bluuebunny/crossref_metadata_2025 huggingface dataset:
Sequential Point Estimation of a Function of the Exponential Scale Parameter
Authors: Uno Chikara , Isogai Eiichi , Lim Daisy Lou
Published: September 2017

We consider sequential point estimation of a function of the scale parameter of an exponential distribution subject to the loss function given as a sum of the squared error and a linear cost. For a fully sequential sampling scheme, we present a sufficient condition to get a second order approximation to the risk of the sequential procedure as the cost per observation tends to zero. In estimating the mean, our result coincides with that of Woodroofe (1977). Further, in estimating the hazard rate for example, it is shown thatour sequential procedure attains the minimum risk associated with the best fixed sample size procedure up to the order term.
Identification of Multivariate Outliers: A Performance Study
Authors: Filzmoser Peter
Published: September 2017

Three methods for the identification of multivariate outliers (Rousseeuw and Van Zomeren, 1990; Becker and Gather, 1999; Filzmoser et al., 2005) are compared. They are based on the Mahalanobis distance that will be made resistant against outliers and model deviations by robust estimation of location and covariance. The comparison is made by means of a simulation study. Not only the case of multivariate normally distributed data, but also heavy tailed and asymmetric distributions will be considered. The simulations are focused on low dimensional (p = 5) and high dimensional (p = 30) data.
Effects of HRT on biological nitrogen removal in single-stage autotrophic process
Authors: Liang Hong , Liu Shutong , Li Xue , Sun Xueying , Gao Dawen
Published: September 2017

An external circulation Sequencing Batch Reactor (ecSBR) was used to study the efficiency of nitrogen removal by autotrophic microbe. With gradually reducing the dissolved oxygen (DO) concentration from 1.2 mg/L to 0.04 mg/L, the single-stage autotrophic biological nitrogen removal (sABNR) process could be operated stably. After removing the aeration, the process could still stay sABNR stably, and the concentration of NH4+-N was 0.9 mg/L in effluent, the rate of nitrate (produced)/NH4+-N (removed) was in the range of 0.12–0.40. The results showed that the concentration of NH4+-N in effluent was 0.8, 0.8 and 9.9 mg/L with the hydraulic retention time (HRT) at 8 h, 6 h and 4 h respectively, the removal efficiency of ammonia were 98.2%, 98.1% and 73.6% respectively. The rate of nitrate (produced)/NH4+-N (consumed) was 0.05 at HRT 6 h, and the nitrogen loading rate (NLR) and nitrogen removal rate (NRR) were 169.7 and 129.7 g/m3/d, the removal efficiency of total nitrogen (TN) was 77.5%. In conclusion the optimal HRT was 6 h instead of 8 h or 4 h enough for ammonia removal without causing energy wastage.
A thermophilic nitrate-reducing bacterium isolated from production water of a high temperature oil reservoir and its inhibition on sulfate-reducing bacteria
Authors: Liu Jin-Feng , Wu Wei-Lin , Yao Feng , Wang Biao , Zhang Bing-Liang , Mbadinga Serge Maurice , Gu Ji-Dong , Mu Bo-Zhong
Published: September 2017

A thermophilic spore-forming facultative anaerobic bacterium, designated as Njiang2, was isolated from the production water of a high temperature oil reservoir (87°C). The physiological, biochemical and 16S rRNA gene based phylogenetic analysis indicated that Njiang2 belonged to the genus Anoxybacillus. Njiang2 could significantly inhibit H2S production when co-cultured with Desulfotomaculum sp under laboratory conditions, which implied its great potential in mitigation of brine souring in the oil reservoir and in control of biocorrosion caused by sulfate-reducing bacteria. As far as we know, this might be the first report of Anoxybacillus sp. isolated from high temperature oilfield
Interactions of the extremely acidophilic archaeon Ferroplasma acidiphilum with acidophilic bacteria during pyrite bioleaching
Authors: Maulani Nova , Li Qian , Sand Wolfgang , Vera Mario , Zhang Ruiyong
Published: September 2017

Bioleaching has been applied as a successful technique for metal recovery from various mineral sources like low-grade ores, waste materials and tailings. Mixed cultures of bioleaching microorganisms have a high performance in mineral dissolution. Thus far, microbial interactions in bioleaching communities are poorly understood. In this paper, the acidophilic archaeon Ferroplasma acidiphilum and the bacteria Leptospirillum ferriphilum and Sulfobacillus thermosulfidooxidans were chosen to study their interactions during pyrite leaching. The initial attachment to pyrite and pyrite leaching efficiency of pure and mixed populations were investigated. The data indicate: (i) attachment and bioleaching efficiency of L. ferriphilum was reduced in the presence of F. acidiphilum. However, the combination of F. acidiphilum and S. thermosulfidooxidans showed increased leaching, although the initial attachment rate was reduced, when compared to pure cultures. Thus, synergistic or antagonistic interactions may exist between F. acidiphilum and S. thermosulfidooxidans or F. acidiphilum and L. ferriphilum, respectively; (ii) pre-established biofilms of L. ferriphilum inhibited initial attachment to pyrite by cells of F. acidiphilum and did not promote pyrite leaching by F. acidiphilum. In contrast, inactivated biofilm cells of S. thermosulfidooxidans enhanced pyrite bioleaching by F. acidiphilum; (iii) adhesion forces of cells to an AFM tip (Si3N4) seemed to be not correlated to attachment and bioleaching capacity; and (iv) lectins were applied to show and distinguish single species in mixed biofilm populations. Physical contact between cells of S. thermosulfidooxidans and F. acidiphilum was visible.
Una mirada crítica a las teorías predominantes de la responsabilidad social corporativa
Authors: Quinche Martín Fabián Leonardo
Published: September 2017

El presente artículo pretende hacer una evaluación de la visión estratégica (las acciones de responsabilidad social deben ser llevadas a cabo siempre y cuando agreguen valor financiero a la empresa), la teoría de los stakeholders (la gestión de la empresa debe tener en cuenta los intereses de los diversos grupos afectados, por lo que estos influyen en el funcionamiento de la empresa) y la ciudadanía corporativa (participación activa de la empresa en la definición y ejecución de la política social), las cuales son las visiones predominantes sobre la responsabilidad social corporativa, a la luz de los conceptos de sostenibilidad fuerte, democracia e interdisciplinariedad. Se considera que estas visiones han influenciado la forma de ver la sostenibilidad por las instituciones estatales, supraestatales y emisoras de estándares. La evaluación considera que estas perspectivas mantienen el modelo de acumulación del capital basado en la explotación del trabajo y los recursos naturales; no hay un aporte a la sostenibilidad en tanto se prima lo financiero sobre lo social y lo ambiental; y se mantiene un enfoque de gestión que rinde cuentas primordialmente a los propietarios del capital.
Diagnóstico de competitividad del turismo en Boyacá (Colombia)
Authors: Rodríguez Moreno Diana Cristina , Granados Ávila Pilar Nathaly
Published: September 2017

Este artículo presenta un diagnóstico del turismo de Boyacá (Colombia). Para tal efecto se realizó el estudio en siete destinos turísticos mediante la cadena de valor. Se efectuaron 368 entrevistas a empresarios, turistas, habitantes y gobierno. Dentro de las conclusiones se tiene que Boyacá y sus destinos turísticos requieren incrementar su competitividad, sin embargo, los diversos problemas que se encuentran en las cadenas de valor de los destinos turísticos impiden el logro de este objetivo.
Reflexões ético-legais sobre os desafios ao dever médico na assistência ao paciente vulnerável social
Authors: Vasconcelos Camila , Garrafa Volnei
Published: September 2017

La obligación médico-asistencial de mantener una práctica profesional coherente a los aspectos éticos y legales encuentra desafíos cuando enfrenta circunstancias aparentemente contradictorias. Así, tanto situaciones como el debido respeto a la autonomía de los sujetos —especialmente aquellos vulnerables socialmente— pueden parecer confrontarse a los aspectos legales concernientes a la capacidad civil, cuanto el deber de información y aclaración al paciente es capaz de plantear dudas cuando se trata de una circunstancia en la que se debe aplicar el “derecho de no saber”. En este contexto, el artículo analiza estas posibles contradicciones a partir de una breve interpretación lógico-deductiva de sus conceptos en la realidad latinoamericana, según las perspectivas ético-legales. Los enfoques filosóficos foucaultianas ayudan en la comprensión de la entrega de la información como la búsqueda inicial por el empoderamiento del discurso de los pacientes, así como los análisis kantianos sobre la idea de la debida aclaración, dialogan con la comprensión de los conceptos de mayoría y minoría, en debate con los derechos de conocer la verdad o haberlas omitido a los sujetos. La bioética de intervención, como teorización latinoamericana en defensa de los sujetos vulnerables, trae conceptos que favorecen la comprensión contextual de necesaria protección de los sujetos. El ejercicio de la medicina en la asistencia ha encontrado desafíos, siendo necesaria una comprensión ampliada de institutos que puedan favorecer su práctica en respeto a los pacientes, no bastando la comprensión acerca de las cuestiones legales, especialmente en contextos de desprotección y exclusión social.
Vascular Deformation Mapping (VDM) of Thoracic Aortic Enlargement in Aneurysmal Disease and Dissection
Authors: Burris Nicholas S. , Hoff Benjamin A. , Kazerooni Ella A. , Ross Brian D.
Published: September 2017

Thoracic aortic aneurysm is a common and lethal disease that requires regular imaging surveillance to determine timing of surgical repair and prevent major complications such as rupture. Current cross-sectional imaging surveillance techniques, largely based on computed tomography angiography, are focused on measurement of maximal aortic diameter, although this approach is limited to fixed anatomic positions and is prone to significant measurement error. Here we present preliminary results showing the feasibility of a novel technique for assessing change in aortic dimensions, termed vascular deformation mapping (VDM). This technique allows quantification of 3-dimensional changes in the aortic wall geometry through nonrigid coregistration of computed tomography angiography images and spatial Jacobian analysis of aortic deformation. Through several illustrative cases we demonstrate that this method can be used to measure changes in the aortic wall geometry among patients with stable and enlarging thoracic aortic aneurysm and dissection. Furthermore, VDM results yield observations about the presence, distribution, and rate of aortic wall deformation that are not apparent by routine clinical evaluation. Finally, we show the feasibility of superposing patient-specific VDM results on a 3-dimensional aortic model using color 3D printing and discuss future directions and potential applications for the VDM technique.
Cidades como territórios da saúde,educação, cultura e da vida
Authors: Bortolozzi Arlêude
Published: September 2017

Através da linha de pesquisa denominada “Dinâmica territorial, sistemas técnicos atuais e novas práticas socioespaciais”, desenvolvida no Programa de Pós-Graduação da Geografia, no Instituto de Geociências (IG) da Unicamp, é possível incorporar novos conteúdos do espaço geográfico nas análises de diferentes temas. Estes, associados às novas técnicas de informação territorial e de redes telemáticas, possibilitam por sua vez novas reflexões epistemológicas sobre os estudos do local,  que, quando relacionados com outras escalas espaciais, passam a contribuir de forma inquestionável para a ampliação do debate e o entendimento sobre o desenvolvimento urbano.
Perspectivas educacionais em um cenário de novos suportes midiáticos
Authors: Carnicel Amarildo
Published: September 2017

A escolha do tema ‘Educação para a Mí- dia’ como principal eixo de articulação dos textos da presente edição de Resgate – Revista Interdisciplinar de Cultura deve-se à proeminência dessa área de estudos nos dias de hoje. A diversicação, a individualização e a crescente popularização dos suportes de informação, a tendência de universalização do acesso à rede web, bem como a ação cada vez mais concentrada dos grupos midiáticos, são alguns dos fatores que, por si mesmos, implicam necessária re3 exão sobre o tema, sobretudo em se tratando da perspectiva educacional. Note-se, por exemplo, a tendência comum entre os jovens de informar-se tão somente a partir da internet, abandonando (ou sequer chegando a conhecer) os suportes impressos e secundarizando até mesmo a televisão. Esses movimentos, cada vez mais fortes em diferentes segmentos da sociedade moderna, motivaram o educador e professor da Unesp-Assis, Juvenal Zanchetta Junior, a reunir pesquisadores de diferentes contextos para compor a edição. Experiências vividas além de nossas fronteiras corroboram para pensar a realidade pela qual passa a juventude brasileira cada vez mais ‘plugada’ e, de certa maneira, pouco atenta aos suportes midiáticos tradicionais.
ANPEd e Intercom: panorama da produção dos pesquisadores em Educação e Comunicação na última década
Authors: Almeida Lígia Beatriz Carvalho de , Ghaziri Samir Mustapha , Lobato Margareth Cavalcante de Castro
Published: September 2017

O artigo expõe resultados parciais de pesquisa que investiga características das propostas voltadas ao tema educação formal e comunicação, a partir dos artigos publicados entre os anos de 2000 e 2010, nos anais dos grupos de pesquisa sobre Educação e Comunicação ligados à ANPEd e à Intercom. O estudo identificou convergência quanto aos pressupostos teóricos, concepções sobre a instituição escolar e propostas para a educação formal, fatores que ajudam a consolidar um campo de saber específico.
Formar professores de matemática no estado do Maranhão, Brasil: aspectos historiográficos
Authors: Fernandes Déa Nunes , Garnica Antonio Vicente Marafioti
Published: September 2017

O texto apresenta aspectos historiográficos relativos à formação de professores de Matemática em cursos superiores do estado do Maranhão, num período que tem como marco inicial a implantação, na década de 1960, da primeira Licenciatura Plena em Matemática no estado. Seguindo os parâmetros da História Oral, foram entrevistados professores de três instituições públicas de ensino superior do estado que trabalharam como docentes quando da implantação e/ou da elaboração dos projetos dos primeiros cursos de Licenciatura Plena em Matemática e alunos da primeira turma neles graduada.
Estação Ferroviária de Pelotas: espaço de sociabilidade, visualidade e memória urbana
Authors: Schmitz Maira Eveline
Published: September 2017

O tema deste artigo é o espaço ferroviário da cidade de Pelotas, no sul do Rio Grande do Sul, ao final do século XIX. Este foi um momento de mudança na materialidade urbana e busca-se, assim, inferir as novas sociabilidades e práticas sociais construídas no espaço ferroviário, bem como compreender as interpretações e sentidos dados ao local. Para tanto, as fontes analisadas serão fotografias e jornais, utilizando-se as metodologias apropriadas. Indo além, pretende-se perceber como os sentidos dados ao espaço ferroviário naquele momento dialogam com sua situação material e patrimonial hoje.
Osnova and the Origins of the Valuev Directive
Authors: Moser Michael
Published: September 2017

After the Crimean War, Ukrainian intellectuals utilized the temporary liberalization in the Russian Empire to extend the use of the Ukrainian language beyond the spheres of folklore and fine literature, to develop Ukrainian into a modern standard language, and to set measures to disseminate this language among speakers of Ukrainian. These processes were reflected, inter alia, in the journal Osnova (The Foundation) of 1861-62. As my study shows, when the Russian administration issued the Valuev Directive in 1863, it did not ban the Ukrainian language as such, but it effectively banned its standardization and dissemination.
Beyond the Conflict and Weak Civil Society; Stories from Ukraine: Cases of Grassroots Initiatives for Sustainable Development
Authors: Udovyk Oksana
Published: September 2017

This study explores the diversity of grassroots initiatives (GIs) for sustainable development that are emerging in post-EuroMaidan Ukraine. It first focuses on an overview of different theories on civil society and trends in Ukrainian civil society development. Eight cases of GIs are selected to represent different pillars of sustainability work done by the initiatives (economic, social, environmental, and political-institutional). These cases question the arguments behind the weak and pseudo-plenipotentiary vision of civil society in Ukraine, and demonstrate mechanisms of sustainable development suggested by analyzed GIs. In general, this study challenges the myth of a weak civil society in Ukraine, opens up a broader discussion on the meaning and role of civil society, and provides new ideas for building a sustainable society.
Agronomy Journal Turns One Hundred
Authors: Pearson Calvin H. , Ernst Susan M. , Barbarick Ken A. , Hatfield Jerry L. , Peterson Gary A. , Buxton Dwayne R.
Published: September 2017

During 2008 we celebrate the centennial anniversary of Agronomy Journal Many people have certainly been influenced in some way by the science published during the 100‐yr existence of the journal. From Volume 1 up through Volume 98 (2006) there have been more than 30,290 authors who published 15,232 articles totaling 89,056 pages. More than 2545 editors were required to review and edit the papers published in Agronomy Journal, in addition to the manuscripts submitted but not published. As a current snapshot of Agronomy Journal, we published 60% of the manuscripts submitted in 2005. In both 2003 and 2004, we accepted 55% of the manuscripts submitted. In a comparison of 48 peer journals in 2005, the impact factor of Agronomy journal ranked 12th at 1.473 and the total citations for the journal ranked fourth at 6723. Commentaries on the early history of Agronomy Journal have been previously published. In our article, we focus on the journal's history during the past 25 yr. We fully expect that the future of Agronomy Journal will be even more exciting, rewarding, challenging, and valued as the past 100 yr. We eagerly look forward to the next 100 yr of Agronomy Journal.
Yield, Yield Components, and Forage Nutritive Value of Alfalfa as Affected by Seeding Rate under Irrigated Conditions
Authors: Lloveras Jaume , Chocarro Cristina , Freixes Oscar , Arqué Ezequiel , Moreno Alberto , Santiveri Francisca
Published: September 2017

Persistence is a critical component of alfalfa (Medicago sativa L.) crop yield. Our objective was to determine the effect of seeding rate on alfalfa persistence, yield, and yield components and how they evolved over time in irrigated areas with long growing seasons. Two alfalfa cultivars were seeded at four seeding rates (10, 20, 30, and 40 kg ha−1), in three consecutive experiments, and evaluated over a 3‐yr period to provide total data for nine location years. Seed rates of 10 kg ha−1 [8.75 kg ha−1 of pure live seed (PLS)] produced total 3‐yr dry matter (DM) yields of between 50.8 and 58.9 Mg ha−1. Seed rates only affected total 3‐yr DM yields in one of the three experiments. The mean number of shoots per m−2 was 488 and this was not affected by seed rates. The effect of seed density on mean shoot weight depended on the experiment. The annual average crude protein (CP) concentration varied from 159 g kg−1 to 224 g kg−1 while the leaf to stem ratio varied from 0.87 to 1.17. The results suggest that CP and leaf to stem ratios (LSR) were either little influenced or not influenced by seed density. The DM yields and yield components indicate that 8.75 kg ha−1 of PLS could be sufficient to ensure adequate DM production. Results also suggest that in a Mediterranean climate in which sprinkler irrigation is applied, there is little justification for high seeding rates under good establishment conditions.
Peanut Response to Planting Date and Potential of Canopy Reflectance as an Indicator of Pod Maturation
Authors: Carley Danésha S. , Jordan David L. , Dharmasri L. Cecil , Sutton Turner B. , Brandenburg Rick L. , Burton Michael G.
Published: September 2017

Determining when to dig peanut (Arachis hypogea L.) is complicated because of its indeterminate growth habit. Pod mesocarp color is often used an indicator of pod maturation. However, this process is time consuming and is usually based on a relatively small subsample of pods from peanut fields. Research was conducted during 2003–2005 to determine if reflectance of the peanut canopy, using multispectral imaging (350–2500 nm), could be used as an indicator of pod maturation. The cultivars VA 98R and NC‐V 11 were planted beginning in early May through early June during each year with reflectance and the percentage of pods at optimum maturity (percentage of pods with brown or black mesocarp color) determined in mid‐September. The highest yield observed for VA 98R across the 3 yr of the experiment was noted when peanut was planted in mid‐May rather than early or late May or when planted in early June when peanut was dug based on optimum pod maturity using pod mesocarp color. Pod yield for the cultivar NC‐V 11 did not differ when comparing planting dates. For cultivar VA 98R, Pearson's correlations were significant for all bandwidth categories except the normalized difference vegetation index (NDVI) when reflectance was compared with percentage of mature pods. Reflectance for NC‐V 11 was not significant for any of the correlations even though significant differences in the percentage of mature pods were noted in mid September when comparing planting dates. These data suggest that canopy reflectance could potentially aid in predicting pod maturation, but more research is needed to determine feasibility of this approach.
A Simple Spectral Index Using Reflectance of 735 nm to Assess Nitrogen Status of Rice Canopy
Authors: Lee Yuh‐Jyuan , Yang Chwen‐Ming , Chang Kuo‐Wei , Shen Yuan
Published: September 2017

Spatial distribution of canopy N status is the primary information needed for precision management of N fertilizer. This study demonstrated the feasibility of a simple spectral index (SI) using the first derivative of canopy reflectance spectrum at 735 nm (dR/dλ|735) to assess N concentration of rice (Oryza sativa L.) plants, and then validated the applicability of a simplified imaging system based on the derived spectral model from the dR/dλ|735 relationship in mapping canopy N status within field. Results showed that values of dR/dλ|735 were linearly related to plant N concentrations measured at the panicle formation stage. The leaf N accumulation per unit ground area was better fitted than other ratio‐based SIs, such as simple ratio vegetation index (SRVI), normalized difference vegetation index (NDVI), R810/R560, and (R1100 − R660)/(R1100 + R660), and remained valid when pooling more data from different cropping seasons in varied years and locations. A simplified imaging system was assembled and mounted on a mobile lifter and a helicopter to take spectral imageries for mapping canopy N status within fields. Results indicated that the imaging system was able to provide field maps of canopy N status with reasonable accuracy (r = 0.465–0.912, root mean standard error [RMSE] = 0.100–0.550) from both remote sensing platforms.
Spatial Analysis of Early Wheat Canopy Normalized Difference Vegetative Index: Determining Appropriate Observation Scale
Authors: Pena‐Yewtukhiw E. M. , Schwab G. J. , Grove J. H. , Murdock L. W. , Johnson J. T.
Published: September 2017

Efficient use of real‐time canopy sensors requires knowledge of the scale (resolution) of variation in the measured canopy property. Knowing the amount of needed optical data requires estimation of the optimal combination of physical sensor density (number of sensors along the applicator boom) and sensor output density (sensor readings per unit distance along the travel path). The objective of this study was to determine the sampling grid size that would adequately describe field variation in canopy normalized difference vegetative index (NDVI) by varying either physical sensor density or sensor output density. Wheat (Triticum aestivum L.) canopy NDVI data were collected at Feekes growth stage 3 in five fields in central and western Kentucky in February of 2004 or 2005. Spatial structure of NDVI was characterized by variogram analysis across grid sizes ranging from 0.56 (high‐density) to 5.1 m2 and both semivariance and spatial structure parameters for high‐density data sets were compared to those obtained with decreasing numbers of sampling points (greater grid size). Nugget, range, and sill values were maintained across evaluated grid sizes in four of five site‐years. Correlations between each field's high‐density semivariance values and those for the “low‐density” data sets were generally high (1.0 < R2 < 0.8) for all site‐years, but there were many cases where intercepts deviated significantly from 0.0 and slopes deviated significantly from 1.0. Observed differences in individual sensor performance did not influence the pattern of NDVI spatial structure. Grid size could be increased from 0.56 to 5.1 m2 without significantly affecting the measured spatial structure of canopy NDVI in most fields. Wheat growers might achieve spatially optimal N applications with lower data resolution and less capital intense machinery.
Improving the CERES‐Maize Model Ability to Simulate Water Deficit Impact on Maize Production and Yield Components
Authors: López‐Cedrón Francisco X. , Boote Kenneth J. , Piñeiro Juan , Sau Federico
Published: September 2017

Crop models are potential tools for designing water‐efficient strategies and should be tested for accurate prediction of water deficit effects on production. The objective of this research was to test and improve the CERES‐Maize model (CERES‐4.0) for ability to predict accurately maize biomass and grain yield components under water‐limiting conditions in an environment where the model had previously given good predictions under irrigated conditions. Under a water‐limited environment in northwest Spain, CERES‐4.0 failed to simulate sufficiently high growth and yield; thus we evaluated aspects of model believed responsible for the poor performance. The model was tested with two evapotranspiration options [Priestley‐Taylor (PT) and Penman–Monteith reference method (PFAO56, FAO no. 56 manual)] and with two values for the coefficient (KEP) that partitions evapotranspiration (ET) between crop transpiration and soil evaporation (default: KEP = 0.685; alternate: KEP = 0.500). The PT option with KEP = 0.685 underpredicted grain yield and biomass due to too early and too severe simulated water extraction. Predictions of biomass and grain yield with both PT and PFAO56 were improved when a KEP of 0.500 was used instead of the default 0.685. The PFAO56, the less water demanding of the tested crop reference (ETo) equations, gave the best predictions. In addition, a systematic underprediction of grain number and grain size with the default model in response to water deficit was observed, regardless of ET option or KEP value. Model predictions of the latter two variables was improved by replacing the default CERES‐4.0 function that computes seed number per plant with the function of Edmeades and Daynard (1979).
Estimating Ground Cover of Field Crops Using Medium‐Resolution Multispectral Satellite Imagery
Authors: Maas Stephan J. , Rajan Nithya
Published: September 2017

Remote sensing is useful for estimating plant canopy characteristics, such as leaf area index (LAI) and ground cover (GC). When the source of remote sensing data is medium‐resolution satellite imagery, plant canopy characteristics can be estimated for numerous fields within an agricultural region. In this study, a procedure was developed to estimate GC of field crops from medium‐resolution satellite image data in the red and near‐infrared (NIR) spectral bands. In the procedure, GC is estimated from the ratio of the perpendicular vegetation index (PVI) value calculated for an image pixel to the PVI value corresponding to full vegetation canopy. Two main advantages of this procedure are that it does not rely on empirical relationships, and that it can use raw satellite digital count data without conversion to surface reflectance or normalization for scene‐to‐scene differences in brightness. A field study was conducted in 2006 in the Texas High Plains to collect ground‐based observations of GC for 31 agricultural fields containing various crops for testing the procedure. The GC for these fields was estimated using the procedure from Landsat‐5 TM image data acquired on four dates during the growing season. Statistical analysis of the linear regression between satellite‐based estimates of GC and corresponding ground‐based observations of GC indicated that the regression was not different from a 1:1 relationship. Statistical analysis also indicated that the average of the satellite‐based estimates of GC was not significantly different from the average of the ground‐based observations of GC. The results suggest that, on average, estimates of GC determined using this procedure should be within 6% of their true values. The relative simplicity of this procedure should facilitate the quantification of vegetation resources in agricultural regions.
Establishment and Growth of Self‐Seeded Winter Cereal Cover Crops in a Soybean–Corn Rotation
Authors: McDonald Paul B. , Singer Jeremy W. , Wiedenhoeft Mary H.
Published: September 2017

Perpetuating cereal cover crops through self‐seeding may increase adoption by reducing risk and cost. Winter rye (Secale cereale L.), wheat (Triticum aestivum L.), and triticale (× Triticosecale Wittmack) were used to develop self‐seeding cover crop systems in a soybean [Glycine max (L.) Merr.]–corn (Zea mays L.) rotation. Cereals were planted and managed chemically and mechanically in varying configurations. The objectives were to (i) quantify temporal establishment patterns after one cycle of self‐seeding, (ii) quantify shoot biomass, N uptake, and seed production growing concurrently with corn, and (iii) quantify cover crop establishment after two cycles of self‐seeding. Final plant densities for most species by treatment combinations were fully established within 1 wk after soybean (Cycle 1) harvest. Fall green ground cover after soybean was consistently higher with wheat and ranged from 16 to 61%. Straw biomass the following July ranged from 50.4 to 79.1 g m−2 in wheat, 20.1 to 39.3 g m−2 in triticale, and 0.0 to 52.7 g m−2 in rye. Combined spring and maturity maximum N uptake was 20.7, 21.2, and 35.0 kg ha−1 for triticale, wheat, and rye. Cycle two cover crop seed production was greatest in wheat and ranged from 559 to 1280 seeds m−2. Wheat also consistently had greater self‐seeding plant establishment after two cycles than rye and triticale, which ranged from 5 to 21% of the original plant densities and 19 to 64% of the cycle one plant densities. Future research on self‐seeding cereal cover crops should focus on efficient technologies for seed dispersal.
Tie‐Ridge Tillage for High Altitude Pulse Production in Northern Ethiopia
Authors: Tesfahunegn Gebreyesus Brhane , Wortmann Charles S.
Published: September 2017

Pulses including faba bean (Vicia faba L.), lentil (Lens culinaris Medic.), and field pea (Pisum sativum L.) are important components of the cropping systems of semiarid high‐altitude northern Ethiopia. Yield potential is often constrained by severe water deficits during grain fill which might be alleviated by reducing runoff throughout the season using microbasin or tie‐ridge tillage. Research was conducted to determine the effects of time of tie‐ridge tillage and planting method on soil water availability and on the performance of these three pulse crops. The site was at 2740 m altitude on Torriorthent sandy loam or loamy sand soils. Eight treatments, including a 3 × 2 factorial of tillage × planting method, were evaluated in separate trials for each crop species in 2005 and 2006 with a randomized block design with three replications. Tie‐ridge tillage improved soil water availability compared with the traditional practice of planting without ridges, and soil water was least depleted during the growing season with tie‐ridge formation at 4 wk after planting (TR4WAP) when the first weeding was done. Grain yield and nodulation were also highest with TR4WAP, with mean grain yield increases of 79, 31, and 96% for faba bean, lentil, and field pea, respectively, compared with flat planting. Tie‐ridging at other times typically resulted in increased grain yield compared with traditional flat planting if planted on the ridge, but decreased yield with in‐furrow planting. Mean grain yield was 48, 23, and 35% with planting on the ridge compared with in‐furrow if tie‐ridging was done before planting for faba bean, lentil, and field pea, respectively. Soil water availability, however, was higher with in‐furrow planting. Tie‐ridging, or possibly reshaping earlier‐formed tie‐ridges, at the time of the first weeding after planting was most effective in improving pulse yield.
Strategies to Improve Nitrogen Use Efficiency in Winter Cereal Crops under Rainfed Conditions
Authors: Arregui L. M. , Quemada M.
Published: September 2017

Developing fertilizer strategies that increase nitrogen use efficiency (NUE) could reduce unnecessary input costs to farmers and environmental impact of N losses. Two field experiments were performed in northern Spain to evaluate alternative N fertilization strategies to improve NUE in winter cereal crops (wheat [Triticum aestivumL.] and barley [Hordeum vulgareL.]). The strategies were: (i) adjusting the fertilizer rate by soil mineral N before N application; (ii) splitting of N fertilizer application; and (iii) the use of fertilizer with a nitrification inhibitor (3,4‐dimethylpyrazole phosphate, DMPP). The experiments were designed as a completely randomized block design with seven treatments and four replications. Treatments included a control, two single applications, one with DMPP, and four split N applications. Nitrogen balance was calculated according to the general equation of conservation of mass for any soil–crop system from which N‐efficiency parameters were determined. Grain yield followed a quadratic‐plus‐plateau model with different optimum N rate depending on the year (71 and 98 kg N ha−1in 2002–2003 and 2003–2004, respectively). Adjusting N fertilizer rate by soil mineral N before N application gave a maximum yield and a similar NUE to the optimum N rate predicted by the model. Neither applying N in two doses nor including a nitrification inhibitor with a single dose showed any advantages in terms of yield or N efficiency.
Soybean Aphid Feeding Injury and Soybean Yield, Yield Components, and Seed Composition
Authors: Beckendorf Eric A. , Catangui Michael A. , Riedell Walter E.
Published: September 2017

Information that describes soybean aphid (Aphis glycines Matsumura) feeding injury effects on soybean [Glycine max (L.) Merr.] yield and seed composition is needed to develop better management practices for this invasive pest. This 2‐yr controlled‐infestation field study measured aphid populations and the effects of those populations on soybean seed yield, yield components (shoot biomass, pods plant−1, seeds pod−1, and 100 seed weight), and seed composition (oil and protein concentrations) when infested at the vegetative (V5) or reproductive (R2) development stages. In 2003, initial infestation rates of 10, 50, or 100 aphids plant−1 applied at V5 resulted in population peaks of 21,000, 18,000, and 12,000 aphids plant−1 and maximum cumulative aphid‐days of 381,000, 327,000, and 242,000, respectively. In 2004, initial infestation rates of 1, 3, 10, 50, or 100 aphids plant−1 applied at V5 resulted in population peaks of 4,600, 9,400, 14,000, 22,000, and 21,000 aphids plant−1 and maximum cumulative aphid‐days of 101,000, 229,000, 355,000, 514,000, and 537,000. In both years, the same infestation rates applied at R2 resulted in population peaks and cumulative aphid‐day values that were about 42 to 88% lower than the V5 infestation dates. Seed yield, yield components, and seed oil concentration declined linearly as peak aphid numbers plant−1 and maximum cumulative aphid‐days plant−1 increased. In contrast, seed protein concentration increased linearly with increasing peak aphid numbers plant−1. Relating these aphid population parameters at the plant growth stages studied enables producers to make informed decisions about the need for and timing of pest management treatments.
Nitrogen Use Efficiency and Nitrogen Uptake of juncea Canola under Diverse Environments
Authors: Gan Y. , Malhi S. S. , Brandt S. , Katepa‐Mupondwa F. , Stevenson C.
Published: September 2017

Nitrogen accounts for the largest energy input in oilseed production. Understanding N use characteristics of oilseed crops will help improve N use efficiency and minimize production costs. This study determined nitrogen use efficiency (NUE, defined as seed yield produced per unit of N supply), nitrogen fertilizer use efficiency (NFUE, defined as seed yield produced per unit of fertilizer N), and crop N uptake for oilseed crops under diverse environments. Five oilseed crops, namely Brassica juncea, B. napus, and B. rapa canolas, and B. juncea and Sinapis alba mustards, were grown at seven rates of N fertilizer (0, 25, 50, 100, 150, 200, and 250 kg N ha−1), at 11 sites (year × location combinations) in Saskatchewan from 2003 to 2005. At sites with low soil N supply or low rainfall, alba mustard, juncea canola, and rapa canola had lower NUE and NFUE than juncea mustard and napus canola. At sites with high soil N supply or rainfall, napus canola had the greatest NUE and was the most sensitive to the gradient of productivity among the five oilseeds. All oilseed species responded to N fertilizer rates in a similar manner; both NUE and NFUE decreased as N fertilizer rate increased. The minimum NUE and NFUE were obtained with N fertilizer rate greater than 150 kg N ha−1. At sites with low soil N supply or rainfall, alba mustard had the least NUE or NFUE response to increasing N fertilizer rates and napus canola the greatest. At sites with high soil N supply or rainfall, juncea mustard had the least NUE and NFUE response to increasing N fertilizer rates and rapa canola the greatest. On average, seed N uptake was greatest for juncea canola and juncea mustard and least for alba and rapa canola. The five oilseed species had similar response patterns of seed N uptake to N fertilizer rates, while the magnitude of response varied among species. Improving NUE in oilseed production systems requires optimizing rates of N fertilizer which vary depending on environmental conditions, and soil N supply and rainfall during the critical growth period of the oilseed crops play an important role in affecting NUE.
Metal Immobilization in Soils Using Synthetic Zeolites
Authors: Oste Leonard A. , Lexmond Theo M. , Van Riemsdijk Willem H.
Published: September 2017

In situ immobilization of heavy metals in contaminated soils is a technique to improve soil quality. Synthetic zeolites are potentially useful additives to bind heavy metals. This study selected the most effective zeolite in cadmium and zinc binding out of six synthetic zeolites (mordenite‐type, faujasite‐type, zeolite X, zeolite P, and two zeolites A) and one natural zeolite (clinoptilolite). Zeolite A appeared to have the highest binding capacity between pH 5 and 6.5 and was stable above pH 5.5. The second objective of this study was to investigate the effects of zeolite addition on the dissolved organic matter (DOM) concentration. Since zeolites increase soil pH and bind Ca, their application might lead to dispersion of organic matter. In a batch experiment, the DOM concentration increased by a factor of 5 when the pH increased from 6 to 8 as a result of zeolite A addition. A strong increase in DOM was also found in the leachate of soil columns, particularly in the beginning of the experiment. This resulted in higher metal leaching caused by metal–DOM complexes. In contrast, the free ionic concentration of Cd and Zn strongly decreased after the addition of zeolites, which might explain the reduction in metal uptake observed in plant growth experiments. Pretreatment of zeolites with acid (to prevent a pH increase) or Ca (to coagulate organic matter) suppressed the dispersion of organic matter, but also decreased the metal binding capacity of the zeolites due to competition of protons or Ca.
Arsenic Remobilization in a Shallow Lake
Authors: Linge Kathryn L. , Oldham Carolyn E.
Published: September 2017

Oxic resuspension occurs regularly in shallow lakes, yet its role as a mechanism for contaminant remobilization remains ill defined. This study investigated contaminant remobilization during sediment resuspension and determined whether changes in contaminant sediment partitioning reflected the mechanisms controlling remobilization. Arsenic‐contaminated sediment from a shallow wetland was subjected to simulated resuspension under a range of differing initial pH conditions. The effect of resuspension on As partitioning was evaluated using a fractionation scheme targeting the dissolved, ion exchangeable, carbonate, organic, amorphous iron oxide, crystalline iron oxide, and apatite fractions. Rate investigations demonstrated that arsenic remobilization occurred on timescales similar to resuspension events, with concentrations reaching steady state within 24 h. The sediment also buffered slurry pH to 8.3 in experiments where the initial pH was between 4 and 10. This pH regulation was attributed to carbonate dissolution or acid–base equilibria of surface base functional groups, although iron oxide and organic matter dissolution did occur in experiments with an initial pH outside this range. Remobilization caused losses in arsenic associated with the ion exchangeable, organic, and amorphous iron fractions but changes in initial pH have a negligible effect on arsenic remobilization or partitioning within the well‐buffered region. Resuspension released approximately 20% of the total sediment arsenic, although calculations indicated that a single resuspension event would not significantly change water column arsenic concentrations. While not conclusively proving the mechanisms of remobilization, fractionation gave valuable insight into the effect of sediment resuspension on contaminant remobilization.
Copper Release from Chemical Root‐Control Baskets in Hardwood Tree Production
Authors: Kosuta Sonja , Hamel Chantal , Dalpé Yolande , St‐Arnaud Marc
Published: September 2017

The City of Montreal, Canada, evaluated the environmental impact and usefulness of in‐ground copper (Cu)‐treated baskets in controlling root growth of hardwood trees in nursery culture. Using baskets planted with 5‐yr‐old Norway maple (Acer platanoides L.) trees, the amount and temporal pattern of Cu release from the basket surface into soil was determined for two copper formulations: Cu metal powder and Cu(OH)2 Release of both Cu formulations from the basket surface decreased exponentially over time, with Cu concentration at the basket surface dropping to 2% of the initial Cu applied by the end of the second field season. Total Cu content increased significantly in the soil around the baskets (from 7 to 28 mg Cu kg−1 soil) and in the baskets (from 7 to 50–70 mg Cu kg−1 soil) over the two years of the study. Three levels of phosphorus application (33, 66, and 100% of the regular nursery rate of 465 kg ha−1 yr−1) did not affect release of Cu from the basket surface. The release of Cu metal at 28 and 105 d in the field was significantly increased by inoculation with the symbiotic arbuscular mycorrhizal fungus (AMF) Glomus intraradices Schenck & Smith; however, AMF inoculation had no affect on Cu(OH)2 release. Trees grown in Cu‐treated baskets and inoculated with G. intraradices had similar colonization to non‐inoculated trees, suggesting that inoculation was not very effective and that AMF inoculum was already present in the root ball of the trees at planting. After two years, copper basket–grown trees had significantly less root colonization than isolated control trees growing in the open field. This strongly suggests that conditions inside the baskets were not favorable to AMF.
Nitrogen Contamination in the Yellow River Basin of China
Authors: Xia Xinghui , Zhou Jingsong , Yang Zhifeng
Published: September 2017

Nitrogen contamination is one of the most serious problems in the Yellow River of China. This study was conducted to analyze monitoring data on nitrogen contamination for the Yellow River basin in the years 1980, 1990, 1997, and 1999. Several significant results have arisen from the study. First, in conjunction with an increase in economic indexes from the Yellow River's upper basin to its lower basin, the nitrogen concentration in the tributaries also showed an increasing trend from the upper to the lower basin, which, in turn, led to an increase in the nitrogen concentration of the mainstream from the upper to the lower reaches. Second, nitrogen in the river water in the mainstream and the tributaries of the Yellow River was attributed mainly to point sources. In spite of the fact that the ratio of point to nonpoint sources decreased from 2.7 in 1990 to 1.8 in 1997 for total inorganic nitrogen in river water at the Tongguan Station in the lower basin, point sources increased more than nonpoint sources. Third, the ammonium nitrogen and total inorganic nitrogen content of the river water increased significantly in the mainstream and the tributaries during the 1980–1999 period, a change caused by an increase in wastewater discharge and nitrogenous fertilizer application in the Yellow River catchment.
Sorption Kinetics of Toluene in Humin under Two Different Levels of Relative Humidity
Authors: Shih Yang‐hsin , Wu Shian‐chee
Published: September 2017

To identify any resistant fraction for desorption of toluene from humin and to quantify the sorption–desorption rates, the time courses of toluene sorption to compressed humin disks and to a thin humin film were investigated. The apparent diffusivity of toluene with humin disks ranges from 10−8 to 10−9 cm2/s and increases with temperature, based on the weight change of humin disks mounted on a microbalance and on the results simulated by use of a diffusion model. No detectable level of residual toluene was found after desorption, as revealed either by the gravimetric analysis or by the Fourier transform infrared (FTIR) spectrum obtained at either low or high humidity. The time scale for intrinsic vapor sorption without mass transfer hindrance is less than a few minutes with the thin film. All the results indicate that the sorption of toluene to humin is reversible and mainly diffusion controlled. This finding helps to better understand the sorption kinetics associated with humin and soil organic matter.