bluuebunny/crossref_metadata_2025_split huggingface dataset:
Water Quality Impacts of Converting to a Poultry Litter Fertilization Strategy
Authors: Harmel R. D. , Torbert H. A. , Haggard B. E. , Haney R. , Dozier M. 
Published: June 2010

ABSTRACTWhen improperly managed, land application of animal manures can harm the environment; however, limited watershed‐scale runoff water quality data are available to research and address this issue. The water quality impacts of conversion to poultry litter fertilization on cultivated and pasture watersheds in the Texas Blackland Prairie were evaluated in this three‐year study. Edge‐of‐field N and P concentrations and loads in surface runoff from new litter application sites were compared with losses under inorganic fertilization. The impact on downstream nutrient loss was also examined. In the fallow year with no fertilizer application, nutrient losses averaged 3 kg N ha−1 and 0.9 kg P ha−1 for the cultivated watersheds and were below 0.1 kg ha−1 for the pasture watersheds. Following litter application, PO4–P concentrations in runoff were positively correlated to litter application rate and Mehlich‐3 soil P levels. Following litter application, NO3–N and NH4–N concentrations in runoff were typically greater from cultivated watersheds, but PO4–P concentrations were greater for the pasture watersheds. Total N and P loads from the pasture watersheds (0.2 kg N ha−1 and 0.7 kg P ha−1) were significantly lower than from the cultivated watersheds (32 kg N ha−1 and 5 kg P ha−1) partly due to lower runoff volumes from the pasture watersheds. Downstream N and P concentrations and per‐area loads were much lower than from edge‐of‐field watersheds. Results demonstrate that a properly managed annual litter application (4.5 Mg ha−1 or less depending on litter N and P content) with supplemental N should supply necessary nutrients without detrimental water quality impacts.
Interrelationship of Macropores and Subsurface Drainage for Conservative Tracer and Pesticide Transport
Authors: Fox Garey A. , Malone Rob , Sabbagh George J. , Rojas Ken 
Published: June 2010

ABSTRACTMacropore flow results in the rapid movement of pesticides to subsurface drains, which may be caused in part by a small portion of macropores directly connected to drains. However, current models fail to account for this direct connection. This research investigated the interrelationship between macropore flow and subsurface drainage on conservative solute and pesticide transport using the Root Zone Water Quality Model (RZWQM). Potassium bromide tracer and isoxaflutole, the active ingredient in BALANCE herbicide [(5‐cyclopropyl‐4‐isoxazolyl) [2(methylsulfonyl)‐4‐(trifluoromethyl)phenyl] methanone], with average half‐life of 1.7 d were applied to a 30.4‐ha Indiana corn (Zea mays L.) field. Water flow and chemical concentrations emanating from the drains were measured from two samplers. Model predictions of drain flow after minimal calibration reasonably matched observations (slope = 1.03, intercept = 0.01, and R2 = 0.75). Without direct hydraulic connection of macropores to drains, RZWQM under predicted bromide and isoxaflutole concentration during the first measured peak after application (e.g., observed isoxaflutole concentration was between 1.2 and 1.4 μg L−1, RZWQM concentration was 0.1 μg L−1). This research modified RZWQM to include an express fraction relating the percentage of macropores in direct hydraulic connection to drains. The modified model captured the first measured peak in bromide and isoxaflutole concentrations using an express fraction of 2% (e.g., simulated isoxaflutole concentration increased to 1.7 μg L−1). The RZWQM modified to include a macropore express fraction more accurately simulates chemical movement through macropores to subsurface drains. An express fraction is required to match peak concentrations in subsurface drains shortly after chemical applications.
Field Water Balance of Landfill Final Covers
Authors: Albright William H. , Benson Craig H. , Gee Glendon W. , Roesler Arthur C. , Abichou Tarek , Apiwantragoon Preecha , Lyles Bradley F. , Rock Steven A. 
Published: June 2010

ABSTRACTLandfill covers are critical to waste containment, yet field performance of specific cover designs has not been well documented and seldom been compared in side‐by‐side testing. A study was conducted to assess the ability of landfill final covers to control percolation into underlying waste. Conventional covers employing resistive barriers as well as alternative covers relying on water‐storage principles were monitored in large (10 × 20 m), instrumented drainage lysimeters over a range of climates at 11 field sites in the United States. Surface runoff was a small fraction of the water balance (0–10%, 4% on average) and was nearly insensitive to the cover slope, cover design, or climate. Lateral drainage from internal drainage layers was also a small fraction of the water balance (0–5.0%, 2.0% on average). Average percolation rates for the conventional covers with composite barriers (geomembrane over fine soil) typically were less than 12 mm/yr (1.4% of precipitation) at humid locations and 1.5 mm/yr (0.4% of precipitation) at arid, semiarid, and subhumid locations. Average percolation rates for conventional covers with soil barriers in humid climates were between 52 and 195 mm/yr (6–17% of precipitation), probably due to preferential flow through defects in the soil barrier. Average percolation rates for alternative covers ranged between 33 and 160 mm/yr (6 and 18% of precipitation) in humid climates and generally less than 2.2 mm/yr (0.4% of precipitation) in arid, semiarid, and subhumid climates. One‐half (five) of the alternative covers in arid, semiarid, and subhumid climates transmitted less than 0.1 mm of percolation, but two transmitted much more percolation (26.8 and 52 mm) than anticipated during design. The data collected support conclusions from other studies that detailed, site‐specific design procedures are very important for successful performance of alternative landfill covers.
Structural and Sorption Characteristics of Adsorbed Humic Acid on Clay Minerals
Authors: Wang Kaijun , Xing Baoshan 
Published: June 2010

ABSTRACTClay–humic complexes are commonly distributed in natural environments. They play very important roles in regulating the transport and retention of hydrophobic organic contaminants in soils and sediments. This study examined the structural changes of humic acid (HA) after adsorption by clay minerals and determined phenanthrene sorption by clay–humic complexes. Solid‐ and liquid‐state 13C nuclear magnetic resonance (NMR), for the first time, provided direct evidence for HA fractionation during adsorption on mineral surfaces, that is, aliphatic fractions were preferentially adsorbed by clay minerals while aromatic fractions were left in the solution. The ratio of UV absorbance of HA at 465 and 665 nm (E4 to E6 ratio), which is related to aromaticity, corroborated with the NMR results. For both montmorillonite and kaolinite, adsorbed HA fractions had higher sorption linearity (N) and affinity (Koc) than the source HA. The Koc of adsorbed HA for the clay–humic complexes could be up to several times higher than that of the source HA. This large increase may be contributed by the low polarity of the bound HA. Moreover, for each mineral, the N values of adsorbed HA increased with increasing HA loading. It is believed that HA may develop a more condensed structure on mineral surface at lower HA loading level due to the stronger interactions between HA and mineral surface as a result of close contacts.
Straining, Attachment, and Detachment of Cryptosporidium Oocysts in Saturated Porous Media
Authors: Bradford S. A. , Bettahar M. 
Published: June 2010

ABSTRACTAccurate knowledge of the transport and deposition behavior for pathogenic Cryptosporidium parvum oocysts is needed to assess contamination and protect water resources. Experimental and modeling studies were undertaken to examine the roles of attachment, detachment, and straining on oocyst transport and retention. Saturated column studies were conducted using Ottawa aquifer sands (U.S. Silica, Ottawa, IL) with median grain sizes of 710, 360, and 150 μm. Decreasing the median sand size tended to produce lower effluent concentrations, greater oocyst retention in the sand near the column inlet, and breakthrough of oocysts at later times. Oocyst transport data also exhibited concentration tailing. Mathematical modeling of the oocyst transport data using fitted first‐order attachment and detachment coefficients provided a satisfactory description of the observed effluent concentration curves, but a poor characterization of the oocyst spatial distribution. Modeling of these data using an irreversible straining term that is depth dependent provided a better description of the oocyst spatial distribution, but could not account for the observed effluent concentration tailing or late breakthrough times. A more physically realistic description of the data was obtained by modeling attachment, detachment, and straining. The percentage of total oocysts retained by straining was estimated from effluent mass balance considerations to be 68% for 710‐μm sand, 79% for 360‐μm sand, and 87% for 150‐μm sand. Straining coefficients were then selected to achieve these percentages of total oocyst retention, and attachment and detachment coefficients were fitted to the effluent concentration curves. Dramatic differences in the predicted oocyst breakthrough curves were observed at greater transport distances for the various model formulations (inclusion or exclusion of straining). Justification for oocyst straining was provided by trends in the transport data, simulation results, pore size distribution information, and published literature.
In Situ Ground Water Denitrification in Stratified, Permeable Soils Underlying Riparian Wetlands
Authors: Kellogg D. Q. , Gold A. J. , Groffman P. M. , Addy K. , Stolt M. H. , Blazejewski G. 
Published: June 2010

ABSTRACTThe ground water denitrification capacity of riparian zones in deep soils, where substantial ground water can flow through low‐gradient stratified sediments, may affect watershed nitrogen export. We hypothesized that the vertical pattern of ground water denitrification in riparian hydric soils varies with geomorphic setting and follows expected subsurface carbon distribution (i.e., abrupt decline with depth in glacial outwash vs. negligible decline with depth in alluvium). We measured in situ ground water denitrification rates at three depths (65, 150, and 300 cm) within hydric soils at four riparian sites (two per setting) using a15N‐enriched nitrate “push–pull” method. No significant difference was found in the pattern and magnitude of denitrification when grouping sites by setting. At three sites there was no significant difference in denitrification among depths. Correlations of site characteristics with denitrification varied with depth. At 65 cm, ground water denitrification correlated with variables associated with the surface ecosystem (temperature, dissolved organic carbon). At deeper depths, rates were significantly higher closer to the stream where the subsoil often contains organically enriched deposits that indicate fluvial geomorphic processes. Mean rates ranged from 30 to 120 μg N kg−1d−1within 10 m versus <1 to 40 μg N kg−1d−1at >30 m from the stream. High denitrification rates observed in hydric soils, down to 3 m within 10 m of the stream in both alluvial and glacial outwash settings, argue for the importance of both settings in evaluating the significance of riparian wetlands in catchment‐scale N dynamics.
Influence of Phytase on Water‐Soluble Phosphorus in Poultry and Swine Manure
Authors: Angel C. Roselina , Powers Wendy J. , Applegate Todd J. , Tamim Nada M. , Christman Mary C. 
Published: June 2010

ABSTRACTThe effect of dietary non‐phytin phosphorus (NPP) and phytase (PHY) concentration on total phosphorus (TP) and water‐soluble phosphorus (WSP) excretion was determined. Diets tested in broiler experiments were: National Research Council nutrient requirements for non‐phytin phosphorus (NRC), NRC + PHY, reduced non‐phytin phosphorus (RED), and RED + PHY. Turkey and swine experiment diets included NRC, RED, and RED + PHY. For all experiments, except broiler Experiment 1, excreta were: (i) boiled, antibiotic added, then frozen; (ii) boiled, antibiotic added, incubated (37°C for 72 h), then frozen; and (iii) incubated, boiled, antibiotic added, then frozen. In Experiment 1, excreta were collected and frozen or incubated for 24 or 48 h. In broiler Experiment 1, WSP was not affected by phytase but increased with post‐excretion incubation. In a broiler Experiment 2, reducing NPP resulted in reduced excreta TP and WSP (11.3 to 8.3 and 5.3 to 2.7 g kg−1). Feeding RED + PHY diets resulted in less TP and WSP (7.6 and 0.6 g kg−1) as compared with NRC + PHY (11.2 and 3.9 g kg−1, Experiment 3). Incubation resulted in increased WSP, irrespective of phytase addition such that WSP as a percent of TP was similar among treatments. Addition of antibiotics before incubation prevented the increase in WSP. Similar results were observed with turkey and swine. Therefore, when phytase is used properly (i.e., with a simultaneous reduction of NPP), WSP or WSP as a percent of TP are not affected. The increase in WSP as a percent of TP post‐excretion is a function of excreta microbial activity and not dietary phytase addition.
Relating Soil Phosphorus to Dissolved Phosphorus in Runoff: A Single Extraction Coefficient for Water Quality Modeling
Authors: Vadas P. A. , Kleinman P. J. A. , Sharpley A. N. , Turner B. L. 
Published: June 2010

ABSTRACTPhosphorus transport from agricultural soils contributes to eutrophication of fresh waters. Computer modeling can help identify agricultural areas with high potential P transport. Most models use a constant extraction coefficient (i.e., the slope of the linear regression between filterable reactive phosphorus [FRP] in runoff and soil P) to predict dissolved P release from soil to runoff, yet it is unclear how variations in soil properties, management practices, or hydrology affect extraction coefficients. We investigated published data from 17 studies that determined extraction coefficients using Mehlich‐3 or Bray‐1 soil P (mg kg−1), water‐extractable soil P (mg kg−1), or soil P sorption saturation (%) as determined by ammonium oxalate extraction. Studies represented 31 soils with a variety of management conditions. Extraction coefficients from Mehlich‐3 or Bray‐1 soil P were not significantly different for 26 of 31 soils, with values ranging from 1.2 to 3.0. Extraction coefficients from water‐extractable soil P were not significantly different for 17 of 20 soils, with values ranging from 6.0 to 18.3. The relationship between soil P sorption saturation and runoff FRP (μg L−1) was the same for all 10 soils investigated, exhibiting a split‐line relationship where runoff FRP rapidly increased at P sorption saturation values greater than 12.5%. Overall, a single extraction coefficient (2.0 for Mehlich‐3 P data, 11.2 for water‐extractable P data, and a split‐line relationship for P sorption saturation data) could be used in water quality models to approximate dissolved P release from soil to runoff for the majority of soil, hydrologic, or management conditions. A test for soil P sorption saturation may provide the most universal approximation, but only for noncalcareous soils.
Phosphorus Speciation in Broiler Litter and Turkey Manure Produced from Modified Diets
Authors: Toor Gurpal S. , Peak J. Derek , Sims J. Thomas 
Published: June 2010

ABSTRACTModifying poultry diets by reducing mineral P supplementation and/or adding phytase may change the chemical composition of P in manures and affect the mobility of P in manure‐amended soils. We studied the speciation of P in manures produced by broiler chickens and turkeys from either normal diets, or diets with reduced amounts of non‐phytate phosphorus (NPP) and/or phytase, using a combination of chemical fractionation and synchrotron X‐ray absorption near edge structure (XANES) spectroscopy. All broiler litters were rich in dicalcium phosphate (65–76%), followed by aqueous phosphate (13–18%), and phytic acid (7–20%); however, no hydroxylapatite was observed. Similarly, normal turkey manure had 77% of P as dicalcium phosphate and had no hydroxylapatite, while turkey manure from diets that had reduced NPP and phytase contained equal proportions of dicalcium phosphate (33–45%) and hydroxylapatite (35–39%). This is attributed to the higher total Ca to P ratio (>2) in modified turkey manures that resulted in transformation of more soluble (dicalcium phosphate) to less soluble P compounds (hydroxylapatite). Chemical fractionation showed that H2O‐extractable P was the predominant form in broiler litter (56–77%), whereas aqueous phosphate determined with XANES was <18% indicating that H2O probably dissolved mineral forms of P (e.g., dicalcium phosphate). Results show that HCl extraction primarily removed phytic acid from broiler litters and normal turkey manure, while it removed a mixture of hydroxylapatite and phytic acid from modified turkey manures. The combination of chemical fractionation and XANES provided information about the nature of P in these manures, which may help to devise best management practices for manure use.
Gaseous Nitrogen and Carbon Losses from Pig Manure Derived from Different Diets
Authors: Velthof Gerard L. , Nelemans Jaap A. , Oenema Oene , Kuikman Peter J. 
Published: June 2010

ABSTRACTManipulation of the diets of pigs may alter the composition of the manure and thereby the environmental and agricultural qualities of the manure. Laboratory studies were performed to quantify the effect of manipulation of pig diets on the chemical composition of the derived manure (slurry), the potential emission of methane (CH4) and ammonia (NH3) during anaerobic storage of the manure, and the potential nitrous oxide (N2O) and carbon dioxide (CO2) emission after application of the manure to soil. The diets differed in contents of crude protein and salt (CaSO4), and the type and contents of nonstarch polysaccharides (NSP). Emissions of NH3 and CH4 during storage were smaller at a low than at a high dietary protein content. The emission of NH3 was significantly related to the contents of ammonium (NH4), total N, and pH. The emission of CH4 was significantly related to contents of dry matter, total C, and volatile fatty acids in the manure. The effect of manure composition on N2O emission markedly differed between the two tested soils, which points at interactions with soil properties such as the organic matter content. These types of interactions require soil‐specific recommendations for mitigation of N2O emission from soil‐applied pig manure by manipulation of the diet. From the tested diets, decreasing the protein content has the largest potential to simultaneously decrease NH3 and CH4 emissions during manure storage and N2O emission from soil. An integral assessment of the environmental and agricultural impact of handling and application of pig manure as a result of diet manipulation provides opportunities for farmers to maximize the value of manures as fertilizer and soil conditioner and to minimize N and C emissions to the environment.
A Methodology to Estimate the Denitrifying Capacity of a Riparian Wetland
Authors: Maître Véronique , Cosandey Anne‐Claude , Parriaux Aurèle , Guenat Claire 
Published: June 2010

ABSTRACTNumerous studies have shown that riparian wetlands can play an important role in reducing nitrate concentrations before the ground water discharges into streams. Denitrification has been identified as an important process for this removal. Several approaches have been proposed to predict the denitrifying removal capacity of a riparian wetland, but no widely used tool exists to precisely quantify this capacity at the landscape scale. We propose such a methodology based on modeling the spatial variation of soil–water interactions in the entire riparian wetland. Mean values of denitrification enzyme activity (DEA) within three soil‐denitrifying classes were 604, 212, and 24 ng N g−1 h−1 for Classes 3, 2, and 1, respectively. The study area, having a ground surface of about 15000 m2, was underlain by an aquifer with a calculated volume of 60000 m3, less than 10000 m3 of which corresponded to active denitrifying horizons (Classes 2 and 3). By volume, approximately 30% of Class 3 and 70% of Class 2 were interacting with ground water. The denitrifying removal capacity of our wetland was calculated to be about 1.8 kg N m−2 yr−1 The calculated denitrifying capacity of our site was less than expected. This is due to the fact that not all ground water interacts with the horizons having the highest denitrifying capacity. Thus, we show that whatever the system is, specific local pedological and hydrogeological conditions and their interactions are paramount in controlling the denitrification process.
Phosphorus Flux from Bottom Sediments in Lake Eucha, Oklahoma
Authors: Haggard B. E. , Moore P. A. , DeLaune P. B. 
Published: June 2010

ABSTRACTPhosphorus inputs into reservoirs include external sources from the watershed and internal sources from the reservoir bottom sediments. This study quantified sediment P flux in Lake Eucha, northeastern Oklahoma, USA, and evaluated the effectiveness of chemical treatment to reduce sediment P flux. Six intact sediment–water columns were collected from three sites in Lake Eucha near the reservoir channel at depths of 10 to 15 m. Three intact sediment and water columns from each site were incubated for 21 d at approximately 22°C under aerobic conditions, and three were incubated under anaerobic conditions (N2 with 300 ppm CO2); sediment P flux was estimated over the 21 d for each core. The overlying water in the cores was bubbled with air for approximately 1 wk and then treated with aluminum sulfate (alum). The cores were incubated at approximately 22°C for an additional 14 d under aerobic or anaerobic conditions, and sediment P flux after alum treatment was estimated for each core. Sediment P flux was approximately four times greater under anaerobic conditions compared with aerobic conditions. Alum treatment of the intact sediment–water columns reduced (8×) sediment P flux under anaerobic conditions. Internal P flux (1.03 and 4.40 mg m−2 d−1 under aerobic and anaerobic conditions, respectively) was greater than external P flux (0.13 mg m−2 d−1). The internal P load (12 Mg yr−1) from reservoir bottom sediments was almost 25% of the external P load (approximately 48 Mg yr−1) estimated using a calibrated watershed model.
L'enfance du rêve
Authors: Menès Martine 
Published: June 2010

Freud s’étonne que chez les enfants apparaissent à la fois les rêves de désir non voilés, confirmant sa théorie, et des cauchemars fréquents, qui, apparemment, la contredisent. « Cas limite », écrit-il, qui ne va pourtant pas jusqu’à contredire la formule générale car derrière le contenu manifeste des cauchemars freudiens célèbres, les loups de Sergueï, le chien de Sandy, se cache un contenu de désir réprimé. Lacan va plus loin. Chez le jeune enfant, même dans le simple rêve de réalisation de désir, il y a, dit-il, l’affirmation d’un désir inter-dit. Un pas de plus est franchi dans le cauchemar où l’angoisse rompt, dit-il, « le sommeil du sujet quand le rêve débouche sur le réel du désiré ». Des vignettes cliniques illustrent cette fonction du cauchemar de l’enfance.
Un homme-symptôme
Authors: Lalvée Brigitte 
Published: June 2010

Comment une fixation passionnelle, avec ses connotations de transgression de l’interdit, peut venir faire symptôme en recouvrant l’absence du rapport sexuel auquel elle se substitue ; comment l’irruption d’une maladie, pour lequel l’hypothèse psychosomatique d’une « écriture dans la chair » sera retenue, a pu se faire l’amorce d’un deuil et d’une nouvelle écriture, autre que celle du symptôme, ouvrant la voie à une forme de sublimation ; comment, enfin, un acting out court-circuita l’isolement de l’objet regard et le repérage du plus-de-jouir ainsi que du désir restés cryptés dans le symptôme : c’est ce déroulement d’une cure interrompue au bout de trois ans qui sera retracé et interrogé ici.