bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydraulic jumps in trapezoidal and circular channels
Authors: Mitchell S. B.
Published: May 2008

Reliable prediction of upstream and downstream depths in a hydraulic jump is essential for hydraulic design in open channels. A series of algorithms is proposed for estimating the ratio of conjugate depths in a hydraulic jump in a horizontal channel over a range of Froude numbers and for a range of different trapezoidal and circular sections running part-full. By solving the momentum equation using appropriate values for the depth of centroid below the free surface, an iterative approach is proposed that uses the Newton–Raphson method and produces satisfactory agreement with recent published experimental data. The resulting graphs of conjugate depth ratio y2/y1 against F1 were also used to form the basis of a series of equations of best-fit lines that could be used as first approximations for use in hydraulic design problems. The results obtained were also used to predict the energy loss in the hydraulic jump. It is envisaged that the algorithms described here could be incorporated into standard design spreadsheets for use by practitioners involved in civil engineering hydraulics design.
Implementing resource efficiency in Hampshire County Council
Authors: Reid J. M. , Lomas T. , Flavell A.
Published: May 2008

Local authorities have many opportunities to influence resource efficiency: they are major construction clients and can directly require the implementation of sustainable construction measures in activities such as highways. In addition, as planning authorities, they can encourage or require sustainability measures in new construction through specifications for adoptable highways; as mineral planning authorities they can ensure that adequate facilities are available for the production of high-quality recycled materials. Maximising this potential requires a clear lead from the top, liaison between different departments within the council and their contractors and suppliers, and engagement with industry, developers and community groups. These points are illustrated by the approach that Hampshire County Council, Portsmouth City Council and Southampton City Council have adopted to maximise material resource efficiency. This paper describes the approach and presents a case study to illustrate how the principles can be put into practice in the context of a household waste recycling centre. Ongoing measures to engage the construction sector in Hampshire are described. There will be a continuing need for such activities if targets set for the use of recycled and secondary aggregates are to be achieved.
TRANSIENT DYNAMICS OF PELAGIC PRODUCER–GRAZER SYSTEMS IN A GRADIENT OF NUTRIENTS AND MIXING DEPTHS
Authors: Jäger Christoph G. , Diehl Sebastian , Matauschek Christian , Klausmeier Christopher A. , Stibor Herwig
Published: May 2008

Phytoplankton–grazer dynamics are often characterized by long transients relative to the length of the growing season. Using a phytoplankton–grazer model parameterized for Daphnia pulex with either flexible or fixed algal carbon : nutrient stoichiometry, we explored how nutrient and light supply (the latter by varying depth of the mixed water column) affect the transient dynamics of the system starting from low densities. The system goes through an initial oscillation across nearly the entire light–nutrient supply space. With flexible (but not with fixed) algal stoichiometry, duration of the initial algal peak, timing and duration of the subsequent grazer peak, and timing of the algal minimum are consistently accelerated by nutrient enrichment but decelerated by light enrichment (decreasing mixing depth) over the range of intermediate to shallow mixing depths. These contrasting effects of nutrient vs. light enrichment are consequences of their opposing influences on food quality (algal nutrient content): algal productivity and food quality are positively related along a nutrient gradient but inversely related along a light gradient. Light enrichment therefore slows down grazer growth relative to algal growth, decelerating oscillatory dynamics; nutrient enrichment has opposite effects. We manipulated nutrient supply and mixing depth in a field enclosure experiment. The experimental results were qualitatively much more consistent with the flexible than with the fixed stoichiometry model. Nutrient enrichment increased Daphnia peak biomass, decreased algal minimum biomass, decreased the seston C:P ratio, and accelerated transient oscillatory dynamics. Light enrichment (decreasing mixing depth) produced the opposite patterns, except that Daphnia peak biomass increased monotonously with light enrichment, too. Thus, while the model predicts the possibility of the “paradox of energy enrichment” (a decrease in grazer biomass with light enrichment) at high light and low nutrient supply, this phenomenon did not occur in our experiment.
LONG‐TERM BURNING INTERACTS WITH HERBIVORY TO SLOW DECOMPOSITION
Authors: Kay Adam D. , Mankowski Josh , Hobbie Sarah E.
Published: May 2008

Fires can generate spatial variation in trophic interactions such as insect herbivory. If trophic interactions mediated by fire influence nutrient cycling, they could feed back on the more immediate consequences of fire on nutrient dynamics. Here we consider herbivore‐induced effects on oak litter quality and decomposition within a long‐term manipulation of fire frequency in central Minnesota, USA. We focused on bur oak (Quercus macrocarpa) trees, which are common across the fire frequency gradient and are often heavily infested with either lace bugs (Corythuca arcuata) or aphids (Hoplochaithropsus quercicola). We used targeted exclusion to test for herbivore‐specific effects on litter chemistry and subsequent decomposition rates. Lace bug exclusion led to lower lignin concentrations in litterfall and subsequently accelerated decomposition. In contrast, aphid exclusion had no effect on litterfall chemistry or on decomposition rate, despite heavy infestation levels. Effects of lace bug herbivory on litterfall chemistry and decomposition were similar in burned and unburned areas. However, lace bug herbivory was much more common in burned than in unburned areas, whereas aphid herbivory was more common in unburned areas. These results suggest that frequent fires promote oak–herbivore interactions that decelerate decomposition. This effect should amplify other influences of fire that slow nitrogen cycling.
Subcellular distribution and potential detoxification mechanisms of mercury in the liver of the javan mongoose (Herpestes javanicus) in amamioshima Island, Japan
Authors: Horai Sawako , Furukawa Tatsuhiko , Ando Tetsuo , Akiba Suminori , Takeda Yasuo , Yamada Katsushi , Kuno Katsuji , Abe Shintaro , Watanabe Izumi
Published: May 2008

In a previous study, we showed that Hg accumulated to high levels in the liver of the Javan mongoose (Herpestes javanicus), a terrestrial mammal that lives on Amamioshima Island, Japan. This suggests a sophisticated mechanism of hepatic Hg detoxication. Assay of the subcellular localization of Hg and the expression of protective enzymes provides important clues for elucidating the mechanism of Hg detoxication. In the present study, the concentrations of 11 elements (Mg, Cr, Mn, Fe, Cu, Zn, Se, Rb, Cd, total Hg [T-Hg] and organic Hg [O-Hg], and Pb) were determined in the liver and in five liver subcellular fractions (plasma membrane, mitochondria, nuclei, microsome, and cytosol) of this species. As the T-Hg level increased, T-Hg markedly distributed to the plasma membrane. The T-Hg levels in all subcellular fractions correlated with Se levels. Although the T-Hg level in the microsomal fraction was relatively low, the ratio of O-Hg to T-Hg was significantly lower in the microsomes than in the other fractions. Significant positive correlations were found between the level of glutathione-S-transferase-π, a marker of oxidative stress, and the O-Hg and T-Hg levels, but the correlation was better with O-Hg than with T-Hg. Western blot analysis of thioredoxin reductase 2 (TrxR2), a protein involved in protecting cells from mitochondrial oxidative stress, showed that the level of TrxR2 correlated with that of T-Hg. High TrxR2 levels may be one mechanism by which the Javan mongoose attenuates the toxicity of the high Hg levels present in the liver.
Toxicity of the pesticide alpha-cypermethrin to four soil nontarget invertebrates and implications for risk assessment
Authors: Hartnik Thomas , Sverdrup Line E , Jensen John
Published: May 2008

Alpha-cypermethrin, a synthetic pyrethroid, is used as an insecticide in agricultural settings and is increasingly replacing organophosphates and carbamates because of lower application rates and lower toxicity to mammals. Because very little is known about the acute and chronic toxicity of this compound for soil-living organisms, the present study investigated acute and sublethal toxicity of alpha-cypermethrin for four terrestrial invertebrate species in an agricultural soil from Norway. Bioassays with the earthworm Eisenia fetida, the potworm Enchytraeus crypticus, the springtail Folsomia candida, and the land snail Helix aspersa were performed according to slightly modified versions of Organization for Economic Cooperation and Development (Paris, France) or International Organization for Standardization (Geneva, Switzerland) guidelines and resulted in median lethal concentrations of greater than >1,000 to 31.4 mg/kg and sublethal no-observed-effect concentrations of 2.51 to 82 mg/kg. A high acute to chronic ratio was found, especially in the earthworms. Interspecies differences in sensitivity may be explained by differences in exposure and differences in metabolization rate. When based on measured pore-water concentrations, terrestrial species overall appear to be approximately one order of magnitude less sensitive than aquatic species. Effect assessments conducted according to European guideline for risk assessment of pesticides reveal that assessments based on acute toxicity tests are not always conservative enough to determine environmentally safe concentrations in soil. Mandatory incorporation of sublethal toxicity data will ensure that in regions with temperate climate, the effects of pesticides on populations of soil-living organisms are unlikely.
Total arsenic accumulation in yabbies (Cherax destructor clark) exposed to elevated arsenic levels in victorian gold mining areas, Australia
Authors: Williams Gemma , West Jan M , Snow Elizabeth T
Published: May 2008

Arsenic is a proven carcinogen often found at high concentrations in association with gold and other heavy metals. The freshwater yabby, Cherax destructor Clark (Decapoda, Parastacidae), is a ubiquitous species native to Australia's central and eastern regions, with a growing international commercial market. However, in this region of Australia, yabby farmers often harvest organisms from old mine tailings dams with elevated environmental arsenic levels. Yabbies exposed to elevated environmental arsenic were found to accumulate and store as much as 100 μg/g arsenic in their tissues. The accumulation is proportional to the concentration of arsenic in the sediment and is high enough to be of concern for people who eat the yabbies. A comparison of arsenic levels in wild and lab-fed animals also was performed. Although there was no significant difference in the level of arsenic in the various organs of the wild animals, the animals purchased from a yabby farm showed a significantly higher arsenic concentration in their hepatopancreas (3.7 ± 0.9 μg/g) compared to other organs (0.6–1.8 μg/g). Furthermore, after a 40-d exposure to food containing 200 to 300 μg/g inorganic arsenic, arsenate (As[V])-exposed animals showed a significant increase in tissue-specific arsenic accumulation, whereas arsenite (As[III])-exposed animals showed a lower, nonsignificant increase in As uptake, primarily in the hepatopancreas. These results have important implications for yabby growers and consumers alike.
Levels and distribution of polybrominated diphenyl ethers in various tissues of foraging hens from an electronic waste recycling area in South China
Authors: Liang Shu-Xuan , Zhao Qian , Qin Zhan-Fen , Zhao Xing-Ru , Yang Zhong-Zhi , Xu Xiao-Bai
Published: May 2008

Levels and distribution of polybrominated diphenyl ethers (PBDEs) in various tissues of hens foraging near an electronic wastes stack spot in Taizhou, China, were studied. With high-resolution gas chromatography/negative chemical ionization mass spectrometry analysis, 37 PBDE congeners from di- to hepta-brominated and BDE 209 were identified and quantified in the liver, heart, skin, fat, intestine, muscle, blood, oviduct, ovum, gizzard, spleen, and kidney tissues of hens. Based on lipid weight in all analyzed tissues, muscle exhibited the highest PBDE concentrations (17,977 ng/g lipid wt), BDE 209 was the dominant congener, and the sum of quantified PBDEs followed the order muscle > fat > intestine > heart > liver > oviduct > gizzard > blood > skin > ovum. Principal component analysis results indicated that the hen muscle tissue was characterized by BDE 32, 209, 28, and 75 congeners; hen intestine, heart, and blood tissues were characterized by BDE 153, 99, 183, 138, 154, 47, and 100 congeners; and hen skin, liver, oviduct, ovum, gizzard, spleen, kidney, and fat tissues had a similar PBDE congener profile. The present study also indicated that the PBDE congeners were persistent enough to accumulate through the human food chain and that deca-BDE might be potential risk to ecoenvironment.
Toxicological responses of red-backed salamanders (Plethodon cinereus) to subchronic soil exposures of 2,4,6-trinitrotoluene
Authors: Bazar Mathew A , Quinn Michael J , Mozzachio Kristie , Johnson Mark S
Published: May 2008

Since World War I, trinitrotoluene (TNT) has been the most commonly used explosive. Environmental contamination associated with synthesis, manufacture of weapons, and use during training exercises has been extensive, with soil concentrations reaching 145,000 mg/kg. Some of these areas include habitats for amphibian species. Earlier studies have shown that salamanders dermally absorb TNT from soil. To ascertain what soil concentrations of TNT are toxic to amphibians, red-backed salamanders (Plethodon cinereus) were exposed to one of five concentrations of TNT in soil for 28 d and evaluated for indicators of toxicity. A total of 100 salamanders were randomly sorted by weight and assigned to target TNT concentrations in soil of either 3,000, 1,500, 750, 325, or 0 mg/kg dry weight. Food consisted of uncontaminated flightless Drosophila melanogaster. Survival was reduced in salamanders exposed to 1,500 and 3,000 mg/kg by 10 and 55%, respectively. Most mortality/morbidity occurred within the first week of exposure. Salamanders had a reduction in hemoglobin at 750 mg/kg or greater and a reduction in red blood cell concentration at 1,500 mg/kg or greater. Food consumption was affected in salamanders at 750 mg/kg or greater; a reduction in body mass and liver glycogen content also occurred at and above this concentration. Splenic congestion also was observed in salamanders from these groups. These data suggest that soil TNT concentrations of 373 ± 41.0 mg/kg or greater result in reduced body mass, reduced feed intake, and hematological effects.
History, Achievements, and Current Status of Genetic Resources Conservation
Authors: Damania Adi B.
Published: May 2008

This paper has been written to look back at the early period of crop genetic resources conservation and inform readers of what has been achieved so far and what needs to be done in the future. The recognition of the value of crop genetic resources and early efforts at collecting germplasm by pioneer plant explorers, such as F.N. Meyer and N.I. Vavilov, and some of the strategies they employed are described. Historic examples of collection, evaluation, and utilization of genetic resources, notably by the late J.R. Harlan and other U.S. agronomists, are highlighted. The use of wild progenitors in improving biotic and abiotic stress tolerance has been covered. Previous and present status of genetic resources collection and storage, both ex situ in gene banks and in situ in the natural habitats of crops and their wild progenitors, is discussed. The creation of agrobiodiversity is a dynamic process and hence the work on conservation of genetic resources has to continue. With the increasing use of biotechnology in crop improvement, the value of germplasm already collected and conserved will substantially increase as researchers seek out new sources of useful genes in the future.
Development and Impact of Vegetative Propagation in Forage and Turf Bermudagrasses
Authors: Hanna Wayne W. , Anderson William F.
Published: May 2008

The beauty and uniformity of vegetatively propagated grasses on golf course greens, fairways and tees, and on athletic fields and lawns and the superiority of the vegetatively propagated forage grasses that we enjoy today did not happen by accident. Risks were taken, innovative approaches were used, new equipment was developed and modified, and public institutions and private industry teamed up to make what we have today a reality. In the 1940s and 1950s, pioneering discoveries and advances were made in inventing equipment, establishing protocols, and developing consumer confidence. Vegetative reproduction in bermudagrass revolutionized the golf and athletic field industries by providing a superior, high‐quality, uniform playing surface. It maximized profitability of the forage industry for cattle (Bos taurus) by providing the very best genotypes for farmers and ranchers to plant for grazing and hay. Although vegetative propagation of forage and turf started with Cynodon hybrids in a small area of the United States, the practice has expanded on a commercial scale to numerous species around the world.
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: May 2008

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.
Teaching and Learning in Agronomy: One Hundred Years of Peer‐Reviewed Conversations
Authors: Grabau Larry J.
Published: May 2008

The American Society of Agronomy (ASA) published its first peer‐reviewed article about teaching in Volume 1 of the Proceedings of the American Society of Agronomy (PASA), and has built on that foundation for 100 yr. Articles have also appeared in the Journal of the American Society of Agronomy (JASA) from 1913 to 1948, in Agronomy Journal (AJ) from 1949 to 1971, in the Journal of Agronomic Education (JAE) from 1972 to 1991, and in the Journal of Natural Resources and Life Sciences Education (JNRLSE) from 1992 through the present. The ASA CD archives were used to locate publications through 2001, and the ASA/JNRLSE websites for 2002–2006 papers. The objectives of this article were to: (i) celebrate the centennial milestone by recounting the collective accomplishments of teaching manuscripts, and (ii) identify key trends in ASA teaching publications over the society's first 100 yr. In the 1920s, 28 papers were published, focusing on the development of courses and curricula for the emerging study of agronomy. From 1954 to 1971, articles on agronomic education were included in JASA or AJ, but set apart in a separate category. With journals dedicated to teaching (JAE and JNRLSE), the modern era (1972–2006) has seen much higher publication rates. Initiatives have included: writing skills, simulation models, international development, capstone courses, diversity support, engaging games, reflective memoirs, decision cases, new undergraduate programs, and web lessons. Through JNRLSE, ASA is well‐positioned to be a leader in the publication of peer‐reviewed teaching materials into the 21st century.
Long‐Term Agronomic Performance of Organic and Conventional Field Crops in the Mid‐Atlantic Region
Authors: Cavigelli Michel A. , Teasdale John R. , Conklin Anne E.
Published: May 2008

Despite increasing interest in organic grain crop production, there is inadequate information regarding the performance of organically‐produced grain crops in the United States, especially in Coastal Plain soils of the mid‐Atlantic region. We report on corn (Zea mays L.), soybean [Glycine max (L.) Merr.], and wheat (Triticum aestivum L.) yields at the USDA‐ARS Beltsville Farming Systems Project (FSP), a long‐term cropping systems trial established in Maryland in 1996 to evaluate the sustainability of organic and conventional grain crop production. The five FSP cropping systems include a conventional no‐till corn–soybean–wheat/soybean rotation (NT), a conventional chisel‐till corn–soybean–wheat/soybean rotation (CT), a 2‐yr organic corn–soybean rotation (Org2), a 3‐yr organic corn–soybean–wheat rotation (Org3), and a 4‐ to 6‐yr organic corn–soybean–wheat–hay rotation (Org4+). Average corn grain yield during 9 yr was similar in NT and CT (7.88 and 8.03 Mg ha−1, respectively) but yields in Org2, Org3, and Org4+ were, respectively, 41, 31, and 24% less than in CT. Low N availability explained, on average, 73% of yield losses in organic systems relative to CT while weed competition and plant population explained, on average, 23 and 4%, respectively, of these yield losses. The positive relationship between crop rotation length and corn yield among organic systems was related to increasing N availability and decreasing weed abundance with increasing rotation length. Soybean yield averaged 19% lower in the three organic systems (2.88 Mg ha−1) than in the conventional systems (3.57 Mg ha−1) and weed competition alone accounted for this difference. There were no consistent differences in wheat yield among cropping systems. Crop rotation length and complexity had little impact on soybean and wheat yields among organic systems. Results indicate that supplying adequate N for corn and controlling weeds in both corn and soybean are the biggest challenges to achieving equivalent yields between organic and conventional cropping systems.
Rice Growth, Grain Yield, and Floodwater Nutrient Dynamics as Affected by Nutrient Placement Method and Rate
Authors: Kapoor Vibhu , Singh U. , Patil S. K. , Magre H. , Shrivastava L. K. , Mishra V. N. , Das R. O. , Samadhiya V. K. , Sanabria J. , Diamond R.
Published: May 2008

The loss of major nutrients can be high in rice (Oryza sativaL.) fields, particularly rainfed rice, where water flowing from field to field during periods of high rainfall not only reduces the nutrient use efficiencies but also has the potential for environmental degradation. We examined the influence of deep point placement of N, P, and K briquettes compared to broadcast incorporation of N, P, and K on floodwater nutrient loads after fertilizer application and on the performance of wet season rice in a Vertisol. Broadcast application of N as urea resulted in an average 10 times higher amounts of ammonium N in floodwater compared to deep placement of urea briquette. The broadcast application of single superphosphate resulted in 67 times higher amounts of P in floodwater than plots receiving deep placed P. The floodwater NH4+–N and P content in the deep placement treatments were negligible—similar to floodwater N and P content without fertilizer application. The floodwater K amounts were also significantly lower with deep placed N–P–K briquettes. Significantly higher grain and straw yields, total N, P, and K uptake, and N and P use efficiencies were observed with deep placement of N–P–K compared to broadcast application of N–P–K. Deep placed N–P briquettes gave significantly higher grain yield, straw biomass, total P and K uptake, apparent P recovery, and agronomic N and P use efficiencies when plant spacing was reduced from 20 by 20 cm to 20 by 10 cm. Closer plant spacing led to better utilization of P and K and provided opportunities for deep placement of N–P or N–P–K briquettes in soils with low available P. Combining site specific characteristics (high soil pH, low percolation rate, high rainfall and surface runoffs) with plant spacing and N–P–K briquettes prepared based on site‐specific nutrient requirements offers potential for higher yields, improved fertilizer use efficiency, balanced fertilization, and reduced nutrient losses.
The Magruder Plots: Untangling the Puzzle
Authors: Girma Kefyalew , Holtz Starr L. , Arnall Daryl B. , Tubaña Brenda S. , Raun William R.
Published: May 2008

Long‐term experiments play a vital role in revealing dynamic soil and weather processes that directly influence sustainable crop production and ecosystem health. The objective of this review paper is to present one of the oldest long‐term continuous winter wheat (Triticum aestivum L.) experiments, the Magruder Plots, and their contribution to the scientific community regarding questions of yield response to amendments, yield stability, percentage organic matter (OM) lost over time, soil nutrient status, microbial activity, weed population, and information on the economic return from winter wheat production. Alexander C. Magruder initiated the experiment in 1892 and is in progress to date. The original plot was started to evaluate wheat production on native prairie soils without fertilization. After 6 yr the principal investigator split the initial plot into two and fertilized one half with cattle manure. The experiment was then modified to include 10 treatments in 1930 by Dr. Horace J. Harper to answer several soil fertility related questions. Since 1947, six treatments have remained intact that evaluate simple combinations of manure, and inorganic N, P, K, and lime. Following 114 yr of continuous winter wheat production under conventional tillage, the check plot that has never received any fertilizer addition continues to produce wheat grain yields of >1 Mg ha−1. Despite the decline in soil organic matter from 4 to 1% during this time period, wheat grain yields continue to show slight increases with time, likely due to improved genetics. While continuous wheat without rotation is not recommended, this 114‐yr study documents the feasibility.
William J. Beal: Pioneer Applied Botanical Scientist and Research Society Builder
Authors: Beard James B , Cookingham Peter O.
Published: May 2008

Professor William James Beal (1833–1924) became a leading educator and researcher in applied plant science while serving on the faculty of the new State Agricultural College in Michigan from 1871 to 1910. He was a key leader of the experimental movement of agricultural botany. Beal conducted the (i) first demonstration of hybrid vigor by controlled crossing of corn lines, 1878; (ii) initiation of the oldest ongoing U.S. botanical experiment involving the vitality of buried seeds, 1879; and (iii) first turfgrass experiments, including polystand compatibility, 1880. He initiated early, extensive seed purity/viability testing in 1877, and also organized the oldest, continuously operating U.S. botanical garden in 1877. He was an early advocate for forest conservation and reforestation. These works resulted in more than 1200 papers, plus seven extensive texts. Beal was a key proponent of scholarly communications among the few isolated scientists active in applied botany and in agricultural research. His efforts contributed to the formation of several important early national agricultural science organizations. Beal was a key founder and first President of the (i) Society for the Promotion of Agricultural Science (SPAS), 1880; (ii) Association of Botanists in the United States Agricultural Experiment Stations, 1889; (iii) Botanical Club of the American Association for the Advancement of Science, 1888; and (iv) Michigan Academy of Science, 1884. The visionary outlook in organization of the SPAS was a vital pioneering step leading to formation of the American Society of Agronomy in 1907.
Second Generation European Corn Borer Injury and Irish Potato Physiology, Yield, and Quality
Authors: Ziems Jesse R. , Hoback W. Wyatt , Higley Leon G. , Hunt Thomas E. , Fernandes Odair A. , Bastos Cristina , de Freitas Bueno Adeney
Published: May 2008

European corn borer (ECB) [Ostrinia nubilalis (Hübner)] (Lepidoptera: Crambidae) is known to infest Irish potato (Solanum tuberosum L.) but only causes economic damage during the first generation in East Coast potato producing areas. However, in Nebraska, second generation ECB infest potato plants during the bulking period and may reduce yield and/or potato quality. Experiments were conducted in 2001, 2002, and 2003 to examine physiological and yield effects of second generation ECB injury to potato in Nebraska. Pike, Atlantic, and three Frito Lay proprietary varieties (FL1867, FL1879, and FL1833) were used. Experimental plots were infested with four ECB egg masses per plant to simulate ECB infestation by second‐generation larvae; controls received no egg masses. Photosynthetic rates, tuber weights, tuber size grades, solids, and fry quality were measured. Potato plants with ECB infestation had significantly reduced photosynthetic rates on ECB‐infested stems and on uninfested stems on the same plant when larvae were in the fifth instar. When insects were in the fourth instar, photosynthetic rates were reduced only on ECB‐infested stems. In 2001, ECB infestation reduced the average mass of large tubers and increased the amount of small tubers in FL1867 and FL1879. In 2002, significant yield reductions were not observed. Across both years, ECB‐infested plots produced fewer large (65‐ to 100‐mm diam.) tubers than control plots. Other tuber properties and chip qualities were unaffected. This study indicates that second generation ECB infestation of approximately 30% infested plants results in economic loss for some chipping varieties and affects tuber bulking. In contrast to east coast growers, Midwest potato farmers must be concerned with second generation ECB.
Response of Corn and Cotton to Starter Phosphorus on Soils Testing Very High in Phosphorus
Authors: Cahill Sheri , Johnson Amy , Osmond Deanna , Hardy David
Published: May 2008

Phosphorus from agricultural lands poses a problem in water resources. In 2003, more than 48% of soil samples submitted to the North Carolina Department of Agriculture and Consumer Services (NCDA&CS) soil testing laboratory tested very high in soil P (>120 mg dm−3 P). As soil test P increases, off‐site P loss increases, through erosion, soluble P runoff, or leaching. On soils testing above high soil test P (60–120 mg dm−3 P), studies from the northeast and midwest United States demonstrate that no corn (Zea mays L.) or cotton (Gossypium spp.) yield response from additional fertilizer is expected. However, there have been limited studies on the effects of starter‐P fertilizer on soils with very high P status in North Carolina and the southeast. Therefore, we undertook a study in the three physiographic regions (coastal plain, piedmont, and mountains) of North Carolina to determine if the use of starter‐P fertilizer would affect the growth of corn and cotton on soils having very high soil test P. Treatments were starter N and P, and starter N only. Treatment differences were not observed for corn, while the N‐only treatment had greater tissue N than the N‐ and P‐starter treatment in Piedmont cotton. Additionally, the use of only starter‐N is typically more cost effective than using both N and P starter fertilizer. For production, environmental, and economic reasons, starter‐P fertilizer is not warranted on North Carolina fields with very high soil test P values.
Year, Region, and Temperature Effects on the Quality of Minnesota's Soybean Crop
Authors: Naeve Seth L. , Huerd Sheri C.
Published: May 2008

Bulk commodity soybean [Glycine max (L.) Merr.] can now be sourced with great specificity through rail and container purchases. The objective of this study was to determine whether analyses of farmer‐grown soybean seed samples could detect significant regional differences in soybean quality traits. Through analysis of 2706 farmer volunteered soybean samples representing harvests from 2003–2005, we found significant year and region effects on seed quality. An independent variable, temperature during seed filling (Tsf) was created for each soybean sample by kriging local daily mean air temperatures from 135 weather stations. A region × year interaction was noted for protein and the sum of protein and oil concentrations, but using Tsf as a covariate eliminated this interaction. The variable Tsf correlated with average regional oil concentrations such that oil concentration increased at a rate of 6.6 g kg−1 °C−1. Overall, farmer produced and volunteered soybean samples provide an excellent means of identifying within‐state soybean seed quality variation. Additionally, local climate data (Tsf) can be used to predict this variation in regional soybean seed quality.
Agronomic and Economic Performance Characteristics of Conventional and Low‐External‐Input Cropping Systems in the Central Corn Belt
Authors: Liebman Matt , Gibson Lance R. , Sundberg David N. , Heggenstaller Andrew H. , Westerman Paula R. , Chase Craig A. , Hartzler Robert G. , Menalled Fabián D. , Davis Adam S. , Dixon Philip M.
Published: May 2008

We conducted a 9‐ha field experiment near Boone, IA, to test the hypothesis that yield, weed suppression, and profit characteristics of low‐external‐input (LEI) cropping systems can match or exceed those of conventional systems. Over a 4‐yr period, we compared a conventionally managed 2‐yr rotation system {corn (Zea mays L.)/soybean [Glycine max (L.) Merr.]} with two LEI systems: a 3‐yr corn/soybean/small grain + red clover (Trifolium pratense L.) rotation, and a 4‐yr corn/soybean/small grain + alfalfa (Medicago sativa L.)/alfalfa rotation. Synthetic N fertilizer use was 59 and 74% lower in the 3‐ and 4‐yr systems, respectively, than in the 2‐yr system; similarly, herbicide use was reduced 76 and 82% in the 3‐ and 4‐yr systems. Corn and soybean yields were as high or higher in the LEI systems as in the conventional system, and weed biomass in corn and soybean was low (≤4.2 g m−2) in all systems. Experimentally supplemented giant foxtail (Setaria faberi Herrm.) seed densities in the surface 20 cm of soil declined in all systems; supplemented velvetleaf (Abutilon theophrasti Medik.) seed densities declined in the 2‐ and 4‐yr systems and remained unchanged in the 3‐yr system. Without subsidy payments, net returns were highest for the 4‐yr system ($540 ha−1 yr−1), lowest for the 3‐yr system ($475 ha−1 yr−1), and intermediate for the 2‐yr system ($504 ha−1 yr−1). With subsidies, differences among systems in net returns were smaller, as subsidies favored the 2‐yr system, but rank order of the systems was maintained.
Active Sensor Reflectance Measurements of Corn Nitrogen Status and Yield Potential
Authors: Solari Fernando , Shanahan John , Ferguson Richard , Schepers James , Gitelson Anatoly
Published: May 2008

Active sensor reflectance assessments of corn (Zea mays L.) canopy N status are advocated to direct variable N applications and improve N use efficiency (NUE). Our goals were to determine: (i) growth stage and (ii) sensor vegetation index with greatest sensitivity in assessing N status and grain yield. Variable crop N was generated by supplying N at different amounts and times in three field studies. Chlorophyll meter (CM) and sensor data were gathered at two vegetative (V11 and V15) and two reproductive (R1 and R3) growth stages, using the Crop Circle sensor that measures reflectance in visible (590 nm) and near infrared (NIR) (880 nm) bands. Sensor data were converted to the normalized difference vegetation index (NDVI590) and chlorophyll index (CI590) values. Grain yields were also determined. Sensor indices were more highly correlated with CM readings for vegetative vs. reproductive growth (r2 of 0.85 vs. 0.55). The CM vs. CI590 slope was over twice the NDVI590 slope value, indicating CI590 was more sensitive than NDVI590 in assessing canopy greenness. Indices did not differ in ability to distinguish yield variation. Results indicate sensor CI590 values collected during vegetative growth are best suited to direct variable N applications.
Proso Millet Yield and Residue Mass following Direct Harvest with a Stripper‐Header
Authors: Henry W. Brien , Nielsen David C. , Vigil Merle F. , Calderón Francisco J. , West Mark S.
Published: May 2008

Proso millet (Panicum miliaceum L.) (PM) is an important crop for dryland rotations in the central Great Plains. The crop is traditionally swathed before combining to promote uniform drying of the panicle and to minimize seed shattering losses. Direct harvesting of PM with a stripper‐header would eliminate the swathing operation resulting in cost savings, and increased standing crop residues to enhance erosion protection, snow catch, and precipitation storage efficiency. This study was conducted to determine yield differences between conventionally swathed and stripper‐header harvested PM and to compare PM residue mass and orientation following the two harvest techniques. The study was conducted over four growing seasons at Akron, CO. Proso millet was harvested either by swathing and then picking up the swath with a combine, or by direct harvesting with a stripper‐header attached to the combine. Seed yields and moisture contents at harvest were not significantly different between treatments. About 20% more seed was found on the ground with the stripper‐header harvest than with the conventionally swathed harvest, but the increased shattering resulted in only about 1% loss of the average final yield. Using a stripper‐header resulted in both the standing residue mass and the silhouette area index following harvest to be four times greater than in conventionally swathed PM. A stripper‐header can be used to successfully direct harvest PM thereby reducing harvest costs and increasing surface crop residues following harvest.
“Drop It Like It's Hot”
Authors: Fitts Mako
Published: May 2008

This paper describes results from a qualitative study of the music video production industry and the creative process in rap music video production and artist marketing. Participant responses are presented in three areas: the music video production process, recent trends in rap music videos, and the music video set as a site of gender exploitation. Findings suggest a concern over artistic freedom of expression and the mechanical production of the “booty video” formula that saturates music video programming and is a template for rap videos. Participants agreed that there is something lackluster about rap music played on radio and aired on music video programming. Additionally, gendered hierarchies on video sets create divisions among women working in various positions, and discourage women from supporting one another, which, from a black feminist perspective, does not accommodate an ethic of care and personal responsibility.
Successional patterns of plant species and community diversity in a semi‐deciduous tropical forest under shifting cultivation
Authors: Kassi N'Dja Justin K. , Decocq Guillaume
Published: May 2008

Question:

Does shifting cultivation contribute to plant diversity in an Afrotropical semi‐deciduous forest lacking large‐scale natural disturbance?

Location:

Sanaimbo forest, Côte d'Ivoire (Ivory Coast).

Methods:

We surveyed species assemblages, structural attributes of diversity, and life‐history traits along a 30‐year chronosequence of abandoned fields, comparatively to old‐growth and selectively logged forest stands.

Results:

Patterns of species assemblages strongly changed with fallow area age, with respect to species'light requirements, suggesting niche partitioning along the successional gradient. Species richness, diversity and equitability were all increasing along this gradient. There were clear shifts in life‐history traits spectra as the forest recovered, especially regarding leaf shape, lifespan and hairiness, diaspore dispersal, seed size, resprouting capacity, and life forms. Early colonization by the invasiveChromolaena odoratadid not appear to impair secondary succession. Soil type influenced old‐growth forest vegetation but not fallow vegetation. After 30 years of forest regrowth, plant communities exhibited endemism rates similar to those of ancient forests.

Conclusions:

Shifting cultivation appears to be a sustainable land use when small‐sized fields are embedded in a forest matrix and when agriculture lasts only one to few years, preserves remnant trees, excludes fire and keeps several years between two clearing episodes. It may even contribute to the high biodiversity maintenance at the whole forest scale, by conserving the successional mosaic. However, conservation of old‐growth forest patches is required for a number of climax tree species.
Adrenergic Response of Splanchnic Arteries from Cirrhotic Patients: Role of Nitric Oxide, Prostanoids, and Reactive Oxygen Species
Authors: Salcedo Adely , Garijo Jesús , Monge Luis , Fernández Nuria , García-Villalón Angel Luis , Turrión Víctor Sánchez , Cuervas-Mons Valentín , DiéGuez Godofredo
Published: May 2008

Peripheral and splanchnic vasodilatation in cirrhotic patients has been related to hyporesponsiveness to vasoconstrictors, but studies to examine the vascular adrenergic response provide contradictory results. Hepatic arteries from cirrhotic patients undergoing liver transplantation and mesenteric arteries from liver donors were obtained. Segments 3 mm long from these arteries were mounted in organ baths for testing isometric adrenergic response. The concentration-dependent contraction to noradrenaline (10−8 to 10−4 M) was similar in hepatic and mesenteric arteries, and prazosin (α 1-adrenergic antagonist, 10−6 M), but not yohimbine (α 2-adrenergic antagonist, 10−6 M), produced a rightward parallel displacement of this contraction in both types of arteries. Phenylephrine (α 1-adrenergic agonist, 10−8 to 10−4 M) and clonidine (α 2-adrenergic agonist, 10−8 to 10−4 M) also produced concentration-dependent contractions that were comparable in hepatic and mesenteric arteries. The inhibitor of cyclooxygenase meclofenamate (10−5 M), but not the inhibitor of nitric oxide synthesis Nw-nitro-l-arginine methyl ester (l-NAME, 10−4 M), potentiated the response to noradrenaline in hepatic arteries; neither inhibitor affected the response to noradrenaline in mesenteric arteries. Diphenyleneiodonium (DPI; 5 × 10−6 M), but neither catalase (1000 U/ml) nor tiron (10−4 M), decreased the maximal contraction for noradrenaline similarly in hepatic and mesenteric arteries. Therefore, it is suggested that, in splanchnic arteries from cirrhotic patients, the adrenergic response and the relative contribution of α 1- and α 2-adrenoceptors in this response is preserved, and prostanoids, but not nitric oxide, may blunt that response. Products dependent on NAD(P)H oxidase might contribute to the adrenergic response in splanchnic arteries from control and cirrhotic patients.
Differential Expression of Mimecan and Thioredoxin Domain–Containing Protein 5 in Colorectal Adenoma and Cancer: A Proteomic Study
Authors: Wang Yinghong , Ma Yu , Lü Bingjian , Xu Enping , Huang Qiong , Lai Maode
Published: May 2008

Adenoma is the major precursor lesion of colorectal cancer, one of the most common cancers worldwide. The elucidation of the molecular mechanism underlying adenoma is essential for early detection, prevention, and intervention of colorectal cancer. Using a combination of two-dimensional gel electrophoresis and mass spectrometry, we identified 27 differentially expressed proteins in adenoma, compared with matched normal mucosa and cancer tissue. Seventeen proteins were upregulated and six downregulated in adenoma when compared with the same proteins in individual-matched normal mucosa. Four were downregulated, but none upregulated in adenoma when compared with the same proteins in matched cancer tissue. Two novel proteins, mimecan and thioredoxin domain–containing protein 5 (TXNDC5), were further validated by Western blot in 8 colorectal adenomas and 19 cancers that were matched with normal mucosa. All adenoma and cancer tissues did not express mimecan, but all normal mucosa did ( P < 0.01). In contrast, TXNDC5 was significantly upregulated in colorectal adenoma and cancer tissues as compared with that in normal mucosa ( P < 0.05). This study clearly demonstrated that absence of mimecan and upregulation of TXNDC5 are involved in the early development of colorectal cancer. Thus, the differentially expressed proteins might serve as potential biomarkers for colorectal cancer detection and intervention.
Moderately High Folic Acid Supplementation Exacerbates Experimentally Induced Liver Fibrosis in Rats
Authors: Marsillach Judit , Ferré Natàlia , Camps Jordi , Riu Francesc , Rull Anna , Joven Jorge
Published: May 2008

Under certain clinical circumstances, folic acid can have undesirable effects. We investigated the following: (i) the effects of moderately high folic acid supplementation on the course of liver impairment in CCl4-treated rats and (ii) the influence of folic acid supplements on the hepatic recovery following the interruption of the CCl4-induced toxic injury. Four experimental groups of rats were used: CCl4-treated rats (0.5 ml of CCl4 twice a week ip) fed standard chow for up to 12 weeks (Group A); treated rats fed chow supplemented with 25 mg/kg folic acid from weeks 6 to 12 (Group B); treated rats fed a standard diet but with CCl4 discontinued after 6 weeks to allow for tissue recovery over 4 weeks (Group C); rats as Group C but fed a diet supplemented with 25 mg/kg folic acid from weeks 6 to 10 (Group D). Liver and blood samples were obtained for biochemical, histological, and gene expression analyses. Animals that received the supplement had a higher content of collagen, activated stellate cells, and apoptotic parenchymal cells in biopsy tissue at weeks 8 and 10 of treatment and more extensive alterations in serum albumin and bilirubin concentrations (Group B vs. Group A). In some of the time periods analyzed, alterations were observed in the expression of genes related to apoptosis (B-cell leukemia/lymphoma 2, inhibitor of apoptosis 2) and to fibrosis (procollagen I, matrix metalloproteinase 7). In the recovery period (Groups C and D), folic acid administration was associated with increased hepatic inflammation and apoptosis and with a decrease in the tissue inhibitor of metalloproteinase-3 expression following 1 week of recovery. We conclude that folic acid administration aggravates the development of fibrosis in CCl4-treated rats. Follow-up studies are needed to determine whether folic acid treatment would be contraindicated in patients with chronic liver diseases.