties that promote the application of Revised Soil Classification System RSCS to natural soils.

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Proske, Ulrike, Henk Heijnis et Patricia Gadd. « Using X-ray fluorescence core scanning to assess acid sulfate soils ». Soil Research 52, n^o 8 (2014) : 760. http://dx.doi.org/10.1071/sr14103.

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During the formation of acid sulfate soils (ASS), several chemical elements in the sediment are mobilised. These elements are removed from the sediment or become enriched as precipitates in distinct horizons. The stratigraphic depth in which these precipitates accumulate is element-specific and is located either within the oxidised or in a transitional zone between the oxidised and the reduced zone. Aim of this study is to demonstrate how X-ray fluorescence core scanning, together with detailed sediment descriptions, can be used to perform an initial assessment of these different zones in ASS in a fast and cost-effective manner. We measured the chemical element signatures of K, Fe, Pb, Sr, Zn, Ni, Y, Mn and Ca in two sediment cores from Western Australia where ASS are suspected to occur. The oxidised zone in both cores is characterised by the occurrence of jarosite, which is indicated by pale straw yellow mottling and synchronous peaks in Fe/Ti, K/Ti, Pb/Ti and Sr/Ti, and of other secondary Fe-oxides, which are indicated by reddish mottling and synchronous peaks in Fe/Ti and Pb/Ti. The transition zone into reduced material is marked by synchronous peaks in Zn/Ti, Ni/Ti, Y/Ti and Mn/Ti. Based on these characteristic signatures, we broadly estimated the depth of the oxidised and the transitional zone at both sites.

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Akhmetova, G. V. « Geochemical features of soils in an undulating glaciolacustrine sandy plain in the middle taiga subzone of Karelia ». Dokuchaev Soil Bulletin, n^o 100 (3 janvier 2020) : 53–82. http://dx.doi.org/10.19047/0136-1694-2019-100-53-82.

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The geochemically conjugate series of soils (Albic Podzol – Albic Podzol Gleyc – Hystosol) formed on an undulating glaciolacustrine plain in the middle taiga of Karelia was investigated. Surveys for redox conditions showed them to vary from oxidizing in automorphic soils to reducing in soils occupying accumulation-favoring locations. The geochemical coefficients descriptive of the features of accumulation and directions of migration in the studied soils were calculated and analyzed. The distribution of silicic acid and a majority of sesquioxides inside the profile of the studied soils is typical of podzols. The podzolic horizons of the soils occupying interstitial positions have a faster outmigration of elements than in automorphic soils, while their Al-Fe-humic horizons accumulate aluminum, iron, titanium and phosphorus. All the soils are deficient in a majority of microelements as compared to their background levels; very low concentrations were determined for nickel, cobalt and manganese. The content of copper and sometimes zinc is at the background level. The distribution of the studied elements across the soil profile follows the accumulation-eluviation-illuviation pattern, but the scope of variation in the migration of elements varies among topographic positions. In well-drained locations microelements are quite monotonously distributed through the lower part of the soil profile, while soils in transitional landscapes have a higher differentiation of microelements. The differentiation of the catena through lateral migration is of the transient eluviation type, i.e. soils in lower-lying positions are poorer in the studied elements than soils in automorphic positions. This pattern is due to the natural characteristics of the area: low surface slope, homogeneous sandy parent material, low humus content in soil.

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Rech, Aline, Elisa Pacheco, Jakcemara Caprario, Julio Cesar Rech et Alexandra Rodrigues Finotti. « Low-Impact Development (LID) in Coastal Watersheds : Infiltration Swale Pollutant Transfer in Transitional Tropical/Subtropical Climates ». Water 14, n^o 2 (14 janvier 2022) : 238. http://dx.doi.org/10.3390/w14020238.

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The control of runoff pollution is one of the advantages of low-impact development (LID) or sustainable drainage systems (SUDs), such as infiltration swales. Coastal areas may have characteristics that make the implementation of drainage systems difficult, such as sandy soils, shallow aquifers and flat terrains. The presence of contaminants was investigated through sampling and analysis of runoff, soil, and groundwater from a coastal region served by an infiltration swale located in southern Brazil. The swale proved to be very efficient in controlling the site’s urban drainage volumes even under intense tropical rainfall. Contaminants of Cd, Cu, Pb, Zn, Cr, Fe, Mn and Ni were identified at concentrations above the Brazilian regulatory limit (BRL) in both runoff and groundwater. Soil concentrations were low and within the regulatory limits, except for Cd. The soil was predominantly sandy, with neutral pH and low ionic exchange capacity, characteristic of coastal regions and not very suitable for contaminant retention. Thus, this kind of structure requires improvements for its use in similar environments, such as the use of adsorbents in soil swale to increase its retention capacity.

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Altuhafi, Fatin, Béatrice A. Baudet et Peter Sammonds. « The mechanics of subglacial sediment : an example of new “transitional” behaviour ». Canadian Geotechnical Journal 47, n^o 7 (juillet 2010) : 775–90. http://dx.doi.org/10.1139/t09-136.

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A series of isotropic compression tests and drained and undrained triaxial compression tests have been performed on glacial sediment from Iceland. Langjökull sediment, which is well graded, is thought to have reached a critical grading during deposition and transportation. Multiple parallel normal compression lines (NCLs) were found, but a unique critical state line (CSL) could be identified. This is unlike other so-called “transitional” soils, whose grading varies between reasonably well graded to gap graded, which tend to have distinct NCLs and critical state lines depending on the specimen density. It is thought that in the case of the Langjökull sediment studied, its particular strain history that involved incessant shearing during deposition accounts for the difference in behaviour. This provides the interesting case of a soil that has been crushed to a critical grading in situ, which depends on the mineralogy of the grains, which was then sampled and tested. Despite the unique grading, samples with a range of different void ratios can be prepared and the combination of grading and density seems to set a fabric that cannot be changed by compression, resulting in multiple parallel NCLs. At the critical state, however, the fabric has been destroyed and the CSL is unique.

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Pochernyaeva, E. P., V. O. Okata, O. V. Kotovych et V. M. Yakovenko. « Influence of irrigated mineralized waters on properties of ordinary chernozem in the conditions of Prysamaria Dniprovske ». Ecology and Noospherology 31, n^o 2 (25 octobre 2020) : 93–98. http://dx.doi.org/10.15421/032015.

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Irrigation of lands in arid climates helps to solve the problem of water deficit of soils in order to increase their fertility. However, under the influence of mineralized waters used for irrigation, there is a degradation of chemical, physico-chemical, water-physical and physical properties of soils. Soil monitoring is one of the effective mechanisms that allowsassessing the current state of soils and predicting the negative consequences of economic activity in the future. The area where the research was conducted is in the zone of insufficient moisture where there is an annual deficit of water balance of soils. Irrigation in the studied areas began in the mid-70s of the last century and lasted until 1992. The waters of the Samara River were used for this purpose. The total mineralization of water during the growing season reaches 3515 mg/dm3. It is possible to estimate the degree of transformation of soils that have been under the influence of irrigation waters for a long time in relation to the indicators of virgin soils. The zonal soils of the research area are CalcicChernozems. The analysis of macromorphological indicators showed that irrigation soils differ from the reference ones by the thickness of the organogenic horizon, density and structure. The results of the analysis of the aqueous extract of the reference soils show the absence of salinization with water-soluble salts. Their content varies in the range from 0.051 to 0.078 %. A maximum of one salt is observed in the soil profile, namely in the transitional horizon at a depth of 45–63 cm. Below this depth, the content of water-soluble salts progressively decreases. The total content and distribution of water-soluble salts in the soil profile of irrigated soils has some differences from the reference soils. In the upper part of the humus horizon, the total amount of water-soluble salts is smaller, which can be attributed to the effects of machining and better aeration, as well as the intensive removal of their vegetation. Below these horizons, the amount of water-soluble salts progressively increases and reaches a maximum in the soil-forming rock. The nature of the distribution in the soil profile and the total amount of salts isnot typical for Calcic Chernozems and ismore similar to those of Gleyic Calcic Chernozems. The maximum amount of water-soluble salts is concentrated in the parent rock. Their percentage indicates the absence of salinity in both studied soils. But guided by the method of calculating the content of toxic water-soluble salts in the soil, in the reference soils, this figure reaches 0.21 t/ha in a meter layer of soil, and in irrigation 0.42 t/ha. The results of studies of physicochemical parameters show that a higher content of metabolic calcium is characteristic of the reference soils, and its distribution in the soils along the profile of both options is relatively similar. In contrast, the distribution of exchangeable magnesium in the soil profile varies greatly, especially in the reference soils. In irrigated soils, the ratio of exchangeable calcium to magnesium is more stable and varies in the range from 4.2 to 7.9, which may be the result of prolonged irrigation. According to the obtained physicochemical parameters, irrigation soils have weak salinity in the lower part of the transition horizon. This indicator, together with the ratio of exchangeable calcium to magnesium, indicates eluvial-illuvial processes that for some time contributed to the redistribution in the soil profile of both water-soluble salts and exchangeable cations. Evaluation of the degree of salinity of soils showed the absence of salinization in the reference soils, as well as in the upper part of the humus horizons of irrigated soils. Given the buffering of irrigated soils, weak salinity is present only in the upper part of the transition horizon.

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Oliveira, Jaime, José Antonio Molina et Gonzalo Navarro. « BOVEDA, the Bolivian Vegetation Ecology Database : first stage, the Chacoan forests ». Vegetation Classification and Survey 3 (24 octobre 2022) : 191–97. http://dx.doi.org/10.3897/vcs.84418.

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Bolivia is a country exceptionally rich in biodiversity and home to about 20,000 vascular plant species and 15 plant formations. Therefore, it is particularly important to document the biodiversity of this territory. The aim of the Bolivian Vegetation Ecology Database (BOVEDA; GIVD ID SA-BO-005) is to record floristic and ecological data of Bolivian vegetation. In the first stage, the database hosts 320 relevés from one of the most unique biogeographical units in the country, the Chaco. In total, 633 species belonging to 114 families have been recorded. Data on vegetation structure, soil, flooding regime and geomorphology have also been stored. The following nine vegetation structural types were identified: (1) deciduous forests of alluvial plains on well to moderately well drained soils; (2) deciduous to semideciduous Chaco forests transitional to the Andes; (3) deciduous and sclerophyllous Cerrado thorn-woodlands and shrublands transitional to the Chaco (Abayoy); (4) xeromorphic thorn shrubland and thickets on vertic, poorly drained soils; (5) woodlands and savannas on sand dunes and aeolian surfaces; (6) freshwater swamp forests; (7) saltwater swamp forests; (8) phreatophytic forests; (9) deciduous to semideciduous Chaco forests transitional to the Chiquitania. Further steps will be to incorporate new types of vegetation already recorded in the field such as Altiplano shrublands, Andean wetlands, Andean Polylepis forests, and vegetation of the dry inter-Andean valleys. Taxonomic reference: Jørgensen et al. (2015). Abbreviations: BOVEDA = Bolivian Vegetation Ecology Database; GIVD = Global Index of Vegetation-Plot Databases.

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Xosrov qızı Məcnunlu Musabəyli, Könül. « Status of land use in Mil-Aran Karabakh cadastral region ». NATURE AND SCIENCE 11, n^o 06 (23 août 2021) : 24–29. http://dx.doi.org/10.36719/2707-1146/11/24-29.

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Mil-Aran Karabakh cadastral region includes Barda, Agjabadi, Beylagan, Tartar regions as a whole, Aghdam, Aghdara region and Khojavend plain lands. Gray-meadow, meadow-forest, subasar alluvial meadow, gray, meadow-swamp, chestnut, meadow-chestnut soils are spread in the territory of this cadastral region. Grass-gray soils are transitional and are distributed in the strip between the gray-brown (chestnut) and meadow gray-brown (chestnut) soils of the dry steppes and the gray soils growing in drier conditions. Very large areas of the described lands are used for irrigated agriculture. The subasar regime of rivers and the resulting fresh alluvial sediments play a key role in the formation of subasar meadow-forest soils. During the autumn season, especially during floods, the rhythm of soil formation is repeatedly disrupted. This, of course, is reflected in the properties and morphological structure of these soils. Areas with gray soils have an arid semi-desert and dry steppe climate with an average annual temperature of 13.5-14.60. The temperature of the hot months is much higher. Unlike subasar meadow-forest lands of our republic, subasar-meadow soils are formed under meadows and shrubs. Rich grasses play an important role in enriching these soils with organic matter and ash elements. Meadow-swamp lands are spread in a relatively limited area of the republic. These soils are usually formed in the low and lowlands of the relief. The ecological and geographical features of the meadow-brown soils are in many respects similar to those of the brown soils. However, hydrothermal conditions are distinguished by the large seasonal differences, additional moisture due to surface and ground moisture. Our area is subject to varying degrees of salinization and erosion. We know that saline soils are lands with salts that are easily soluble in water in a 2-meter layer of soil. The effect of groundwater on soil salinization also depends on the degree of mineralization of that water. In this case, the crisis rate of groundwater mineralization is taken. Key words: Groundwater, mineralization rate,salt accumulation, irrigated soils, drainage rate

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Malynovska, I. M. « THE SPATIAL STRUCTURE OF GRAY FOREST SOIL BACTERIAL CENOSIS UNDER DIFFERENT CONDITIONS OF USE ». Agriciltural microbiology 25 (29 juin 2017) : 36–42. http://dx.doi.org/10.35868/1997-3004.25.36-42.

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Under the conditions of the stationary experiment (agrarian soils) and in the 22-year-old deposit areas, the state of microbiocenoses of individual horizons of gray forest soil: humusaccumulative (0–29 cm), illuvial (30–50 cm), transitional from illuvial horizon to solid (92– 110 cm) was studied. It was established that the quantity and physiological and biochemical activity of the microorganisms of the studied ecological-trophic groups, the intensity and direction of the mineralization processes are changing by the soil profile. The nature and extent of such changes significantly depends on the way the soil is used.

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Holovko, Serhii. « A NEW APPROACH TO REPAIR OF NON-RIGID ROAD PAVEMENT TRANSITIONAL TYPE ». Avtoshliakhovyk Ukrayiny 264, n^o 4 (21 décembre 2020) : 47–51. http://dx.doi.org/10.33868/0365-8392-2020-4-264-47-51.

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Earlier, due to insufficient financing of the road industry, funds were allocated on a leftover basis for the repair of local roads, over time the condition of these roads has deteriorated significantly. So, given the ramified network of local roads, the issue of restoring the condition of local roads is a very urgent problem. Conducted exploratory studies of the application of stabilization technology to restore the condition of local roads show that this technology is progressive, since it allows reusing existing materials while ensuring the required strength of the pavement. However, design engineers rarely use this technology, probably due to insufficient research on this approach. The task is to investigate the possibility of using stabilization technology with the use of crushed stone layers of different composition and their maximum reuse, when repairing transitional pavements. Analysis shows that there are many cases where transitional structures have significant heterogeneity and low strength. This is formed due to a weak crushed stone base and waterlogging of the subgrade soils. Over time, soil particles penetrate into the crushed stone layer and weaken the contacts between the crushed stones, as a result of which rut, pits and subsidence form on the road, which significantly complicates the movement of vehicles. Studies of the composition of existing bases show that if in a dispersed system the amount of crushed stone grains is more than 50% by volume, then a contact frame is formed in the material. Intergranular voids are filled with soil or fine aggregate, processing with such a small amount of a mineral binder (cement or lime) allows it to be significantly strengthened, as well as to create bonds between the soil and crushed stone. Modern self-propelled soil mixing machines (recycler-stabilizer) allow in one pass to perform milling (loosening) and mixing of materials of existing transitional pavement to a depth of 40 cm. Taking into account the dependence of the distribution of normal stress in a two-layer half-space, it can be seen that stabilization of the foundation to a depth of 40 cm will allow the subgrade soil to work without exceeding the permissible shear deformations. The construction of the experimental site in Berezivka, Odessa region, confirmed the assumptions about the effectiveness of the proposed solution to restore the strength of transitional pavement. Keywords: non-rigid pavement of transition type, modulus of elasticity, stabilization, rubble, soil, cold recycling.

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Liu, Yaxu, Zhuang Liu, Erwin Oh et Dominic Ek Leong Ong. « Strength and Microstructural Assessment of Reconstituted and Stabilised Soft Soils with Varying Silt Contents ». Geosciences 11, n^o 8 (21 juillet 2021) : 302. http://dx.doi.org/10.3390/geosciences11080302.

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The study of the strength of reconstituted and stabilised soft soils is very important in geotechnical engineering. The soil particles, such as clay, sand, and silt play important roles in determining the behaviour of soils. The behaviour of clay and sand particles are unique; however, the behaviour of silt particles lie in a transitional form between sand and clay. Therefore, this paper seeks to investigate (a) the effect of silt contents on the strength of soft soils; (b) the effect of silt content on the strength of cement-stabilised soft soils; and (c) the microstructure of the soft soil specimens stabilised by cement with varying particle size distribution. A series of tests consisting in consolidated, isotropic undrained (CIU) triaxial tests, unconfined compressive strength (UCS) tests, and scanning electron microscope (SEM) images were conducted in this study to achieve these objectives. In conclusion, the relationship between the silt content and critical state behaviour of soft soils (both clay and silt particles) are proposed. For the cement-stabilised specimens, the unconfined compressive strength increases with the increase in silt content when the cement content is 10%. However, the UCS decreases with the increase in silt content when cement content is 30%. With cement content ranging from 15–25%, the UCS increases at first with the increase of silt content but decreases once the silt content reaches a ‘saturation’ point.

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Boadu, Fred Kofi, et Frederick Owusu-Nimo. « Influence of petrophysical and geotechnical engineering properties on the electrical response of unconsolidated earth materials ». GEOPHYSICS 75, n^o 3 (mai 2010) : G21—G29. http://dx.doi.org/10.1190/1.3374465.

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We have investigated the influence of petrophysical and geotechnical engineering properties of unconsolidated near-surface geomaterials (soils) on their electrical responses or measurements. Complex resistivity measurements were performed at a constant effective stress on 32 samples of varying textures and compositions. Petrophysical and engineering properties that inherently affect the mechanical and strength behavior of the samples — that is, fines content, pore-size parameter, specific surface area, and fractal dimension of the grain-size distributions — were obtained from geotechnical analysis. The electrical parameters that describe the electrical response of the samples — that is, resistivity amplitude [Formula: see text], phase shift [Formula: see text], percent frequency effect (PFE), loss tangent [Formula: see text], and the normalized phase [Formula: see text] — are computed from the electrical measurements. Crossplots of the electrical and engineering parameters provide useful infor-mation on how the geotechnical properties of the soil material influence the electrical measurements. In particular, [Formula: see text] and [Formula: see text] values are strongly influenced by variations in the petrophysical and engineering properties [Formula: see text] in comparison with the other electrical parameters. Soils become more dissipative as their specific surface area increases. The PFE values are less sensitive [Formula: see text] to the petrophysical and engineering properties. Analysis of the correlations also indicates that characteristic or transitional values of the fines content (18%) and pore size [Formula: see text] exist, beyond which the phase and normalized phase values are insensitive to their respective increases. The characteristic value of 18% fines content is close to values reported in previous studies, which signifies transition in strength behavior of soils and, thus, such relations could be important in noninvasive strength assessment and monitoring of soils. Normalized phase values were used to assess the relative amount of fines in the studied soils.

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Jayawardane, NS, et WS Meyer. « Measuring air-filled porosity changes in an irrigated swelling clay soil ». Soil Research 23, n^o 1 (1985) : 15. http://dx.doi.org/10.1071/sr9850015.

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An in-situ method for measuring air filled porosity (�a) of soils using a neutron meter was developed and evaluated for a layered, swelling clay soil. Bulk density-volumetric moisture content relationships of soil layers were used to calculate the regressions of volumetric moisture content on �a. These regressions were combined with calibration equations of the neutron meter to obtain relationships between �a and neutron counts. The �a values predicted from measured neutron count ratios show good agreement with �a values calculated from the measured bulk densities and moisture contents in a transitional red-brown earth. The method provides a rapid and non-destructive measurement of �a. Soil aeration in a transitional red-brown earth under two irrigation treatments was assessed using neutron counts to monitor the changes in �a profiles. Large soil cores which were flooded had lower profile �a values than did cores which were not flooded. However, differences were small, owing apparently to the very low rates of infiltration and redistribution. The potential use of this method to continuously monitor changes in �a profiles allows frequent calculation of aeration stress indices, which may be used to predict crop responses and yield losses due to poor aeration.

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Yen, Pau Y., William C. Koskinen et Edward E. Schweizer. « Dissipation of Alachlor in Four Soils as Influenced by Degradation and Sorption Processes ». Weed Science 42, n^o 2 (juin 1994) : 233–40. http://dx.doi.org/10.1017/s0043174500080334.

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Laboratory studies were conducted to determine the influence of degradation and sorption processes on the dissipation of alachlor in one Colorado soil (Kim clay loam) and three Minnesota soils (Port Byron silt loam, Webster silty clay loam, and Estherville sandy loam) as a function of soil depth. Persistence and movement of alachlor in an irrigated corn production system also were determined on the Kim soil. Laboratory degradation data fit first-order kinetics, and rate constants ranged from 0.0094 to 0.0251 d-1and varied with soil type and depth. For instance, in 60- to 75-cm-depth Kim soil, alachlor degraded at a slower rate (k = 0.011 d-1) than in surface soil samples (k = 0.022 d-1). Alachlor sorption to the four soils was moderate (Kf= 0.7 to 7.4; Kf,oc= 71 to 470) and concentration dependent (1/n < 1.0). Significant hysteretic desorption of alachlor from soils also was observed (1/n desorption < 1/n sorption). The combined effect of degradation and sorption processes has been used to classify a chemical's potential to leach to groundwater. Based on Kf,ocand dissipation half-life, alachlor would be classified as a “leacher” in Kim, Port Byron, and Estherville soils and classified as transitional between “leacher” and “nonleacher” in the Webster soil. The dissipation first-order rate constant (k) of alachlor in Kim soil in the field was 0.036 α 0.012 d-1. Dissipation was apparently not due to leaching since bromide applied at the same time remained in the top 15 cm during the first 28 d. It appears that laboratory-derived leaching indices may overestimate actual leaching and should be used with caution for predictive or regulatory purposes.

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Neidhardt, Harald, Florian Achten, Simon Kern, Marc Schwientek et Yvonne Oelmann. « Phosphorus Pool Composition in Soils and Sediments of Transitional Ecotones under the Influence of Agriculture ». Journal of Environmental Quality 48, n^o 5 (8 août 2019) : 1325–35. http://dx.doi.org/10.2134/jeq2019.01.0012.

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Manaenkov, Alexander S., et Alexander S. Ponomarev. « Forest Sustainability of Ecotopes of the Volga-Akhtuba Floodplain when Cultivating Pine Plantations ». Lesnoy Zhurnal (Forestry Journal), n^o 4 (5 juillet 2022) : 127–45. http://dx.doi.org/10.37482/0536-1036-2022-4-127-145.

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In the south of European Russia, the largest sand massifs are found in the zone of dry steppes and semi-deserts. Effective utilization of such lands requires creation of protective forest planting of drought-resistant coniferous species like Scots pine and Crimean pine. The productivity and longevity of such stands vary widely over the territory and depends on the presence of additional to atmospheric precipitation water supply and the root layer mineral supply. In this regard, sand massifs of steppificated river valleys composed of multiphase or single-phase polymineral rocks are of particular interest for afforestation. One of the most important objects of afforestation is the Northern (within the Volgograd region) highest and most drained part of the Volga-Akhtuba floodplain. Volga River damming by the Volga Hydroelectric Station (Volga GES) led to a restructuring of surface and ground water regimes, formation of new conditions of water and mineral nutrition and changes in other important factors of forest ecosystems in the area. The research aims at developing a classification of the Volga-Akhtuba floodplain ecotopes by water-mineral nutrition conditions, cultivation, expected productivity and longevity of pine plantings. We studied relationships of growth parameters of Pinus silvestris L. stands with soil-ground and hydrological conditions in different ecotopes of the large hilly and transitional floodplains after the Volga River damming by the Volga GES. Dynamics patterns of this relationship were revealed. It was found that in the northern part of the Volga-Akhtuba valley (approximately up to the Kapustin Yar – Kamenny Yar line) with increasing stratification, heavier granulometric composition of the root layer to sandy loam layer, lowering the surface level at a small distance from the drainage channel moisture supply and growth of Scots pine plantations improve, forest suitability of ecotopes increases. There is a risk of early decay and death of high-density pine forests in periods of low water and dry years on soils underlain by thick loams. Three groups of ecotope forest suitability were identified according to these indicators, as well as the conditions for the creation of forest plantations, productivity and longevity of plantings. The least favorable ecotopes are in the highlands of the hilly and transitional floodplains with minor soils of different composition on single-phase open-textured sands with deep (more than 4–5 m) groundwater table during low-water season. The most favorable are welldrained areas of the transitional floodplain with light soils on thick stratified predominantly sandy loam sediments, as well as on sands with close to the surface groundwater occurrence. Average ecotopes in terms of conditions are poorly drained areas of the transitional floodplain with minor sandy loam and loamy soils on deep loams.

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Fazlutdinova, Alfiya, Yunir Gabidullin, Rezeda Allaguvatova et Lira Gaysina. « Diatoms in Kamchatka’s Hot Spring Soils ». Diversity 12, n^o 11 (18 novembre 2020) : 435. http://dx.doi.org/10.3390/d12110435.

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Diatoms inhabiting terrestrial habitats that are affected by thermal activity remain poorly studied, despite significant interest in the biodiversity of hot springs. The Kamchatka peninsula is characterized by the presence of 30 active volcanoes associated with hydrotherms. Our study involved a survey of diatom diversity in soils around the Malki, Upper Paratunka, and Dachnie thermal springs on the Kamchatka peninsula. A total of 49 diatom taxa were found. The genera Pinnularia, Planothidium, Fragilariforma, Epithemia, Halamphora, Gomphonema, Nitzschia, Aulocoseira, Sellaphora, Surirella, and Navicula were the most common. Pinnularia cf. subcapitata and Planothidium lanceolatum were dominant in all springs. Diatom communities in the soils near the thermal springs included both aquatic and terrestrial species, which may reflect the transitional nature of habitats at the borders of hot springs and soils. To gain a better understanding of the diversity of diatom communities in soils near thermal springs, broader worldwide studies are necessary.

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Longui, Eduardo L., Natalia O. Costa, Roque Cielo-Filho, Carmen R. Marcati, Diego Romeiro, Kishore S. Rajput, Israel L. Lima et Sandra M. B. Florsheim. « Wood and Leaf Anatomy of Copaifera langsdorffii Dwarf Trees ». IAWA Journal 35, n^o 2 (2014) : 170–85. http://dx.doi.org/10.1163/22941932-00000058.

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There are various parameters that affect tree height and may cause dwarfism. Our goal was to study the anatomical variations in the leaf and xylem structure in dwarf and normal trees of Copaifera langsdorffii and their correlation with physico-chemical properties of the soils. Trees from two spatially close but different vegetation types, transitional forest and rupestrian field, showed markedly different wood and leaf characteristics. Adult trees of C. langsdorffii show normal height (up to 25 m) in transitional forests while in the rupestrian field they show dwarfism (small trees up to 2.5 m tall). Physical soil characteristics (such as rocky crust, low water availability due to shallow soil) presumably limit root growth and affect the rate of photosynthesis, which consequently affect the extension growth of the plant. Compared to normal trees, C. langsdorffii dwarf trees are characterized by narrow vessels and a higher proportion of vessels in multiples, features of the water transport system/hydraulic structure known to prevent embolism, wider rays with a greater potential to store starch, and higher stomatal density and potential conductance index.

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Wang, Fangting, Ke Bao, Changsheng Huang, Xinwen Zhao, Wenjing Han et Zhibin Yin. « Adsorption and pH Values Determine the Distribution of Cadmium in Terrestrial and Marine Soils in the Nansha Area, Pearl River Delta ». International Journal of Environmental Research and Public Health 19, n^o 2 (11 janvier 2022) : 793. http://dx.doi.org/10.3390/ijerph19020793.

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Cadmium is a toxic element with a half-life of several decades, which can accumulate in the human body by entering the food chain and seriously harm health. The cadmium adsorption and desorption processes in the soil directly affect the migration, transformation, bioavailability, and ecotoxicity of this element in soil-plant systems. Coastal zones are located in the transitional zone between land and sea, and large amounts of terrigenous material input have important environmental effects on this ecosystem. The pH, hydrodynamic conditions, soil organic matter (SOM), and other factors defining the sea-land interaction within the sedimentary environment are significantly different from those defining land facies. In order to study the key factors affecting cadmium adsorption in soils at the sea-land interface in the Nansha area of the Pearl River Delta, a test was conducted on a column of undisturbed soil. The results showed that the adsorption constant KF and the Cd2+ adsorption capacity of marine soils were higher than those of terrestrial soils. However, the saturation adsorption of cadmium in terrestrial sediments was higher than in marine sediments. Soil pH was an important factor affecting cadmium adsorption capacity in both terrestrial and ma-rine sediments. Neutral and alkaline topsoil conditions inhibited the vertical migration of cadmium, while the acidic environment favored it. The higher the clay and SOM were, the stronger the Cd2+ adsorption capacity of the soil was. These findings suggest that the distribution of cadmium in marine and continental sedimentary soils is not only related to adsorption, but also to the physical and chemical processes occurring in different sedimentary environments.

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Otsubo, Masahide, Troyee Tanu Dutta, Manushak Durgalian, Reiko Kuwano et Catherine O'Sullivan. « Particle-scale insight into transitional behaviour of gap-graded materials – small-strain stiffness and frequency response ». E3S Web of Conferences 92 (2019) : 14006. http://dx.doi.org/10.1051/e3sconf/20199214006.

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This study aims to develop a fundamental understanding of the role of fine particles on the small-strain stiffness of gap-graded granular soils. Stiffness was measured using cyclic triaxial probes, which give a measure of static stiffness, and dynamic wave propagation data, from which the dynamic stiffness can be measured. Assemblies of loosely packed spherical particles were considered. In the laboratory, local deformation transducers were used to measure the static stiffness, while the dynamic stiffness was calculated from stress wave velocities, measured using planar piezoelectric elements. To relate the particle-scale responses to the overall soil stiffness, complementary discrete element method (DEM) simulations were performed in which both static and dynamic stiffnesses were measured. Both the laboratory and the DEM data indicate that at low fines contents (< 30%) the stiffness decreases with increasing fines content. When the fines content increases from 30% to 35% there is a sharp increase in stiffness with increasing fines content; this is understood to mark the transition point at which the fines start to contribute significantly to the overall behaviour. Analyses of the frequency domain response of shear wave signals revealed that the lowpass frequency increases significantly at this transition point. This observation can be used to develop experimental interpretation protocols to assess to what extent fines are contributing to the overall soil stiffness.

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Schmotzer, András. « New locality of Lepidium Cartilagineum in the Hortobágy Region (East Hungary) ». Acta Biologica Plantarum Agriensis 9, n^o 1 (2021) : 16–31. http://dx.doi.org/10.21406/abpa.2021.9.1.16.

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A new locality of the halophyte Lepidium cartilagineum (J. C. Mayer) Thell. (Brassicaceae) was recorded at the eastern margin of the Hortobágy region, at Nagyhegyes. Despite the fact that the species is not rare in saline steppes in Hungary, it occurs exclusively on solonchak soils. The soil of the one previously documented location at Hortobágy region is not typical solonetz, with transitional solonchak characteristics. The locality found at ‘Sirály-rét’ (Elep, Nagyhegyes) is in a typical alkaline grassland, where the species grows in Puccinellietum limosae and transitional Camphorosmetum annuae communities. This contribution also includes 14 phytocoenological relevés taken at the locality and a comparison of the two, so far documented locations in the region. The author takes the position that this occurrence is to be regarded as native, mostly based on the habitat specifications (such as developed berm formations), vegetation structure and species composition. The continuity of the grassland patch is also proved by available historical maps and aerial photographs.

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Wasak, K., et M. Drewnik. « Land use effects on soil organic carbon sequestration in calcareous leptosols in former pastureland – a case study from the Tatra Mountains (Poland) ». Solid Earth Discussions 7, n^o 2 (7 mai 2015) : 1577–610. http://dx.doi.org/10.5194/sed-7-1577-2015.

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Abstract. The purpose of the paper is to show SOC sequestration rates in calcareous shallow soils in reforested areas in Tatra Mts. with a particular focus on the different forms of organic matter (OM) storage. Three plant communities creating a mosaic on the slopes of the valley were taken into account. After 50 years since the conversion of pastureland to grassland, dwarf pine shrub, and larch forest on soils, the development of genetic soil horizons as well as SOC sequestration in soil occur despite the steepness of slopes. SOC stock is the highest in soils under larch forest (63.5 mg ha−1, SD 16.3), while in soil under grassland and under dwarf pine shrub, this value is smaller (47.5 mg ha−1, SD 13.3 and 42.9 mg ha−1, SD 22.0 respectively). The highest amount of mineral-associated OM inside stable microaggregates (MOM FF3) is found in grassland soil (21.9–27.1% of SOC), less under dwarf pine shrub (16.3–19.3% of SOC) and larch forest (15.3–17.7% of SOC). The pool of mineral-associated OM inside transitional macroaggregates (MOM FF2) is found in soil under dwarf pine shrub (39.2–59.2% of SOC), with less under larch forest (43.8–44.7% of SOC) and the least in grassland soil (37.9–41.6% of SOC). The highest amount of the free light particulate fraction (POM LF1) is found in soil under dwarf pine shrub (6.6–10.3% of SOC), with less under larch forest (2.6–6.2% of SOC) and the least in grassland soil (1.7–4.8% of SOC).

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Jordán, A., J. García-Moreno, Á. J. Gordillo-Rivero, L. M. Zavala et A. Cerdà. « Organic carbon, water repellency and soil stability to slaking under different crops and managements : a case study at aggregate and intra-aggregate scales ». SOIL Discussions 1, n^o 1 (29 août 2014) : 295–325. http://dx.doi.org/10.5194/soild-1-295-2014.

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Abstract. This research studies the distribution of organic C and intensity of water repellency in soil aggregates with different size and in the interior of aggregates from Mediterranean soils under different crops (apricot, citrus and wheat) and management (conventional tilling and no tilling/mulching). For this, undisturbed aggregates were sampled and carefully divided in size fractions (0.25–0.5, 0.5–1, 1–2, 2–5, 5–10 and 10–15 mm) or peeled to obtain separated aggregate layers (exterior, transitional and interior). Organic C content in the fine earth fraction of soils under different crops did not show important variations, although it increased significantly from conventionally tilled to mulched soils. The distribution of organic C content in aggregates with different size varied among soils under different crops, generally increasing with decreasing size. At the intra-aggregate level, organic C concentrated preferably in the exterior layer of aggregates from conventionally tilled soils, probably because of recent organic inputs or leachates. In the case of mulched soils, higher concentrations were observed, but no significant differences among aggregate regions were found. The intensity of water repellency, determined by the ethanol method, did not show great variations among crops, but increased significantly from conventionally tilled to mulched soils. Coarser aggregates were generally wettable, while finer aggregates showed slight water repellency. Regardless of variations in the distribution of organic C in aggregate layers from conventionally tilled soils, great or significant differences in the distribution of water repellency at the intra-aggregate level were not found in any case. Finally, the intensity of water repellency was much more important than the concentration of organic C in the stability to slaking of aggregates.

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Morandini, Thiago L. C., et Adilson L. Leite. « Shear Strength of Tropical Soils and Bentonite Mixtures for Barrier Design ». Soils and Rocks 39, n^o 3 (1 septembre 2016) : 239–48. http://dx.doi.org/10.28927/sr.393239.

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Compacted clayey tropical soils have great potential to be used as barriers in waste disposal facilities, considering that some technical requirements are fulfilled (e.g. hydraulic conductivity; compatibility after disposal; shear strength; swelling/cracking, etc). In turn, the bentonite addition is relevant for the cases where the hydraulic conductivity must be lowered, and therefore investigations on the changes of the mechanical parameters of tropical soils induced by the bentonite addition are of great interest. This paper presents the results of a laboratory investigation on the shear strength of different samples of tropical soils and their mixtures with bentonite in the proportions of 0, 3, 6, 9 and 12% (dry weight basis). The tropical soil samples were collected considering the lateritic, transitional and non-lateritic behavior according to the MCT-M (Modified-Miniature-Compacted-Tropical) classification. The laboratory tests consisted of CU (ConsolidatedUndrained) triaxial tests under the confining stresses of 100, 200 and 400 kPa. The results have showed that the addition of bentonite produced a significant increase in the plasticity of the tropical soil samples (PI increases 4 to 6 times), considerably reduced their friction angle (by as much as 11o ) and stiffness at peak (modulus reductions of 2.5 to 4 MPa) and gave rise to a slight increase in their cohesion (up to 12 kPa). These facts must be considered in the barrier stability analyses when heavy loads are applied. The important role of the shear strength on barrier design is highlighted.

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Kim, D. G., R. Vargas, B. Bond-Lamberty et M. R. Turetsky. « Effects of soil rewetting and thawing on soil gas fluxes : a review of current literature and suggestions for future research ». Biogeosciences 9, n^o 7 (9 juillet 2012) : 2459–83. http://dx.doi.org/10.5194/bg-9-2459-2012.

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Abstract. The rewetting of dry soils and the thawing of frozen soils are short-term, transitional phenomena in terms of hydrology and the thermodynamics of soil systems. The impact of these short-term phenomena on larger scale ecosystem fluxes is increasingly recognized, and a growing number of studies show that these events affect fluxes of soil gases such as carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), ammonia (NH3) and nitric oxide (NO). Global climate models predict that future climatic change is likely to alter the frequency and intensity of drying-rewetting events and thawing of frozen soils. These future scenarios highlight the importance of understanding how rewetting and thawing will influence dynamics of these soil gases. This study summarizes findings using a new database containing 338 studies conducted from 1956 to 2011, and highlights open research questions. The database revealed conflicting results following rewetting and thawing in various terrestrial ecosystems and among soil gases, ranging from large increases in fluxes to non-significant changes. Studies reporting lower gas fluxes before rewetting tended to find higher post-rewetting fluxes for CO2, N2O and NO; in addition, increases in N2O flux following thawing were greater in warmer climate regions. We discuss possible mechanisms and controls that regulate flux responses, and recommend that a high temporal resolution of flux measurements is critical to capture rapid changes in gas fluxes after these soil perturbations. Finally, we propose that future studies should investigate the interactions between biological (i.e., microbial community and gas production) and physical (i.e., porosity, diffusivity, dissolution) changes in soil gas fluxes, apply techniques to capture rapid changes (i.e., automated measurements), and explore synergistic experimental and modelling approaches.

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