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  • Baveye, Philippe C  (20)
  • Directory of Open Access Journals (DOAJ)  (20)
  • 1
    Language: English
    In: Revista Brasileira de Ciência do Solo, 01 June 2015, Vol.39(3), pp.637-642
    Description: In recent years, many researchers have claimed that world reserves of rock phosphate were getting depleted at an alarming rate, putting us on the path to scarcity of that essential resource within the next few decades. Others have claimed that such alarmist forecasts were frequent in the past and have always been proven unfounded, making it likely that the same will be true in the future. Both viewpoints are directly relevant to the level of funding devoted to research on the use of phosphate fertilizers. In this short essay, it is argued that information about future reserves of P or any other resource are impossible to predict, and therefore that the threat of a possible depletion of P reserves should not be used as a key motivation for an intensification of research on soil P. However, there are other, more compelling reasons, both geopolitical and environmental, to urgently step up our collective efforts to devise agricultural practices that make better use of P than is the case at the moment.
    Keywords: Reservas de Fósforo ; Disponibilidade de Fósforo ; Depleção de Fósforo ; Segurança Alimentar
    ISSN: 1806-9657
    Source: Directory of Open Access Journals (DOAJ)
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  • 2
    Language: English
    In: PLoS ONE, 01 January 2015, Vol.10(9), p.e0137205
    Description: There is currently a significant need to improve our understanding of the factors that control a number of critical soil processes by integrating physical, chemical and biological measurements on soils at microscopic scales to help produce 3D maps of the related properties. Because of technological limitations, most chemical and biological measurements can be carried out only on exposed soil surfaces or 2-dimensional cuts through soil samples. Methods need to be developed to produce 3D maps of soil properties based on spatial sequences of 2D maps. In this general context, the objective of the research described here was to develop a method to generate 3D maps of soil chemical properties at the microscale by combining 2D SEM-EDX data with 3D X-ray computed tomography images. A statistical approach using the regression tree method and ordinary kriging applied to the residuals was developed and applied to predict the 3D spatial distribution of carbon, silicon, iron, and oxygen at the microscale. The spatial correlation between the X-ray grayscale intensities and the chemical maps made it possible to use a regression-tree model as an initial step to predict the 3D chemical composition. For chemical elements, e.g., iron, that are sparsely distributed in a soil sample, the regression-tree model provides a good prediction, explaining as much as 90% of the variability in some of the data. However, for chemical elements that are more homogenously distributed, such as carbon, silicon, or oxygen, the additional kriging of the regression tree residuals improved significantly the prediction with an increase in the R2 value from 0.221 to 0.324 for carbon, 0.312 to 0.423 for silicon, and 0.218 to 0.374 for oxygen, respectively. The present research develops for the first time an integrated experimental and theoretical framework, which combines geostatistical methods with imaging techniques to unveil the 3-D chemical structure of soil at very fine scales. The methodology presented in this study can be easily adapted and applied to other types of data such as bacterial or fungal population densities for the 3D characterization of microbial distribution.
    Keywords: Sciences (General)
    E-ISSN: 1932-6203
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  • 3
    Language: English
    In: Frontiers in Environmental Science, 01 February 2015, Vol.3
    Description: Current estimates of global soil C are slightly over 4000 Pg C, which is more than five and a half times the amount of carbon currently in the atmosphere or, put differently, is equivalent to about 400 times the amount of C released yearly to the atmosphere by fossil fuel consumption or cement manufacture...
    Keywords: Food Security ; Global Climate Change ; Microorganisms ; Soil Structure ; Soil Organic Matter ; Soil Science Research ; Environmental Sciences
    E-ISSN: 2296-665X
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  • 4
    Language: English
    In: Frontiers in Environmental Science, 01 June 2016, Vol.4
    Description: Over the last few years, considerable attention has been devoted in the scientific literature and in the media to the concept of ecosystem services of soils. The monetary valuation of these services, demanded by many governments and international agencies, is often depicted as a necessary condition for the preservation of the natural capital that soils represent. This focus on soil services is framed in the context of a general interest in ecosystem services that allegedly started in 1997, and took off in earnest after 2005. The careful analysis of the literature proposed in this article shows that, in fact, interest in the multifunctionality of soils emerged already in the mid-60s, at a time when hundreds of researchers worldwide were trying, and largely failing, to figure out how to put price tags meaningfully on nature's services. Soil scientists, since, have tried to better understand various functions/services of soils, as well as their possible relation with key soil characteristics, like biodiversity. They have also tried to make progress on the challenging quantification of soil functions/services. However, researchers have shown very little interest in monetary valuation, undoubtedly in part because it is not clear what economic and financial markets might do with prices of soil functions/services, even if we could somehow come up with such numbers, and because there is no assurance at all, based on neoclassical economic theory, that markets would manage soil resources optimally. Instead of monetary valuation, focus in the literature has been put on decision-making methods, like Multi-Criteria Decision Analysis (MCDA) and Bayesian Belief Networks (BBN), which do not require the systematic monetization of soil functions/services and easily accommodate deliberative approaches involving a variety of stakeholders. A prerequisite to progress in such public deliberations is that participants be very cognizant of the extreme relevance of soils to many aspects of their daily life. We argue that, as long as this prerequisite is satisfied, the combination of deliberative decision-making methods and of a sound scientific approach to the quantification of soil functions/services is a very promising avenue to manage effectively and ethically the priceless heritage that soils constitute.
    Keywords: Decision Making ; Sustainability ; Valuation ; Commodification ; Land Use and Management ; Ecosystem Services ; Environmental Sciences
    E-ISSN: 2296-665X
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  • 5
    Language: English
    In: Frontiers in Environmental Science, 01 November 2018, Vol.6
    Description: [...]Shelef et al. review the value of native plants and local production as a means to promote food diversity and agricultural resilience. [...]Chedraoui et al. review in detail the literature devoted to Capparis spinosa (L.), a xerophilous species with a broad range of benefits and potentialities for...
    Keywords: Agroecology ; Best Management Practices ; Biotic and Abiotic Stresses ; Environmental Sustainability ; Native Plants ; Environmental Sciences
    E-ISSN: 2296-665X
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  • 6
    Language: English
    In: Frontiers in Ecology and Evolution, 01 December 2018, Vol.6
    Description: For the last 20 years, the concept of ecosystem has constituted one of the key pillars on which the study of “ecosystem services,” i.e., the benefits that human populations derive from nature, has been based. Yet, at this stage, one could argue that, in general and especially in fields related to agriculture, the ecosystem framework tends to limit unnecessarily the range of benefits to humans that are considered in practice, to hinder the necessary measurement of services, and to make it challenging to convince individuals to take nature's services into account in their decision making. In the present Perspective piece, we analyze these 3 arguments in detail, conclude that the current focus on ecosystems is more a liability than an asset in the field, and suggest a return to the less constraining notions of “nature's functions and services,” without a necessary tie to ecosystems.
    Keywords: Assessment ; Ecosystem Services ; Sustainability ; Sustainable Development ; Nature Valuation ; Natural Capital ; Ecology
    E-ISSN: 2296-701X
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  • 7
    Language: English
    In: Chemistry Central Journal, 01 December 2018, Vol.12(1), pp.1-7
    Description: Abstract In spite of the development of new measurement techniques in recent years, the rapid and accurate speciation of thallium in environmental aqueous samples remains a challenge. In this context, a novel method of solid phase extraction (SPE), involving the anion exchange resin AG1-X8, is proposed to separate Tl(I) and Tl(III). In the presence of diethylene triamine pentacetate acid (DTPA), Tl(III) and Tl(I) can be separated by selective adsorption of Tl(III)-DTPA onto the resin, Tl(III) is then eluted by a solution of HCl with SO2. The validity of this method was confirmed by assays of standard solutions of Tl(I) and Tl(III). The proposed method is shown to have an outstanding performance even in solutions with a high ratio of Tl(I)/Tl(III), and can be applied to aqueous samples with a high concentration of other electrolytes, which could interfere with the measurement. Portable equipment and reagents make it possible to use the proposed method routinely in the field.
    Keywords: Thallium (III) ; Speciation ; Spe ; Ag1-X8 ; Chemistry
    E-ISSN: 1752-153X
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  • 8
    Language: English
    In: Frontiers in Microbiology, 01 July 2018, Vol.9
    Description: There is still no satisfactory understanding of the factors that enable soil microbial populations to be as highly biodiverse as they are. The present article explores in silico the hypothesis that the heterogeneous distribution of soil organic matter, in addition to the spatial connectivity of the soil moisture, might account for the observed microbial biodiversity in soils. A multi-species, individual-based, pore-scale model is developed and parameterized with data from 3 Arthrobacter sp. strains, known to be, respectively, competitive, versatile, and poorly competitive. In the simulations, bacteria of each strain are distributed in a 3D computed tomography (CT) image of a real soil and three water saturation levels (100, 50, and 25%) and spatial heterogeneity levels (high, intermediate, and low) in the distribution of the soil organic matter are considered. High and intermediate heterogeneity levels assume, respectively, an amount of particulate organic matter (POM) distributed in a single (high heterogeneity) or in four (intermediate heterogeneity) randomly placed fragments. POM is hydrolyzed at a constant rate following a first-order kinetic, and continuously delivers dissolved organic carbon (DOC) into the liquid phase, where it is then taken up by bacteria. The low heterogeneity level assumes that the food source is available from the start as DOC. Unlike the relative abundances of the 3 strains, the total bacterial biomass and respiration are similar under the high and intermediate resource heterogeneity schemes. The key result of the simulations is that spatial heterogeneity in the distribution of organic matter influences the maintenance of bacterial biodiversity. The least competing strain, which does not reach noticeable growth for the low and intermediate spatial heterogeneities of resource distribution, can grow appreciably and even become more abundant than the other strains in the absence of direct competition, if the placement of the resource is favorable. For geodesic distances exceeding 5 mm, microbial colonies cannot grow. These conclusions are conditioned by assumptions made in the model, yet they suggest that microscale factors need to be considered to better understand the root causes of the high biodiversity of soils.
    Keywords: Soil ; Pore Scale ; Organic Matter ; Resource Allocation ; Bacteria ; Biodiversity ; Biology
    E-ISSN: 1664-302X
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  • 9
    Language: English
    In: Frontiers in Environmental Science, 01 November 2016, Vol.4
    Description: When confronted with a great piece of art or research, one often wonders about what made it possible, what method was used by its author, in part so one can try to emulate it in one's own activities. Upon the retirement of Garrison Sposito after a long and very distinguished career, we considered that, as former doctoral students of Gary's, we were in a privileged position to write, in our own words and from our perspective, an account of the various key ingredients of his very successful method. In the following, we identify and review six components of this method, respectively his thorough bibliographical coverage, extreme rigor in research, meticulous crafting of manuscripts, parallel focus on several disciplines, firm conviction that it is not necessary to go out of one's way to promote good ideas or competent people, and finally his reluctance to jump on bandwagons. We hope that this analysis of the pillars of Gary's method, at least as we see them, will not only help pay tribute to an outstanding thinker, but also inspire and provide a roadmap to all those who strive to better themselves as researchers.
    Keywords: Publishing ; Epistemology ; Scientific Research ; Mentoring ; Scientific Method ; Environmental Sciences
    E-ISSN: 2296-665X
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  • 10
    Language: English
    In: Frontiers in Environmental Science, 01 June 2017, Vol.5
    Description: Groundwater contamination by oocysts of the waterborne pathogen Cryptosporidium parvum is a significant cause of animal and human disease worldwide. Although research has been undertaken in the past to determine how specific physical and chemical properties of soils affect the risk of groundwater contamination by C. parvum, there is as yet no clear conclusion concerning the range of mobility of C. parvum that one should expect in field soils. In this context, the key objective of this research was to determine the magnitude of C. parvum transport in a number of soils, under conditions in which fast and preferential transport has been successfully prevented. C. parvum oocysts were applied at the surface of different soils and subjected to artificial rainfall. Apparently for the first time, quantitative PCR was used to detect and enumerate oocysts in the soil columns and in the leachates. The transport of oocysts by infiltrating water, and the considerable retention of oocysts in soil was demonstrated for all soils, although differences in the degree of transport were observed with soils of different types. More oocysts were found in leachates from sandy loam soils than in leachates from loamy sand soils and the retention of oocysts in different soils did not significantly differ. The interaction of various processes of the hydrologic system and biogeochemical mechanisms contributed to the transport of oocysts through the soil matrix. Results suggest that the interplay of clay, organic matter, and Ca2+ facilitates and mediates the transfer of organic matter from mineral surfaces to oocysts surface, resulting in the enhanced breakthrough of oocysts through matrices of sandy loam soils compared to those of loamy sand soils. Although the number of occysts that penetrate the soil matrix account for only a small percentage of initial inputs, they still pose a significant threat to human health, especially in groundwater systems with a water table not too distant from the soil surface. The results of the research demonstrate a critical need for the simultaneous study of the interaction of various processes affecting oocysts transport in the subsurface, and for its expansion into complex systems, in order to obtain a coherent picture of the behavior of C. parvum oocysts in soils.
    Keywords: Cryptosporidium ; Microorganisms ; Groundwater ; Soil Transport ; Qpcr ; Environmental Sciences
    E-ISSN: 2296-665X
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