bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differences Between New and Long-Standing US Gun Owners: Results From a National Survey
Authors: Wertz Joseph , Azrael Deborah , Hemenway David , Sorenson Susan , Miller Matthew 
Published: May 2018

Objectives. To quantify the proportion of current US gun owners who are new to owning firearms and compare new versus long-standing gun owners with respect to their firearms and firearm-related behaviors. Methods. We performed a cross-sectional analysis of a nationally representative probability-based online survey conducted in 2015 in the United States. We defined new gun owners as current firearm owners who acquired all of their firearms within the past 5 years, but who lived in a home without a gun at some time over the past 5 years. We defined long-standing firearm owners as all other current gun owners. Results. New gun owners represented 10% of all current US adult gun owners. In addition to being younger than long-standing gun owners, new gun owners were more likely to be liberal, own fewer guns, own handguns, own guns only for protection, and store guns in a safe manner. Conclusions. Gun ownership is dynamic, with approximately 1 million Americans becoming new gun owners each year. Public Health Implications. Clinical guidelines should be updated to explicitly endorse re-evaluating household firearm status at regular intervals.
Models of Thermal Enhanced Oil Recovery in Fractured Reservoirs
Authors: Ziegler V. M. 
Published: May 2018

Summary
Models for steam or hot-water injection into a fractured diatomite or shale reservoir are developed from existing analytic models of energy transport and countercurrent imbibition.
Radial convective heat flow through a horizontal fracture system is modeled with conductive heat flow into the low-permeability matrix. The flow geometry approximates hot-fluid injection into a five-spot pattern. Recovery mechanisms accounted for in the models include capillary imbibition and thermal expansion. Temperature dependence of viscosity and interfacial tension (IFT) are included in the imbibition estimate. Laboratory data are needed to quantify the magnitude of the imbibition mechanism, which is usually the primary contributor to oil recovery. Reservoir properties representative of either the Belridge Diatomite or the Antelope Shale, two giant fractured oil reservoirs, are used for the model forecasts. Currently, however, only temperature-dependent imbibition data for diatomite reservoirs are available.
The steamflood model has been partially validated against a large-scale project in the Belridge Diatomite. By use of public-domain information, a reasonable comparison was obtained between the model and the field project during a 4-year injection period. Comparison with conventional thermal simulation was also performed, and it indicated reasonable agreement with the steamflood analytical model.
The models have been used to determine the key factors determining the success of thermal recovery in fractured, low-permeability reservoirs. Steam injection is shown to be superior to hot-water injection in heating the matrix. Key factors enhancing recovery include reduced fracture spacing, increased matrix permeability, and increased injection temperature. Model results indicate that steamflood recoveries of more than 40% of the original oil in place (OOIP) may be achieved by injection in diatomite containing light oil. Application to diatomites containing heavy oil also shows good performance. Successful application in diatomite reservoirs is forecast to be possible in the current low oil-price environment. Economic application in fractured shales, assuming similar imbibition behavior as in diatomites, would require a higher oil price because of the higher well costs and lower oil content relative to diatomite projects.
Because of the significant volumes of remaining oil in place (OIP) in both the diatomite and shale reservoirs, the application of thermal enhanced oil recovery (EOR) to these resources represents the logical next step in steamflood development.
Hydromulch Application to Bare Soil: Soil Temperature Dynamics and Evaporative Fluxes
Authors: O'Brien Peter L. , Acharya Umesh , Alghamdi Rashad , Niaghi Ali Rashid , Sanyal Debankur , Wirtz Jeremy , Daigh Aaron L. M. , DeSutter Thomas M. 
Published: May 2018

Core Ideas
Hydromulch was applied to disturbed, bare soil at two rates.
Micro‐Bowen ratio systems quantified soil temperature and evaporation.
Hydromulch moderated temperature fluctuations, especially daily maximums.
Hydromulch application reduced evaporation following rainfall.
North Dakota State Univ., Dep. of Soil Science, Fargo, ND 58108.
Soil disturbance reduces plant‐residue cover and can leave bare soil susceptible to erosion, extreme temperature fluctuations, and increased evaporation. Under such conditions, establishing vegetation is difficult. To overcome these difficulties, managing disturbed lands by applying surface cover may be a good step toward soil reclamation. Hydromulch is often applied to stabilize soil after disturbance, but its influence on soil temperature and evaporation has not been described. This study assessed soil temperature over time and used the surface energy balance to quantify evaporation from bare soil (0×), and two rates of hydromulch application, 1× and 3× (by weight) of manufacturer's recommended rate. Diurnal temperature extremes were highest in the 0× and least in the 3×. Evaporation was highest in the 0× during the final 18 d of data collection and lowest in the 3×. These findings indicate that temperature fluctuations decrease and evaporation is reduced when hydromulch is applied to bare soil, suggesting it may aid in soil reclamation.
Trifoliolate Leaflet Chloride Concentrations for Characterizing Soybean Yield Loss from Chloride Toxicity
Authors: Cox Dillon D. , Slaton Nathan A. , Ross W. Jeremy , Roberts Trenton L. 
Published: May 2018

Chloride includer soybean cultivars are more susceptible to chloride toxicity than excluder cultivars.
The critical tissue chloride concentration defining toxicity is lower for excluder cultivars.
Yield loss from chloride toxicity can be predicted by tissue analysis.
Chloride toxicity is a yield limiting problem for soybean [Glycine max (L.) Merr.] production, but limited information is available to accurately diagnose and manage Cl toxicity. The research objective was to determine how incremental additions of Cl affect the yield of Cl excluder and includer cultivars and develop critical leaflet‐Cl concentrations that indicate when yield loss from Cl toxicity begins. Six soybean cultivars, three Cl‐includer and three Cl‐excluder cultivars, were planted at five site‐years. Chloride solution containing CaCl2∙2H2O and MgCl2∙6H2O salts was applied to the soil surface beginning at late vegetative growth with final rates ranging from 0 to 1010 kg Cl ha−1. Tissue Cl concentration was measured by sampling trifoliolate leaflets during reproductive growth. Critical leaflet‐Cl concentrations at the R3 stage were developed by regressing relative soybean yield across leaflet‐Cl concentration for each cultivar Cl rating. Chloride addition reduced soybean seed yield, on average, by 17% for Cl includer and 5% for excluder cultivars. Leaflet‐Cl concentration explained 56% of the variability in relative grain yield for Cl excluders and includers. Relative seed yield declined linearly at 2.6% (1000 mg Cl kg)−1 for cultivars within each Cl rating group with 5% yield loss expected when concentrations exceeded 3923 mg Cl kg−1 for includers and 1885 mg Cl kg−1 for excluders. The ability to predict when potentially toxic amounts of Cl are taken up using tissue analysis is the first step in developing management strategies that may help mitigate yield loss.
Yield and Quality Characteristics of Drip‐Irrigated Soybean under Different Irrigation Levels
Authors: Aydinsakir Koksal 
Published: May 2018

Core Ideas
Different irrigation levels affected the yield and quality components of soybean.
Deficit irrigation decreased soybean protein content.
Water deficit treatments caused an increase in the oil content in soybean.
Soybean can be irrigated to 75% of Class A pan evaporation in semiarid conditions with limited water resources.
This study was conducted to determine the effects of deficit irrigation levels on the yield and quality of soybean [Glycine max (L.) Merr.]. Five different irrigation applications designated as full irrigation (I100) with no water stress and slight (I75), mild (I50), severe water stress (I25) and no irrigation (I0) treatments based on the amount of evaporation measured by a Class A pan. The results showed that irrigation levels applied has statistically significant effect on yield and yield components. Water deficit stress significantly (P < 0.01) increased oil content while it decreased protein content. The highest water use obtained in I100 treatment, while the lowest was found in I0 treatment in both years. The maximum yield was obtained from under I100, I75, I50, I25 and I0 treatments as much as 4.01, 3.95, 3.57, 2.83 and 1.92 t ha−1 in 2014 and 4.11, 3.60, 3.24, 2.61 and 1.81 t ha−1 in 2015, respectively. Compared with I100, the 2‐yr average yield reduction for I0, I25, I50, and I75 were 54, 32, 17, and 8%, respectively. The water use efficiency varied from 5.2 to 8.7 kg ha−1 mm−1 in the first year and from 5.6 to 8.3 kg ha−1 mm−1 in the second year, respectively. Based on the results of this study, soybean can be irrigated as much as 100% of Class A pan evaporation in regions with no water scarcity. Under deficit irrigation conditions, as an option, soybean can be irrigated as much as 75% of pan evaporation under Western Mediterranean conditions of Turkey.
Effects of Subsoiling Tillage on Soil Properties, Maize Root Distribution, and Grain Yield on Mollisols of Northeastern China
Authors: Feng Xiaomin , Hao Yubo , Latifmanesh Hojatollah , Lal Rattan , Cao Tiehua , Guo Jinrui , Deng Aixing , Song Zhenwei , Zhang Weijian 
Published: May 2018

Core Ideas
Subsoil tillage (∼30 cm) reduced compaction and increased moisture and N availability on Mollisols.
Subsoiling increased the vertical and horizontal distribution of maize roots between rows rather than in row.
Grain and dry matter yield were 6.3 and 3.7% greater under subsoiling than conventional tillage.
Subsoiling increased maize yield due to improved soil conditions and roots distribution.
Soil compaction creates unfavorable soil physical and nutrient conditions, restrains root penetration and distribution, and reduces crop yield. A field experiment was established to assess the effects of tillage treatments on soil properties, root distribution, and grain yield of maize (Zea mays L.) on some Mollisols of Northeastern China. The two treatments included in rotary tillage (RT) and subsoiling tillage (ST). The results showed that soil bulk density, penetration resistance, soil moisture, available nitrogen content, root distribution of maize, and grain yield were significantly affected by tillage systems. Compared with RT, ST had lower soil bulk density and penetration resistance, but greater soil moisture and available nitrogen contents, especially in subsoil layer (i.e., 15‐ to 45‐ cm). The ST practice significantly increased the average root length density by 13.0% than that of RT mainly due to better vertical and horizontal distribution between the rows. Average grain yield and dry matter weight of maize increased by 693 kg ha−1 (6.3%) and 933 kg ha−1 (3.7%), respectively, under ST compared with those under RT. These data show that subsoiling tillage can loosen the soil, fracture the plow pan, increase the availability and infiltration of soil moisture and nitrogen in subsoil layers, improve the vertical and horizontal extension of maize root system in the soil, and increase grain yield on Mollisols of Northeastern China.
Physiological and Morphological Response of a Drought‐Tolerant Maize Hybrid to Agronomic Management
Authors: Lindsey A. J. , Barker D. J. , Metzger J. D. , Mullen R. W. , Thomison P. R. 
Published: May 2018

Core Ideas
Variability in morpho‐physiological traits was documented between hybrids.
Hybrid responses to agronomic management differed in magnitude for select traits.
Traits that improved light interception and utilization were correlated to yield.
Concerns about limited water availability have led to the release of a new generation of drought‐tolerant maize (Zea mays L.) hybrids, but limited research is available on the morphological and physiological traits that may confer tolerance in these hybrids and the plasticity of these traits under different agronomic management practices. A field study was conducted in 2013 and 2014 at three Ohio locations to investigate physiological responses of a drought‐tolerant hybrid (P1352) and a conventional hybrid (P1184) to plant population (59,000 or 104,000 plants ha−1) under May and June planting dates, and correlate physiological traits to grain yield. Measurements included net photosynthetic rate, stomatal conductance, light interception, specific leaf area (SLA), and grain yield. Despite favorable conditions for maize growth, the drought‐tolerant hybrid maintained similar or greater photosynthetic rates (8–10% greater) with a lower stomatal conductance (22–30% less) compared with the conventional hybrid. Across site‐years, the drought‐tolerant and conventional hybrid exhibited similar morphological and physiological responses to plant population and planting date with some variance in magnitude of response for specific traits. The drought‐tolerant hybrid produced greater biomass and SLA than the conventional hybrid, exhibited greater light interception than the conventional hybrid (97 vs. 95%, respectively), and produced 2.5% greater grain yield than the conventional hybrid. Traits correlated to grain yield included plant height, light interception, photosynthetic rate, SLA, and chlorophyll fluorescence. Future evaluations in both stressed and non‐stressed conditions should be conducted with additional hybrid pairs to provide further validation.
Temperature and Manure Placement in a Snowpack Affect Nutrient Release from Dairy Manure during Snowmelt
Authors: Vadas Peter A. , Stock Melanie N. , Feyereisen Gary W. , Arriaga Francisco J. , Good Laura W. , Karthikeyan K. G. 
Published: May 2018

Agricultural nutrient management is an issue due to N and P losses from fields and water quality degradation. Better information is needed on the risk of nutrient loss in runoff from dairy manure applied in winter. We investigated the effect of temperature on nutrient release from liquid and semisolid manure to water, and of manure quantity and placement within a snowpack on nutrient release to melting snow. Temperature did not affect manure P and NH4–N release during water extraction. Manure P release, but not NH4–N release, was significantly influenced by the water/manure solids extraction ratio. During snowmelt, manure P release was not significantly affected by manure placement in the snowpack, and the rate of P release decreased as application rate increased. Water extraction data can reliably estimate P release from manure during snowmelt; however, snowmelt water interaction with manure of greater solids content and subsequent P release appears incomplete compared with liquid manures. Manure NH4–N released during snowmelt was statistically the same regardless of application rate. For the semisolid manure, NH4–N released during snowmelt increased with the depth of snow covering it, most likely due to reduced NH3 volatilization. For the liquid manure, there was no effect of manure placement within the snowpack on NH4–N released during snowmelt. Water extraction data can also reliably estimate manure NH4–N release during snowmelt as long as NH3 volatilization is accounted for with liquid manures for all placements in a snowpack and semisolid manures applied on top of snow.Core Ideas
Nutrient loss in runoff from winter‐applied manure can be significant.
Cold temperatures do not decrease nutrient release from manure to water.
Nutrient release from manure during snowmelt is not a function of placement in a snowpack.
Laboratory extraction data can be used to estimate nutrient release from manure during snowmelt.
Solid manure may release less P during snowmelt than liquid manures.
Speciation of Phosphorus from Agricultural Muck Soils to Stream and Lake Sediments
Authors: Audette Yuki , O'Halloran Ivan P. , Nowell Peter M. , Dyer Richard , Kelly Ross , Voroney R. Paul 
Published: May 2018

The nature and management of agricultural soils can influence the forms of legacy P present in affected sediments; however, few studies have specifically characterized P in sediments affected by polder agriculture. In this study, the speciation of P as it flows from the muck soils of the Holland Marsh to the sediments of the West Holland River and Lake Simcoe, Ontario, Canada, was investigated. The distribution of P fractions and the characterization of organic P were analyzed by the sequential fractionation method and solution 31P nuclear magnetic resonance spectroscopy, respectively. Organic P was the predominant P form (∼58% of total P) in muck soils, whereas the redox‐sensitive P fraction was predominant in surface stream sediments rich in organic matter (∼41–48% of total P), despite these sediments exhibiting near‐neutral pH and high concentrations of both Ca and P. The proportion of relatively recalcitrant organic P forms was much greater in the muck soils than that exhibited by both stream and lake sediments. The decreasing proportion of recalcitrant organic P forms in sediments downstream from the Holland Marsh indicated the potential for faster organic P cycling. Our findings support the notion that diesters and pyrophosphate should be monitored, in addition to loosely bound inorganic P, due to their potential impact on water quality. The unique environment of the streams and lake area is considered to be particularly vulnerable to excessive fertilizer P use in adjacent croplands.Core Ideas
The predominant P fraction in muck soil was recalcitrant organic P.
The predominant P fraction in organic matter‐rich sediments was redox‐sensitive P.
The predominant form of organic P in sediments was labile orthophosphate diesters.
Organic P cycles faster in stream sediments than that in muck soils.
Probing Oxytetracycline Sorption Mechanism on Kaolinite in a Single Ion and Binary Mixtures with Phosphate using In Situ ATR‐FTIR Spectroscopy
Authors: Dolui Manisha , Rakshit Sudipta , Essington Michael E. , Lefèvre Grégory 
Published: May 2018

Core Ideas
Oxytetracycline retention on kaolinite in the presence of phosphate was evaluated.
Advanced in situ ATR‐FTIR spectroscopic probe revealed detailed interaction mechanism.
Both oxytetracycline and phosphate bonded on kaolinite via an inner‐sphere mechanism.
Sorption increased for oxytetracycline and phosphate as pH and the initial concentration increased.
Phosphate did not influence oxytetracycline adsorption.
The presence of co‐adsorbing ions can influence antibiotic retention behavior on mineral surfaces. Thus, a thorough evaluation of antibiotic sorption mechanisms in single ion and in competitive sorption systems is essential to predict antibiotic fate and behavior in the environment. Molecular level understanding of these sorption mechanisms is possible by using in situ attenuated total reflectance Fourier transform infrared spectroscopy (ATR‐FTIR). This tool can identify detailed surface interactions of the functional groups of antibiotics with soil minerals. This study investigates the sorption mechanisms of oxytetracycline (OTC) on kaolinite in a single ion and in binary mixtures with phosphate [P(V)] as a function of solution properties using in situ ATR‐FTIR spectroscopy. Three different systems were investigated: P(V) sorption, OTC sorption, and competitive sorption of OTC and P(V) on kaolinite. The results of P(V) alone and OTC alone systems indicated that sorption increased with decreasing pH and increasing initial adsorbate concentration. The major IR bands for P(V) indicated that the sorption occurred via an inner‐sphere mechanism. For OTC, involvement of amide (–CONH2), carbonyl (>C=O) and dimethyl amino groups [–N(CH3)2] in retention were noted by the IR bands. For sorption of OTC and P(V) in binary mixtures, the IR bands of OTC and P(V) sorption on kaolinite did not change relative to the single adsorbate systems, indicating a lack of competitive effects. These findings are important for assessing the potential mobilization of OTC in chemically‐complex soil and sediment environments where P(V) can co‐occur.
Using Water Stable Isotopes in the Unsaturated Zone to Quantify Recharge in Two Contrasted Infiltration Regimes
Authors: Barbecot Florent , Guillon Sophie , Pili Eric , Larocque Marie , Gibert-Brunet Elisabeth , Hélie Jean-François , Noret Aurélie , Plain Caroline , Schneider Vincent , Mattei Alexandra , Meyzonnat Guillaume 
Published: May 2018

Core Ideas
Soil water stable isotope profiles can be used to quantify groundwater recharge.
Climate conditions are recorded in water stable isotope profiles of the unsaturated zone.
Soil water isotope profiles provide insight into the seasonality of recharge events.
A reliable estimate of recharge is needed for the sustainable management of groundwater resources. Water stable isotope (δ18O and δ2H) profiles in the unsaturated zone are frequently used to quantify groundwater recharge based on the seasonality of water isotopic compositions in precipitation. A very simple approach consists of integrating the soil water content between peak values of soil water isotopic composition, typically corresponding to precipitation signatures from warm and cold seasons. When precipitation isotopic compositions are available, a conceptual surface water isotopes budget and lumped parameter dispersion model can be computed. These models were applied on two field sites with similar permeable soils with grass cover but contrasting recharge regimes and seasonality, one in the Paris Basin (France) with continuous recharge from autumn to spring and the other in the St. Lawrence Lowlands (Quebec, Canada) with episodic recharge in fall and after snowmelt. For the two sites, the peak‐to‐peak method and isotope surface budget led to comparable recharge intensities. At least at the Paris Basin site, evaporation was shown to slightly modify the average unsaturated zone and hence groundwater isotope composition. The proposed parameterization of isotope fractionation due to evaporation allows qualitative estimation of the fraction of evaporation, at least during the recharge seasons. In spite of its simplifications and limitations, the proposed parsimonious model can give estimates of recharge in a variety of sites even if they are not well characterized, as it benefits from the large availability of monthly isotopic compositions in precipitation.