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Journal of Environmental Quality : Just Published

 

Accepted, edited articles are published here after author proofing to provide rapid publication and better access to the newest research. Articles are compiled into issues at dl.sciencesocieties.org/publications/jeq, which includes the complete archive.

Citation | Articles posted here are considered published and may be cited by the doi.

Maguire, R.O., P.J. A. Kleinman, C.J. Dell, D.B. Beegle, R.C. Brandt, J.M. McGrath, and Q.M. Ketterings. 2011. Manure application technology in reduced tillage and forage systems: A review. J. Environ. Qual. doi: 10.2134/jeq2009.0228

Current issue: J. Environ. Qual. 45(1)



  • ANTIBIOTICS IN AGROECOSYSTEMS: STATE OF THE SCIENCE

    • Michael J. Rothrock, Kelli L. Hiett, Jean Y. Guard and Charlene R. Jackson
      Antibiotic Resistance Patterns of Major Zoonotic Pathogens from All-Natural, Antibiotic-Free, Pasture-Raised Broiler Flocks in the Southeastern United States

      The use of antibiotics in agroecosystems has been implicated in the rise in antibiotic resistance (AR), which can affect environmental, animal, and human health. To determine the environmental impact of antibiotic use in agroecosystems, appropriate background levels of AR in agricultural environments in the absence of antibiotic application must be determined. Therefore, to determine background levels of AR in broiler production, four target microbes (Escherichia coli, Salmonella, Campylobacter, and Listeria) were isolated from 15 all-natural, antibiotic-free, pasture-raised broiler flocks from six farms within the southeastern United States. The AR profiles of these isolates were characterized using the CDC National Antimicrobial Resistance Monitoring System for Enteric Bacteria (NARMS), and these resistance patterns were compared across target microbes and farms and throughout the life cycle of the flocks along the farm-to-fork continuum. (continued)

      Core Ideas:
      • Determining background levels of AR in antibiotic-free agroecosystems is essential.
      • AR within antibiotic-free broiler production is dynamic among the zoonotic pathogens.
      • Multidrug resistance was greater in Salmonella and Listeria.
      • Multidrug resistance was farm specific for Salmonella and Campylobacter.
      • E. coli was not an appropriate indicator of AR in other Gram-negative organisms, including Salmonella.

      doi:10.2134/jeq2015.07.0366
      Published: December 18, 2015



  • ATMOSPHERIC POLLUTANTS AND TRACE GASES

    • Mindy J. Spiehs, Tami M. Brown-Brandl, David B. Parker, Daniel N. Miller, Elaine D. Berry and James E. Wells
      Ammonia, Total Reduced Sulfides, and Greenhouse Gases of Pine Chip and Corn Stover Bedding Packs

      Bedding materials may affect air quality in livestock facilities. Our objective in this study was to compare headspace concentrations of ammonia (NH3), total reduced sulfides (TRS), carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) when pine wood chips (Pinus spp.) and corn stover (Zea mays L.) were mixed in various ratios (0, 10, 20, 30, 40, 60, 80, and 100% pine chips) and used as bedding with manure. Air samples were collected from the headspace of laboratory-scaled bedded manure packs weekly for 42 d. Ammonia concentrations were highest for bedded packs containing 0, 10, and 20% pine chips (equivalent to 501.7, 502.3, and 502.3 mg m−3, respectively) in the bedding mixture and were lowest when at least 80% pine chips were used as bedding (447.3 and 431.0 mg m−3, respectively for 80 and 100% pine chip bedding). (continued)

      Core Ideas:
      • Producers can use bedding material to help reduce gas emissions from livestock facilities.
      • Ammonia concentrations were highest when bedding contained 20% or less pine chips.
      • Total reduced sulfides were highest when 100% pine chips were used in the bedding mixture.
      • Greenhouse gases were largely unaffected by including pine chips in bedding mixtures.
      • Bedding materials of 30–40% pine and 60–70% corn may be ideal to reduce gas emissions.

      doi:10.2134/jeq2015.09.0466
      Published: February 12, 2016



    • Chris Pratt, Matthew Redding, Jaye Hill, Grant Brown and Maren Westermann
      Clays Can Decrease Gaseous Nutrient Losses from Soil-Applied Livestock Manures

      Clays could underpin a viable agricultural greenhouse gas (GHG) abatement technology given their affinity for nitrogen and carbon compounds. We provide the first investigation into the efficacy of clays to decrease agricultural nitrogen GHG emissions (i.e., N2O and NH3). Via laboratory experiments using an automated closed-vessel analysis system, we tested the capacity of two clays (vermiculite and bentonite) to decrease N2O and NH3 emissions and organic carbon losses from livestock manures (beef, pig, poultry, and egg layer) incorporated into an agricultural soil. Clay addition levels varied, with a maximum of 1:1 to manure (dry weight). (continued)

      Core Ideas:
      • Technologies to mitigate agricultural GHG emissions are in demand.
      • We tested the ability of clays to abate GHG emissions from soil + manure mixes.
      • To our knowledge, this is the first study of its kind.
      • The clays showed strong promise to decrease N emissions by as much as 90%.
      • The clays also showed potential to boost C retention in soil + manure systems.

      doi:10.2134/jeq2015.11.0569
      Published: February 5, 2016



  • BIOREMEDIATION AND BIODEGRADATION

    • Brandon H. Gilroyed, Cheyenne Conrad, Xiying Hao, Tim A. McAllister, Kim Stanford and Tim Reuter
      Composting for Biocontained Cattle Mortality Disposal and Associated Greenhouse Gas and Leachate Emissions

      Composting can be an effective means of biodegrading livestock mortalities in emergency disposal situations, such as disease outbreaks. Within the past decade, our knowledge detailing composting has increased substantially. However, research data linking the environmental impact of composting to atmospheric and terrestrial systems are limited. We investigated composting efficacy, greenhouse gas emissions, and leachate properties from two static compost piles, each containing 16 cattle mortalities, built with either beef manure (BM) or wood shavings (WS) as envelope material. (continued)

      Core Ideas:
      • Mortality composting limits environmental emission of unwanted substances tested.
      • Greenhouse gases are significantly lower with wood shaving as envelopment versus manure.
      • DNA fingerprints in soil show increased bacterial and gene diversity from compost leachate.

      doi:10.2134/jeq2015.06.0314
      Published: January 22, 2016



  • ENVIRONMENTAL MICROBIOLOGY

    • Melissa L. Partyka, Ronald F. Bond, Jennifer A. Chase, Luana Kiger and Edward R. Atwill
      Multistate Evaluation of Microbial Water and Sediment Quality from Agricultural Recovery Basins

      Agricultural recovery basins are an important conservation practice designed to provide temporary storage of sediment and water on farms before low-volume discharge. However, food safety concerns have been raised regarding redistribution of captured sediment and water to fields used for human food production. The purpose of this study was to examine the potential microbiological risk that recovery basins may contribute to nearby produce fields and to evaluate characteristics that may influence or mitigate those risks. Water and sediment samples were collected from participating farms in three states and evaluated for bacterial indicators and pathogens over several months. (continued)

      Core Ideas:
      • Pathogen occurrence in on-farm recovery basins varies by region and irrigation water source.
      • Wildlife, domestic animals, and vegetation were not correlated with pathogen occurrence.
      • Allowing captured sediments to dry may greatly reduce microbial load before reapplication.

      doi:10.2134/jeq2015.06.0323
      Published: January 29, 2016



  • ENVIRONMENTAL MODELS, MODULES, AND DATASETS

    • Michael A. Jahne, Shane W. Rogers, Thomas M. Holsen, Stefan J. Grimberg, Ivan P. Ramler and Seungo Kim
      Bioaerosol Deposition to Food Crops near Manure Application: Quantitative Microbial Risk Assessment

      Production of both livestock and food crops are central priorities of agriculture; however, food safety concerns arise where these practices intersect. In this study, we investigated the public health risks associated with potential bioaerosol deposition to crops grown in the vicinity of manure application sites. A field sampling campaign at dairy manure application sites supported the emission, transport, and deposition modeling of bioaerosols emitted from these lands following application activities. Results were coupled with a quantitative microbial risk assessment model to estimate the infection risk due to consumption of leafy green vegetable crops grown at various distances downwind from the application area. (continued)

      Core Ideas:
      • Leafy green crops may be contaminated by bioaerosols from nearby manure sources.
      • Estimates of deposition and associated risk have not previously been established.
      • Field-based measurements, models, and QMRA were used to assess these risks.
      • Median and peak risks were 1:6700 and 1:18 at 100 m, 1:92,000 and 1:1200 at 1000 m.
      • A 160-m setback distance is recommended based on a 1:10,000 acceptable median risk.

      doi:10.2134/jeq2015.04.0187
      Published: February 12, 2016



    • Ao Li, Benjamin D. Duval, Robert Anex, Peter Scharf, Jenette M. Ashtekar, Phillip R. Owens and Charles Ellis
      A Case Study of Environmental Benefits of Sensor-Based Nitrogen Application in Corn

      Crop canopy reflectance sensors make it possible to estimate crop N demand and apply appropriate N fertilizer rates at different locations in a field, reducing fertilizer input and associated environmental impacts while maintaining crop yield. Environmental benefits, however, have not been quantified previously. The objective of this study was to estimate the environmental impact of sensor-based N fertilization of corn using model-based environmental Life Cycle Assessment. Nitrogen rate and corn grain yield were measured during a sensor-based, variable N-rate experiment in Lincoln County, MO. (continued)

      Core Ideas:
      • Efficient use and application of N fertilizer likely reduces environmentally harmful N losses.
      • Sensor-based N fertilization has the promise of maximizing yield while minimizing N loss.
      • Sensor-based fertilization maintained corn yield and reduced losses of NO3− and N2O.
      • Sensor-based fertilization yielded life cycle GWP, acidification, and eutrophication benefits.

      doi:10.2134/jeq2015.07.0404
      Published: January 29, 2016



  • HEAVY METALS IN THE ENVIRONMENT

    • Jordan G. Hamilton, Richard E. Farrell, Ning Chen, Renfei Feng, Joel Reid and Derek Peak
      Characterizing Zinc Speciation in Soils from a Smelter-Affected Boreal Forest Ecosystem

      HudBay Minerals, Inc., has mined and/or processed Zn and Cu ore in Flin Flon, MB, Canada, since the 1930s. The boreal forest ecosystem and soil surrounding these facilities have been severely impacted by mixed metal contamination and H2SO4 deposition. Zinc is one of the most prevalent smelter-derived contaminants and has been identified as a key factor that may be limiting revegetation. Metal toxicity is related to both total concentrations and speciation; therefore, X-ray absorption spectroscopy and X-ray fluorescence mapping were used to characterize Zn speciation in soils throughout the most heavily contaminated areas of the landscape. (continued)

      Core Ideas:
      • Zinc was found to be a mixture of franklinite, aqueous Zn, and adsorption species.
      • Absence or presence of an invasive grass species influences Zn speciation and concentrations.
      • The presence of invasive grasses allows tetrahedrally coordinated Zn adsorption species.
      • Zinc–Al hydroxy interlayer material shows the potential to reduce Zn phytotoxicity.

      doi:10.2134/jeq2015.03.0145
      Published: January 4, 2016



  • LANDSCAPE AND WATERSHED PROCESSES

    • Alisa C. Morrison, Arthur J. Gold and Marguerite C. Pelletier
      Evaluating Key Watershed Components of Low Flow Regimes in New England Streams

      Water resource managers seeking to optimize stream ecosystem services and abstractions of water from watersheds need an understanding of the importance of land use, physical and climatic characteristics, and hydrography on different low flow components of stream hydrographs. Within 33 USGS gaged watersheds of southern New England, we assessed relationships between watershed variables and a set of low flow parameters by using an information-theoretical approach. The key variables identified by the Akaike Information Criteria (AIC) weighting factors as generating positive relationships with low flow events included percent stratified drift, mean elevation, drainage area, and mean August precipitation. The extent of wetlands in the watershed was negatively related to low flow magnitudes. (continued)

      Core Ideas:
      • Watershed features affect the resilience of streams to sustain low flows.
      • Stratified glacial drift deposits help sustain low flows of streams.
      • Watersheds with high % wetlands warrant careful management of withdrawals.
      • Urban development is not among the strongest predictors of low flows.

      doi:10.2134/jeq2015.08.0434
      Published: February 12, 2016



  • ORGANIC COMPOUNDS IN THE ENVIRONMENT

    • Carla Patrícia Silva, Diana L. D. Lima, Marta Otero and Valdemar I. Esteves
      Photosensitized Degradation of 17β-estradiol and 17α-ethinylestradiol: Role of Humic Substances Fractions

      Photodegradation of 17α-ethinylestradiol (EE2) and 17β-estradiol (E2) was investigated under simulated solar radiation. Photodegradation kinetics in the absence and presence of humic substances (HSs) fractions (humic acids [HAs], fulvic acids [FAs], and XAD-4), were compared. Although all three fractions were responsible for a noticeable increase on photodegradation rates, the effects were greater for FA and XAD-4. Half-life time decreased from 46 and 94 h (direct photodegradation) for EE2 and E2, respectively, to 6.4, 2.1, and 2.7 h (for EE2) and 5.7, 2.9, and 3.1 h (for E2) in the presence of HAs, FAs, and XAD-4, respectively. (continued)

      Core Ideas:
      • XAD-4 and FAs were the HSs fractions responsible for higher photodegradation.
      • t1/2 (EE2) decreased from 46 h (ultrapure water) to 2.1–6.4 h (with humic substances).
      • t1/2 (E2) decreased from 94 h (ultrapure water) to 5.7–2.9 h (with humic substances).
      • The highest photodegradation was obtained in the estuarine sample.
      • 1O2 and OH· had a minor participation on the photodegradation in the matrix studied.

      doi:10.2134/jeq2015.07.0396
      Published: February 5, 2016



  • PLANT AND ENVIRONMENT INTERACTIONS

    • Bart G. H. Timmermans and Nick van Eekeren
      Phytoextraction of Soil Phosphorus by Potassium-Fertilized Grass-Clover Swards

      In the development of the Dutch National Ecological Network, many hectares of arable land are converted to nature areas to protect plant and animal species. This encompasses development of species-rich grasslands. On former agricultural land on sandy soils, this development is often hampered by relatively high phosphorus (P) levels, which also cause eutrophication. Standard practices to decrease the amount of P are either topsoil removal or long-term mowing of low-yielding established grassland. (continued)

      Core Ideas:
      • Intensively harvested grass-clover is an effective tool to reduce excess P from topsoil.
      • On sandy soils a potassium source is necessary for this technique to be successful.
      • Soil P phytoextraction (“mining”) can reduce P enough for species-rich grassland development.
      • Soil balances suggest reduced leaching of P, declining the P load to surface water.

      doi:10.2134/jeq2015.08.0422
      Published: January 29, 2016



  • SHORT COMMUNICATIONS

    • Sarah M. Collier, Andrew P. Dean, Lawrence G. Oates, Matthew D. Ruark and Randall D. Jackson
      Does Plant Biomass Manipulation in Static Chambers Affect Nitrous Oxide Emissions from Soils?

      One of the most widespread approaches for measurement of greenhouse gas emissions from soils involves the use of static chambers. This method is relatively inexpensive, is easily replicated, and is ideally suited to plot-based experimental systems. Among its limitations is the loss of detection sensitivity with increasing chamber height, which creates challenges for deployment in systems including tall vegetation. It is not always possible to avoid inclusion of plants within chambers or to extend chamber height to fully accommodate plant growth. (continued)

      Core Ideas:
      • Biomass manipulation infrequently affects nitrous oxide emission.
      • Effects of biomass manipulation on emissions may vary by system.
      • Effects of biomass manipulation on emissions do not appear to intensify with time.
      • Considered collectively, minor treatment effects may amount to significant trends.
      • Biomass presence has a small but significant effect on volume and flux estimation.

      doi:10.2134/jeq2015.07.0377
      Published: January 22, 2016



  • SPECIAL SECTION: ANTIBIOTICS IN AGROECOSYSTEMS: STATE OF THE SCIENCE

    • Rebecca M. Nordenholt, Keith W. Goyne, Robert J. Kremer, Chung-Ho Lin, Robert N. Lerch and Kristen S. Veum
      Veterinary Antibiotic Effects on Atrazine Degradation and Soil Microorganisms

      Veterinary antibiotics (VAs) in manure applied to agricultural lands may change agrichemical degradation by altering soil microbial community structure or function. The objectives of this study were to investigate the influence of two VAs, sulfamethazine (SMZ) and oxytetracycline (OTC), on atrazine (ATZ) degradation, soil microbial enzymatic activity, and phospholipid fatty acid (PLFA) markers. Sandy loam soil with and without 5% swine manure (w/w) was amended with 0 or 500 μg kg−1 14C radiolabeled ATZ and with 0, 100, or 1000 μg kg−1 SMZ or OTC and incubated at 25°C in the dark for 96 d. The half-life of ATZ was not significantly affected by VA treatment in the presence or absence of manure; however, the VAs significantly (p < 0.05) inhibited ATZ mineralization in soil without manure (25–50% reduction). (continued)

      Core Ideas:
      • Veterinary antibiotics (VAs) did not affect atrazine degradation kinetics.
      • Atrazine mineralization was reduced 25 to 50% in soil treated with VAs.
      • VAs had limited effect on the activities of particular soil microbial enzymes.
      • Soil microbial community structure was adversely altered by VAs.
      • VAs inhibit atrazine metabolite degradation due to microbial community change.

      doi:10.2134/jeq2015.05.0235
      Published: February 12, 2016



    • Martha R. Zwonitzer, Michelle L. Soupir, Laura R. Jarboe and Douglas R. Smith
      Quantifying Attachment and Antibiotic Resistance of Escherichia coli from Conventional and Organic Swine Manure

      Broad-spectrum antibiotics are often administered to swine, contributing to the occurrence of antibiotic-resistant bacteria in their manure. During land application, the bacteria in swine manure preferentially attach to particles in the soil, affecting their transport in overland flow. However, a quantitative understanding of these attachment mechanisms is lacking, and their relationship to antibiotic resistance is unknown. The objective of this study is to examine the relationships between antibiotic resistance and attachment to very fine silica sand in Escherichia coli collected from swine manure. (continued)

      Core Ideas:
      • Greater levels of attachment were found in E. coli from conventional swine systems.
      • A significant relationship exists between resistance and attachment for organic swine systems.
      • Greater resistance to 9 of 13 antibiotics was found in conventional swine system E. coli.

      doi:10.2134/jeq2015.05.0245
      Published: February 12, 2016



    • Inoka D. Amarakoon, Francis Zvomuya, Srinivas Sura, Francis J. Larney, Allan J. Cessna, Shanwei Xu and Tim A. McAllister
      Dissipation of Antimicrobials in Feedlot Manure Compost after Oral Administration versus Fortification after Excretion

      Fortification of manure with antimicrobials is one approach to studying their dissipation. However, fortified antimicrobials may not accurately model dissipation that occurs after antimicrobials have been administered to livestock in feed and excreted in manure. This study examined the dissipation of antimicrobials excreted in manure versus those added directly to manure (fortified). Steers were fed a diet containing (kg−1 feed) (i) 44 mg chlortetracycline, (ii) 44 mg each of chlortetracycline and sulfamethazine, (iii) 11 mg tylosin, and (iv) no antimicrobials (control). (continued)

      Core Ideas:
      • Composting enhances biodegradation of antimicrobials in manure.
      • Antimicrobial dissipation follows first-order kinetics.
      • Dissipation rate depends on whether the antimicrobial is excreted or fortified.

      doi:10.2134/jeq2015.07.0408
      Published: February 12, 2016



    • Crystal A. McCall, Elizabeth Bent, Tue S. Jørgensen, Kari E. Dunfield and Marc B. Habash
      Metagenomic Comparison of Antibiotic Resistance Genes Associated with Liquid and Dewatered Biosolids

      Municipal biosolids (MBs) that are land-applied in North America are known to possess an active microbial population that can include human pathogens. Activated sludge is a hotspot for the accumulation of antibiotics and has been shown to be a selective environment for microorganisms that contain antibiotic resistance genes (ARGs); however, the prevalence of ARGs in MBs is not well characterized. In this study, we enriched the plasmid metagenome from raw sewage sludge and two CP2 MBs, a mesophilic anaerobic digestate and a dewatered digestate, to evaluate the presence of ARGs in mobile genetic elements. The CP2-class biosolids are similar to Class B biosolids in the United States. (continued)

      Core Ideas:
      • The biosolid plasmid-enriched metagenomes contained a wide variety of antibiotic resistance genes.
      • Nonculture based methods were used to concentrate plasmids.
      • Mobile genetic and circular elements were identified in the biosolid plasmid-enriched metagenome.

      doi:10.2134/jeq2015.05.0255
      Published: February 12, 2016



    • Jean E. McLain, Eddie Cytryn, Lisa M. Durso and Suzanne Young
      Culture-based Methods for Detection of Antibiotic Resistance in Agroecosystems: Advantages, Challenges, and Gaps in Knowledge

      Various culture-based methodologies are used in assessment of antibiotic resistance in samples collected in agroecosystems. Culture-based methods commonly involve isolating target bacteria on general or selective media and assessing growth in response to specific concentrations of antibiotics. The advantages of culture-based methods are multifold. In particular, isolation of bacteria is key to understanding phenotypic characteristics of isolates and their resistance patterns, and most national and international antibiotic resistance monitoring projects are isolate based. (continued)

      Core Ideas:
      • Culture-based methods provide reproducible results with minimal error.
      • Culture-based methods enable isolation of specific target organisms.
      • These methods often involve screening at a range of antibiotic concentrations.
      • Culture-based methods provide key data on multiple antibiotic resistance.
      • Both molecular and cultivation methods are needed for full insight into resistomes.

      doi:10.2134/jeq2015.06.0317
      Published: February 12, 2016



    • Cheng-Hua Liu, Ya-Hui Chuang, Hui Li, Brian J. Teppen, Stephen A. Boyd, Javier M. Gonzalez, Cliff T. Johnston, Johannes Lehmann and Wei Zhang
      Sorption of Lincomycin by Manure-Derived Biochars from Water

      The presence of antibiotics in agroecosystems raises concerns about the proliferation of antibiotic-resistant bacteria and adverse effects to human health. Soil amendment with biochars pyrolized from manures may be a win-win strategy for novel manure management and antibiotics abatement. In this study, lincomycin sorption by manure-derived biochars was examined using batch sorption experiments. Lincomycin sorption was characterized by two-stage kinetics with fast sorption reaching quasi-equilibrium in the first 2 d, followed by slow sorption over 180 d. (continued)

      Core Ideas:
      • Manure-derived biochars had lasting sequestration potential to lincomycin.
      • Lincomycin sorption on manure-derived biochars followed two-phase kinetics.
      • Long-term lincomycin sorption was controlled by slow diffusion into biochar pores.

      doi:10.2134/jeq2015.06.0320
      Published: January 29, 2016



    • Srinivas Sura, Dani Degenhardt, Allan J. Cessna, Francis J. Larney, Andrew F. Olson and Tim A. McAllister
      Transport of Three Antimicrobials in Runoff from Windrows of Composting Beef Cattle Manure

      Rain runoff from windrowed or stockpiled manure may contain antimicrobials with the potential to contaminate surface and ground water. To quantify the concentration of antimicrobials transported in runoff from windrowed manure, antimicrobials were administered continuously in feed to beef cattle (Bos taurus) as follows: 44 mg of chlortetracycline kg−1 feed (dry weight), a 1:1 mixture of 44 mg of chlortetracycline and 44 mg sulfamethazine kg−1 feed, and 11 mg of tylosin kg−1 feed. Cattle in a fourth treatment group received no antimicrobials (control). Manure from the cattle was used to construct two windrows per treatment. (continued)

      Core Ideas:
      • Antimicrobials were detected in composting windrow manure.
      • Runoff from composting windrows contained antimicrobials.
      • Order of transport in runoff: tylosin > sulfamethazine > chlortetracycline.
      • Antimicrobials dissipated during windrow composting.

      doi:10.2134/jeq2015.05.0254
      Published: January 29, 2016



    • Sarah C. Hafner, Thomas Harter and Sanjai J. Parikh
      Evaluation of Monensin Transport to Shallow Groundwater after Irrigation with Dairy Lagoon Water

      Animal waste products from concentrated animal feeding operations are a significant source of antibiotics to the environment. Monensin, an ionophore antibiotic commonly used to increase feed efficiency in livestock, is known to have varied toxicological effects on nontarget species. The current study builds on prior studies evaluating the impact of dairy management on groundwater quality by examining the transport of monensin in an agricultural field with coarse-textured soils during irrigation with lagoon wastewater. The dairy is located in California’s San Joaquin Valley, where groundwater can be encountered <5 m below the surface. (continued)

      Core Ideas:
      • Changes in groundwater chemistry can be observed within days of field irrigation.
      • Shallow aquifer with sandy soil presents a vulnerable site for contaminant transport.
      • Monensin is not rapidly transported to groundwater after a single irrigation event.
      • Leakage from waste storage systems results in monensin groundwater contamination

      doi:10.2134/jeq2015.05.0251
      Published: January 22, 2016



    • Elizabeth Luby, A. Mark Ibekwe, Julie Zilles and Amy Pruden
      Molecular Methods for Assessment of Antibiotic Resistance in Agricultural Ecosystems: Prospects and Challenges

      Agricultural ecosystems are of special interest for monitoring the potential for antibiotic resistance to spread through the environment and contribute to human exposure. Molecular methods, which target DNA, RNA, and other molecular components of bacterial cells, present certain advantages for characterizing and quantifying markers of antibiotic resistance and their horizontal gene transfer. These include rapid, unambiguous detection of targets; consistent results; and avoidance of culture bias. However, molecular methods are also subject to limitations that are not always clearly addressed or taken into consideration in the interpretation of scientific data. (continued)

      Core Ideas:
      • Molecular tools target DNA, RNA, or proteins as markers of antibiotic resistance.
      • Molecular tools test for antibiotic resistance potential, not its expression or host.
      • Molecular methods and gene targets must be consistent with research questions.
      • Experimental design, controls, and statistics are important in agroecosystem studies.
      • Need to link molecular data from agroecosystems with human health risk end points.

      doi:10.2134/jeq2015.07.0367
      Published: January 22, 2016



    • Joshua S. Wallace and Diana S. Aga
      Enhancing Extraction and Detection of Veterinary Antibiotics in Solid and Liquid Fractions of Manure

      Analysis of veterinary antibiotics in separated liquid and solid fractions of animal manures is vital because of wide variations in the composition of agriculturally applied manure. Differentiation of antibiotic concentrations is important between liquid and solid manures, as their sorption onto the solid fraction depends on physicochemical properties of each antibiotic and manure composition (e.g., organic content, pH) and because each fraction may be treated and reused differently. Here, an efficient and sensitive method for the analysis of 22 veterinary antibiotics in the liquid and solid fractions of manure is reported. Tetracycline (TC), macrolide, and sulfonamide antibiotics were extracted from liquid manure by liquid–liquid extraction (LLE) with methanol following acidification with acetic acid. (continued)

      Core Ideas:
      • Efficient extraction and sensitive analysis of antibiotics in liquid and solid fractions of manures.
      • Solid–liquid separation allows for targeting of mobile and immobile antibiotic residues.
      • Analytical advances result in improved analyte detection.
      • Insights into analyte chemistry are critical in optimizing analyte extraction and analysis.

      doi:10.2134/jeq2015.05.0246
      Published: January 22, 2016



    • Shanwei Xu, Srinivas Sura, Rahat Zaheer, George Wang, Alanna Smith, Shaun Cook, Andrew F. Olson, Allan J. Cessna, Francis J. Larney and Tim A. McAllister
      Dissipation of Antimicrobial Resistance Determinants in Composted and Stockpiled Beef Cattle Manure

      Windrow composting or stockpiling reduces the viability of pathogens and antimicrobial residues in manure. However, the impact of these manure management practices on the persistence of genes coding for antimicrobial resistance is less well known. In this study, manure from cattle administered 44 mg of chlortetracycline kg−1 feed (dry wt. basis) (CTC), 44 mg of CTC and 44 mg of sulfamethazine kg−1 feed (CTCSMZ), 11 mg of tylosin kg−1 feed (TYL), and no antimicrobials (control) were composted or stockpiled over 102 d. (continued)

      Core Ideas:
      • Dissipation of antimicrobial resistance genes was higher in composted than stockpiled manure.
      • Inclusion of antimicrobials in diet did not increase most anti-microbial resistance genes in manure.
      • Antimicrobials did alter copy numbers of bacteria in manure.
      • Measured genes declined from 0.5 to 3 log in stockpiled and composted manure.

      doi:10.2134/jeq2015.03.0146
      Published: August 28, 2015



    • Lisa M. Durso, David A. Wedin, John E. Gilley, Daniel N. Miller and David B. Marx
      Assessment of Selected Antibiotic Resistances in Ungrazed Native Nebraska Prairie Soils

      The inherent spatial heterogeneity and complexity of antibiotic-resistant bacteria and antibiotic resistance (AR) genes in manure-affected soils makes it difficult to sort out resistance that can be attributed to human antibiotic use from resistance that occurs naturally in the soil. This study characterizes native Nebraska prairie soils that have not been affected by human or food-animal waste products to provide data on background levels of resistance in southeastern Nebraskan soils. Soil samples were collected from 20 sites enumerated on tetracycline and cefotaxime media; screened for tetracycline-, sulfonamide-, β-lactamase–, and macrolide-resistance genes; and characterized for soil physical and chemical parameters. All prairies contained tetracycline- and cefotaxime-resistant bacteria, and 48% of isolates collected were resistant to two or more antibiotics. (continued)

      Core Ideas:
      • Native Nebraska prairie soils have measurable amounts of antibiotic resistance.
      • Phenotypic and genotypic measures of resistance vary within and between sites.
      • Ungrazed prairie soils can provide background data on resistance in Nebraskan soils.
      • Assessments of resistance on farms should include the collection of background data.
      • Background resistance should be considered when measuring impact of management.

      doi:10.2134/jeq2015.06.0280
      Published: December 18, 2015



    • Matti Ruuskanen, Johanna Muurinen, Axel Meierjohan, Katariina Pärnänen, Manu Tamminen, Christina Lyra, Leif Kronberg and Marko Virta
      Fertilizing with Animal Manure Disseminates Antibiotic Resistance Genes to the Farm Environment

      The dissemination of antibiotic resistance genes to the environment is an important factor causing increased prevalence of resistant pathogens. Manure is an important fertilizer, but it contains diverse resistance genes. Therefore, its application to fields may lead to increased abundance of resistance genes in the environment. Farming environments exposed to animal manure have not been studied extensively in countries with comparably low antibiotic use, such as Finland. (continued)

      Core Ideas:
      • Resistance is disseminated from Finnish farms, although the use of antibiotics is limited.
      • The antibiotic resistance genes were more abundant in stored than in fresh manure.
      • Genes encoding carbapenemase were found despite the lack of on-farm use.

      doi:10.2134/jeq2015.05.0250
      Published: December 11, 2015



    • Murugan Subbiah, Shannon M. Mitchell and Douglas R. Call
      Not All Antibiotic Use Practices in Food-Animal Agriculture Afford the Same Risk

      The World Health Organization has identified quinolones, third- and fourth-generation cephalosporins, and macrolides as the most important antibiotics in human medicine. In the context of agricultural use of antibiotics, the principle zoonotic agents of concern are Salmonella enterica, Campylobacter spp., Escherichia coli, and Enterococcus spp. Antibiotic exposure provides a selective advantage to resistant strains of these bacteria relative to their susceptible conspecifics. This is a dose-dependent process, and consequently antibiotic use practices that involve higher doses will exert greater and longer-lasting selective pressure in favor of resistant bacterial populations and will therefore increase the probability of transmission to people and other animals. (continued)

      Core Ideas:
      • The use of antibiotics in agriculture is thought to contribute to antibiotic resistance worldwide.
      • Risk assessment should focus on the largest potential contributors to antibiotic resistance.
      • Antibiotic dose and administration practices are key variables.
      • Excreted antibiotics may play an important role, but not all antibiotics remain active in soil.
      • The use of quinolones in agriculture deserves special scrutiny.

      doi:10.2134/jeq2015.06.0297
      Published: January 4, 2016



    • Stephanie B. Kulesza, Rory O. Maguire, Kang Xia, Julia Cushman, Katharine Knowlton and Partha Ray
      Manure Injection Affects the Fate of Pirlimycin in Surface Runoff and Soil

      Antibiotics used in animal agriculture are of increasing environmental concern due to the potential for increased antibiotic resistance after land application of manure. Manure application technology may affect the environmental behavior of these antibiotics. Therefore, rainfall simulations were conducted on plots receiving three manure treatments (surface application, subsurface injection, and no manure control) to determine the fate and transport of pirlimycin, an antibiotic commonly used in dairy production. Rainfall simulations were conducted immediately and 7 d after application of dairy manure spiked with 128 ng g−1 (wet weight) pirlimycin. (continued)

      Core Ideas:
      • Dairy manure injection reduced pirlimycin in runoff compared with surface application.
      • The majority of pirlimycin lost in runoff was dissolved in runoff water.
      • Dairy manure injection resulted in a slower transformation rate of pirlimycin.

      doi:10.2134/jeq2015.06.0266
      Published: January 4, 2016



    • Kuldip Kumar and Satish C. Gupta
      A Framework to Predict Uptake of Trace Organic Compounds by Plants

      Application of manure, biosolids, and recycled wastewater to croplands could be a potential pathway through which trace organic compounds (TOrCs) may be taken up by food crops. We present a framework to prepare a short list of TOrCs for detailed risk assessment and evaluation in terms of bioaccumulation. The framework was modified from Lipinski’s method to predict drug permeability based on four critical properties: (i) molecular weight (MW); (ii) lipophilicity (expressed as logKow, the octanol–water partition coefficient); (iii) H-bond acceptors; and (iv) H-bond donors. The literature shows that the compounds with MW ranging from 200 to 500 can readily diffuse through mammalian membranes, the uptake of compounds with logKow >5 is hindered, and an excessive number of H-bond donors and H-bond acceptors reduces the permeability across a mammalian membrane bilayer. (continued)

      Core Ideas:
      • The “Rule of 3” is an important tool to predict uptake by crops.
      • Organic chemicals with certain chemical properties may not be taken up by crops.
      • Organic compounds following the “Rule of 3” may be better candidates for phytoremediation.

      doi:10.2134/jeq2015.06.0261
      Published: January 4, 2016



    • Alison M. Franklin, Clinton F. Williams, Danielle M. Andrews, Emily E. Woodward and John E. Watson
      Uptake of Three Antibiotics and an Antiepileptic Drug by Wheat Crops Spray Irrigated with Wastewater Treatment Plant Effluent

      With rising demands on water supplies necessitating water reuse, wastewater treatment plant (WWTP) effluent is often used to irrigate agricultural lands. Emerging contaminants, like pharmaceuticals and personal care products (PPCPs), are frequently found in effluent due to limited removal during WWTP processes. Concern has arisen about the environmental fate of PPCPs, especially regarding plant uptake. The aim of this study was to analyze uptake of sulfamethoxazole, trimethoprim, ofloxacin, and carbamazepine in wheat (Triticum aestivum L.) plants that were spray-irrigated with WWTP effluent. (continued)

      Core Ideas:
      • Wheat plants irrigated with WWTP effluent can take up certain pharmaceuticals.
      • Wheat plant uptake of pharmaceuticals varies based on chemical characteristics.
      • Pharmaceutical uptake in crops raises questions about low-level exposures in humans.

      doi:10.2134/jeq2015.05.0257
      Published: December 3, 2015



    • Terence R. Whitehead and Michael A. Cotta
      Examination of the Aerobic Microflora of Swine Feces and Stored Swine Manure

      Understanding antibiotic resistance in agricultural ecosystems is critical for determining the effects of subtherapeutic and therapeutic uses of antibiotics for domestic animals. This study was conducted to ascertain the relative levels of antibiotic resistance in the aerobic bacterial population to tetracycline, tylosin, and erythromycin. Swine feces and manure samples were plated onto various agar media with and without antibiotics and incubated at 37°C. Colonies were counted daily. (continued)

      Core Ideas:
      • The aerobic microflora of swine feces and manure contain novel bacterial species.
      • Antibiotic-resistant aerobic bacteria are present in swine feces and manure.
      • Tetracycline resistance genes can be identified in the bacterial isolates.
      • Aerobic bacteria contribute to the total antibiotic resistance reservoirs.

      doi:10.2134/jeq2015.05.0248
      Published: December 3, 2015



    • Marilyn C. Roberts and Stefan Schwarz
      Tetracycline and Phenicol Resistance Genes and Mechanisms: Importance for Agriculture, the Environment, and Humans

      Recent reports have speculated on the future impact that antibiotic-resistant bacteria will have on food production, human health, and global economics. This review examines microbial resistance to tetracyclines and phenicols, antibiotics that are widely used in global food production. The mechanisms of resistance, mode of spread between agriculturally and human-impacted environments and ecosystems, distribution among bacteria, and the genes most likely to be associated with agricultural and environmental settings are included. Forty-six different tetracycline resistance (tet) genes have been identified in 126 genera, with tet(M) having the broadest taxonomic distribution among all bacteria and tet(B) having the broadest coverage among the Gram-negative genera. (continued)

      Core Ideas:
      • Updates resistance genes that are important in the environment, agriculture, and humans.
      • Suggests best genes to use for screening the environment.
      • Provides correct nomenclature for tetracycline and phenicol resistance genes.
      • Provides tables that will be useful to researchers.

      doi:10.2134/jeq2015.04.0207
      Published: November 25, 2015



  • SPECIAL SECTION: MOVING DENITRIFYING BIOREACTORS BEYOND PROOF OF CONCEPT

    • William T. Pluer, Larry D. Geohring, Tammo S. Steenhuis and M. Todd Walter
      Controls Influencing the Treatment of Excess Agricultural Nitrate with Denitrifying Bioreactors

      Denitrifying bioreactors have been suggested as effective best management practices to reduce nitrate and nitrite (NOx) in large-scale agricultural tile drainage. This study combines experiments in flow-through laboratory reactors with in situ continuous monitoring and experiments in a pair of field reactors to determine the effectiveness of reactors for small-scale agriculture in New York. It also compares the use of a typical woodchip media with a woodchip and biochar mixture. Laboratory results showed linear increase in NOx removal with both increased inflow concentration and increased residence time. (continued)

      Core Ideas:
      • Flow-through lab reactors show a linear increase in NOx removal with residence time.
      • Lab reactors show a linear increase in NOx removal at higher inflow NOx concentration.
      • Field reactors significantly reduce NOx outflow from tile-drained agriculture in NY.
      • Field reactor experiment results do not follow linear inflow NOx trend found in lab.
      • Biochar amendments show no significant removal of phosphorus in field reactors.

      doi:10.2134/jeq2015.06.0271
      Published: February 12, 2016



    • Owen Fenton, Mark G. Healy, Fiona P. Brennan, Steven F. Thornton, Gary J. Lanigan and Tristan G. Ibrahim
      Holistic Evaluation of Field-Scale Denitrifying Bioreactors as a Basis to Improve Environmental Sustainability

      Denitrifying bioreactors convert nitrate-nitrogen (NO3–N) to di-nitrogen and protect water quality. Herein, the performance of a pilot-scale bioreactor (10 m long, 5 m wide, 2 m deep) containing seven alternating cells filled with either sandy loam soil or lodgepole pine woodchip and with a novel “zig-zag” flow pattern was investigated. The influent water had an average NO3–N concentration of 25 mg L−1. The performance of the bioreactor was evaluated in two scenarios. (continued)

      Core Ideas:
      • Holistic assessment of pilot-scale denitrifying bioreactors highlighted pollution swapping.
      • A sustainability index across two scenarios identified net production or removal of pollutants.
      • A detailed within-bioreactor assessment identified the provenance of losses.
      • Damage cost to the environment and human health assessment justified conversion to a new setup.
      • This approach allows for a holistic assessment and improvement of a denitrifying bioreactor.

      doi:10.2134/jeq2015.10.0500
      Published: February 5, 2016



    • Femke Rambags, Chris C. Tanner, Rebecca Stott and Louis A. Schipper
      Fecal Bacteria, Bacteriophage, and Nutrient Reductions in a Full-Scale Denitrifying Woodchip Bioreactor

      Denitrifying bioreactors using woodchips or other slow-release carbon sources can be an effective method for removing nitrate (NO3) from wastewater and tile drainage. However, the ability of these systems to remove fecal microbes from wastewater has been largely uninvestigated. In this study, reductions in fecal indicator bacteria (Escherichia coli) and viruses (F-specific RNA bacteriophage [FRNA phage]) were analyzed by monthly sampling along a longitudinal transect within a full-scale denitrifying woodchip bioreactor receiving secondary-treated septic tank effluent. Nitrogen, phosphorus, 5-d carbonaceous biochemical oxygen demand (CBOD5), and total suspended solids (TSS) reduction were also assessed. (continued)

      Core Ideas:
      • Denitrifying bioreactors are a technology for nitrate removal from wastewater.
      • We show a full-scale bioreactor can also remove fecal bacteria and viruses.
      • Fecal bacteria and viruses were reduced by >2.9 log10.
      • Median effluent concentration of E. coli was 20 MPN (100 mL)−1.
      • Median effluent concentration of F-specific RNA phage was 3 PFU (100 mL) −1.

      doi:10.2134/jeq2015.06.0326
      Published: January 22, 2016



    • Emily M. Bock, Brady Coleman and Zachary M. Easton
      Effect of Biochar on Nitrate Removal in a Pilot-Scale Denitrifying Bioreactor

      Denitrifying bioreactors (DNBRs) harness the natural capacity of microorganisms to convert bioavailable nitrogen (N) into inert nitrogen gas (N2) by providing a suitable anaerobic habitat and an organic carbon energy source. Woodchip systems are reported to remove 2 to 22 g N m−3 d−1, but the potential to enhance denitrification with alternative substrates holds promise. The objective of this study was to determine the effect of adding biochar, an organic carbon pyrolysis product, to an in-field, pilot-scale woodchip DNBR. Two 25-m3 DNBRs, one with woodchips and the other with woodchips and a 10% by volume addition of biochar, were installed on the Delmarva Peninsula, Virginia. (continued)

      Core Ideas:
      • Novel biochar amendment to denitrifying bioreactor investigated on Delmarva Peninsula.
      • Biochar can enhance N removal in woodchip denitrifying bioreactors.
      • Biochar may also serve as a temporary N sink and mitigate the first flush.

      doi:10.2134/jeq2015.04.0179
      Published: September 18, 2015



    • Mark B. David, Lowell E. Gentry, Richard A. Cooke and Stephanie M. Herbstritt
      Temperature and Substrate Control Woodchip Bioreactor Performance in Reducing Tile Nitrate Loads in East-Central Illinois

      Tile drainage is the major source of nitrate in the upper Midwest, and end-of-tile removal techniques such as wood chip bioreactors have been installed that allow current farming practices to continue, with nitrate removed through denitrification. There have been few multiyear studies of bioreactors examining controls on nitrate removal rates. We evaluated the nitrate removal performance of two wood chip bioreactors during the first 3 yr of operation and examined the major factors that regulated nitrate removal. Bioreactor 2 was subject to river flooding, and performance was not assessed. (continued)

      Core Ideas:
      • Bioreactor performance decreased greatly after Year 1.
      • Tile water temperature was limiting factor as wood chips aged.
      • Little N2O emitted from wood chip bed.
      • Bioreactor would need to be six times larger for this field and nitrate load.

      doi:10.2134/jeq2015.06.0296
      Published: November 25, 2015



    • Natasha L. Hoover, Alok Bhandari, Michelle L. Soupir and Thomas B. Moorman
      Woodchip Denitrification Bioreactors: Impact of Temperature and Hydraulic Retention Time on Nitrate Removal

      Woodchip denitrification bioreactors, a relatively new technology for edge-of-field treatment of subsurface agricultural drainage water, have shown potential for nitrate removal. However, few studies have evaluated the performance of these reactors under varied controlled conditions including initial woodchip age and a range of hydraulic retention times (HRTs) and temperatures similar to the field. This study investigated (i) the release of total organic C (TOC) during reactor start up for fresh and weathered woodchips, (ii) nitrate (NO3–N) removal at HRTs ranging from 2 to 24 h, (iii) nitrate removal at influent NO3–N concentrations of 10, 30, and 50 mg L−1, and (iv) NO3–N removal at 10, 15, and 20°C. Greater TOC was released during bioreactor operation with fresh woodchips, whereas organic C release was low when the columns were packed with naturally weathered woodchips. (continued)

      Core Ideas:
      • The results are useful for informing field-specific design of denitrification woodchip bioreactors.
      • Nitrate-N concentration reductions increased from 8 to 55% as hydraulic retention time increased.
      • Nitrate-N removal showed a stepped increase with temperature.
      • Weathered woodchips as a bioreactor substrate may reduce initial C losses to surface waters.

      doi:10.2134/jeq2015.03.0161
      Published: November 12, 2015



    • Christine Lepine, Laura Christianson, Kata Sharrer and Steven Summerfelt
      Optimizing Hydraulic Retention Times in Denitrifying Woodchip Bioreactors Treating Recirculating Aquaculture System Wastewater

      The performance of wood-based denitrifying bioreactors to treat high-nitrate wastewaters from aquaculture systems has not previously been demonstrated. Four pilot-scale woodchip bioreactors (approximately 1:10 scale) were constructed and operated for 268 d to determine the optimal range of design hydraulic retention times (HRTs) for nitrate removal. The bioreactors were operated under HRTs ranging from 6.6 to 55 h with influent nitrate concentrations generally between 20 and 80 mg NO3 –N L−1. These combinations resulted in N removal rates >39 g N m−3 d−1, which is greater than previously reported. (continued)

      Core Ideas:
      • Woodchip bioreactor design parameters for aquaculture wastewater were developed.
      • This application resulted in the highest N removal rates reported (39 g N m−3 d−1).
      • Retention times differ for optimized removal efficiency versus removal rate.
      • Sulfate reduction intensified under prolonged N-limited environments.

      doi:10.2134/jeq2015.05.0242
      Published: November 12, 2015



  • SURFACE WATER QUALITY

    • Yamen M. Hoque, Shivam Tripathi, Mohamed M. Hantush and Rao S. Govindaraju
      Aggregate Measures of Watershed Health from Reconstructed Water Quality Data with Uncertainty

      Risk-based measures such as reliability, resilience, and vulnerability (R-R-V) have the potential to serve as watershed health assessment tools. Recent research has demonstrated the applicability of such indices for water quality (WQ) constituents such as total suspended solids and nutrients on an individual basis. However, the calculations can become tedious when time-series data for several WQ constituents have to be evaluated individually. Also, comparisons between locations with different sets of constituent data can prove difficult. (continued)

      Core Ideas:
      • Multidimensional WQ data were aggregated into one-dimensional time series.
      • Aggregate data retained information in original data sets; data uncertainty was quantified.
      • Risk-based indices have potential to serve as watershed health assessment tools.
      • Indices calculated from aggregate data and uncertainty showed overall watershed health.

      doi:10.2134/jeq2015.10.0508
      Published: February 12, 2016



  • URBAN POLLUTANTS

    • Lisbeth L. Johannsen, Karin Cederkvist, Peter E. Holm and Simon T. Ingvertsen
      Aluminum Oxide–Coated Sand for Improved Treatment of Urban Stormwater

      Infiltration facilities for urban stormwater runoff, such as biofilters, rain gardens, and curb extensions, typically contain an engineered soil mixture for effective drainage and retention of pollutants. The treatment efficiency of such soils is generally considered high for many pollutants. However, recent studies have revealed that in situ mobilization of soil organic matter may cause leaching of a range of pollutants and therefore diminish the long-term performance of engineered soils. The purpose of this study was to develop and test sand coated with aluminum (Al) oxides for improving the retention of organic matter and a range of common pollutants in engineered soils. (continued)

      Core Ideas:
      • Methodology to coat sand with Al oxides for use in engineered soils was developed.
      • We successfully upscaled coating method to large-scale production.
      • Coating stable toward mechanical stress, NaCl, pH, and redox sensitivity.
      • Coating with Al oxides increased sorption capacity toward DOC significantly.

      doi:10.2134/jeq2015.06.0287
      Published: January 29, 2016



  • WASTE MANAGEMENT

    • Shital Poudyal, Valtcho D. Zheljazkov, Charles L. Cantrell and Thijs Kelleners
      Coal-Bed Methane Water Effects on Dill and Its Essential Oils

      Pumping water from coal seams decreases the pressure in the seam and in turn releases trapped methane; this is the most common and economic method of methane extraction. The water that is pumped out is known as “coal-bed methane water” (CBMW), which is high in sodium and other salts. In the past 25 yr, the United States has seen a 16-fold increase in the production of coal bed methane gas, and trillions of cubic meters are yet to be extracted. There is no sustainable disposal method for CBMW, and there are very few studies investigating the effects of this water on plants and their secondary metabolites and on soil properties. (continued)

      Core Ideas:
      • Coal-bed methane production results in coproduced waste water, also called CBMW.
      • Sustainable disposal of CBMW is a challenge.
      • We determined the effect CBMW on soil and on the biomass and essential oil composition of dill.
      • CBMW increased dill ether but reduced carvone in the oil; biomass and oil yields were not affected.
      • CBMW increased electrical conductivity and Na but not pH or cation exchange capacity.

      doi:10.2134/jeq2015.05.0215
      Published: February 12, 2016



    • Ajaykannan Ilango and Olivier Lefebvre
      Characterizing Properties of Biochar Produced from Simulated Human Feces and Its Potential Applications

      This study presents a comprehensive characterization of biochar obtained from simulated human feces (SHF) with a view to improve human waste sanitization and stabilization before usage as a resource. The possible applications of SHF are as a fuel, as a soil amendment, or for emerging applications (e.g., activated carbon precursor and odor control), depending on the charring conditions. Simulated human feces were charred under different conditions of peak temperature (200–800°C), heating rate (2–50°C min−1), and holding time (0.5–6.0 h); these parameters have been shown to have the largest influence on the thermal and physicochemical characteristics of the final product. The peak temperature was shown to have a higher impact than the heating rate or the holding time. (continued)

      Core Ideas:
      • Biochar was produced successfully from simulated human feces.
      • Maximum energy densification and improved combustion properties achieved at 400°C.
      • Biochar aromatization increased with temperature between 400 and 600°C.
      • Black carbon was obtained at 800°C.
      • Applications are soil amendment (low T), carbon sequestration, and fuel (high T).

      doi:10.2134/jeq2015.07.0397
      Published: January 29, 2016



  • WETLANDS AND AQUATIC PROCESSES

    • D. E. Fenstermacher, M. C. Rabenhorst, M. W. Lang, G. W. McCarty and B. A. Needelman
      Carbon in Natural, Cultivated, and Restored Depressional Wetlands in the Mid-Atlantic Coastal Plain

      Aerial extent of wetland ecosystems has decreased dramatically since precolonial times due to the conversion of these areas for human use. Wetlands provide various ecosystem services, and conservation efforts are being made to restore wetlands and their functions, including soil carbon storage. This Mid-Atlantic Regional USDA Wetland Conservation Effects Assessment Project study was conducted to evaluate the effects and effectiveness of wetland conservation practices along the Mid-Atlantic Coastal Plain. This study examined 48 wetland sites in Delaware, Maryland, Virginia, and North Carolina under natural, prior converted cropland, and 5- to 10-yr post wetland restoration states. (continued)

      Core Ideas:
      • Drainage and conversion of depressional wetlands to agricultural land lower soil C stocks.
      • In RSWs, C levels did not differ significantly from those in prior converted cropland.
      • The scraping/excavation approach to restore wetlands appears to lower C stocks in RSWs.
      • The scraping/excavation technique causes soil compaction, affecting C sequestration rates.
      • Alternate restoration techniques should be used to help assure function of restored wetlands.

      doi:10.2134/jeq2015.04.0186
      Published: February 12, 2016



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