bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microcosm Studies on Anaerobic Phosphate Flux and Mineralization of Lake Sediment Organic Carbon
Authors: Song Jing , Luo Yongming , Zhao Qiguo , Christie Peter 
Published: June 2010

ABSTRACTLake sediment has long been recognized as an important source of nutrients such as phosphorus. To gain a better understanding of phosphorus flux at the sediment–water interface, it is crucial to investigate the sediment porewater. There is also growing concern and interest in identifying whether organic‐rich sediment is an important source of greenhouse gases such as CO2 and CH4 In the present study, we took sediment samples from West Lake, a shallow hypereutrophic lake in Hangzhou, Zhejiang Province, China and incubated subsamples under anaerobic conditions at 25°C for 182 d using a specially designed microcosm that permits repeated extraction of sediment porewater and sampling of headspace gases. Anaerobic phosphate fluxes and mineralization of sediment organic carbon were measured. Average diffusive flux of soluble phosphorus was 0.81 mg P m−2 d−1 during the initial 18 d of incubation. Decomposition of sediment organic C followed zero‐order reaction kinetics and methane accounted for about 50% of the mineralization products. The results suggest that organic‐rich sediments can be important sources of P and methane under anaerobic conditions. Laboratory studies simulating field conditions and field studies are necessary to determine the contribution of sediment as a source of P and greenhouse gases.
Response of Biogeochemical Indicators to a Drawdown and Subsequent Reflood
Authors: Corstanje R. , Reddy K. R. 
Published: June 2010

ABSTRACTTemporal oscillations in hydrology are a common occurrence in wetlands and can result in alternating flooded and drained conditions in the surface soil. These oscillations in water levels can stimulate microbial activities and result in the mobilization and redistribution of significant amounts of carbon (C), nitrogen (N), and phosphorus (P). The goal of this study was to experimentally simulate a drawdown and reflood of marsh soil from a nutrient‐enriched site and a reference site of a wetland (Blue Cypress Marsh Conservation Area, Florida). The goal was to better understand the changes in biogeochemistry and microbial activities present in these soils as a result of hydrological fluctuations. Measurements of dissolved reactive phosphorus (DRP), ammonia, and nitrate in the floodwater indicated significantly higher (α = 0.05) NH4+ and DRP fluxes from the nutrient‐enriched site; floodwaters in the cores from both sites contained significant NO3− concentrations (9.6 mg N L−1), which was rapidly consumed over the core incubation period (30 d). Water level drawdown and reflooding initially stimulated the soil microbial biomass, methanogenic rates, and extracellular enzyme activities (acid phosphatase and β‐glucosidase). The anaerobic microbial metabolic activities (CO2) where initially significantly (α = 0.05) enhanced by the reflood, resulting in roughly equivalent rates as the aerobic respiratory activities (CO2), presumably as a function of the high water column NO3− levels. This study illustrates that the reflood event in the hydrological cycles in a wetland can significantly stimulate the activities of hydrolytic enzymes and microbiological communities in these soils.
Construction of Platinum‐Tipped Redox Probes for Determining Soil Redox Potential
Authors: Wafer Carrie C. , Richards J. Barrett , Osmond Deanna L. 
Published: June 2010

ABSTRACTRedox probes are typically constructed by soldering Pt wire to a metal wire or rod, such as copper or brass. The junction between the Pt and wire or rod is often sealed with an epoxy resin and hardener or with heat‐shrink tubing. Microcracks (small cracks invisible to the unaided eye) can form in the hardened resin and result in incorrect readings. The hardened resin is not easily removed, making repairs difficult. Heat‐shrink tubing is thin, lacks rigidity, and can be damaged in the soil. The method described in this paper used a thick‐walled, adhesive‐lined terminal insulator to seal the junction. The terminal insulators were easily applied and removed, which made faulty probes easy to repair. Two‐hundred forty probes were made with this method and eight were made with a marine epoxy resin. The probes were tested with a redox buffer solution (Light Solution) and were usable if they read +476 ± 10 mV. The probes were installed 0.76 and 1.5 m deep in the soil. The ability of the probes to provide reliable redox readings was examined by testing selected probes after 10 mo of use and testing all of the probes after completion of the study (19 mo). Ten of the twelve probes tested after 10 mo worked satisfactorily, while the other two clearly malfunctioned before testing. After the study was completed, 236 of the 240 of the probes worked satisfactorily. These results indicate that the construction method presented produces reliable, long‐lasting probes.
Nitrogen Mineralization from Organic Residues
Authors: Cabrera M. L. , Kissel D. E. , Vigil M. F. 
Published: June 2010

ABSTRACTResearch on nitrogen (N) mineralization from organic residues is important to understand N cycling in soils. Here we review research on factors controlling net N mineralization as well as research on laboratory and field modeling efforts, with the objective of highlighting areas with opportunities for additional research. Among the factors controlling net N mineralization are organic composition of the residue, soil temperature and water content, drying and rewetting events, and soil characteristics. Because C to N ratio of the residue cannot explain all the variability observed in N mineralization among residues, considerable effort has been dedicated to the identification of specific compounds that play critical roles in N mineralization. Spectroscopic techniques are promising tools to further identify these compounds. Many studies have evaluated the effect of temperature and soil water content on N mineralization, but most have concentrated on mineralization from soil organic matter, not from organic residues. Additional work should be conducted with different organic residues, paying particular attention to the interaction between soil temperature and water content. One‐ and two‐pool exponential models have been used to model N mineralization under laboratory conditions, but some drawbacks make it difficult to identify definite pools of mineralizable N. Fixing rate constants has been used as a way to eliminate some of these drawbacks when modeling N mineralization from soil organic matter, and may be useful for modeling N mineralization from organic residues. Additional work with more complex simulation models is needed to simulate both gross N mineralization and immobilization to better estimate net N mineralized from organic residues.
Occurrence and Fate of Pharmaceuticals and Personal Care Products (PPCPs) in Biosolids
Authors: Xia Kang , Bhandari Alok , Das Keshav , Pillar Greg 
Published: June 2010

ABSTRACTEach year, large quantities of pharmaceuticals and personal care products (PPCPs) are used worldwide. Once conveyed to wastewater treatment plants, PPCPs can remain unchanged or undergo partial or complete transformation during wastewater treatment processes before discharge into the environment via effluent and biosolids for land application. Biosolids can be a major sink for some PPCPs. Previous investigations have indicated that land application of biosolids may be a potential important route through which PPCPs enter the environment. However, no information is available on exactly how closely the concentrations of PPCPs in the environmental media are related to the land application of PPCP‐containing biosolids. This paper reviews currently available information on the occurrence of PPCPs in biosolids, methods of analysis, the potential fate of PPCPs in biosolids‐applied soils, and composting as a potential means for removal of PPCPs from biosolids.
Using Soil Moisture and Spatial Yield Patterns to Identify Subsurface Flow Pathways
Authors: Gish T. J. , Walthall C. L. , Daughtry C. S. T. , Kung K.‐J. S. 
Published: June 2010

ABSTRACTSubsurface soil water dynamics can influence crop growth and the fate of surface‐applied fertilizers and pesticides. Recently, a method was proposed using only ground‐penetrating radar (GPR) and digital elevation maps (DEMs) to identify locations where subsurface water converged into discrete pathways. For this study, the GPR protocol for identifying horizontal subsurface flow pathways was extended to a 3.2‐ha field, uncertainty is discussed, and soil moisture and yield patterns are presented as confirming evidence of the extent of the subsurface flow pathways. Observed soil water contents supported the existence of discrete preferential funnel flow processes occurring near the GPR‐identified preferential flow pathways. Soil moisture also played a critical role in the formation of corn (Zea mays L.) grain yield patterns with yield spatial patterns being similar for mild and severe drought conditions. A buffer zone protocol was introduced that allowed the impact of subsurface flow pathways on corn grain yield to be quantified. Results indicate that when a GPR‐identified subsurface clay layer was within 2 m of the soil surface, there was a beneficial impact on yield during a drought year. Furthermore, the buffer zone analysis demonstrated that corn grain yields decreased as the horizontal distance from the GPR‐identified subsurface flow pathways increased during a drought year. Averaged real‐time soil moisture contents at 0.1 m also decreased with increasing distance from the GPR‐identified flow pathways. This research suggests that subsurface flow pathways exist and influence soil moisture and corn grain yield patterns.
Degradation ofN‐Nitrosodimethylamine (NDMA) in Landscape Soils
Authors: Yang W. C. , Gan J. , Liu W. P. , Green R. 
Published: June 2010

ABSTRACTN‐nitrosodimethylamine (NDMA), a potential carcinogen, was commonly found in treated wastewater as a by‐product of chlorination. As treated water is increasingly used for landscape irrigation, there is an imperative need to understand the leaching risk for NDMA in landscape soils. In this study, adsorption and incubation experiments were conducted using landscape soils planted with turfgrass, ground cover, and trees. Adsorption of NDMA was negligibly weak (Kd< 1) in all soils, indicating that NDMA has a high potential for moving with percolating water in these soils. Degradation of NDMA occurred at different rates among these soils. At 21°C, the half‐life (t1/2) of NDMA was 4.1 d for the ground cover soil, 5.6 d for the turfgrass soil, and 22.5 d for the tree soil. The persistence was substantially prolonged after autoclaving or when incubated at 10°C. The rate of degradation was not significantly affected by the initial NDMA concentration or addition of organic and inorganic nutrient sources. The relative persistence was inversely correlated with soil organic matter content, soil microbial biomass, and soil dehydrogenase activity, suggesting the importance of microorganisms in NDMA degradation in these soils. These results suggest that the behavior of NDMA depends closely on the vegetation cover in a landscape system, and prolonged persistence and increased leaching may be expected in soils with sparse vegetation due to low organic matter content and limited microbial activity.
How Accurate Is the Assessment of Phosphorus Pools in Poultry Litter by Sequential Extraction?
Authors: Hunger Stefan , Sims J. Thomas , Sparks Donald L. 
Published: June 2010

ABSTRACTAmending poultry litter with Al sulfate (alum) has proven effective in reducing water‐soluble P in the litter and in runoff from fields that have received litter applications. Although its effectiveness has been demonstrated on a macroscopic scale in the field or in the poultry houses, little is known about P speciation in either alum‐amended or unamended litter. This knowledge is important for the evaluation of long‐term stability and bioavailability of P, which is a necessary prerequisite for the assessment of the sustainability of intensive poultry operations. Here we report results from an investigation of alum‐amended poultry litter (PL) that combined a chemical extraction sequence with solid‐state 31P nuclear magnetic resonance (NMR) spectroscopic analysis of the residues. Aluminum is predominantly found in the fine size separate (<125 μm), indicating that the alum added to the poultry houses hydrolyzed without being completely dispersed in the litter. The NMR spectra confirmed the hypothesis that calcium phosphate phases are only dissolved during extraction with dilute acid and phosphate associated with Al is mainly dissolved during extraction with NaOH. Extraction of phosphate associated with Al was incomplete, however, as evidenced by 31P NMR spectroscopy. It could also be demonstrated that the extraction sequence overestimates the calcium phosphate fraction by an order of magnitude in this particular sample. Results from sequential chemical extraction should therefore be used with caution when assessing the magnitude of different phosphate pools in poultry litter.
The Relationship between Greenhouse Gas Emissions and the Intensity of Milk Production in Ireland
Authors: Casey J. W. , Holden N. M. 
Published: June 2010

ABSTRACTEuropean Union agri‐environmental schemes aim to reduce the environmental impact of agricultural production, but were developed before consideration of greenhouse gas emissions from agriculture. Life cycle assessment methodology provided a framework for comparing emissions as kg CO2 equivalent per kg of energy corrected milk (ECM) (kg CO2 kg−1 ECM yr−1) and per hectare (kg CO2 ha−1 yr−1) for farms both within and outside the Irish agri‐environmental scheme. The agri‐environmental scheme farms operate extensive systems from 40 to 120 cows producing between 3032 and 5946 kg ECM cow−1 lactation−1 The cows are fed on grass, conserved silage, and concentrates. Supplementation ranged between 250 and 620 kg cow−1 yr−1 The conventional farms had between 30 and 77 milking cows producing 4736 to 6944 kg ECM cow−1 lactation−1 Supplementation ranged from 400 to 1000 kg cow−1 yr−1 The emissions from each unit were estimated using published emissions factors and possible error was evaluated by using ranges for each factor. Calculated emissions ranged from 0.92 to 1.51 kg CO2 kg−1 ECM yr−1 and 5924 to 8323 kg CO2 ha−1 On average, total emissions from conventional farms were around 18% (p = 0.01) greater than the agri‐environmental scheme farms and emissions per hectare (total area required) were 17% greater (p = 0.02) but there was no significant difference (p = 0.335) in terms of emission per unit milk produced. To evaluate greenhouse gas emissions for each farm in terms of the system intensity it was necessary to define a measure of intensification and area per liter of milk produced that was best.
Assessment of Herbicide Leaching Risk in Two Tropical Soils of Reunion Island (France)
Authors: Bernard H. , Chabalier P. F. , Chopart J. L. , Legube B. , Vauclin M. 
Published: June 2010

ABSTRACTApplication of organic chemicals to a newly irrigated sugarcane (Saccharum officinarum L.) area located in the semiarid western part of Reunion Island has prompted local regulatory agencies to determine their potential to contaminate ground water resources. For that purpose, simple indices known as the ground water ubiquity score (Gustafson index, GUS), the retardation factor (RF), the attenuation factor (AF), and the log‐transformed attenuation factor (AFT) were employed to assess the potential leaching of five herbicides in two soil types. The herbicides were alachlor [2‐chloro‐2′,6′‐diethyl‐N‐(methoxy‐methy) acetanilide], atrazine [2‐chloro‐4‐(ethylamino)‐6‐(isopropylamino)‐1,3,5‐triazine], diuron [3‐(3,4‐dichlorophenyl)‐1,1‐dimethylurea], 2,4‐D [(2,4‐dichlorophenoxy) acetic‐acid], and triclopyr [((3,5,6‐trichloro‐2‐pyridyl)oxy) acetic‐acid]. The soil types were Vertic (BV) and Andepts (BA) Inceptisols, which are present throughout the Saint‐Gilles study area on Reunion Island. To calculate the indices, herbicide sorption (Koc) and dissipation (half‐life, DT50) properties were determined from controlled batch experiments. Water fluxes below the root zone were estimated by a capacity‐based model driven by a rainfall frequency analysis performed on a 13‐yr data series. The results show a lower risk of herbicide leaching than in temperate regions due to the tropical conditions of the study area. Higher temperatures and the presence of highly adsorbent soils may explain smaller DT50 and higher Koc values than those reported in literature concerning temperate environments. Based on the RF values, only 2,4‐D and triclopyr appear mobile in the BV soil, with all the other herbicides being classified from moderately to very immobile in both soils. The AFT values indicate that the potential leaching of the five herbicides can be considered as unlikely, except during the cyclonic period (about 40 d/yr) when there is a 2.5% probability of recharge rates equal to or higher than 50 mm/d. In that case, atrazine in both soils, 2,4‐D and triclopyr in the BV soil, and diuron and alachlor in the BA soil present a high risk of potential contamination of ground water resources.
Les croyances religieuses : entre raison, symbolisation et expérience
Authors: Lamine Anne-Sophie 
Published: June 2010

Résumé Est-il possible de prendre en compte les trois dimensions de la croyance religieuse : les processus de rationalisation, ceux de symbolisation et le croire en acte (et en présence, en émotion) ? Ces approches sont discutées, à partir de leurs appuis théoriques (Weber, Schutz/Luckmann et Simmel/Wittgenstein) et de cas empiriques, ainsi que l’articulation entre elles. On montre qu’il y a d’une part une dimension rationnelle dans le fait de rendre des expériences ou des croyances signifiantes et plausibles et d’autre part une dimension existentielle de la croyance comme vécu ou comme pratique, qui peut — temporairement ou durablement — suspendre l’analyse rationnelle, la justification, l’explication réflexive. Les trois dimensions explicatives de la croyance apparaissent donc comme complémentaires et compatibles.
Croyances fantastiques et rationalité
Authors: Renard Jean-Bruno 
Published: June 2010

Résumé Raymond Boudon a appliqué sa théorie générale de la rationalité à la connaissance ordinaire et à la connaissance scientifique, principalement les sciences humaines. Les croyances fantastiques, c’est-à-dire l’affirmation de l’existence d’êtres ou de phénomènes extraordinaires, sont fréquemment expliquées, à cause de leur étrangeté, par l’irrationalité humaine ou par un « besoin de merveilleux ». Elles relèvent pourtant aussi, le plus souvent, de la rationalité subjective. L’article explorera les « bonnes raisons de croire » à des choses incroyables comme les sirènes, le monstre du Loch Ness, le yéti, les extraterrestres, les phénomènes paranormaux…
Éthique et engagement dans un groupe antispéciste
Authors: Turina Isacco 
Published: June 2010

Résumé Cet article présente les résultats d’une enquête ethnographique sur une association italienne qui lutte pour les droits des animaux, en se focalisant sur les aspects éthiques de cette forme d’engagement. Par contraste avec l’antispécisme des philosophes moraux, je me propose de définir la version élaborée par ce groupe comme « antispécisme anti-humaniste », vu que, au sein de ce collectif, la défense des animaux va de pair avec un mépris pour les hommes et une méfiance généralisée envers l’humanité, jugée moralement inférieure aux autres espèces et vouée à l’extinction. Dans un deuxième temps, j’analyse les actions entreprises par le groupe en deux sphères distinctes : celle de l’éthique, qui renvoie à l’œuvre de Weber, et celle de la morale, définie d’après Durkheim. Je suggère que cette distinction peut se révéler utile dans le développement d’une sociologie empirique des phénomènes éthiques, qui semble de plus en plus urgente pour mieux comprendre et analyser les sociétés pluralistes contemporaines.
De la poésie aux poèmes : quel questionnement du poétique dans le secondaire ?
Authors: Larraburu-Dedouret Sandrine 
Published: June 2010

L’enseignement de la poésie se réduit trop souvent à une approche de l’histoire culturelle, voire à une histoire des formes. Comment en sortir ? Lire, étudier des poèmes pose et doit susciter des interrogations sur le rapport à la langue, le rapport à l’histoire, la question du sujet, l’écoute d’une voix et l’enjeu de sa réception. L’enjeu de la poéticité doit rester au centre des préoccupations car ce serait renoncer à la littérature que de réduire le texte poétique à une pratique de la lecture, de l’oral ou même de l’écriture, et d’essayer de lui trouver une fonction rentable ou utilitariste.
Deux mots seulement : une traversée des bimots de Julien Blaine
Authors: Maunet Isabelle 
Published: June 2010

L’article propose, comme son titre l’indique, « une traversée des bimots de Julien Blaine », l’un des pionniers des poésies dites action ou élémentaire. Cette étude formule quelques-unes des données fondamentales qui régissent l’univers de ces singuliers poèmes constitués de deux mots mis en et sous tension. De cet entre-deux, fondé sur un principe d’économie littérale, nait une variation sur le temps, l’espace, la langue et le poème, qu’on peut déployer dans des ateliers de littérature (pratique de lecture-écriture) de l’école primaire au lycée.
L'éthique des comportements concurrentiels: une approche perceptuelle
Authors: Dornier Raphaël , Goetschmann Michel , Cothias Vanessa 
Published: June 2010

Résumé L’objectif de cet article est de déterminer, dans une perspective exploratoire, dans quelle mesure la création de chartes éthiques collectives dans le secteur de la production de voyage a un impact sur le caractère non-éthique des comportements concurrentiels, tels que perçus par les dirigeants. Nos résultats montrent que si la plupart des dirigeants interrogés estiment que de telles chartes ont un impact positif sur le caractère éthique des comportements concurrentiels, elles peuvent aussi être « instrumentalisées » par certains voyagistes, essentiellement pour améliorer leur image.
Multidimensionnalité des enjeux du paysage : de l'évaluation à la décision
Authors: Plottu Éric , Plottu Béatrice 
Published: June 2010

Le paysage présente plusieurs sources de valorisation (écologique, économique, ...) qu’il convient d’intégrer dans l’évaluation et la prise de décision. La notion de Valeur Économique Totale, distinguant valeurs d’usage et de non-usage, permet de rendre compte de la diversité de ces sources de valorisation. Toutefois, la définition purement monétaire de ces valeurs ne permet pas de restituer la multidimensionnalité des enjeux soulevés par la gestion du paysage, sous-jacents à ces valeurs. Nous proposons de ré-interpréter la valeur du paysage au sein d’un cadre d’analyse multidimensionnelle basé sur la distinction de trois niveaux d’enjeux - identitaire, stratégique, de rentabilité -, liés à la gestion de l’espace. Nous montrons que la règle d’agrégation de type Comparer Agréger et l’utilisation des méthodes d’aide multicritère à la décision permettent de rendre cette approche opérationnelle et d’éclairer la décision.
La participation électorale : un déficit inégalé
Authors: Muxel Anne 
Published: June 2010

Résumé Seuls quatre Européens sur dix ont participé aux élections européennes de 2009. Par rapport à 2004, l’abstention a encore progressé d’un peu plus de deux points. Une nouvelle fois, les abstentionnistes forment le premier parti européen. L’abstention ne peut être analysée ni comme un phénomène linéaire ni comme un comportement homogène. Des facteurs à la fois sociologiques, institutionnels, et politiques entrent en ligne de compte. Par ailleurs elle s’inscrit dans un mouvement de transformation du rapport au vote. Mais son ampleur signe avant toute autre chose l’européanisation d’un enjeu crucial pour la réalisation de l’Europe politique : l’information et l’éducation à la citoyenneté européenne.