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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. 46(5)



  • DATASETS

    • B. Wu, I. Wiekenkamp, Y. Sun, A. S. Fisher, R. Clough, N. Gottselig, H. Bogena, T. Pütz, N. Brüggemann, H. Vereecken and R. Bol
      A Dataset for Three-Dimensional Distribution of 39 Elements Including Plant Nutrients and Other Metals and Metalloids in the Soils of a Forested Headwater Catchment

      Quantification and evaluation of elemental distribution in forested ecosystems are key requirements to understand element fluxes and their relationship with hydrological and biogeochemical processes in the system. However, datasets supporting such a study on the catchment scale are still limited. Here we provide a dataset comprising spatially highly resolved distributions of 39 elements in soil profiles of a small forested headwater catchment in western Germany (http://teodoor.icg.kfa-juelich.de/ibg3searchportal2/dispatch?searchparams=freetext-Wuestebach&metadata.detail.view.id=7d37ae00-20f6-408e-8660-33bfba07c869) to gain a holistic picture of the state and fluxes of elements in the catchment. The elements include both plant nutrients and other metals and metalloids that were predominately derived from lithospheric or anthropogenic inputs, thereby allowing us to not only capture the nutrient status of the catchment but to also estimate the functional development of the ecosystem. (continued)

      Core Ideas:
      • A dataset of elemental concentrations for four soil horizons of a forested catchment
      • Highly linked with a previous dataset on lateral and vertical distribution of nutrients
      • The dataset can be used to explore biogeochemical elements and their fluxes in natural soil systems

      doi:10.2134/jeq2017.05.0193
      Published: October 5, 2017



  • ENVIRONMENTAL MODELS, MODULES, AND DATASETS

    • Yijun Yao, Fang Mao, Shuaishuai Ma, Yihong Yao, Eric M. Suuberg and Xianjin Tang
      Three-Dimensional Simulation of Land Drains as a Preferential Pathway for Vapor Intrusion into Buildings

      Preferential pathways can be significant vapor intrusion (VI) contributors, causing potentially higher inhalation risk to residents of affected buildings than that arising through traditional intrusion pathways. To assess land drains as a preferential pathway, a three-dimensional model, validated using data from a 4-yr field study, was used to study the roles of subfoundation soil permeability on soil gas flow and indoor depressurization. Results indicated that it is almost impossible for an indirect preferential pathway like a land drain ending in subfoundation soils with a permeability <10−11 m2 to affect indoor air quality if the land drain connects to a source with the same vapor concentration as that of the groundwater source beneath the building. An equation was developed to estimate the threshold permeability. (continued)

      Core Ideas:
      • The influences of land drain depend on subfoundation soil permeability.
      • An equation was developed to estimate the threshold soil permeability.
      • The influences on indoor air may last for months after the pathway is turned off.
      • CPM might cause lower instead of higher indoor concentration.

      doi:10.2134/jeq2017.05.0211
      Published: October 5, 2017



  • ORGANIC COMPOUNDS IN THE ENVIRONMENT

    • Robert S. Dungan, Daniel D. Snow and David L. Bjorneberg
      Occurrence of Antibiotics in an Agricultural Watershed in South-Central Idaho

      The polar organic compound integrative sampler (POCIS) is a tool that has been effectively used to passively sample organic pollutants over long periods in aquatic environments. In this study, POCIS were used to investigate the spatial and temporal occurrence of 21 antibiotics in irrigation return flows and upstream sites of an intensively managed agricultural watershed in south-central Idaho. The antibiotic metabolite, erythromycin-H2O, and the antibiotics monensin, oxytetracycline, sulfadimethoxine, sulfamethazine, sulfamethoxazole, trimethoprim, and tylosin were detected at frequencies ranging from 3.1 to 62.5%, with monensin having the highest rate of detection. The fact that monensin was the most frequently detected compound indicates that it is entering return flows in runoff from fields that had received livestock manure or wastewater. (continued)

      Core Ideas:
      • Passive samplers were used to sequester antibiotics in surface waters.
      • Eight of 21 antibiotics were detected in an intensively managed agricultural watershed.
      • Monensin was the most frequently detected antibiotic (62.5% of samples).
      • Antibiotics detected were associated with both veterinary and human uses.

      doi:10.2134/jeq2017.06.0229
      Published: September 28, 2017



  • SPECIAL SECTION: ENVIRONMENTAL INDICATORS

    • Hongkai Qi, Zhiming Qi, T. Q. Zhang, C. S. Tan and Debasis Sadhukhan
      Modeling Phosphorus Losses through Surface Runoff and Subsurface Drainage Using ICECREAM

      Modeling soil phosphorus (P) losses by surface and subsurface flow pathways is essential in developing successful strategies for P pollution control. We used the ICECREAM model to simultaneously simulate P losses in surface and subsurface flow, as well as to assess effectiveness of field practices in reducing P losses. Monitoring data from a mineral-P-fertilized clay loam field in southwestern Ontario, Canada, were used for calibration and validation. After careful adjustment of model parameters, ICECREAM was shown to satisfactorily simulate all major processes of surface and subsurface P losses. (continued)

      Core Ideas:
      • The ICECREAM model’s first trial simulating P losses in both runoff and drainage.
      • ICECREAM satisfactorily simulated tile drainage and crop P uptake.
      • The model adequately simulated total P loss and its response to P fertilization.
      • Exceptional care should be taken in simulating particulate P under high drainage flow.
      • Spring tillage and fertilizer injection were recommended to reduce P loss.

      doi:10.2134/jeq2017.02.0063
      Published: September 7, 2017



    • Bei Chu and Frieda Eivazi
      Enhanced Dissipation of Selected Herbicides in a Simulated Organic Matrix Biobed: A System to Control On-Farm Point-Source Pollution

      Most farms have a centralized location to fill spray tanks with pesticides and to flush and clean application equipment. These sites, depending on the frequency of use, could be significant sources of surface and groundwater contamination. One approach to minimize this contamination is to install a treatment system, such as a biobed. This study sought to construct a biobed and test the effects of different biomix materials in enhancing the dissipation of herbicides widely used in crop production. (continued)

      Core Ideas:
      • Biobed material composition and ratio were evaluated.
      • The dissipation rates of atrazine and pendimethalin were enhanced in biomixes.
      • Phenol oxidase was higher in peat biomixes than in compost.
      • A mobile, low-cost system was designed to capture contamination on-farm.

      doi:10.2134/jeq2016.04.0124
      Published: December 28, 2016



    • Ying Wang and Nora Fung Yee Tam
      Glutathione–Ascorbate Cycle Is an Early Warning Indicator of Toxicity of BDE-47 in Mangroves

      Mangroves are often exposed to contamination by polybrominated diphenyl ethers (PBDEs) from wastewater discharges and solid waste dumping. As one of the most prevalent and toxic PBDE congeners in the environment, 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) and its oxidative stress deserves more attention. In plants, the glutathione–ascorbate (GSH-AsA) cycle plays an important role in the defensive processes against oxidative stress. However, the importance of this cycle in mangroves to defend against PBDE toxicity has not been reported. (continued)

      Core Ideas:
      • BDE-47 posed oxidative stress to Kandelia obovata seedlings.
      • Leaf and root biomass of K. obovata was suppressed after short BDE-47 exposure.
      • GSH-AsA cycle-related antioxidants changed significantly immediately after exposure.
      • GSH-AsA cycle was a more sensitive indicator to BDE-47 toxicity than growth.
      • AsA and GPx were early warning indicators to PBDE toxicity in mangrove plants.

      doi:10.2134/jeq2016.04.0141
      Published: October 13, 2016



  • SPECIAL SECTION: SYNCHROTRON RADIATION-BASED METHODS FOR ENVIRONMENTAL BIOGEOCHEMISTRY

    • Chammi P. Attanayake, Ganga M. Hettiarachchi, Qing Ma, Gary M. Pierzynski and Michel D. Ransom
      Lead Speciation and In Vitro Bioaccessibility of Compost-Amended Urban Garden Soils

      In situ soil amendments can modify the Pb bioavailability by changing soil Pb speciation. Urban soils from three vegetable gardens containing different total Pb concentrations were used. The study evaluated how compost amendment and aging of soil-compost mixture in situ affected the following: (i) soil Pb speciation in the field and (ii) change of soil Pb speciation during an in vitro bioaccessibility extraction mimicking gastric phase dissolution at pH 2.5. X-ray absorption fine structure spectroscopy was used to determine Pb speciation in amended and nonamended soils and residues left after in vitro bioaccessibility extraction of those soils. (continued)

      Core Ideas:
      • The dominant Pb species in the tested urban soils were Pb-Fh and Pb-Org.
      • The fraction of Pb-Org was increased as soil-compost mixture aged.
      • During the in vitro extraction, Pb-Fh was dissolved, and Pb-Org and HP were formed.
      • aged soil-compost mixture reduced pb-fh dissolution during the in vitro extraction.

      doi:10.2134/jeq2017.02.0065
      Published: September 7, 2017



    • Dean Hesterberg, Ian McNulty and Juergen Thieme
      Speciation of Soil Phosphorus Assessed by XANES Spectroscopy at Different Spatial Scales

      Precise management of soil phosphorus (P) to meet competing demands of agriculture and environmental protection can benefit from more comprehensive characterization of P speciation in soils. Our objectives were to provide spatial context for spectroscopic analyses of soil P speciation in relation to molecular-scale species and landscape-scale management of P, and to compare soil P-species diversity from spectroscopic measurements at submicron and millimeter scales. The spatial range of ∼26 orders of magnitude between atomic and field scales presents a challenge to upscaling and downscaling information from spectroscopic analyses of soils. Scanning fluorescence X-ray microscopy images of a 50-μm × 45-μm area of an organic soil sample showed heterogeneous distributions of P, Al, and Si. (continued)

      Core Ideas:
      • Diverse molecular-scale species of phosphorus occur in a soil.
      • XANES analysis at different scales connects speciation across scales.
      • Microscale XANES spectroscopy analysis improves detection of minor P species.
      • Bulk-sample XANES spectroscopy analyzes major P species in a representative volume.

      doi:10.2134/jeq2016.11.0431
      Published: July 27, 2017



    • Anne-Lise Mariet, Géraldine Sarret, Carole Bégeot, Anne-Véronique Walter-Simonnet and Frédéric Gimbert
      Lead Highly Available in Soils Centuries after Metallurgical Activities

      Lead (Pb)-contaminated sites that resulted from past mining and smelting activities still pose toxicological and ecotoxicological issues worldwide. A large body of research has been dedicated to evaluating the contamination and proposing mitigation strategies for recently contaminated sites (from the 19th century until the present). The possible impact of older contaminations has been much less investigated. The present study focuses on soils affected by Pb-silver mining and smelting activities during the 15th to 18th centuries. (continued)

      Core Ideas:
      • Lead persists in bioavailable form several centuries after waste deposition.
      • Lead was mainly sorbed on Fe-Mn (oxyhydr)oxides.
      • PbS in soil points to the use of slag as a kitchen-garden amendment.

      doi:10.2134/jeq2016.12.0469
      Published: May 18, 2017



    • Olivier Proux, Eric Lahera, William Del Net, Isabelle Kieffer, Mauro Rovezzi, Denis Testemale, Mohammed Irar, Sara Thomas, Antonio Aguilar-Tapia, Elena F. Bazarkina, Alain Prat, Marie Tella, Mélanie Auffan, Jérôme Rose and Jean-Louis Hazemann
      High-Energy Resolution Fluorescence Detected X-Ray Absorption Spectroscopy: A Powerful New Structural Tool in Environmental Biogeochemistry Sciences

      The study of the speciation of highly diluted elements by X-ray absorption spectroscopy (XAS) is extremely challenging, especially in environmental biogeochemistry sciences. Here we present an innovative synchrotron spectroscopy technique: high-energy resolution fluorescence detected XAS (HERFD-XAS). With this approach, measurement of the XAS signal in fluorescence mode using a crystal analyzer spectrometer with a ∼1-eV energy resolution helps to overcome restrictions on sample concentrations that can be typically measured with a solid-state detector. We briefly describe the method, from both an instrumental and spectroscopic point of view, and emphasize the effects of energy resolution on the XAS measurements. (continued)

      Core Ideas:
      • Study shows high-resolution spectroscopic data for an improved speciation determination.
      • Speciation of trace elements down and below the μg g−1 level is shown.
      • Measurements are made in vivo or at natural concentration.

      doi:10.2134/jeq2017.01.0023
      Published: May 8, 2017



    • Ryo Sekine, Ezzat R. Marzouk, Maryam Khaksar, Kirk G. Scheckel, John P. Stegemeier, Gregory V. Lowry, Erica Donner and Enzo Lombi
      Aging of Dissolved Copper and Copper-based Nanoparticles in Five Different Soils: Short-term Kinetics vs. Long-term Fate

      With the growing availability and use of copper-based nanomaterials (Cu-NMs), there is increasing concern regarding their release and potential impact on the environment. In this study, the short-term (≤5 d) aging profile and the long-term (135 d) speciation of dissolved Cu, copper oxide, and copper sulfide nanoparticles (CuO-NPs and CuS-NPs) were investigated in five different soils using X-ray absorption spectroscopy. Soil pH was found to strongly influence the short-term chemistry of the Cu-NMs added at 100 mg kg−1 above background. Low pH soils promoted rapid dissolution of CuO-NPs that effectively aligned their behavior to that of dissolved Cu within 3 d. (continued)

      Core Ideas:
      • Short-term reactions of Cu are form (dissolved or nanoparticle) and soil chemistry dependent.
      • In low pH soils, CuO-NPs dissolved rapidly and behaved similarly to dissolved Cu.
      • CuO-NPs persisted longer in alkaline soils and soils with high organic matter content.
      • In the long term, Cu, CuO-NPs, and CuS-NPs transform into Cu bound to FeO(OH) or NOM.
      • Chemical fate of Cu added to soils is largely independent of the original Cu form.

      doi:10.2134/jeq2016.12.0485
      Published: May 8, 2017



    • Jason W. Stuckey, Jianjun Yang, Jian Wang and Donald L. Sparks
      Advances in Scanning Transmission X-Ray Microscopy for Elucidating Soil Biogeochemical Processes at the Submicron Scale

      Organic matter, minerals, and microorganisms are spatially associated in complex organo-mineral assemblages within soils. A mechanistic understanding of processes occurring within organo-mineral assemblages requires noninvasive techniques that minimize any disturbance to the physical and chemical integrity of the sample. Synchrotron-based soft (50–2200 eV) X-ray spectromicroscopic techniques, including scanning transmission X-ray microscopy (STXM), transmission X-ray microscopy (TXM), X-ray photoemission electron microscopy (X-PEEM), and scanning photoelectron microscopy (SPEM), coupled with microspectroscopy (e.g., near-edge X-ray absorption fine structure; NEXAFS) allow for determining the spatial association and speciation of most elements found in soils while maintaining sample integrity. (continued)

      Core Ideas:
      • Analysis of soil processes requires techniques able to speciate light and heavy elements.
      • STXM-NEXAFS determines the speciation of spatially associated light and heavy elements.
      • STXM-NEXAFS enables elucidation of microaggregate and biomineral formation mechanisms.
      • Advances in synchrotron-based STXM will allow for wavelength-limited spatial resolution.

      doi:10.2134/jeq2016.10.0399
      Published: April 13, 2017



    • Stephen R. Sutton, Antonio Lanzirotti, Matthew Newville, Mark L. Rivers, Peter Eng and Liliana Lefticariu
      Spatially Resolved Elemental Analysis, Spectroscopy and Diffraction at the GSECARS Sector at the Advanced Photon Source

      X-ray microprobes (XRM) coupled with high-brightness synchrotron X-ray facilities are powerful tools for environmental biogeochemistry research. One such instrument, the XRM at the Geo Soil Enviro Center for Advanced Radiation Sources Sector 13 at the Advanced Photon Source (APS; Argonne National Laboratory, Lemont, IL) was recently improved as part of a canted undulator geometry upgrade of the insertion device port, effectively doubling the available undulator beam time and extending the operating energy of the branch supporting the XRM down to the sulfur K edge (2.3 keV). Capabilities include rapid, high-resolution, elemental imaging including fluorescence microtomography, microscale X-ray absorption fine structure spectroscopy including sulfur K edge capability, and microscale X-ray diffraction. These capabilities are advantageous for (i) two-dimensional elemental mapping of relatively large samples at high resolution, with the dwell times typically limited only by the count times needed to obtain usable counting statistics for low concentration elements, (ii) three-dimensional imaging of internal elemental distributions in fragile hydrated specimens, such as biological tissues, avoiding the need for physical slicing, (iii) spatially resolved speciation determinations of contaminants in environmental materials, and (iv) identification of contaminant host phases. (continued)

      Core Ideas:
      • X-ray microprobes are powerful tools for environmental biogeochemistry.
      • Upgraded GSECARS XRM operates down to the sulfur K edge.
      • Capabilities: spatially resolved elemental analysis, spectroscopy, and diffraction.
      • Advanced Photon Source upgrade will further advance XRM capabilities.

      doi:10.2134/jeq2016.10.0401
      Published: February 23, 2017



    • Ranju R. Karna, Matt Noerpel, Aaron R. Betts and Kirk G. Scheckel
      Lead and Arsenic Bioaccessibility and Speciation as a Function of Soil Particle Size

      Bioavailability research of soil metals has advanced considerably from default values to validated in vitro bioaccessibility (IVBA) assays for site-specific risk assessment. Previously, USEPA determined that the soil-size fraction representative of dermal adherence and consequent soil ingestion was <250 μm. This size fraction was widely used in testing efforts for both in vivo and in vitro experiments. However, recent studies indicate the <150-μm size fraction better represents the particle size that adheres to skin for potential ingestion. (continued)

      Core Ideas:
      • Identified critical knowledge gaps regarding the <250-μm vs. <150-μm particle size used for IVBA.
      • Wider implementation of the <150-μm size fraction maintains past validation with <-250 μm fraction.
      • Regardless of increase in total and extractable Pb and As, %IVBA results remained consistent.
      • Using <150-μm particle size for IVBA requires much higher volumes/masses of soils.
      • Synchrotron-based speciation is significant in bioavailability studies to understand the fate and transport of contaminants.

      doi:10.2134/jeq2016.10.0387
      Published: February 23, 2017



    • Marina Colzato, Marcos Y. Kamogawa, Hudson W.P. Carvalho, Luís R.F. Alleoni and Dean Hesterberg
      Temporal Changes in Cadmium Speciation in Brazilian Soils Evaluated Using Cd L III –Edge XANES and Chemical Fractionation

      Chemical speciation of soil cadmium (Cd) dictates its mobility and potential toxicity in the environment. Our objective was to compare temporal changes in speciation of Cd(II) reacted with samples from six Brazilian soils having varying Cd(II) sorption capacities. Cadmium LIII–edge X-ray absorption near edge structure (XANES) analysis showed there were short-term changes in speciation after reaction with 4.45 mmol Cd kg−1 for 0.5 and 6 h. Chemical fractionation evaluated changes in Cd extractability after reaction with 89 μmol Cd kg−1 for up to 4 mo. (continued)

      Core Ideas:
      • Cadmium speciation showed weak and variable evidence for temporal changes.
      • No evidence for progressive natural attenuation of soil cadmium was found.
      • Cadmium(II) bonded preferentially with soil organic matter and oxide minerals.

      doi:10.2134/jeq2016.08.0316
      Published: February 2, 2017



    • Peter M Kopittke, Peng Wang, Enzo Lombi and Erica Donner
      Synchrotron-based X-Ray Approaches for Examining Toxic Trace Metal(loid)s in Soil–Plant Systems

      Elevated levels of trace metal(loid)s reduce plant growth, both in soils contaminated by industrial activities and in acid agricultural soils. Although the adverse effects of trace metal(loid)s have long been recognized, there remains much unknown both about their behavior in soils, their toxicity to plants, and the mechanisms that plants use to tolerate elevated concentrations. Synchrotron-based approaches are being utilized increasingly in soil–plant systems to examine toxic metal(loid)s. In the present review, brief consideration is given to the theory of synchrotron radiation. (continued)

      Core Ideas:
      • Synchrotron analyses allow in situ analyses of metal(loid)s in soils and plants.
      • This review provides a brief introduction to the theory of synchrotron radiation.
      • The distribution and speciation of metal(loid)s in soils and plants is reviewed.

      doi:10.2134/jeq2016.09.0361
      Published: February 2, 2017



  • SPECIAL SECTION: THE EVOLVING SCIENCE OF PHOSPHORUS SITE ASSESSMENT

    • Tamie L. Veith, Sarah C. Goslee, Doug B. Beegle, Jennifer L. Weld and Peter J. A. Kleinman
      Analyzing Within-County Hydrogeomorphological Characteristics as a Precursor to Phosphorus Index Modifications

      Phosphorus (P) site assessment is used nationally and internationally to assess the vulnerability of agricultural fields to P loss and identify high-risk areas controlling watershed P export. Current efforts to update P site assessment tools must ensure that these tools are representative of the range of conditions to which they will be applied. We sought to identify key parameters available in public GIS data that are descriptive of potential source areas in Pennsylvania and that ensure that modifications of the P Index span all feasible parameter combinations. Relevant soil and topographic variables were compiled for Pennsylvania at 30-m resolution, and areas within 90 m of permanent streams were extracted. (continued)

      Core Ideas:
      • Hydraulic properties and organic matter are key for grouping near-stream soils.
      • Discontinuities across soil surveys prevent modeling regions across counties.
      • Two to five groups per county are sufficient to classify most near-stream soils.
      • Cluster analysis of environmental data provides a focus for revising the P Index.

      doi:10.2134/jeq2016.10.0416
      Published: August 10, 2017



    • Andrew Sharpley, Peter Kleinman, Claire Baffaut, Doug Beegle, Carl Bolster, Amy Collick, Zachary Easton, John Lory, Nathan Nelson, Deanna Osmond, David Radcliffe, Tamie Veith and Jennifer Weld
      Evaluation of Phosphorus Site Assessment Tools: Lessons from the USA

      Critical source area identification through phosphorus (P) site assessment is a fundamental part of modern nutrient management planning in the United States, yet there has been only sparse testing of the many versions of the P Index that now exist. Each P site assessment tool was developed to be applicable across a range of field conditions found in a given geographic area, making evaluation extremely difficult. In general, evaluation with in-field monitoring data has been limited, focusing primarily on corroborating manure and fertilizer “source” factors. Thus, a multiregional effort (Chesapeake Bay, Heartland, and Southern States) was undertaken to evaluate P Indices using a combination of limited field data, as well as output from simulation models (i.e., Agricultural Policy Environmental eXtender, Annual P Loss Estimator, Soil and Water Assessment Tool [SWAT], and Texas Best Management Practice Evaluation Tool [TBET]) to compare against P Index ratings. (continued)

      Core Ideas:
      • Concern over the accuracy of P Indices has led to calls for their evaluation.
      • Insufficient field data exist to evaluate P site assessment tools comprehensively.
      • Researchers can use nonpoint source models as surrogates to field data if vetted first.
      • There is no scientific justification for a single national P Index.

      doi:10.2134/jeq2016.11.0427
      Published: August 3, 2017



    • Amy L. Shober, Anthony R. Buda, Kathryn C. Turner, Nicole M. Fiorellino, A. Scott Andres, Joshua M. McGrath and J. Thomas Sims
      Assessing Coastal Plain Risk Indices for Subsurface Phosphorus Loss

      Phosphorus (P) Index evaluations are critical to advancing nutrient management planning in the United States. However, most assessments until now have focused on the risks of P losses in surface runoff. In artificially drained agroecosystems of the Atlantic Coastal Plain, subsurface flow is the predominant mode of P transport, but its representation in most P Indices is often inadequate. We explored methods to evaluate the subsurface P risk routines of five P Indices from Delaware, Maryland (two), Virginia, and North Carolina using available water quality and soils datasets. (continued)

      Core Ideas:
      • We evaluated subsurface P routines of five P Indices in artificially drained soils.
      • Subsurface P ratings mostly accorded with P loads in leachate and ditch drainage.
      • Water extractable P at the seasonal high water table was a proxy for ditch P loss.
      • Useful P Index predictions hinged on accurate depictions of subsurface water flux.
      • Increased monitoring and modeling of subsurface P loss is needed to test P Indices.

      doi:10.2134/jeq2017.03.0102
      Published: July 20, 2017



    • Deanna Osmond, Carl Bolster, Andrew Sharpley, Miguel Cabrera, Sam Feagley, Adam Forsberg, Charles Mitchell, Rao Mylavarapu, J. Larry Oldham, David E. Radcliffe, John J. Ramirez-Avila, Dan E. Storm, Forbes Walker and Hailin Zhang
      Southern Phosphorus Indices, Water Quality Data, and Modeling (APEX, APLE, and TBET) Results: A Comparison

      Phosphorus (P) Indices in the southern United States frequently produce different recommendations for similar conditions. We compared risk ratings from 12 southern states (Alabama, Arkansas, Florida, Georgia, Kentucky, Louisiana, Mississippi, North Carolina, Oklahoma, South Carolina, Tennessee, and Texas) using data collected from benchmark sites in the South (Arkansas, Georgia, Mississippi, North Carolina, Oklahoma, and Texas). Phosphorus Index ratings were developed using both measured erosion losses from each benchmark site and Revised Universal Soil Loss Equation 2 predictions; mostly, there was no difference in P Index outcome. The derived loss ratings were then compared with measured P loads at the benchmark sites by using equivalent USDA–NRCS P Index ratings and three water quality models (Annual P Loss Estimator [APLE], Agricultural Policy Environmental eXtender [APEX], and Texas Best Management Practice Evaluation Tool [TBET]). (continued)

      Core Ideas:
      • Southern region P Indices estimate P losses as well as water quality models.
      • APLE and TBET P-loss predictions were more similar than were results from APEX.
      • Assigning potential P-loss risk from P Indices to any given water resource is challenging.

      doi:10.2134/jeq2016.05.0200
      Published: July 20, 2017



    • Claire Baffaut, Nathan O. Nelson, John A. Lory, G.M.M.M. Anomaa Senaviratne, Ammar B. Bhandari, Ranjith P. Udawatta, Daniel W. Sweeney, Matt J. Helmers, Mike W. Van Liew, Antonio P. Mallarino and Charles S. Wortmann
      Multisite Evaluation of APEX for Water Quality: I. Best Professional Judgment Parameterization

      The Agricultural Policy Environmental eXtender (APEX) model is capable of estimating edge-of-field water, nutrient, and sediment transport and is used to assess the environmental impacts of management practices. The current practice is to fully calibrate the model for each site simulation, a task that requires resources and data not always available. The objective of this study was to compare model performance for flow, sediment, and phosphorus transport under two parameterization schemes: a best professional judgment (BPJ) parameterization based on readily available data and a fully calibrated parameterization based on site-specific soil, weather, event flow, and water quality data. The analysis was conducted using 12 datasets at four locations representing poorly drained soils and row-crop production under different tillage systems. (continued)

      Core Ideas:
      • Uncalibrated, APEX produced unacceptable site-specific sediment and TP estimates.
      • Acceptable runoff estimates do not translate to acceptable water quality estimates.
      • Distributions of successfully calibrated performance indicator values were normal.
      • Calibration of the APEX model with water quality data remains an essential step.

      doi:10.2134/jeq2016.06.0226
      Published: April 13, 2017



    • Zachary M. Easton, Peter J.A. Kleinman, Anthony R. Buda, Dustin Goering, Nichole Emberston, Seann Reed, Patrick J. Drohan, M. Todd Walter, Pat Guinan, John A. Lory, Andrew R. Sommerlot and Andrew Sharpley
      Short-term Forecasting Tools for Agricultural Nutrient Management

      The advent of real-time, short-term farm management tools is motivated by the need to protect water quality above and beyond the general guidance offered by existing nutrient management plans. Advances in high-performance computing and hydrologic or climate modeling have enabled rapid dissemination of real-time information that can assist landowners and conservation personnel with short-term management planning. This paper reviews short-term decision support tools for agriculture that are under various stages of development and implementation in the United States: (i) Wisconsin’s Runoff Risk Advisory Forecast (RRAF) System, (ii) New York’s Hydrologically Sensitive Area Prediction Tool, (iii) Virginia’s Saturated Area Forecast Model, (iv) Pennsylvania’s Fertilizer Forecaster, (v) Washington’s Application Risk Management (ARM) System, and (vi) Missouri’s Design Storm Notification System. Although these decision support tools differ in their underlying model structure, the resolution at which they are applied, and the hydroclimates to which they are relevant, all provide forecasts (range 24–120 h) of runoff risk or soil moisture saturation derived from National Weather Service Forecast models. (continued)

      Core Ideas:
      • Advances in weather forecasting, data management, and modeling improve nutrient management.
      • New tools facilitate improved farm decisions in response to real-time weather.
      • Nutrient management can be performed operationally and strategically with real-time tools.

      doi:10.2134/jeq2016.09.0377
      Published: April 13, 2017



    • Nathan O. Nelson, Claire Baffaut, John A. Lory, G.M.M.M. Anomaa Senaviratne, Ammar B. Bhandari, Ranjith P. Udawatta, Daniel W. Sweeney, Matt J. Helmers, Mike W. Van Liew, Antonio P. Mallarino and Charles S. Wortmann
      Multisite Evaluation of APEX for Water Quality: II. Regional Parameterization

      Phosphorus (P) Index assessment requires independent estimates of long-term average annual P loss from fields, representing multiple climatic scenarios, management practices, and landscape positions. Because currently available measured data are insufficient to evaluate P Index performance, calibrated and validated process-based models have been proposed as tools to generate the required data. The objectives of this research were to develop a regional parameterization for the Agricultural Policy Environmental eXtender (APEX) model to estimate edge-of-field runoff, sediment, and P losses in restricted-layer soils of Missouri and Kansas and to assess the performance of this parameterization using monitoring data from multiple sites in this region. Five site-specific calibrated models (SSCM) from within the region were used to develop a regionally calibrated model (RCM), which was further calibrated and validated with measured data. (continued)

      Core Ideas:
      • Regionally calibrated APEX produced very good estimates of site-specific runoff.
      • Regionally calibrated APEX failed to adequately estimate sediment loss.
      • Regionally calibrated APEX P-loss estimates were worse than site-specific models.
      • APEX runoff estimates are adequate for rigorous evaluation of P Index runoff components.
      • APEX sediment loss estimates are unsuitable for evaluation of P Index.

      doi:10.2134/jeq2016.07.0254
      Published: March 30, 2017



    • Quirine M. Ketterings, Sebastian Cela, Amy S. Collick, Stephen J. Crittenden and Karl J. Czymmek
      Restructuring the P Index to Better Address P Management in New York

      The New York Phosphorus Index (NY-PI) was introduced in 2001 after the release of the state’s first Concentrated Animal Feeding Operation (CAFO) Permit that required a nutrient management plan developed in accordance with NRCS standards. The stakeholder-based approach to development of the NY-PI, combined with a requirement for all regulated farms to determine a NY-PI score for all fields, ensured widespread adoption. While P management greatly improved over time, the initial NY-PI overemphasized soil-test P (STP), allowing for P addition if STP was low, even if the risk of P transport was high. Our goal was to develop a new PI approach that incentivizes implementation of best management practices (BMPs) where P-transport risk is high, building on feedback from certified planners (survey), analysis of a planner-supplied 33,000+ field database with NY-PI information, and modeling of the impacts of specific BMPs on P runoff using data from a central NY CAFO farm. (continued)

      Core Ideas:
      • Stakeholder engagement is essential to develop improved Phosphorus Indices (PIs).
      • A “Transport × BMP”-based PI incentivizes BMP use where risk of P transport is high.
      • In a “Transport × BMP”-based PI, soil-test P sets rate limits to enhance P balances.
      • A “Transport × BMP”-based PI can reduce barriers to regionalization of PIs within watersheds.

      doi:10.2134/jeq2016.05.0185
      Published: March 2, 2017



    • Carl H. Bolster, Adam Forsberg, Aaron Mittelstet, David E. Radcliffe, Daniel Storm, John Ramirez-Avila, Andrew N. Sharpley and Deanna Osmond
      Comparing an Annual and a Daily Time-Step Model for Predicting Field-Scale Phosphorus Loss

      A wide range of mathematical models are available for predicting phosphorus (P) losses from agricultural fields, ranging from simple, empirically based annual time-step models to more complex, process-based daily time-step models. In this study, we compare field-scale P-loss predictions between the Annual P Loss Estimator (APLE), an empirically based annual time-step model, and the Texas Best Management Practice Evaluation Tool (TBET), a process-based daily time-step model based on the Soil and Water Assessment Tool. We first compared predictions of field-scale P loss from both models using field and land management data collected from 11 research sites throughout the southern United States. We then compared predictions of P loss from both models with measured P-loss data from these sites. (continued)

      Core Ideas:
      • We compared predictions of P loss between an empirically-based and process-based model.
      • Predictions from both models were well correlated with each other.
      • The process-based model did not result in noticeably better predictions of P loss.
      • APLE predicted greater DP loss and TBET predicted greater PP loss.
      • Results indicate the need for improving accuracy of both models.

      doi:10.2134/jeq2016.04.0159
      Published: January 19, 2017



    • Peter A. Vadas, Laura W. Good, William E. Jokela, K.G. Karthikeyan, Francisco J. Arriaga and Melanie Stock
      Quantifying the Impact of Seasonal and Short-term Manure Application Decisions on Phosphorus Loss in Surface Runoff

      Agricultural phosphorus (P) management is a research and policy issue due to P loss from fields and water quality degradation. Better information is needed on the risk of P loss from dairy manure applied in winter or when runoff is imminent. We used the SurPhos computer model and 108 site–years of weather and runoff data to assess the impact of these two practices on dissolved P loss. Model results showed that winter manure application can increase P loss by 2.5 to 3.6 times compared with non-winter applications, with the amount increasing as the average runoff from a field increases. (continued)

      Core Ideas:
      • Winter application of dairy manure can significantly increase P loss in surface runoff.
      • Producers have few options to reduce P manure loss by avoiding near-term runoff.
      • Models can help quantify the effect of management on manure P loss in runoff.

      doi:10.2134/jeq2016.06.0220
      Published: January 19, 2017



    • David B. Baker, Laura T. Johnson, Remegio B. Confesor and John P. Crumrine
      Vertical Stratification of Soil Phosphorus as a Concern for Dissolved Phosphorus Runoff in the Lake Erie Basin

      During the re-eutrophication of Lake Erie, dissolved reactive phosphorus (DRP) loading and concentrations to the lake have nearly doubled, while particulate phosphorus (PP) has remained relatively constant. One potential cause of increased DRP concentrations is P stratification, or the buildup of soil-test P (STP) in the upper soil layer (<5 cm). Stratification often accompanies no-till and mulch-till practices that reduce erosion and PP loading, practices that have been widely implemented throughout the Lake Erie Basin. To evaluate the extent of P stratification in the Sandusky Watershed, certified crop advisors were enlisted to collect stratified soil samples (0–5 or 0–2.5 cm) alongside their normal agronomic samples (0–20 cm) (n = 1758 fields). (continued)

      Core Ideas:
      • P stratification increases surficial soil-test levels by 55% over agronomic cores.
      • Agronomic soil-test levels are not good indicators of surficial soil-test levels.
      • Soils in maintenance range account for the largest proportion of DRP runoff risks.
      • Targeted stratification reduction could reduce DRP runoff more than drawdown.
      • Stratification reduction could reduce DRP runoff more quickly than drawdown.

      doi:10.2134/jeq2016.09.0337
      Published: January 19, 2017



    • Ammar B. Bhandari, Nathan O. Nelson, Daniel W. Sweeney, Claire Baffaut, John A. Lory, Anomaa Senaviratne, Gary M. Pierzynski, Keith A. Janssen and Philip L. Barnes
      Calibration of the APEX Model to Simulate Management Practice Effects on Runoff, Sediment, and Phosphorus Loss

      Process-based computer models have been proposed as a tool to generate data for Phosphorus (P) Index assessment and development. Although models are commonly used to simulate P loss from agriculture using managements that are different from the calibration data, this use of models has not been fully tested. The objective of this study is to determine if the Agricultural Policy Environmental eXtender (APEX) model can accurately simulate runoff, sediment, total P, and dissolved P loss from 0.4 to 1.5 ha of agricultural fields with managements that are different from the calibration data. The APEX model was calibrated with field-scale data from eight different managements at two locations (management-specific models). (continued)

      Core Ideas:
      • The APEX model has limited ability to simulate effects of changing management.
      • If available, multiple management should be used to calibrate and validate the model.
      • Policy makers must exercise caution in using model-estimated P losses to evaluate PIs.

      doi:10.2134/jeq2016.07.0272
      Published: December 15, 2016



    • William I. Ford, Kevin W. King, Mark R. Williams and Remegio B. Confesor Jr.
      Modified APEX model for Simulating Macropore Phosphorus Contributions to Tile Drains

      The contribution of macropore flow to phosphorus (P) loadings in tile-drained agricultural landscapes remains poorly understood at the field scale, despite the recognized deleterious impacts of contaminant transport via macropore pathways. A new subroutine that couples existing matrix-excess and matrix-desiccation macropore flow theory and a modified P routine is implemented in the Agricultural Policy Environmental eXtender (APEX) model. The original and modified formulation were applied and evaluated for a case study in a poorly drained field in Western Ohio with 31 months of surface and subsurface monitoring data. Results highlighted that a macropore subroutine in APEX improved edge-of-field discharge calibration and validation for both tile and total discharge from satisfactory and good, respectively, to very good and improved dissolved reactive P load calibration and validation statistics for tile P loads from unsatisfactory to very good. (continued)

      Core Ideas:
      • The field-scale APEX model is modified to account for macropore P contributions.
      • APEX modifications significantly improve hydrology and P simulations for a case study.
      • Macropore flow contributes approximately 48% of flow and 43% of P annually.
      • The model has potential for informing pathway partitioning in P site assessment tools.

      doi:10.2134/jeq2016.06.0218
      Published: December 1, 2016



    • Alisha Spears Mulkey, Frank J. Coale, Peter A. Vadas, Gary W. Shenk and Gopal X. Bhatt
      Revised Method and Outcomes for Estimating Soil Phosphorus Losses from Agricultural Land in the Chesapeake Bay Watershed Model

      Current restoration efforts for the Chesapeake Bay watershed mandate a timeline for reducing the load of nutrients and sediment into receiving waters. The Chesapeake Bay watershed model (WSM) has been used for two decades to simulate hydrology and nutrient and sediment transport; however, spatial limitations of the WSM preclude edge-of-field scale representation of phosphorus (P) losses. Rather, the WSM relies on literature-derived, county-scale rates of P loss (targets) for simulated land uses. An independent field-scale modeling tool, Annual Phosphorus Loss Estimator (APLE), was used as an alternative to the current WSM approach. (continued)

      Core Ideas:
      • APLE estimated P losses were compared with the Chesapeake Bay Watershed Model’s (WSM) losses.
      • Substituting the APLE estimated P loss into the WSM improved calibration performance.
      • Findings suggest the importance of well-estimated transport factors in modeling P losses.

      doi:10.2134/jeq2016.05.0201
      Published: October 6, 2016



    • Mark R. Williams, Kevin W. King, Gregory A. LaBarge, Remegio B. Confesor Jr. and Norman R. Fausey
      Edge-Of-Field Evaluation of the Ohio Phosphorus Risk Index

      The Phosphorus Index (PI) has been the cornerstone for phosphorus (P)-based management and planning over the past twenty years, yet field-scale evaluation of many state PIs has been limited. In this study, P loads measured in surface runoff and tile discharge from 40 agricultural fields in Ohio with prevailing management practices were used to evaluate the Ohio PI. Annual P loads were highly variable among fields (dissolved reactive P: 0.03–4.51 kg ha−1, total P: 0.03–6.88 kg ha−1). Both measured annual dissolved reactive P (R2 = 0.36, p < 0.001) and total P (R2 = 0.25, p < 0.001) loads were significantly related to Ohio PI score. (continued)

      Core Ideas:
      • Measured P loads from 40 fields were used to evaluate the Ohio Phosphorus Index.
      • Risk of P loss was linearly related to both measured annual and averaged P loads.
      • Field P management recommendations varied among local, state, and national metrics.
      • Field datasets should be used to improve and calibrate the Ohio Phosphorus Index.

      doi:10.2134/jeq2016.05.0198
      Published: September 15, 2016



    • Adam Forsberg, David E. Radcliffe, Carl H. Bolster, Aaron Mittelstet, Daniel E. Storm and Deanna Osmond
      Evaluation of the TBET Model for Potential Improvement of Southern P Indices

      Due to a shortage of available phosphorus (P)-loss datasets, simulated data from an accurate quantitative P transport model could be used to evaluate a P Index. The objective of this study was to compare predictions from the Texas Best Management Practice Evaluation Tool (TBET) against measured P-loss data to determine whether the model could be used to improve P Indices in the southern region. Measured P-loss data from field-scale study sites in Arkansas, Georgia, and North Carolina were used to assess the accuracy of TBET for predicting field-scale loss of P. We found that event-based predictions using an uncalibrated model were generally poor. (continued)

      Core Ideas:
      • Predictions from an accurate P transport model could be used to evaluate a P Index.
      • Predictions from an uncalibrated TBET model were generally poor.
      • A calibrated TBET model was better but did not meet the performance criteria.
      • A curve number approach for runoff could be incorporated into P Indices.

      doi:10.2134/jeq2016.06.0210
      Published: January 19, 2017January 19, 2017



  • THE EVOLVING SCIENCE OF PHOSPHORUS SITE ASSESSMENT

    • Nicole M. Fiorellino, Joshua M. McGrath, Peter A. Vadas, Carl H. Bolster and Frank J. Coale
      Use of Annual Phosphorus Loss Estimator (APLE) Model to Evaluate a Phosphorus Index

      The Phosphorus (P) Index was developed to provide a relative ranking of agricultural fields according to their potential for P loss to surface water. Recent efforts have focused on updating and evaluating P Indices against measured or modeled P loss data to ensure agreement in magnitude and direction. Following a recently published method, we modified the Maryland P Site Index (MD-PSI) from a multiplicative to a component index structure and evaluated the MD-PSI outputs against P loss data estimated by the Annual P Loss Estimator (APLE) model, a validated, field-scale, annual P loss model. We created a theoretical dataset of fields to represent Maryland conditions and scenarios and created an empirical dataset of soil samples and management characteristics from across the state. (continued)

      Core Ideas:
      • Our methods expanded upon methods developed by Bolster to modify and evaluate PIs.
      • Our methods provide practical guidance to other states for modification of PIs.
      • A theoretical dataset was simulated to represent geographical conditions in Maryland.
      • Removal of categorical variables and weights increased PI and P loss correlation.
      • Fertilizer and subsurface components should be evaluated like surface components.

      doi:10.2134/jeq2016.05.0203
      Published: May 8, 2017



  • VADOSE ZONE PROCESSES AND CHEMICAL TRANSPORT

    • Muhammad Emdadul Haque, Chongyang Shen, Tiantian Li, Haoxue Chu, Hong Wang, Zhen Li and Yuanfang Huang
      Influence of Biochar on Deposition and Release of Clay Colloids in Saturated Porous Media

      Although the potential application of biochar in soil remediation has been recognized, the effect of biochar on the transport of clay colloids, and accordingly the fate of colloid-associated contaminants, is unclear to date. This study conducted saturated column experiments to systematically examine transport of clay colloids in biochar-amended sand porous media in different electrolytes at different ionic strengths. The obtained breakthrough curves were simulated by the convection–diffusion equation, which included a first-order deposition and release terms. The deposition mechanisms were interpreted by calculating Derjaguin–Landau–Verwey–Overbeek interaction energies. (continued)

      Core Ideas:
      • We examined the transport of clay colloids in biochar-amended sand porous media.
      • Clay colloids were more favorably deposited in biochar than in sand.
      • The half-tube-like cavities on biochar surfaces favor deposition in secondary minima.
      • Core Ideas Clay colloids were reversibly and irreversibly deposited in biochar in 1:1 and 2:1 electrolytes, respectively.

      doi:10.2134/jeq2017.06.0223
      Published: September 28, 2017



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