bluuebunny/crossref_metadata_2025 huggingface dataset:
Aceitabilidade e estabilidade físico-química de barras de cereais elaboradas à base de aveia e linhaça dourada
Authors: Colussi Rosana , Baldin Fabiana , Biduski Barbara , Noello Carla , Hartmann Valéria , Gutkoski Luiz Carlos
Published: January 2014

Matérias-primas de elevado valor nutricional e com propriedades funcionais devem ser utilizadas no desenvolvimento de produtos benéficos à saúde do consumidor. Neste trabalho, objetivou-se estudar combinações de aveia e linhaça dourada na elaboração de barras de cereais, sendo avaliadas a composição química, a aceitabilidade sensorial e a estabilidade pelo período de 60 dias de armazenamento. As barras de cereais foram elaboradas com o emprego de ingredientes secos e agentes ligantes, nas proporções de 70% e 30%, respectivamente. O delineamento empregado foi o de mistura binária com variações proporcionais nas formulações, sendo realizadas três repetições no ponto central. As barras de cereais foram avaliadas por 35 provadores não treinados quanto à aceitabilidade e à intenção de compra. A estabilidade foi avaliada pela determinação de acidez graxa, índice de peróxidos e atividade de água, e a composição química, pela determinação de umidade, proteínas, cinzas, lipídios, fibra alimentar e carboidratos. Para a composição química, foi realizada a análise de regressão, obtendo-se os coeficientes de determinação e falta de ajuste. Nas demais determinações, os resultados foram analisados pelo emprego da análise da variância (ANOVA) e as médias foram comparadas pelo teste de Tukey a 5% de significância. A aveia combinada com linhaça dourada pode ser utilizada na elaboração de barras de cereais por apresentar características sensoriais adequadas e ser fonte de fibras. A formulação de melhor aceitabilidade sensorial foi o ponto central, com emprego de 50% de aveia e 50% de linhaça dourada. As barras de cereais apresentam boa estabilidade devido à baixa atividade de água e à não formação de peróxidos.
Estabilidade da polpa de morango atomizada utilizando diferentes agentes carreadores
Authors: Oliveira Maria Isabel Sousa , Tonon Renata Valeriano , Nogueira Regina Isabel , Cabral Lourdes Maria Corrêa
Published: January 2014

Este trabalho teve por objetivo avaliar o efeito de diferentes agentes carreadores (Maltodextrina 5DE, Maltodextrina 10DE, Goma arábica e Capsul®) nas características físico-químicas (umidade, densidade, solubilidade, teor de antocianinas e atividade antioxidante) da polpa de morango desidratada por atomização e armazenada à temperatura ambiente por 90 dias. A utilização dos diferentes agentes carreadores resultou em pós com valores de densidade aparente entre 0,40 e 0,52 g/cm³ e umidade menor do que 2,5%. Todas as amostras foram altamente solúveis, mas os pós obtidos com a Maltodextrina 5DE e com a Goma arábica apresentaram menor higroscopicidade. As isotermas de sorção obtidas foram do tipo III e o modelo de GAB foi o que melhor se ajustou aos dados experimentais. A amostra produzida com goma arábica apresentou a maior concentração de antocianinas e, consequentemente, maior valor de atividade antioxidante, tanto imediatamente após a secagem como ao longo de 90 dias de armazenamento. Os resultados obtidos indicaram que a goma arábica foi o agente carreador mais adequado para a produção de polpa de morango em pó.
An analysis of controls on fire activity in boreal Canada: comparing models built with different temporal resolutions
Authors: Parisien Marc-André , Parks Sean A. , Krawchuk Meg A. , Little John M. , Flannigan Mike D. , Gowman Lynn M. , Moritz Max A.
Published: January 2014

Fire regimes of the Canadian boreal forest are driven by certain environmental factors that are highly variable from year to year (e.g., temperature, precipitation) and others that are relatively stable (e.g., land cover, topography). Studies examining the relative influence of these environmental drivers on fire activity suggest that models making explicit use of interannual variability appear to better capture years of climate extremes, whereas those using a temporal average of all available years highlight the importance of land‐cover variables. It has been suggested that fire models built at different temporal resolutions may provide a complementary understanding of controls on fire regimes, but this claim has not been tested explicitly with parallel data and modeling approaches. We addressed this issue by building two models of area burned for the period 1980–2010 using 14 explanatory variables to describe ignitions, vegetation, climate, and topography. We built one model at an annual resolution, with climate and some land‐cover variables being updated annually, and the other model using 31‐year fire “climatology” based on averaged variables. Despite substantial differences in the variables' contributions to the two models, their predictions were broadly similar, which suggests coherence between the spatial patterns of annually varying climate extremes and long‐term climate normals. Where the models' predictions diverged, discrepancies between the annual and averaged models could be attributed to specific explanatory variables. For instance, annually updating land cover allowed us to identify a possible negative feedback between flammable biomass and fire activity. These results show that building models at more than one temporal resolution affords a deeper understanding of controls on fire activity in boreal Canada than can be achieved by examining a single model. However, in terms of spatial predictions, the additional effort required to build annual models of fire activity may not always be warranted in this study area. From a management and policy standpoint, this key finding should boost confidence in models that incorporate climatic normals, thereby providing a stronger foundation on which to make decisions on adaptation and mitigation strategies for future fire activity.
Space use by female Greater Prairie‐Chickens in response to wind energy development
Authors: Winder V. L. , McNew L. B. , Gregory A. J. , Hunt L. M. , Wisely S. M. , Sandercock B. K.
Published: January 2014

Wind energy development is targeted to meet 20% of U.S. energy demand by 2030. In Kansas, optimal sites for wind energy development often overlap with preferred habitats of Greater Prairie‐Chickens (Tympanuchus cupido), a lek‐mating species of prairie grouse with declining populations. Our goal was to use movement data from radio telemetry to investigate patterns and drivers of seasonal space use by female prairie‐chickens during pre‐ and post‐construction periods at a wind energy facility in northcentral Kansas. We developed individual and population level resource utilization functions (RUFs) for four time periods: the 6‐month breeding and nonbreeding seasons during the pre‐construction stage (2007–2008; n = 28 and 14 females), and the same two seasons during a post‐construction period (2009–2011; n = 102 and 37). RUFs relate non‐uniform space use within a home range to landscape metrics in a multiple regression framework. We selected ten predictor variables that described land cover, habitat patchiness, anthropogenic disturbance, and social behavior of prairie‐chickens. We documented two behavioral responses of females to wind energy development during the breeding season: (1) mean home range size increased approximately two‐fold, and (2) space use had a positive relationship with distance to turbine, which indicated female avoidance of wind turbines. A parallel study of demographic rates in our study population found no negative effects of wind energy development on prairie‐chicken fecundity or survival, but persistent avoidance of wind energy development could result in the local extirpation of prairie‐chicken populations at our study site. Our primary ecological finding was that distance to lek was the strongest predictor of space use during all treatment periods, with relatively high use of areas at short distances from leks in 79% of female home ranges. Thus, lek site surveys should be effective for identifying prairie grouse habitat preferences and monitoring population dynamics when more intensive demographic studies are not feasible. Our study is the first application of resource utilization function techniques to a wildlife population in response to energy development, and our results provide new quantitative insights into the spatial ecology of an upland gamebird of conservation concern.
Ground‐dwelling arthropod responses to succession in a pinyon‐juniper woodland
Authors: Higgins Jacob W. , Cobb Neil S. , Sommer Stefan , Delph Robert J. , Brantley Sandra L.
Published: January 2014

Stand‐replacing wildfire is an infrequent but important disturbance in southwestern pinyon‐juniper woodlands. A typical successional cycle in these woodlands is approximately 300 years or more after a stand‐replacing fire. Arthropods, especially ground‐dwelling taxa, are one of the most abundant and diverse fauna in terrestrial ecosystems and are typically responsive to microhabitat change. Little is known regarding community responses of ground‐dwelling arthropods to changes in woodland successional stages from early ecosystems dominated by grasses, herbaceous plants, and fire adapted shrubs to tree‐dominated old‐growth ecosystems. In 2007 and 2008, within Mesa Verde National Park, Colorado, we compared the community composition of ground‐dwelling arthropods between old‐growth pinyon‐juniper stands that were 300–400 years old and early successional areas recovering from a stand‐replacing fire in 2002. The 2002 fire eliminated the dominant woody vegetation, which was replaced by increased herbaceous vegetation and bare ground. The early successional arthropod community showed a significantly higher abundance in major arthropod taxonomic groups, except spiders, compared to old‐growth woodland. Old‐growth species richness was greater in late August–September, 2007 and greater in early successional habitats during April–July, 2008. Spatial variability of the habitat was much greater in the recently burned early successional plots than the old‐growth late successional plots. The differences in habitat were strongly correlated with arthropod community composition, suggesting that ground‐dwelling arthropods are very sensitive to habitat changes. Habitat affiliation was strong, with 83% (early succession ruderal) and 91% (old‐growth woodland) of the species found primarily or exclusively in one habitat. Many habitat indicator species (defined as species found in significantly greater abundance in one habitat) were found in both burned and old‐growth habitats. Several species were found to be strict specialists exclusive to only one of these habitats. Collectively, the results suggest that heightened concern over loss of old‐growth woodlands is warranted, given the distinct nature of the ground‐dwelling arthropod community in old‐growth habitats.
Influence of Culture and Community Perceptions on Birth and Perinatal Care of Immigrant Women: Doulas’ Perspective
Authors: Kang Hye-Kyung
Published: January 2014

A qualitative study examined the perceptions of doulas practicing in Washington State regarding the influence of cultural and community beliefs on immigrant women’s birth and perinatal care, as well as their own cultural beliefs and values that may affect their ability to work interculturally. The findings suggest that doulas can greatly aid immigrant mothers in gaining access to effective care by acting as advocates, cultural brokers, and emotional and social support. Also, doulas share a consistent set of professional values, including empowerment, informed choice, cultural relativism, and scientific/evidence-based practice, but do not always recognize these values as culturally based. More emphasis on cultural self-awareness in doula training, expanding community doula programs, and more integration of doula services in health-care settings are recommended.
Listen Up: What We Can Learn From Women’s Birth and Postpartum Experiences
Authors: Lothian Judith A.
Published: January 2014

In 2013, Childbirth Connection published findings from a U.S. study of women’s pregnancy, childbirth, and postpartum experiences, Listening to Mothers III. In this issue of The Journal of Perinatal Education, we publish the major survey findings of both the pregnancy and birth survey and the postpartum survey. This editorial discusses some of the major findings of the childbirth survey. Listening to what mothers have to say about their experiences suggests a mandate to “listen up” to what mothers are telling us and continue to advocate for evidence-based maternity care. Articles in this issue of the journal are presented.
A Descriptive Survey of the Educational Preparation and Practices of Antenatal Educators in Ireland
Authors: O’Sullivan Cathy , O’Connell Rhona , Devane Declan
Published: January 2014

Antenatal education is recommended to prospective parents, yet little is known about the educational preparation of the facilitators of this education, or of the educational practices they use. The aim of this study was to investigate the educational preparation and practices of antenatal educators in Ireland. Data were collected using a questionnaire structured on the three components (abilities, opportunities, and means) of Stamler’s theoretical framework of enablement. Eighty-four of the 120 antenatal educators responded (70%), and this included midwives, public health nurses, physiotherapists, and private antenatal educators. Findings describe a picture of varied educational preparation for the antenatal educator with a range of educational practices being used. Within public antenatal classes, large class size was a barrier to providing a participatory educational approach.
Major Survey Findings of Listening to MothersSM III: Pregnancy and Birth
Authors: Declercq Eugene R. , Sakala Carol , Corry Maureen P. , Applebaum Sandra , Herrlich Ariel
Published: January 2014

To understand the experiences and views of childbearing women in the United States and trends over time, Childbirth Connection carried out the third national Listening to Mothers survey among 2,400 women who gave birth in U.S. hospitals to a single baby from mid-2011 to mid-2012 and could participate in English. Harris Interactive conducted the survey using a validated methodology that includes data weighting to ensure that results closely reflect the target population. Results of the initial survey describe experiences from before pregnancy through the early postpartum period, and were reported in Listening to Mothers III: Pregnancy and Birth. A follow-up survey directed to the same participants explored postpartum experiences, attitudes about maternity care, and some additional pregnancy and birth items.
Sodium Intake in a Cross-Sectional, Representative Sample of New York City Adults
Authors: Angell Sonia Y. , Yi Stella , Eisenhower Donna , Kerker Bonnie D. , Curtis Christine J. , Bartley Katherine , Silver Lynn D. , Farley Thomas A.
Published: January 2014

Objectives. We estimated sodium intake, which is associated with elevated blood pressure, a major risk factor for cardiovascular disease, and assessed its association with related variables among New York City adults.

Methods. In 2010 we conducted a cross-sectional, population-based survey of 1656 adults, the Heart Follow-Up Study, that collected self-reported health information, measured blood pressure, and obtained sodium, potassium, and creatinine values from 24-hour urine collections.

Results. Mean daily sodium intake was 3239 milligrams per day; 81% of participants exceeded their recommended limit. Sodium intake was higher in non-Hispanic Blacks (3477 mg/d) and Hispanics (3395 mg/d) than in non-Hispanic Whites (3066 mg/d; both P < .05). Higher sodium intake was associated with higher blood pressure in adjusted models, and this association varied by race/ethnicity.

Conclusions. Higher sodium intake among non-Hispanic Blacks and Hispanics than among Whites was not previously documented in population surveys relying on self-report. These results demonstrate the feasibility of 24-hour urine collection for the purposes of research, surveillance, and program evaluation.
Diet-Beverage Consumption and Caloric Intake Among US Adults, Overall and by Body Weight
Authors: Bleich Sara N. , Wolfson Julia A. , Vine Seanna , Wang Y. Claire
Published: January 2014

Objectives. We examined national patterns in adult diet-beverage consumption and caloric intake by body-weight status.

Methods. We analyzed 24-hour dietary recall with National Health and Nutrition Examination Survey 1999–2010 data (adults aged ≥ 20 years; n = 23 965).

Results. Overall, 11% of healthy-weight, 19% of overweight, and 22% of obese adults drink diet beverages. Total caloric intake was higher among adults consuming sugar-sweetened beverages (SSBs) compared with diet beverages (2351 kcal/day vs 2203 kcal/day; P = .005). However, the difference was only significant for healthy-weight adults (2302 kcal/day vs 2095 kcal/day; P < .001). Among overweight and obese adults, calories from solid-food consumption were higher among adults consuming diet beverages compared with SSBs (overweight: 1965 kcal/day vs 1874 kcal/day; P = .03; obese: 2058 kcal/day vs 1897 kcal/day; P < .001). The net increase in daily solid-food consumption associated with diet-beverage consumption was 88 kilocalories for overweight and 194 kilocalories for obese adults.

Conclusions. Overweight and obese adults drink more diet beverages than healthy-weight adults and consume significantly more solid-food calories and a comparable total calories than overweight and obese adults who drink SSBs. Heavier US adults who drink diet beverages will need to reduce solid-food calorie consumption to lose weight.
Racial Disparities in Life Expectancy in Brazil: Challenges From a Multiracial Society
Authors: Chiavegatto Filho Alexandre Dias Porto , Beltrán-Sánchez Hiram , Kawachi Ichiro
Published: January 2014

Objectives. We calculated life expectancy at birth for Whites, Blacks, and mixed races in Brazil, and decomposed the differences by causes of death.

Methods. We used Ministry of Health death records and 2010 Census population data (190 755 799 residents and 1 136 947 deaths). We applied the Arriaga methodology to calculate decomposition of life expectancy by cause of death. We performed sensitivity analyses for underreporting of deaths, missing data, and numerator–denominator bias.

Results. Using standard life table methods, female life expectancy was highest for mixed races (78.80 years), followed by Whites (77.54 years), then Blacks (76.32 years). Male life expectancy was highest for Whites (71.10 years) followed closely by mixed races (71.08 years), and lower for Blacks (70.11 years). Homicides contributed the most to the relative life expectancy increase for Whites, and cancer decreased the gap. After adjustment for underreporting, missing data, and numerator–denominator bias, life expectancy was higher for Whites than for Blacks and mixed races.

Conclusions. Despite wide socioeconomic differences between Whites and mixed races, standard life table methods showed that mixed races had higher life expectancy than Whites for women, and similar for men. With the increase of multiracial populations, measuring racial disparities in life expectancy will be a fast-growing challenge.
Geographic Residency Status and Census Tract Socioeconomic Status as Determinants of Colorectal Cancer Outcomes
Authors: Hines Robert , Markossian Talar , Johnson Asal , Dong Frank , Bayakly Rana
Published: January 2014

Objectives. We examined the impact of geographic residency status and census tract (CT)-level socioeconomic status (SES) on colorectal cancer (CRC) outcomes.

Methods. This was a retrospective cohort study of patients diagnosed with CRC in Georgia for the years 2000 through 2007. Study outcomes were late-stage disease at diagnosis, receipt of treatment, and survival.

Results. For colon cancer, residents of lower-middle-SES and low-SES census tracts had decreased odds of receiving surgery. Rural, lower-middle-SES, and low-SES residents had decreased odds of receiving chemotherapy. For patients with rectal cancer, suburban residents had increased odds of receiving radiotherapy, but low SES resulted in decreased odds of surgery. For survival, rural residents experienced a partially adjusted 14% (hazard ratio [HR] = 1.14; 95% confidence interval [CI] = 1.07, 1.22) increased risk of death following diagnosis of CRC that was somewhat explained by treatment differences and completely explained by CT-level SES. Lower-middle- and low-SES participants had an adjusted increased risk of death following diagnosis for CRC (lower-middle: HR = 1.16; 95% CI = 1.10, 1.22; low: HR = 1.24; 95% CI = 1.16, 1.32).

Conclusions. Future efforts should focus on developing interventions and policies that target rural residents and lower SES areas to eliminate disparities in CRC-related outcomes.
Intimate Partner Homicide and Corollary Victims in 16 States: National Violent Death Reporting System, 2003–2009
Authors: Smith Sharon G. , Fowler Katherine A. , Niolon Phyllis H.
Published: January 2014

Objectives. We estimated the frequency and examined the characteristics of intimate partner homicide and related deaths in 16 US states participating in the National Violent Death Reporting System (NVDRS), a state-based surveillance system.

Methods. We used a combination of quantitative and qualitative methods to analyze NVDRS data from 2003 to 2009. We selected deaths linked to intimate partner violence for analysis.

Results. Our sample comprised 4470 persons who died in the course of 3350 intimate partner violence–related homicide incidents. Intimate partners and corollary victims represented 80% and 20% of homicide victims, respectively. Corollary homicide victims included family members, new intimate partners, friends, acquaintances, police officers, and strangers.

Conclusions. Our findings, from the first multiple-state study of intimate partner homicide and corollary homicides, demonstrate that the burden of intimate partner violence extends beyond the couple involved. Systems (e.g., criminal justice, medical care, and shelters) whose representatives routinely interact with victims of intimate partner violence can help assess the potential for lethal danger, which may prevent intimate partner and corollary victims from harm.
Cost-Effectiveness of Pit-and-Fissure Sealants on Primary Molars in Medicaid-Enrolled Children
Authors: Chi Donald L. , van der Goes David N. , Ney John P.
Published: January 2014

Objectives. We compared the incremental cost-effectiveness of 2 primary molar sealant strategies—always seal and never seal—with standard care for Medicaid-enrolled children.

Methods. We used Iowa Medicaid claims data (2008–2011), developed a tooth-level Markov model for 10 000 teeth, and compared costs, treatment avoided, and incremental cost per treatment avoided for the 2 sealant strategies with standard care.

Results. In 10 000 simulated teeth, standard care cost $214 510, always seal cost $232 141, and never seal cost $186 010. Relative to standard care, always seal reduced the number of restorations to 340 from 2389, whereas never seal increased restorations to 2853. Compared with standard care, always seal cost $8.12 per restoration avoided (95% confidence interval [CI] = $4.10, $12.26; P ≤ .001). Compared with never seal, standard care cost $65.62 per restoration avoided (95% CI = $52.99, $78.26; P ≤ .001).

Conclusions. Relative to standard care, always sealing primary molars is more costly but reduces subsequent dental treatment. Never sealing costs less but leads to more treatment. State Medicaid programs that do not currently reimburse dentists for primary molar sealants should consider reimbursement for primary molar sealant procedures as a population-based strategy to prevent tooth decay and reduce later treatment needs in vulnerable young children.
Body Mass Index Categories and Mortality Risk in US Adults: The Effect of Overweight and Obesity on Advancing Death
Authors: Borrell Luisa N. , Samuel Lalitha
Published: January 2014

Objectives. We examined the association of body mass index with all-cause and cardiovascular disease (CVD)–specific mortality risks among US adults and calculated the rate advancement period by which death is advanced among the exposed groups.

Methods. We used data from the Third National Health and Nutrition Examination Survey (1988–1994) linked to the National Death Index mortality file with follow-up to 2006 (n = 16 868). We used Cox proportional hazards regression to estimate the rate of dying and rate advancement period for all-cause and CVD-specific mortality for overweight and obese adults relative to their normal-weight counterparts.

Results. Compared with normal-weight adults, obese adults had at least 20% significantly higher rate of dying of all-cause or CVD. These rates advanced death by 3.7 years (grades II and III obesity) for all-cause mortality and between 1.6 (grade I obesity) and 5.0 years (grade III obesity) for CVD-specific mortality. The burden of obesity was greatest among adults aged 45 to 64 years for all-cause and CVD-specific mortality and among women for all-cause mortality.

Conclusions. These findings highlight the impact of the obesity epidemic on mortality risk and premature deaths among US adults.
Estimating Acute Viral Hepatitis Infections From Nationally Reported Cases
Authors: Klevens R. Monina , Liu Stephen , Roberts Henry , Jiles Ruth B. , Holmberg Scott D.
Published: January 2014

Objectives. Because only a fraction of patients with acute viral hepatitis A, B, and C are reported through national surveillance to the Centers for Disease Control and Prevention, we estimated the true numbers.

Methods. We applied a simple probabilistic model to estimate the fraction of patients with acute hepatitis A, hepatitis B, and hepatitis C who would have been symptomatic, would have sought health care tests, and would have been reported to health officials in 2011.

Results. For hepatitis A, the frequencies of symptoms (85%), care seeking (88%), and reporting (69%) yielded an estimate of 2730 infections (2.0 infections per reported case). For hepatitis B, the frequencies of symptoms (39%), care seeking (88%), and reporting (45%) indicated 18 730 infections (6.5 infections per reported case). For hepatitis C, the frequency of symptoms among injection drug users (13%) and those infected otherwise (48%), proportion seeking care (88%), and percentage reported (53%) indicated 17 100 infections (12.3 infections per reported case).

Conclusions. These adjustment factors will allow state and local health authorities to estimate acute hepatitis infections locally and plan prevention activities accordingly.
Carbon Distribution in a Hummocky Landscape from Saskatchewan, Canada
Authors: Landi A. , Mermut A. R. , Anderson D. W.
Published: January 2014

Changes in the topography influence organic and inorganic C contents and δ13C values of soil C across a landscape. The objectives of this research were to: (i) study the effect of landscape on the formation and distribution of pedogenic carbonate and organic matter distribution in a hummocky landscape, and (ii) estimate the amount of organic C and pedogenic carbonate accumulation in local scale in comparison with regional scale using the stable isotope geochemistry techniques and standard characterization analyses. A hummocky landscape, typical of 38% of Saskatchewan's land, with glacial till parent material under virgin grassland, was studied. Organic C content of A horizons range between 20 to 98 g kg−1 Both extremes occurred in level positions of the south‐facing and north‐facing slopes. The lowest δ13C value of organic C (−29.6‰) was measured in a depression and the highest (more positive) was obtained on a shoulder (−21.7‰). The δ13C values of carbonate ranged from −0.9‰ (carbonated parent material) at the 114‐cm depth in level complex to −7.9‰ at depth of 100 cm in footslope complex and depression. The amount and percentage of pedogenic carbonate was higher in north‐facing slopes than in southward slopes. The highest proportion and amount of pedogenic carbonate up to 1‐m depth was found in Calcicryolls in footslope complex position in the north‐facing slope, and likely represents a gain in carbonate through lateral flows. The lowest proportion and amount (34.4% and 33.9 kg m−2) was found in the shoulder complex segment of west‐facing slope and in footslope complex position in east‐west direction. On average, the rate of accumulation is about 1.25 g C m−2 yr−1 of inorganic C (pedogenic carbonate) and 1.25 g C m−2 yr−1 as organic C. These are close to the calculated rate of 1.4 g C m−2 yr−1 for Dark Brown, and 1.3 g C m−2 yr−1 for Black soils (Mollisols) in Saskatchewan.
Organic Matter and Aggregate‐Size Interactions in Saturated Hydraulic Conductivity
Authors: Lado M. , Paz A. , Ben-Hur M.
Published: January 2014

The objective of this study was to investigate the effect of the interaction between organic matter (OM) content and aggregate size on the mechanisms that degrade the soil structure and on the saturated hydraulic conductivity (Ks). Two samples of sandy loam (Humic Dystrudept) containing 2.5 and 3.5% OM, referred to as low‐OM soil and high‐OM soil, respectively, were collected from adjacent fields. Dry samples were sieved to obtain aggregate sizes of <2, 2 to 4, and 4 to 6 mm. Slaking, swelling, and dispersion values were measured for each soil and aggregate size. The saturated hydraulic conductivity was determined in disturbed soil columns by means of a constant‐head device. For the <2‐ and 2‐ to 4‐mm aggregate sizes, Ks of the high‐OM soil was, in general, significantly higher than that of the low‐OM soil. The average Ks for the entire leaching run in the <2‐mm and 2‐ to 4‐mm aggregate sizes was 7.7 and 183 mm h−1, respectively, for the low‐OM soil and 13 and 412 mm h−1, respectively, for the high‐OM soil. Moreover, there was a significant interaction between aggregate size and OM content in their effects on Ks For the low‐ and high‐OM soils, the slaking values were >93 and <6.7% respectively, and the clay dispersion values in deionized water were >2.9% and <2%, respectively. This suggests that the larger decrease in Ks of the low‐OM soil than in the high‐OM soil during wetting and leaching was mainly a result of more intense aggregate slaking and dispersion in the former soil.
Sorption of Organic Carbon Fractions by Spodosol Mineral Horizons
Authors: Ussiri David A. N. , Johnson C. E.
Published: January 2014

Mobility of organic matter (OM) in soils is restricted by sorption to mineral surfaces. We investigated the sorption of hydrophilic and hydrophobic OM fractions on mineral soils of the Hubbard Brook Experimental Forest (HBEF), New Hampshire. Organic matter was extracted with 0.1 M NaOH from O‐ and Bh‐horizons, fractionated into hydrophilic and hydrophobic fractions, and characterized by 13C cross‐polarization magic‐angle spinning (CPMAS) nuclear magnetic resonance (NMR) spectroscopy. Sorption experiments were conducted with E, Bh, Bs1, Bs2, and C horizon soils at suspension pH of 3, 4, and 5. In all horizons, we observed net release of indigenous OM when OM‐free solution was added. Net release of OM was greatest from Bh‐horizon soils, which had the greatest OM content among the horizons we studied. The OM in the equilibrium solutions was primarily hydrophilic (65–97%) regardless of the fraction added. Sorption behavior was related to the content of carboxylic functional groups in the added solution. Hydrophobic OM had greater affinity to soils than hydrophilic OM, and Bh‐horizon OM exhibited greater sorption than O‐horizon OM. Maximum adsorption occurred at pH 4, and decreased with either an increase or decrease in pH. The pH‐dependence of OM sorption probably reflects a balance between lower charge density of carboxyl groups at low pH and lower positive charge of adsorption sites at higher pH. The hydrophilic fraction contained higher organic N than the hydrophobic fraction, suggesting that dissolved organic nitrogen (DON) is more mobile than dissolved organic carbon (DOC) in these soils.
Role of Vegetation in Mitigating Soil Quality Impacted by Forest Harvesting
Authors: Lister T. W. , Burger J. A. , Patterson S. C.
Published: January 2014

The initial growth response of loblolly pine (Pinus taeda L.) to competition control is well documented. However, the benefits of competing vegetation to soil quality have not been thoroughly investigated. A study was conducted: (i) to evaluate the effectiveness of bedding site preparation in recovering soil processes and productivity following disturbance; and (ii) to determine if different levels of vegetation control have differential effects on soil processes that aid in the recovery and maintenance of soil productivity. Study plots were established on a wet pine flat on South Carolina's Coastal Plain. Treatments included a range of three disturbance classes (undisturbed, compression tracked, and churned), two site preparation treatments (flat planted and bedded), and a gradient of vegetation control (no vegetation control, operational level weed control, and complete weed control). Compacted soils generally increased in bulk density (14%) and decreased in macroporosity (25%) and hydraulic conductivity (69%) compared with undisturbed treatments. Churning had no significant net effect on the soil physical properties measured; however, it did increase net N mineralization by over 100% on flat‐planted treatment plots. Bedding fully ameliorated the effects of soil compaction based on the physical properties measured. Trends suggest some improvements in soil quality with increasing levels of non‐crop vegetation biomass; however, during 2 yr of operational vegetation control, the beneficial effects of the non‐crop vegetation were marginal.
Soil Carbon Pools in Adjacent Natural and Plantation Forests of Subtropical Australia
Authors: Chen C. R. , Xu Z. H. , Mathers N. J.
Published: January 2014

Soil C dynamics are not only important to both productivity and sustainability of terrestrial ecosystems, but also contribute significantly to global C cycling. Adjacent natural forest (NF), and first (1R) and second rotation (2R) hoop pine (Araucaria cunninghamii Aiton ex A. Cunn.) plantations in southeast Queensland, Australia, were selected to investigate the effects of conversion of NF to hoop pine plantations and forest management (harvesting and site preparation of plantation) on the size and the nature of C pools in surface (0–10 cm) soils using chemical extraction, laboratory incubation and 13C cross‐polarization with magic‐angle‐spinning nuclear magnetic resonance spectroscopy (13C CPMAS NMR). Conversion from NF to hoop pine plantations not only led to the reduction of soil total C (by 19.8%), water‐soluble organic C (WSOC) (by 17.7%), CaCl2–extractable organic C (by 38.8%), and hot water‐extractable organic C (HWEOC) (by 30.9%) and bioavailability of soil C (as determined by CO2 evolved in the incubation), but also to a change in chemical composition of soil C with lower O‐alkyl C and higher alkyl C under the 1R plantation compared with NF. Harvesting and site preparation did not significantly affect total soil C and most labile C pools (except for a decrease in WSOC), but led to a lower signal intensity in the alkyl C spectral region and a decreased alkyl C/O‐alkyl C (A/O‐A) ratio in the soil under the 2R compared with the 1R plantation. The shifts in the amount and nature of soil C following forest conversion may be attributed to changes in litter inputs, microbial diversity and activity, and the disturbance of soil during harvesting and site preparation.
Specific Retention of Radiocesium in Volcanic Ash Soils Devoid of Micaceous Clay Minerals
Authors: Joussein Emmanuel , Kruyts Nathalie , Righi Dominique , Petit Sabine , Delvaux Bruno
Published: January 2014

The environmental availability of trace radiocesium (137Cs) was studied in soils devoid of weathered micas. The soils were developed from basaltic ash, within a sequence Udand → Tropept → Udalf → Udult from Cameroon. Tropepts and Udalfs are halloysite‐rich and they exhibit a large cation exchange capacity (CEC) and a strong exchange selectivity for K probably due to the presence of halloysite‐smectite mixed‐layered clays. The 137Cs mobility was evaluated in the B horizons through (i) a physicochemical approach using the radiocesium interception potential concept (RIP) and a sequential sorption–desorption procedure, (ii) a biological test assessing the 137Cs rhizospheric mobilization (137Cs‐RM). In a constant K+–Ca2+ background solution, one of the Tropepts and the Udalfs fixed about 76% of the initial 137Cs loading. The second desorption phase in acidic conditions was more discriminating: the Udalfs fixed about 40%, while the other soils fixed 5 to 20% of the initial 137Cs+ loading. The 137Cs‐RM was generally small (3–15%) in all samples and was negatively correlated with the RIP (439–1836 μmol g−1). The specific retention of 137Cs in these soils was thus largely similar to that obtained in soils that contain weathered micas. It demonstrates the presence of 137Cs specific sites in halloysitic soils devoid of such minerals. These sites might be associated with halloysite‐smectite mixed‐layered clays. They were probably formed following wetting‐drying cycles in soils heavily fertilized with K.
XANES Determination of Adsorbed Phosphate Distribution between Ferrihydrite and Boehmite in Mixtures
Authors: Khare Nidhi , Hesterberg Dean , Beauchemin Suzanne , Wang Shan-Li
Published: January 2014

Iron‐ and Al‐(hydr)oxide minerals are important sorbents for retaining PO4in soils. Our objective was to determine the distribution of adsorbed PO4between ferrihydrite and boehmite in aqueous mixtures of these minerals. Phosphate was adsorbed in aqueous suspensions up to maximum concentrations of 1860, 850, and 1420 mmol kg−1for ferrihydrite, boehmite, and 1:1 (by mass) mixtures of these minerals at pH 6. The solids were analyzed as moist pastes using P K‐XANES (X‐ray absorption near edge structure) spectroscopy. The adsorption isotherm for the mixed‐mineral suspensions could essentially be described as a linear combination of Freundlich isotherm models for each single‐mineral system, indicating negligible mineral interactive effects on PO4adsorption in the mixtures. X‐ray absorption near edge structure spectra for PO4adsorbed on ferrihydrite or in ferrihydrite/boehmite mixtures showed a pre‐edge feature at approximately 2146 eV that was absent in boehmite systems. Linear combination fitting of the pre‐edge region of XANES spectra for mixtures with average spectra for PO4adsorbed on boehmite or ferrihydrite alone, indicated that 59 to 97% of the PO4was adsorbed on ferrihydrite in the mixtures. With increasing concentration of adsorbed PO4in the mineral mixtures, the concentration adsorbed on the ferrihydrite component increased linearly. Phosphate distribution trends in the mixtures suggested an affinity preference for ferrihydrite at the lowest adsorbed PO4concentration (100 mmol kg−1minerals), no affinity preference for either mineral at intermediate concentrations (200 to 600 mmol PO4kg−1), and the possibility of a surface precipitate involving Al at the highest concentration (1300 mmol PO4kg−1).
Deriving Boron Adsorption Isotherms from Soil Column Displacement Experiments
Authors: Communar G. , Keren R. , Li FaHu
Published: January 2014

This study was conducted to elucidate the applicability of the column technique to obtain B adsorption isotherms. A column technique based on miscible displacement was used to investigate B equilibrium adsorption and B transport in soil at various pHs and B concentrations. Boron adsorption by soil at equilibrium was described by the Langmuir equation with the pH‐dependent apparent adsorption coefficient. This equation, combined with one‐dimensional convection–dispersion equation (CDE), was used to simulate B transport in soil columns. The results indicated that adsorption equilibrium was reached during the B transport in the homogeneously packed soil columns. The adsorption isotherms that were obtained from the column breakthrough curves (BTCs) and the batch experiments were identical at any given pH. This indicates that under equilibrium conditions, the column technique can be used for calculating B adsorption isotherm parameters for any given pH.
Emissions of N2O from Alfalfa and Soybean Crops in Eastern Canada
Authors: Rochette Philippe , Angers Denis A. , Bélanger Gilles , Chantigny Martin H. , Prévost Danielle , Lévesque Gabriel
Published: January 2014

There is considerable uncertainty relative to the emissions of N2O from legume crops. A study was initiated to quantify N2O fluxes from soils cropped to alfalfa (Medicago sativa L.) and soybean (Glycine max L.), and to improve our understanding of soil and climatic factors controlling N2O emissions from these crops. Measurements were made on three soils cropped to alfalfa, soybean, or timothy (Phleum pratense L.), a perennial grass used as a control. In situ soil‐surface N2O emissions (FN2O) were measured 47 times during the 2001 and 2002 growing seasons. Soil water, NH4–N, NO3–N, and N2O contents, and soil temperature were also determined to explain the variation in gas fluxes. Emissions of N2O were small under the grass where very low soil mineral N content probably limited denitrification and N2O production. Soil mineral N contents under legumes were up to 10 times greater than under timothy. However, soil mineral N contents and FN2O were not closely related, thus suggesting that the soil mineral N pool alone was a poor indicator of the intensity of N2O production processes. Higher FN2O were measured under legume than under timothy in only 6 out of 10 field comparisons (site‐years). Moreover, the emissions associated with alfalfa (0.67–1.45 kg N ha−1) and soybean (0.46–3.08 kg N ha−1) production were smaller than those predicted using the emission coefficient proposed for the national inventory of greenhouse gases (alfalfa = 1.60–5.21 kg N ha−1; soybean = 2.76–4.97 kg N ha−1). We conclude that the use of the current emission coefficient may overestimate the N2O emissions associated with soybean and alfalfa production in eastern Canada.
Soil Aggregation and Carbon and Nitrogen Storage under Soybean Cropping Sequences
Authors: Wright Alan L. , Hons Frank M.
Published: January 2014

Management practices, such as no‐tillage (NT) and high‐intensity cropping sequences, have the potential to enhance C and N sequestration in agricultural soils. The objectives of this study were to investigate the impacts of conventional‐tillage (CT), NT, and multiple cropping sequences on soil organic carbon (SOC) and nitrogen (SON) sequestration and on distribution within aggregate‐size fractions in a southcentral Texas soil after 20 yr of treatment imposition. No‐tillage management increased soil aggregation compared with CT, with the bulk of SOC and SON storage present in larger aggregate‐size fractions (>2 mm, 250 μm to 2 mm) at both soil depths. Multiple cropping systems, such as a grain sorghum [Sorghum bicolor (L.) Moench]/wheat (Triticum aestivum L.)/soybean [Glycine max (L.) Merr] (SWS) rotation and a wheat/soybean (WS) doublecrop had the highest SOC and SON storage, while the continuous monoculture soybean treatment had the lowest storage. Soil organic C and SON storage were significantly greater under NT than CT for all cropping sequences at 0 to 5 cm and for SWS and WS at 5 to 15 cm. At the 0‐ to 5‐cm depth, NT increased SOC storage by 64% and SON storage by 76% compared with CT. However, at 5 to 15 cm, NT only increased SOC storage by 28% and SON storage by 40%. The use of NT showed a greater impact for increasing SON storage than for SOC storage, suggesting that N cycling is an important factor related to soil C sequestration potential.
A CARBON DIOXIDE FLUX GENERATOR FOR TESTING INFRARED GAS ANALYZER‐BASED SOIL RESPIRATION SYSTEMS
Authors: Martin Jonathan G. , Bolstad Paul V. , Norman John M.
Published: January 2014

An artificial flux generation device was developed to test the accuracy of a closed‐dynamic soil respiration system (LICOR 6400). The device consisted of an enclosed reservoir with a porous top; the reservoir contained a volume of CO2 enriched air, which was monitored by an infrared gas analyzer (IRGA). When the internal CO2 concentration within the reservoir was elevated, diffusion rates through the porous medium were measured by recording changes in CO2 concentration within the reservoir. This diffusion‐based artificial flux mimics natural soil respiration, and allows an independent verification of the accuracy of soil respiration measurement systems. We tested a LI‐COR 6400 portable photosynthesis system fitted with a 6400‐09 soil CO2 flux chamber. On average, this system overestimated high flux rates by 2 to 4% and underestimated low flux rates by 4 to 20% over five independent trials. Soil respiration appeared to be sensitive to boundary layer mixing, and ambient CO2 concentrations.
Soil Test Phosphorus and Phosphorus Fractions with Long‐Term Phosphorus Addition and Depletion
Authors: Zhang T. Q. , MacKenzie A. F. , Liang B. C. , Drury C. F.
Published: January 2014

The fate of fertilizer P in soil during crop production has to be determined to evaluate the long‐term economic value and sustainability of fertilizer practices. We assessed changes in soil test P and soil P fractions with continuous P fertilization and soil P depletion under continuous corn (Zea maysL.) in a Ste. Rosalie clay soil (humic Gleysol; fine, mixed, frigid, Typic Humaquept). Soil samples were analyzed for Mehlich‐3 P (M‐3 P) and P fractions using a modified Hedley's procedure. Soil M‐3 P values remained constant in spite of crop removal in soil not receiving fertilizer for 10 yr. Continuous P fertilization at rates from 44 to 132 P ha−1yr−1increased linearly soil M‐3 P, with 6.3 kg P ha−1of net P addition required to increase M‐3 P by 1 mg P kg−1Residual fertilizer P in soil resulted from the continuous P addition were found predominately in labile inorganic P (LPi) (NaHCO3–Pi) and moderately labile Pi(MLPi) (NaOH‐Pi). Increased P rates favored soil P transformation from LPito MLPi, indicating enhanced soil P retention. With P depletion, soil M‐3 P declined in plots previously receiving 132 kg P ha−1yr−1, with 4.2 kg P ha−1crop P removal decreasing soil M‐3 P by 1 mg P kg−1Continuous crop removal of soil residual P (Res‐P) resulted in decreases in soil LPiand increases in MLPi, an indication of increased retention of Res‐P with time. However, moderately stable Pi(HCl‐Pi) remained constant, both with continuous P addition and P depletion. Conversion of residual fertilizer P to less available P forms in soil was a slow process and thus the fate of the Res‐P should be taken into consideration when developing soil nutrient management plans.