bluuebunny/crossref_metadata_2025 huggingface dataset:
Recruitment methods employed in the National Lung Screening Trial
Authors: Marcus Pamela M , Lenz Suzanne , Sammons Donna , Black William , Garg Kavita
Published: June 2012

Objectives

To report participant recruitment experiences in a large, US randomized controlled trial (RCT) of lung cancer screening, with the aim of providing information that may be of use to researchers who wish to conduct similar future studies.

Setting

The National Lung Screening Trial (NLST), an RCT that demonstrated a 20% lung cancer mortality reduction with low dose helical computed tomography screening, relative to single-view chest radiograph screening. Thirty-three US medical centres recruited 53,454 participants from August 2002 through April 2004.

Methods

After recruitment was completed, centre co-ordinators were asked to complete a questionnaire addressing the extent to which specific methods were used and, for each specific method, numbers enrolled and total cost of the effort. Cost per enrollee was calculated. Coordinators also were asked to report lessons learned.

Results

Twenty-two centres returned questionnaires. Use of recruitment method varied by centre. Among centres reporting number enrolled by method, about 19,000 participants were enrolled with direct mail, about 4200 with mass media, and about 1000 with community outreach. Cost per enrollee varied across centres but medians were (US)$101 (direct mail), $79 (mass media), and $4 (community outreach). Co-ordinators reported that it was important to know where to find persons likely to be eligible and interested, and how best to approach them.

Conclusions

Most NLST participants were recruited through direct mail, although median cost per participant was highest for that method.
The impact of media coverage of the Flexible Sigmoidoscopy Trial on English colorectal screening uptake
Authors: Lo Sh , Vart G , Snowball J , Halloran Sp , Wardle J , Von Wagner C
Published: June 2012

Objective

To assess the impact of media coverage of the UK Flexible Sigmoidoscopy Trial on colorectal screening uptake in England.

Setting

In April 2010, publication of the UK Flexible Sigmoidoscopy (FS) Trial results generated considerable media interest in both FS and colorectal cancer (CRC) generally.

Methods

We used routinely collected data from the south of England (excluding London) to analyse return of faecal occult blood test (FOBt) kits within 28 days of the invitation (early uptake) among 60–69 year olds, before (T1, n = 31,229), around the time of (T2, n = 39,571), and one month after (T3, n = 33,430) the FS publicity.

Results

FOBt uptake over the whole period was 58.2%, with 38.4% of the kits returned within 28 days (early uptake). Across the three time periods, early uptake was 35.8% at T1, 39.4% at T2, and 39.7% at T3. Multivariate regression controlling for age, gender and socioeconomic status confirmed that uptake was higher if people received the FOBt kit around the time of the media coverage (T2: odds ratio [OR] = 1.17, 95% CI = 1.13–1.20), or one month after (T3: OR = 1.18, 95% CI = 1.15–1.22) than before (T1). Sub-group analyses demonstrated that the impact was stronger among previous non-responders than among first-time invitees or previous responders (P < 0.001).

Conclusion

Media coverage of the FS Trial appeared to have a small but positive impact on FOBt screening uptake, especially among people who had previously abstained from screening.
The impact of Jade Goody's diagnosis and death on the NHS Cervical Screening Programme
Authors: Lancucki L , Sasieni P , Patnick J , Day Tj , Vessey Mp
Published: June 2012

Objectives

In August 2008 the British reality TV star Jade Goody made public her diagnosis of cervical cancer. In February 2009 it was announced that she was terminally ill and she died a few weeks later. A surge in cervical screening attendances associated with these events was widely reported. This paper aims to quantify the size of that effect across England, its duration, and whether it affected some groups of women more than others.

Setting

The Cervical Screening Programme in England.

Methods

Routinely collected statistics for the months around Jade Goody's diagnosis and death were compared with those for other periods.

Results

About half a million extra cervical screening attendances occurred in England between mid-2008 and mid-2009, the period during which Jade Goody was diagnosed and died; among these were 370 attendances where the test result was suspected neoplasia. At its peak in March 2009, attendance was 70% higher than expected. Increases were seen in both initial and follow-up screening attendances and in colposcopy attendances, and at all ages, though the magnitude was greater for women aged under 50. A substantially greater proportion of the extra attendances of women aged 25–49 on routine recall occurred in women whose attendance was overdue (28% occurred at 60 months or more) and relatively little represented over-screening (8% had been screened within the last 30 months).

Conclusions

The pattern of increased attendance mirrored the pattern of media coverage of Jade Goody's diagnosis and death. It is likely that the increased screening resulted in a number of lives saved.
Tracking expression and subcellular localization of RNA and protein species using high-throughput single cell imaging flow cytometry
Authors: Borah Sumit , Nichols Lisa A. , Hassman Lynn M. , Kedes Dean H. , Steitz Joan A.
Published: June 2012

We report a high-throughput application of multispectral imaging flow cytometry (MIFC) for analyzing the expression and localization of both RNA and protein molecules in a heterogeneous population of cells. The approach was developed using polyadenylated nuclear (PAN) RNA, an abundant, noncoding RNA expressed by Kaposi's sarcoma–associated herpesvirus (KSHV) during the lytic phase of infection. High levels of PAN RNA are, in part, dependent on its interaction with poly(A)-binding protein C1 (PABPC1), which relocalizes from the cytoplasm to the nucleus of lytically infected cells. We quantitatively tracked the cytoplasmic to nuclear translocation of PABPC1 and examined how this translocation relates to the expression and localization of viral RNA and protein molecules in KSHV-infected cells. This high-throughput approach will be useful for other systems in which changes in subcellular localization of RNA and protein molecules need to be monitored simultaneously.
A Colonel Blotto Gladiator Game
Authors: Rinott Yosef , Scarsini Marco , Yu Yaming
Published: June 2012

We consider a stochastic version of the well-known Blotto game, called the gladiator game. In this zero-sum allocation game two teams of gladiators engage in a sequence of one-on-one fights in which the probability of winning is a function of the gladiators' strengths. Each team's strategy is the allocation of its total strength among its gladiators. We find the Nash equilibria and the value of this class of games and show how they depend on the total strength of teams and the number of gladiators in each team. To do this, we study interesting majorization-type probability inequalities concerning linear combinations of gamma random variables. Similar inequalities have been used in models of telecommunications and research and development.
Implementing Changes in Marketing Strategy: The Role of Perceived Outcome-and Process-Oriented Supervisory Actions
Authors: Sarin Shikhar , Challagalla Goutam , Kohli Ajay K.
Published: June 2012

This study investigates the role of supervisors in implementing changes in marketing strategy. The authors propose that perceptions of outcome-oriented supervisory actions influence salespeople's primary appraisals of a strategic change (i.e., whether the change will affect them) and that perceptions of process-oriented supervisory actions influence salespeople's secondary appraisals (i.e., whether they can cope with the impact of the change on them). The results from a study of 828 salespeople in 204 branches of a large distributor of industrial goods provide evidence that perceived outcome risk containment and outcome reward emphasis enhance primary appraisals, whereas perceived process risk containment and process reward emphasis enhance secondary appraisals. In turn, the authors find that salespeople's primary and secondary appraisals influence their change implementation behaviors, leading to successful change implementation. Notably, they also find that (outcome and process) risk containment has a greater influence on appraisals of salespeople with a higher performance orientation, but the effects of (outcome and process) reward emphases are invariant across salespeople's performance orientation. The findings suggest that successful implementation of strategic change may depend not merely or even primarily on giving rewards to salespeople for implementing change but also on limiting salespeople's risks and recognizing them for their change-related efforts.
Characterizing Porosity and Diffusive Properties of Monolithic Cement-Based Solidified/Stabilized Materials
Authors: Goreham V. , Lake C. B. , Yuet P. K.
Published: June 2012

This paper presents the application of a single reservoir diffusion test to determine both the effective porosity of a soil-cement matrix and the diffusivity of tritium through saturated, monolithic, cement solidified/stabilized wasteforms. Testing was performed on a laboratory mixture of cement paste, sand, and kaolinite. The influence of porosity on the proper interpretation of the diffusion tests was examined. Results of tests on three replicate specimens were consistent and indicate effective porosities of 0.26 to 0.28 and effective diffusive coefficients of 2.5 × 10−10 to 3.0 × 10−10 m2/s. The effect of curing time is discussed. Products of the effective diffusion coefficients and porosity (neDe) decreased by 22 % from specimens cured for 14 days to specimens cured for 28 days prior to testing while from 70 to 126 days of curing neDe only changed by 8 %. This suggests that curing should be carried out for greater than 70 days prior to conducting these tests.
Laboratory Studies on Pressure Filtration in Post-Grouting of Drilled Shaft Tips in Clay
Authors: Fang Kai , Zhang Zhongmiao , Zou Jian , Wang Zhijie
Published: June 2012

Practice has proved that significant tip capacity improvement can be realized through pressure grouting for drilled shaft tips in clay. A comprehensive series of laboratory model experiments were conducted in order to study the influence of pressure filtration on tip improvement and provide an insight into the influence factors of pressure filtration. The fundamental variables that could affect pressure filtration behavior, including filtration pressure P, water cement ratio wi, and clay thickness H were studied in these experiments. Results indicate that the velocity of pressure filtration is determined by the velocity of water through clay. The final water cement ratio of grout is maintained at about 0.3 after the pressure filtration process regardless of the initial water content under the pressures of 75–225 kPa. Atomic absorption spectrometry and scanning electron microscopy were used to study the mechanism of exchange of cations. The analyses reveal that the Ca2+ ions from cement grout exchange with Na+ and K+ adsorbed in clay particles. The separated clay particles become more close to each other after the exchange of cations. In addition, the results of laboratory direct shear tests show that the shear strength of the clay after pressure filtration is also increased due to the compression of the clay and the exchange of cations.
Geotechnical Characteristics of an Aerated Soil-Stabilizer Mixture as Backfill Material
Authors: Jo Seon-Ah , Lee Changho , Lim Yujin , Jin Kyu-Nam , Cho Gye-Chun
Published: June 2012

A considerable amount of effort has been made to find alternatives to conventional backfill materials in civil engineering works because conventional backfilling has disadvantages including insufficient compaction and shortages in the supply of natural materials. A flowable and lightweight fill material, specifically an aerated soil-stabilizer mixture (ASSM), is one such alternative to solve these problems. The geotechnical properties of ASSM with various water content levels were measured and analyzed to determine the optimal mixing ratio. The water content level controls the geotechnical characteristics of ASSM. ASSM mixed with a water content of 25 % yields the highest compressive and shear strengths and shows a suitable density and an allowable degree of vertical deformation. A series of laboratory tests was performed to estimate the geotechnical characteristics of the optimally mixed ASSM. The density, vertical deformation, compressive and shear strength, shear modulus, and coefficient of lateral earth pressure at rest (K0) were measured. Its suitability as a backfill material was then investigated in comparisons with other backfill materials. ASSM shows better performance than typical backfill materials, as its strength, shear modulus, and linear threshold strain are higher, whereas its density and K0 values are smaller.
Automated True Triaxial Apparatus and its Application to Over-consolidated Clay
Authors: Ye Guan-lin , Sheng Jia-ren , Ye Bin , Wang Jian-hua
Published: June 2012

A better understanding of long-term mechanical behavior of over-consolidated clay (OC) is important to numerous geotechnical problems. Most previous experimental studies, however, have used sand or normally consolidated clay (NC); only limited reports of the drained true triaxial test of OC are available. In this paper, an electro-pneumatic (E/P) regulator based automatic control true triaxial apparatus is developed. A mixed boundary loading device designed by Nakai Research Group is used in the apparatus. Unlike other loading devices, the membrane covers not only the vertical but also the horizontal rigid platens, which can apply arbitrary three different principal stresses to the block specimen. The loading pattern that can reduce the corner effect and the interference problem is also analyzed. The method to increase the pressure control precision of the E/P regulator as well as the automatic control system is presented. An extra volume change due to water-absorption of membrane during long time drained test is discussed and a simple solution is proposed. The apparatus is used to study the mechanical properties of NC and OC clays under drained condition. The test results show that the initial stiffness, shear strength and dilatancy are largely influenced by the Lode angle. Furthermore, both the NC and OC clays obey the Matsuoka-Nakai criteria well.
Dynamic Actuator for Centrifuge Modeling of Soil-Structure Interaction
Authors: Cabrera Miguel Angel , Caicedo Bernardo , Thorel Luc
Published: June 2012

This paper presents a new dynamic actuator useful to study soil-structure interactions in a centrifuge. This new dynamic apparatus is based on an amplified piezoelectric actuator. Using this device it is possible to create vibrations in the soil sample of different frequencies and amplitudes. The dynamic actuator consists of a set of weights in a single degree of freedom system plus a piezoelectric actuator and a piezoelectric load cell, which measures the dynamic load. A description of the dynamic actuator and its application to dynamic soil-structure interaction under wind turbines is presented. The calibration of the dynamic actuator and some results of centrifuge tests for shallow and embedded foundations are presented.
Prediction of long-term urban stormwater loads at single sites
Authors: May Daniel , Sivakumar Muttucumaru
Published: June 2012

Long-term total phosphorus loads from 17 urban catchments in the USA were predicted using five different measures of central tendency defining site mean concentration (arithmetic mean, geometric mean, median, harmonic mean and flow-weighted mean). Overall, the flow-weighted mean concentration produced the most accurate predictions of long-term loads. The geometric mean produced the second most accurate predictions. Along with the median and harmonic mean, the geometric mean predicted long-term load relatively well at most catchments exhibiting negative correlations between event mean concentration and total event runoff depth. However, they significantly underestimated long-term load at catchments exhibiting a positive correlation between these variables. Better estimates of long-term load at these two catchments were produced using the flow-weighted mean and arithmetic mean. However, the arithmetic mean tended to overestimate long-term load at the remainder of catchments.
A Review on the Challenges for Increased Production of Castor
Authors: Severino Liv S. , Auld Dick L. , Baldanzi Marco , Cândido Magno J. D. , Chen Grace , Crosby William , Tan D. , He Xiaohua , Lakshmamma P. , Lavanya C. , Machado Olga L. T. , Mielke Thomas , Milani Máira , Miller Travis D. , Morris J. B. , Morse Stephen. A. , Navas Alejandro A. , Soares Dartanhã J. , Sofiatti Valdinei , Wang Ming L. , Zanotto Maurício D. , Zieler Helge
Published: June 2012

Castor (Ricinus communisL.) is one of the oldest cultivated crops, but currently it represents only 0.15% of the vegetable oil produced in the world. Castor oil is of continuing importance to the global specialty chemical industry because it is the only commercial source of a hydroxylated fatty acid. Castor also has tremendous future potential as an industrial oilseed crop because of its high seed oil content (more than 480 g kg−1), unique fatty acid composition (900 g kg−1of ricinoleic acid), potentially high oil yields (1250–2500 L ha−1), and ability to be grown under drought and saline conditions. The scientific literature on castor has been generated by a relatively small global community of researchers over the past century. Much of this work was published in dozens of languages in journals that are not easily accessible to the scientific community. This review was conducted to provide a compilation of the most relevant historic research information and define the tremendous future potential of castor. The article was prepared by a group of 22 scientists from 16 institutions and eight countries. Topics discussed in this review include: (i) germplasm, genetics, breeding, biotic stresses, genome sequencing, and biotechnology; (ii) agronomic production practices, diseases, and abiotic stresses; (iii) management and reduction of toxins for the use of castor meal as both an animal feed and an organic fertilizer; (iv) future industrial uses of castor including renewable fuels; (v) world production, consumption, and prices; and (vi) potential and challenges for increased castor production.
A Distributed Cotton Growth Model Developed from GOSSYM and Its Parameter Determination
Authors: Liang Xin‐Zhong , Xu Min , Gao Wei , Reddy K. Raja , Kunkel Kenneth , Schmoldt Daniel L. , Samel Arthur N.
Published: June 2012

Prediction of cotton (Gossypium hirsutum L.) production under a changing climate requires a coupled modeling system that represents climate–cotton interactions. The existing cotton growth model GOSSYM has drawbacks that prohibit its effective coupling with climate models. We developed a geographically distributed cotton growth model from the original GOSSYM and optimized it for coupling with the regional Climate–Weather Research Forecasting model (CWRF). This included software redesign, physics improvement, and parameter specification for consistent coupling of CWRF and GOSSYM. Through incorporation of the best available physical representations and observational estimates, the long list of inputs in the original GOSSYM was reduced to two parameters, the initial NO3 amount in the top 2 m of soil and the ratio of irrigated water amount to potential evapotranspiration. The geographic distributions of these two parameters are determined by optimization that minimizes model errors in simulating cotton yields. The result shows that the redeveloped GOSSYM realistically reproduces the geographic distribution of mean cotton yields in 30‐km grids, within ±10% of observations across most of the U.S. Cotton Belt, whereas the original GOSSYM overestimated yields by 27 to 135% at the state level and 92% overall. Both models produced interannual yield variability with comparable magnitude; however, the temporal correspondence between modeled and observed interannual anomalies was much more realistic in the redeveloped than the original GOSSYM because significant (P = 0.05) correlations were identified in 87 and 40% of harvest grids, respectively. The redeveloped GOSSYM provides a starting point for additional improvements and applications of the coupled CWRF–GOSSYM system to study climate–cotton interactions.
Physical Modeling of U.S. Cotton Yields and Climate Stresses during 1979 to 2005
Authors: Liang Xin‐Zhong , Xu Min , Gao Wei , Reddy K. Raja , Kunkel Kenneth , Schmoldt Daniel L. , Samel Arthur N.
Published: June 2012

Climate variability and changes affect crop yields by causing climatic stresses during various stages of the plant life cycle. A crop growth model must be able to capture the observed relationships between crop yields and climate stresses before its credible use as a prediction tool. This study evaluated the ability of the geographically distributed cotton growth model redeveloped from GOSSYM in simulating U.S. cotton (Gossypium hirsutum L.) yields and their responses to climate stresses during 1979 to 2005. Driven by realistic climate conditions, the model reproduced long‐term mean cotton yields within ±10% of observations at the 30‐km model resolution across virtually the entire U.S. Cotton Belt and correctly captured the critical dependence of their geographic distributions on regional climate characteristics. Significant correlations between simulated and observed interannual variations were found across 87% of the total harvest grids. The model also faithfully represented the predictive role of July to August air temperature and August to September soil temperature anomalies on interannual cotton yield changes on unirrigated lands, with a similar but weaker predictive signal for irrigated lands as observed. The modeled cotton yields exhibited large, positive correlations with July to August leaf area index. These results indicate the model's ability to depict the regional impact of climate stresses on cotton yields and suggest the potential predictive value of satellite retrievals. They also provide a baseline reference for further model improvements and applications in the future study of climate–cotton interactions.
Available Soil Phosphorus Affects Herbage Yield and Stand Persistence in Forage Chicory
Authors: Cassida K. A. , Foster J. G. , Gonzalez J. M. , Zobel R. W. , Sanderson M. A.
Published: June 2012

Low available soil P (ASP) may contribute to poor productivity of forage chicory (Cichorium intybus L.). The effect of ASP on forage yield and stand loss was evaluated over two harvest years for three chicory cultivars (‘Puna’, ‘Forage Feast’, ‘Lacerta’) at sites with low [West Virginia (WV), Gilpin silt loam (fine‐loamy, mixed, mesic Typic Hapludults)] or high [Pennsylvania (PA), Hagerstown silt loam (fine, mixed, semiactive, mesic, Typic Hapludalfs)] ASP. Low (LP), medium (MP), and high (HP) ASP treatments averaged 6, 27, and 41 mg kg−1 of Bray‐P for LP, MP, and HP in WV, and 30 and 41 mg kg−1 for MP and HP in PA. Across all data, critical soil P for 95% of maximum dry matter yield (DMY) was approximately 30 mg kg−1 of Bray‐P. Cumulative DMY of all cultivars increased with soil Bray‐P in the first year after planting, but in the second year, only Forage Feast DMY increased with soil Bray‐P. Cumulative DMY declined 45, 69, and 89% from the first to second year after planting for Puna, Forage Feast, and Lacerta, respectively. Across cultivars and time, stand density increased 12% as ASP increased from LP to MP, but medium to high ASP was associated with stand decline via increased bolting of Lacerta and frost heaving of Forage Feast. Across cultivars and sites, stand densities of less than 50 plants m−2 in September predicted poor cumulative DMY in the following year. Phosphorus fertilization improved overall forage chicory DMY and persistence when ASP was low, but may contribute to bolting, heaving, and stand loss at high ASP.
Spatial Interrelationships between Wheat Phenology, Thermal Time, and Terrain Attributes
Authors: McMaster Gregory S. , Green Timothy R. , Erskine Robert H. , Edmunds Debora A. , Ascough James C.
Published: June 2012

Spatial variation of winter wheat (Triticum aestivum L.) phenology across complex terrain has received little attention despite its importance for assessing overall crop status and making key precision management decisions. Temperature is the environmental factor explaining the greatest variation in phenology, and temperature varies across a landscape. Our primary hypothesis was that variability in thermal time (TT) by landscape position could explain the phenological variation, with a secondary hypothesis that spatial patterns of TT and phenology were related to terrain attributes. Four years of phenology and soil and air temperature data were collected from a 100‐ha field in northeast Colorado. Five developmental stages were monitored at 10 landscape sites each year. Terrain attributes were computed using 5‐m‐grid land surface elevation data. Spatial differences in reaching developmental stages across sites varied from 2 to 12 d within a year. Up to 96% of the phenological variation among years was explained when using a general TT model pooling all data. Refining the TT model, however, by using either air or soil TT at specific sites partially supported the primary hypothesis only for the relatively wetter 2004–2005 and 2006–2007 years (regression relationships explained up to 72% of the variation). Similarly, terrain attributes occasionally explained spatial patterns of phenology in the two wetter years, and attributes with the highest explanatory power varied among years and developmental stages. Further research is needed to better understand the controlling environmental factors and predict spatial patterns of wheat phenology for precision management using terrain attributes.
Rye–Corn Silage Double‐Cropping Reduces Corn Yield but Improves Environmental Impacts
Authors: Krueger Erik S. , Ochsner Tyson E. , Baker John M. , Porter Paul M. , Reicosky Don C.
Published: June 2012

Recent proliferation of large dairies has prompted concern regarding environmental impacts of associated corn silage production and high‐rate manure application. Our objectives were to compare environmental impacts and forage production of monocrop corn (Zea mays L.) silage and rye (Secale cereal L.)–corn silage double‐crop systems with multiple corn planting dates and high‐rate manure application near Morris, MN. From 2007 to 2009, corn for silage was seeded into a silt loam as a monocrop in early and mid‐May and as a double‐crop after rye in mid‐May and early June. Manure was fall applied annually at average total N and P rates of 393 and 109 kg ha−1, respectively. Double‐cropping reduced total forage dry matter (DM) yield 2 of 3 yr and reduced corn DM yield 15 to 25%. Soil NO3–N to 90 cm accumulated at an average rate of 71 kg N ha−1 yr−1 with monocropping, but accumulation was not observed with double‐cropping. Soil organic C concentration from 0 to 5 cm increased in the monocrop (18%) and double‐crop (26%) systems over 3 yr. Average soil solution NO3–N concentration was high with monocropping (52 mg L−1) and double‐cropping (37 mg L−1), but estimated leaching load averaged only 8 kg ha−1 yr−1. Fall and spring ground cover was often less than 10% with monocropping but was usually greater than 30% with double‐cropping. The primary environmental concerns identified for monocrop corn silage were soil NO3–N buildup and inadequate ground cover. Double‐cropping addressed each concern but often decreased forage production.
Spring Wheat Yield and Quality Related to Soil Texture and Nitrogen Fertilization
Authors: Nyiraneza Judith , Cambouris Athyna N. , Ziadi Noura , Tremblay Nicolas , Nolin Michel C.
Published: June 2012

Efficient N fertilization is crucial for economic wheat (Triticum aestivum L.) production and is of great agronomical and environmental significance. A study was conducted at 12 site‐years in eastern Canada to evaluate the effect of soil surface textural groups, N rate (0–200 kg N ha−1) and application timing on grain yield (GY), N uptake, nitrogen uptake efficiency (NUE), grain protein content (GPC), test weight, and thousand kernel weight (TKW). Chlorophyll meter readings (CMR) were taken at tillering and at flowering to assess in‐season wheat N nutrition. Fertilization and soil textural group effects were significant on all measured parameters and their interaction was significant on GPC, TKW, test weight, and CMR. Total N uptake and GPC ranged from 39 to 96 kg N ha−1 and from 13 to 18 g kg−1, respectively, and total N uptake increased proportionally to N rates. Applying N levels >120 kg N ha−1 did not increase total yield, test weight, TKW, or CMR values. The variation in GY, N uptake, and GPC explained by the relative CMR taken at flowering was 87, 88, and 73%, respectively. This study demonstrates that in‐season wheat N nutrition can be monitored by CMR and that surface soil texture is an important parameter that influences wheat N response and wheat quality parameters. Applying half of the recommended rate (120 kg ha−1) at planting and the rest at tillering resulted in a high total yield, high grain N uptake, and the highest GPC price premium.
Corn Yields and No‐Tillage Affects Carbon Sequestration and Carbon Footprints
Authors: Clay David E. , Chang Jiyul , Clay Sharon A. , Stone James , Gelderman Ronald H. , Carlson Gregg C. , Reitsma Kurtis , Jones Marcus , Janssen Larry , Schumacher Thomas
Published: June 2012

The corn (Zea mays L.)–based ethanol carbon footprint is impacted by many factors including the soil's C sequestration potential. The study's objective was to determine the South Dakota corn‐based ethanol surface SOC sequestration potential and associated partial C footprint. Calculated short‐term C sequestration potentials were compared with long‐term sequestration rates calculated from 95,214 producer soil samples collected between 1985 and 2010. National Agricultural Statistics Service (NASS) grain yields, measured root/shoot ratios and harvest indexes, soil organic C (SOC) and nonharvested C (NHC) first‐order rate constants, measured SOC benchmarks [81,391 composite soil samples (0–15 cm) collected between 1985 and 1998], and 34,704 production surveys were used to calculate the short‐term sequestration potentials. The SOC short‐term, area weighted sequestration potential for the 2004 to 2007 time period was 181kg C (ha × yr)−1. This relatively low rate was attributed to a drought that reduced the amount of NHC returned to soil. For the 2008 to 2010 time period, the area weighted short‐term sequestration rate was 341 kg (ha × yr)−1. This rate was similar to the long‐term measured rate of 368 kg C (ha × yr)−1. Findings from these independent SOC sequestration assessments supports the hypothesis that many of the regions surface soils are C sinks when seeded with corn. Based on short‐term C sequestration rates, corn yields, and the corn conversion rate to ethanol, the area weighted surface SOC footprints for the 2004 to 2007 and 2008 to 2010 time periods was –10.4 and –15.4 g CO2 equ MJ−1, respectively.
Soil and Crop Response to Wood Ash and Lime Application in Acidic Soils
Authors: Arshad M. A. , Soon Y. K. , Azooz R. H. , Lupwayi N. Z. , Chang S. X.
Published: June 2012

Wood ash has the properties to be an effective liming material, and research is needed to compare its effectiveness relative to agricultural lime on acidic agricultural soils. Wood ash at a calcium carbonate rate of 6.72 t ha−1 was compared with an equivalent rate of agricultural lime on a clay loam soil with an initial pH of 4.9. Replicated plots were managed under a barley (Hordeum vulgare L.)–canola (Brassica rapa L.)–pea (Pisum sativum L.) rotation for 4 yr (2002–2005). Soil pH increased in the order of: wood ash = lime > control (without lime or wood ash). Available soil P increased in the order of: wood ash > lime ≥ control. The effect of wood ash and lime application on pH and available P was greatest in the 0‐ to 5‐cm depth, less but still significant in the 5‐ to 10‐cm depth, and not significant below 10 cm. The effect on soil aggregation was: wood ash > lime > control. Averaged over 4 yr, application of wood ash increased grain yields of barley, canola, and pea by 49, 59, and 55%, respectively, compared to a corresponding increase of 38, 31, and 49% by agricultural lime. The increase in crop yield with wood ash compared with lime is attributed partly to increased P availability in wood ash‐amended plots. It is concluded that wood ash applied at rates equivalent to agricultural lime improved some soil chemical and physical properties and increased crop production relative to agricultural lime.
Effect of Flooding Duration and Nitrogen Fertilization on Yield and Protein Content of Three Forage Species
Authors: Sigua G. C. , Williams M. , Grabowski J. , Chase C. , Kongchum M.
Published: June 2012

Increasing the availability and improving the quality of surface water in south Florida by temporarily flooding previously drained pastureland is one of the goals of Northern Everglades Restoration Initiative. Bahiagrass (Paspalum notatum Fluegge) is one of the most important forage grasses in the region and although tolerant to short‐ term flooding, bahiagrass is classified as a facultative upland (FACU+) species that suggest dry matter production and plant persistence might be reduced under periods of extended waterlogging. A 2‐yr greenhouse study was conducted in 2008 and 2009 to determine the effect of flooding duration on dry matter yield (DMY) and crude protein content (CPC) of bahiagrass compared to two flooding tolerant forages, limpograss (Hemarthria altissima Poir), and maidencane (Panicum hematomon Schult) and to determine if N fertilization could be used to mitigate flooding effects. Dry matter production and CPC levels varied with flooding durations (P ≤ 0.001) and levels of N fertilization (P ≤ 0.001). Averaged across flooding duration and levels of N, limpograss had the greatest dry matter yield of 11.6 t ha−1 followed by maidencane (8.6 t ha−1) and bahiagrass (8.5 t ha−1) while bahiagrass had the highest CPC of 6.9% followed by maidencane (6.0%) and limpograss (3.7%). The overall yield response of the three forage species: bahiagrass (R2 = 0.95**); limpograss (R2 = 0.93**); and maidencane (R2 = 0.99**) were linearly related to increasing levels of N fertilization. Crude protein contents of three forage species: bahiagrass (R2 = 0.97**), limpograss (R2 = 0.99**), and maidencane (R2 = 0.87**) were also linearly related to increasing levels of N fertilization. Averaged across forage species, dry matter yield of forages fertilized with 200 kg N ha−1 with no flooding were statistically comparable with plants that were fertilized with 200 kg N ha−1and flooded for 84 d. Our results support our hypothesis that the negative impact of flooding could be mitigated by N fertilization.
Yield and Weed Suppression of Crop Mixtures in Organic and Conventional Systems of the Western Canadian Prairie
Authors: Nelson A. G. , Pswarayi A. , Quideau S. , Frick B. , Spaner D.
Published: June 2012

To investigate intercropping as a management strategy to increase crop productivity and weed suppression in organic systems, spring wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), canola (Brassica napus L.) and field pea (Pisum sativum L.) monocultures were compared with two‐, three‐, and four‐crop intercrops containing wheat at two organic and one conventional site in 2006 and 2007, central Alberta, Canada. We measured crop and weed biomass, grain yield, and crop competitiveness against weeds from a replacement design in a completely randomized block experiment. Pea and canola monocrops on organic sites yielded the least of all crop treatments. Conventional crop treatments generally yielded higher than organic treatments. Few land equivalent ratios (LERs) on organic sites were significantly >1.0. Some wheat intercrops without barley showed overyielding (LER > 1.0) potential. Most of the significant LERs were from three‐ and four‐crop intercrops. More than 50% of the intercrops on organic sites significantly suppressed weeds (based on relative weed biomass) and most of these intercrops had barley in the mixture. Barley as a sole crop and in intercrops suppressed weeds better than all other intercrops and sole crops. The wheat–canola intercrop exhibited the best weed suppression of the two‐crop intercrops on organic and conventional sites. The crop densities used in this study may have contributed to the extremely low pea and canola monocrop yields as well as low LERs. Due to this, our findings should be regarded as showing trends and potential from intercrops only. We therefore recommend further studies to establish ideal densities for the intercrops used.
Alfalfa Nitrogen Credit to First‐Year Corn: Potassium, Regrowth, and Tillage Timing Effects
Authors: Yost Matt A. , Coulter Jeffrey A. , Russelle Michael P. , Sheaffer Craig C. , Kaiser Daniel E.
Published: June 2012

Compared with corn (Zea mays L.) following corn, N guidelines for first‐year corn following alfalfa (Medicago sativa L.) in the U.S. Corn Belt suggest that N rates can be reduced by about 168 kg N ha−1 when ≥43 or 53 alfalfa plants m−2 are present at termination. These guidelines have been questioned by practitioners, however, as corn grain yields have increased. We conducted experiments at 16 locations in Minnesota to address questions regarding N availability to first‐year corn after alfalfa relating to the effect of carryover fertilizer K from alfalfa and the amount and timing of alfalfa regrowth incorporation. Corn grain yield, silage yield, and fertilizer N uptake were not affected by carryover K or amount or timing of regrowth incorporation. Maximum corn grain yield ranged from 12.0 to 16.1 Mg ha−1 among locations but responded to fertilizer N at only one. At that location, which had inadequate soil drainage, the economically optimum N rate (EONR) was 85 kg N ha−1, assuming prices of US.87 kg−1 N and US$132 Mg−1 grain. The EONR for silage yield across 6 of 15 locations where it was measured was 40 kg N ha−1, assuming US$39 Mg−1 silage. These results demonstrate that on highly productive medium‐ to fine‐textured soils in the Upper Midwest with ≥43 alfalfa plants m−2 at termination, first‐year corn grain yield is often maximized without fertilizer N, regardless of alfalfa regrowth management or timing of incorporation, but that small N applications may be needed to optimize silage yield.
Response of Continuous Maize with Stover Removal to Living Mulches
Authors: Wiggans Dustin R. , Singer Jeremy W. , Moore Kenneth J. , Lamkey Kendall R.
Published: June 2012

Constraints to maize (Zea mays L.) stover biomass harvest may be mitigated by using a living mulch (LM) to offset C exports and control soil erosion. Living mulches can compete with the main crop for resources. The objective of this research was to quantify competitive effects of LM management systems grown in continuous maize with stover removal. Maize was planted into creeping red fescue (CF) (Festuca rubra L.), Kentucky bluegrass (KB) (Poa pratensis L.), and a mixture of CF and white clover (Trifolium repens L.) (MX) LMs in 2008, 2009, and 2010 near Ames, IA. Management treatments were fall strip‐tillage (ST) and no‐tillage (NT), with either a pre‐planting paraquat burn‐down followed by two glyphosate bands (PQ) or glyphosate bands only (GLY). Kentucky bluegrass PQ ST produced similar grain yields (11,230 kg ha−1) all 3 yr as the no LM control (11,810 kg ha−1) with a harvest index (HI) of 0.55 compared to 0.52 in the control, averaged across years. The control produced greater stover dry matter (SDM) (10,110 kg ha−1) 2 of the 3 yr compared to KB PQ ST (8600 kg ha−1). Total groundcover averaged 80% in KB PQ ST compared to only 45% in the no LM control. These results indicate that a combination of herbicide suppression and ST suppresses LMs adequately to maintain competitive maize grain yields. Additional research under varying climatic conditions will further quantify the risk of LM management systems to increase the sustainable stover harvest of maize biomass feedstocks.
Effects of Zinc Fertilization on Zinc Dynamics in Potentially Zinc‐Deficient Calcareous Soil
Authors: Lu Xinchun , Cui Juan , Tian Xiaohong , Ogunniyi Jumoke E. , Gale William J. , Zhao Aiqing
Published: June 2012

In China, wheat (Triticum aestivum L.) grown on Zn‐deficient calcareous soils often fails to meet the dietary needs of local populations. The effectiveness of Zn application to a potentially Zn‐deficient calcareous soil was measured using two winter wheat cultivars and five Zn fertilizer rates (0, 7.5, 15, 30, 45 kg Zn ha−1). The results showed that Zn fertilizer increased grain Zn concentration in 2008–2009 by 11 to 33%; however, grain Zn concentrations were still insufficient for human dietary requirements. The apparent Zn utilization efficiency was between 0.14 and 0.98%. Within 1 wk of fertilizer Zn application, Zn weakly bound to organic matter (Wbo‐Zn) increased by amounts equivalent to 63.4 to 84.0% of the fertilizer Zn application. Carbonate‐bound Zn increased by amounts equivalent to 6.5 to 10.3% of the fertilizer Zn. The Wbo‐Zn fraction decreased gradually with time, whereas mineral‐bound Zn increased. Calculations indicated that 62.0 to 78.1% of the fertilizer Zn was mineral bound after 639 d. Diethyltriamine pentaacetic acid extractable Zn concentrations increased by 267 to 529% immediately after Zn fertilization but then decreased. In conclusion, available soil Zn concentrations increased quickly after Zn fertilizer application to a potentially Zn‐deficient calcareous soil; however, the available Zn fractions were soon converted to mineral‐bound forms that were unavailable for plant uptake.
Cotton Production as Affected by Irrigation Level and Transitioning Tillage Systems
Authors: DeLaune P. B. , Sij J. W. , Park S. C. , Krutz L. J.
Published: June 2012

Identifying management practices that conserve and protect water resources are very important to a wide variety of stakeholders within semiarid environments. The objective of this study was to develop water management strategies for transitioning tillage systems in cotton (Gossypium hirsutum L.) production within the Texas Rolling Plains when in a subsurface drip irrigation (SDI) system. Five irrigation regimes (0, 33, 66, 100, and 133% evapotranspiration [ET] replacement) and four tillage systems (conventional till, reduced till, no‐till, and no‐till with a terminated cover crop) were evaluated. The study was conducted for 3 yr and treatments were replicated three times in a randomized complete block design. Lint yields were not affected by the main effects of tillage or the interaction of tillage and ET replacement. In contrast ET replacement was a significant factor for lint yields, irrigation water use efficiency, and net returns. Greatest lint yields and net returns were achieved at 100% ET replacement. Fitted models indicated that optimum lint yields and net returns were achieved at 104.5% ET and 102% ET, respectively. Irrigation at 83% ET was within the 95% confidence interval for lint yield. Net returns were significantly higher for no‐till systems compared with conventional till. Thus, adoption of conservation tillage systems should not negatively affect lint yield or net returns in deficit irrigated SDI cotton systems within the Texas Rolling Plains, particularly during the transition from intensively tilled systems to conservation tilled systems.
An Innovative Crop–Forage Intercrop System: Early Cycle Soybean Cultivars and Palisadegrass
Authors: Crusciol C. A. C. , Mateus G. P. , Nascente A. S. , Martins P. O. , Borghi E. , Pariz C. M.
Published: June 2012

Agriculture and livestock integration is a sustainable practice that improves both crop yield and pasture recuperation/formation. However, to achieve success it is important to identify crop cultivars more adapted to intercropping with grasses. Therefore, the objective was to evaluate nutrient concentration and grain yield of soybean [Glycine max (L.) Merr.] cultivars with different life cycles as affected by palisadegrass [Brachiaria brizantha (Hochst. ex A. Rich) Stapf] intercropped in the same furrow at different depths, in a no‐till system, as well as dry matter production and protein concentration of palisadegrass pasture. Experiments were performed during two growing seasons, on a Typic Haplorthox, at Botucatu, São Paulo State, Brazil. The experimental design was a randomized block, arranged in a 2 × 4 factorial scheme, with six replications. Treatments consisted of two cropping systems (sole cropped soybean; soybean and palisadegrass intercropped) and four soybean cultivars (super‐early cycle [Monsoy 6101], early cycle [Embrapa 48], normal cycle [BRS 133], and late cycle [Emgopa 313]). Life cycle duration of the soybean had a marked effect, and only early cycle soybean were successful intercrops. Intercropping palisadegrass with super‐early or early soybean cultivars were viable options to crop‐livestock integration, because they did not affect both soybean or palisadegrass yield. In addition, with these cultivars, it was possible to cultivate grain and then afterward more time for cattle (Bos taurus and Bos indicus) grazing in the same area, providing greater revenue compared to sole soybean cropped or in the intercropping with longer cycle cultivars.
The Impact of Drainage Water Management Technology on Corn Yields
Authors: Delbecq Benoit A. , Brown Jason P. , Florax Raymond J. G. M. , Kladivko Eileen J. , Nistor Adela P. , Lowenberg-DeBoer Jess M.
Published: June 2012

Controlled drainage (drainage water management) restricts outflow during periods of the year when equipment operations are not required in the field. This may increase yields as well as reduce the loss of nutrients with negative environmental externalities. An experiment using controlled drainage was investigated and its impact on corn (Zea maysL.) yields was assessed at the field level in Indiana. Specifically, yield monitor data was analyzed across space and time using a geographic information system and spatial panel regression methods. The use of panel data methods controlling simultaneously for spatial and temporal heterogeneity as well as dependence provides precision agriculture researchers with a powerful framework to model crop sensor data across space and time. During the period 2005 to 2009, controlled drainage was found to outperform free‐flow systems by an average of 0.57 to 1.00 Mg ha−1(5.8–9.8% across the effective range of 0–0.61 m above the water control structure) for the experimental field; however, these aggregate results masked substantial year‐to‐year and within‐field variations.