bluuebunny/crossref_metadata_2025_split huggingface dataset:
A new species of Arthula (Hymenoptera: Ichneumonidae: Cryptinae) from Korea, and its intraspecific seasonal variation
Authors: Oh Seung-Ho , Lee Jong-Wook , Choi Won-Young 
Published: April 2011

AbstractA new species, Arthula biformis Oh and Lee sp. nov., belonging to the cryptine ichneumonid subtribe Sphecophagina Beirne is described from Korea. The new species is composed of two seasonal forms, overwintering and summer, distinguished by color and some morphological features. The overwintering form is much darker than the summer form. Keys to the genera of Sphecophagina and the known species of Arthula Cameron and photographs of diagnostic characters of both color forms of the new species are provided.
Optimization of duplex real-time PCR with melting-curve analysis for detecting the microsporidian parasites Nosema apis and Nosema ceranae in Apis mellifera
Authors: Burgher-MacLellan Karen L. , Williams Geoffrey R. , Shutler Dave , MacKenzie Kenna , Rogers Richard E.L. 
Published: April 2011

AbstractHoney bees, Apis mellifera (L.) (Hymenoptera: Apidae), are parasitized by the microsporidians Nosema apis (Zander) and Nosema ceranae (Fries). Molecular techniques are commonly used to differentiate between these parasites because light microscopy is inadequate. Our objectives were to (i) adapt the previously published duplex polymerase chain reaction (PCR) targeting the 16S rRNA gene of N. apis (321APIS-FOR, 321APIS-REV) and N. ceranae (218MITOC-FOR, 218MITOC-REV) using qualitative real-time PCR assay with SYBR® Green I dye (R-T PCR) and DNA melting-curve analysis, and (ii) determine whether the two Nosema species can be detected simultaneously in honey bees. Total spore counts and purified total genomic DNA were obtained from 37 bee samples (19 individual workers and 18 pooled samples of 15 workers) collected in Nova Scotia, Prince Edward Island, and Newfoundland, Canada. Overall, the prevalence of Nosema species was 86.5% (32/37 samples of bee DNA), based on conventional PCR and the optimized R-T PCR assay. The melting-curve analysis showed three groups of curve profiles that could determine the prevalence of N. apis, N. ceranae, and co-infection (21.9%, 56.2%, and 21.9%, respectively). The duplex R-T PCR assay was efficient, specific, and more sensitive than duplex conventional PCR because co-infection was identified in 5.4% (n = 2) more samples. Sequencing of R-T PCR products confirmed the results of the melting-curve analysis. Duplex R-T PCR with melting-curve analysis is a sensitive and rapid method of detecting N. apis, N. ceranae, and co-infection in honey bees.
Braconid parasitoids (Hymenoptera: Braconidae) of NearcticChoristoneuraspecies (Lepidoptera: Tortricidae), with a summary of other parasitoid families attackingChoristoneura
Authors: Fernández-Triana J. L. , Huber J. T. 
Published: April 2011

AbstractIllustrated identification keys are given for the superfamilies/families of insect parasitoids and the subfamilies, genera, and species of Braconidae reared from species ofChoristoneuraLederer in the Nearctic Region.Goniozus floridanus(Ashmead) (Chrysidoidea: Bethylidae) represents the third superfamily of Hymenoptera, andColpoclypeus florus(Walker) (Hymenoptera: Eulophidae) is added to the list of Chalcidoidea recorded fromChoristoneura. Fifty species of Braconidae in 18 genera and 9 subfamilies are recorded parasitizing 11Choristoneuraspecies; almost half belong to the Microgastrinae. Eight braconids (16%) were found for the first time as parasitoids ofChoristoneura. The first host record is given forOncophanes californicus(Ashmead) (Hormiinae). Known insect parasitoids ofChoristoneuraspp. in the Nearctic Region include 230 species in 106 genera, about 75% of which attack only 1 or 2Choristoneuraspecies each. An additional 36 species are considered incorrectly associated withChoristoneura, an error rate of 14%. The Banchinae (Ichneumonidae, especiallyGlyptaGravenhorst), Pimplinae (Ichneumonidae), and Microgastrinae (Braconidae) made up the greatest proportion of parasitoids. No parasitoids have yet been recorded from five NearcticChoristoneuraspecies.
Molecular evidence for sympatric taxa withinPemphigus betae(Hemiptera: Aphididae: Eriosomatinae)
Authors: Foottit R. G. , Floate K. , Maw E. 
Published: April 2011

AbstractMitochondrial DNA cytochromecoxidase subunit 1 (DNA barcode) and nuclear microsatellite flanking region sequences were used to analyse populations of putative “sugarbeet root aphid”,Pemphigus betaeDoane, from sites in Alberta, Canada. Three sympatric genotypes were revealed, identified asP. betae,P. populivenaeFitch, and an undetermined third species. All three genotypes formed morphologically indistinguishable galls on the same set of cottonwood (PopulusL., Salicaceae) host species, often on the same tree. Gall morphology is frequently used to identifyPemphigusspecies. Our results indicate that this practice may be unreliable for these three taxa at least.
Response of broilers to feeding low-calcium and total phosphorus wheat-soybean based diets plus phytase: Performance, digestibility, mineral retention and tibiotarsus mineralization
Authors: Catalá-Gregori Pablo , García Victoria , Madrid Josefa , Orengo Juan , Hernández Fuensanta 
Published: April 2011

A 42-d trial was conducted with broilers fed a wheat-soy bean-meal-based diet to compare three dietary levels of calcium (Ca) and total phosphorus (TP) plus phytase on growth performance parameters, nutrient digestibility, mineral retention and tibiotarsus bone parameters. Three treatments were compared: a high Ca and TP diet (H−; according to NRC recommendations) without addition of phytase; a moderate Ca and TP diet (M+) with 600 U kg-1 of phytase; and a low Ca and TP diet (L+; similar to local industry practices) with 600 U kg-1 of phytase supplementation. Feed intake and weight gain of broilers fed H− were not different to M+ or L+. Nutrients digestibility at 21 d was improved in animals fed M+ in comparison with H− and L+. Better phosphorus retention was observed for M+ at 21 d of age. The bone mineralization was similar for H− and M+ at 21 d of age, and for H−, M+ and L+ at 42 d of age.
Performance of prohexadione-calcium on shoot growth and fruit quality of apple — Effect of spray surfactants
Authors: Cline J. A. , Embree C. G. , Hebb J. , Nichols D. S. 
Published: April 2011

Vegetative growth control of apples (Malus × domestica Borkh.) is necessary to maintain a balance between growth and cropping. Pruning is a labour-intensive management practice to achieve this and intrinsically stimulates new growth. Prohexadione-calcium (PC) is a plant bio-regulator that effectively regulat es the shoot extension growth of apples and other tree fruits. Previous research has demonstrated that its efficacy can vary based on the use of spray surfactants and adjuvants. This study investigated the efficacy of two rates of Apogee™, the commercial form of PC, used in combination with the spray surfactants Sylgard 309 and LI 700, on extension shoot growth and yield parameters. Experiments were conducted in Ontario on Empire and Nova Scotia on Royal Court™ Cortland apples. Treatments of 0, 75 or 125 mg L-1 PC, with and without either 0.5% (vol/vol.) LI 700 surfactant or 0.05% (vol/vol) Sylgard 309 surfactant were applied to Empire trees, and 75 or 125 mg L-1 PC, with or without 0.5% (vol/vol) LI 700, were applied to Royal Court™ trees. An untreated control treatment was also included for comparison purposes. A total of two sprays were applied to the Empire trees and a total of three sprays were applied to the Royal Court™ trees. PC significantly decreased the vegetative growth of Empire and Royal Court™ trees by approximately 18 to 44%, respectively, and the efficacy of PC was enhanced when combined with either Sylgard 309 or LI 700 surfactant. No additional benefit in vegetative growth control was gained when using Apogee™ at rates of 125 mg L-1 PC, relative to 75 mg L-1 PC. The rate of Apogee™ did not influence the number of fruit or yield per tree or mean fruit size of either cultivar. For Empire, LI 700 and Sylgard 309 significantly reduced the number of fruit per tree, resulting in lower yields and crop densities. In addition, higher mean fruit weights, and a greater distribution of fruit in the larger size categories were observed for LI 700. Fruit from Royal Court trees treated with the highest rate of Apogee™ had higher crop densities, poorer coloured fruit, and a higher percentage of fruit less than 60 mm in diameter. These data provide support for the use of alternative surfactants with Apogee™ other than those listed on the US and Canadian product labels. Key words: Apogee™, Empire, Cortland, Regalis, calcium 3-oxido-5-oxo-4-propionylcyclohex-3-enecarboxylate, surfactant
Denitrification and fluxes of nitrogenous gases from soil under steady oxygen distribution
Authors: Cho C. M. , Burton D. L. , Chang C. 
Published: April 2011

Transport equations for O2, NO3−, NO2−, N2O and N2 were formulated to investigate NO3− stability, denitrification and formation of gaseous nitrogen compounds in a soil profile under different moisture and temperature conditions. The source-sink terms of the transport equations, including those for O2, were based upon competitive Michaelis-Menten type kinetics of denitrification. The equations were solved under various soil and seasonal temperature conditions typical of the Prairie Region of Canada in order to explore the effects of these parameters upon predicted NO3− stability, denitrification product distribution in a soil profile and gaseous N fluxes from the soil surface. The depth to the aerobic-anaerobic interface from the soil surface was controlled by temperature, moisture and microbial activity distributions in the soil. The kinetic expressions predicted that NO3− was generally stable under aerobic conditions since the affinity coefficient of O2 for electrons is much greater than that of NO3−. However, nitrate in the anaerobic zone was subject to denitrification to produce N2O and N2. The N2O produced in the anaerobic zone diffused into the aerobic zone where it was stable and eventually emitted to the atmosphere. As the NO3− concentration decreased, a greater proportion of N was emitted to the atmosphere as N2. Thus, the ratio of N2O to N2 emitted from the soil decreased with decreased NO3−. We found that the potential for denitrification to take place in a soil profile was actually greater in late summer than in mid-summer since subsoil temperatures were higher later on in the season. The ratio of fluxes of N2O to N2 was a function of time, moisture content distribution, the depth at which the maximum reduction of NO3− took place, and NO3− concentration. Key words: Transport, denitrification, gas flux, nitrous oxidenot available
Role of continuous wheat and amendments in ameliorating an artificially eroded Dark Brown Chernozemic soil under dryland conditions
Authors: Dormaar J. F. , Lindwall C. W. , Kozub G. C. 
Published: April 2011

Complete loss of topsoil resulting from erosion or other causes generally results in reduced crop yield. To determine, under dryland conditions, the effect of loss of various amounts of soil and of various amendment practices suitable for use under a cereal production program on soil properties and crop yields, a field was artificially eroded during cut and fill of land-levelling in 1957. Continuous cropping to barley for 7 yr was followed by a wheat-fallow rotation for 22 yr. A continuous wheat experiment was conducted from 1987 to 1991 to determine the effects of five fertility amendments on restoring the productivity to soil from which 10–20 cm and 46+ cm of soil had been removed. In 1990, a below-average precipitation year, after 33 yr and 23 crops, yields from the unfertilized 46+ cm eroded field were only 44% of the yields from the uneroded field. However, with the increased precipitation in 1991 this value was 66%. A one-time topsoil amendment was beneficial in the earlier stages of the experiment, but lost its effect as cultivation mixed it into the "subsoil" over time. Plot treatments with annual applications of manure and high rates of fertilizer generally out-yielded the yields of the check plots of the uneroded treatment. Amendment with straw + fertilizer was not very effective. Soil, once lost, is non-renewable without amendments within the working lifetime of the producer. Key words: Soil erosion, manure, commercial fertilizer, topsoil soil, productivity
Denitrification and nitrous oxide emissions from a Black Chernozemic soil during spring thaw in Alberta
Authors: Nyborg M. , Laidlaw J. W. , Solberg E. D. , Malhi S. S. 
Published: April 2011

Previous field research in Alberta has suggested that denitrification occurs mostly when soil thaws in the spring, with associated soil water saturation. Our objective was to determine if denitrification and N2O emission in fact take place in cold, thawing soil in the field. Denitrification and N2O flux were measured in two springs and the intervening summer. Cylinders were placed in soil in November, 1988, and 57 kg N ha−1 of 15Nlabeled KNO3 was added. Soil 15N mass balance technique showed 23 kg N ha−1 of added-N was lost by 15 May 1989. Gas trappings were made (28 March to 29 April) and nearly all of the N2O emission (3.5 kg N2O-N ha−1) occurred during an 11-d period of thaw. The accumulated N2O flux from 20 June to 31 August was small (0.5 kg N2O-N ha−1, or less); during that time there were no rainfall events intense enough to produce water saturated soil. In 1990, 15N-labeled KNO3 (100 kg N ha−1) was applied on 26 March (outset of the thaw) and mass balance showed 32.7 kg N ha−1of added-N was lost by 7 May. A flux of 16.3 kg N2O-N ha−1 occurred largely in a 10-d period during and immediately after soil thaw. The N2O emitted from soil left a considerable fraction of the lost N unaccounted for. This unaccounted N was most likely lost as gaseous N other than N2O (e.g., N2). We conclude that large amounts of soil nitrate may be denitrified, with smaller amounts emitted as N2O, as the soil thaws and soon thereafter. Key words: Denitrification, frozen soil, thawing soil, nitrogen, nitrous oxide
Use of hot KCl-NH4-N to estimate fertilizer N requirements
Authors: Campbell C. A. , Jamel Y. W. , Jalil A. , Schoenau J. 
Published: April 2011

We need an easy-to-use chemical index for estimating the amount of N that becomes available during the growing season, to improve N use efficiency. This paper discusses how producers may, in future, use crop growth models that incorporate indices of soil N availability, to make more accurate, risk-sensitive estimates of fertilizer N requirements. In a previous study, we developed an equation, using 42 diverse Saskatchewan soils, that related potentially mineralizable N (N0) to NH4N extracted with hot 2 M KCl (X), (i.e., N0 = 37.7 + 7.7X, r2 = 0.78). We also established that the first order rate constant (k) for N mineralization at 35°C is indeed a constant for arable prairie soils (k = 0.067 wk−1). We modified the N submodel of CERES-wheat to include k and N0 (values of N0 were derived from the hot KCl test). With long-term weather data (precipitation and temperature) as input, this model was used to estimate probable N mineralization during a growing season and yield of wheat (grown on fallow or stubble), in response to fertilizer N rates at Swift Current. The model output indicated that the amount of N mineralized in a growing season for wheat on fallow was similar to that for wheat on stubble, as we hypothesized. Further the model indicated that rate of fertilizer N had only minimal effect on N mineralized. We concluded that, despite the importance of knowing the Nmin capability of a soil, it is available water, initial levels of available N and rate of fertilizer N that are the main determinants of yield in this semiarid environment. The theoretical approach we have proposed must be validated under field conditions before it can be adopted for use. Key words: N mineralization, Hot KCl-NH4-N, potentially mineralizable N, CERES-wheat model
Soils as sources and sinks for atmospheric methane
Authors: Topp Edward , Pattey Elizabeth 
Published: April 2011

Methane is considered to be a significant greenhouse gas. Methane is produced in soils as the end product of the anaerobic decomposition of organic matter. In the absence of oxygen, methane is very stable, but under aerobic conditions it is mineralized to carbon dioxide by methanotrophic bacteria. Soil methane emissions, primarily from natural wetlands, landfills and rice paddies, are estimated to represent about half of the annual global methane production. Oxidation of atmospheric methane by well-drained soils accounts for about 10% of the global methane sink. Whether a soil is a net source or sink for methane depends on the relative rates of methanogenic and methanotrophic activity. A number of factors including pH, Eh, temperature and moisture content influence methane transforming bacterial populations and soil fluxes. Several techniques are available for measuring methane fluxes. Flux estimation is complicated by spatial and temporal variability. Soil management can impact methane transformations. For example, landfilling of organic matter can result in significant methane emissions, whereas some cultural practices such as nitrogen fertilization inhibit methane oxidation by agricultural soils. Key words: Methane, methanogenesis, methane oxidation, soil, flux measurement
Description of a dynamic closed chamber for measuring soil respiration and its comparison with other techniques
Authors: Rochette P. , Ellert B. , Gregorich E. G. , Desjardins R. L. , Pattey E. , Lessard R. , Johnson B. G. 
Published: April 2011

Soil respiration is an important component of the net carbon dioxide exchange between agricultural ecosystems and the atmosphere, and reliable estimates of soil respiration are required in carbon balance studies. Most of the field measurements of soil respiration reported in the literature have been made using alkali traps. The use of portable CO2 analysers in dynamic closed chamber systems is recent. The introduction of this new technique requires its evaluation against existing methods in order to compare new information with older data. Nine intercomparisons between dynamic systems and alkali traps were made. Measurements of Fc,s obtained by both chambers showed a good agreement in all but two comparisons in which alkali trap measurements were lower than the dynamic chamber by about 22%. This first report of agreement between both techniques suggests that many measurements made in the past using alkali traps may be comparable to the measurements made more recently using the dynamic chambers. Analysis of the soil temperature and CO2 concentration inside the alkali traps failed to explain why the alkali traps occasionally underestimated the fluxes. Soil respiration measured with a dynamic closed chamber were also compared to eddy-correlation measurements. The results did not reveal any consistent bias between techniques but the scattering was large. This dispersion is likely the result of the difference between the areas measured by the two techniques. Key words: Carbon dioxide, greenhouse gases, CO2 flux, soil carbon
Organic carbon and nitrogen stocks and storage profiles in cool, humid soils of eastern Canada
Authors: Carter M. R. , Angers D. A. , Gregorich E. G. , Bolinder M. A. 
Published: April 2011

Current interest in carbon (C) exchange processes between terrestrial ecosystems and the atmosphere have identified a need to assess soil C stocks or inventories for specific soil types and climates. In this study, the mean store of C and nitrogen (N) was determined in the soil profile of several Gleysolic, Podzolic, Luvisolic, and Brunisolic soils under different agricultural management systems, in the cool, humid region of eastern Canada. Based on a total of 69 management treatments from 16 agroecosystem sites, mean soil C and N densities (to a soil depth of 60 cm) ranged from 3.1 to 13.1 kg C m−2 and from 0.36 to 1.05 kg N m−2 The C:N ratio ranged from 8.3 to 17.1. Distribution of C and N down the soil profile showed a relatively regular pattern of C and N decrease with depth. Estimated C stocks or storage for the 1-m soil depth ranged from 8.3 to 13.3 kg C m−2 for the Gleysolic soils, and 5.4 to 10.5 kg C m−2 for the Podzolic soils, with an overall range and mean for all soils of 3 to 16 kg C m−2 and 9.8 kg C m−2 ± 2.8 This indicates that some agricultural soils in eastern Canada possess a relatively high potential for organic matter storage. Key words: Organic carbon and nitrogen storage, agroecosystem, Gleysol, Podzol, Luvisol, Brunisol, cool-humid climate
Effect of agriculture and of clear-cut forest harvest on landscape-scale soil organic carbon storage in Saskatchewan
Authors: Pennock D. J. , Kessel C. van 
Published: April 2011

The development of sound management approaches to reduce soil organic carbon (SOC) losses presupposes that we thoroughly understand the sources of these losses. We used a landscape-scale research design to estimate human-induced SOC losses by comparing SOC storage in undisturbed landscapes with comparable landscapes disturbed by clear-cutting of forests in the Mixedwood/Gray Luvisolic zone of central Saskatchewan and by agricultural activity in the Black soil zone. A 14.0% decrease in soil organic carbon storage in the upper 45 cm of the soil (from 57.1 Mg ha−1 in mature Mixedwood sites to 49.1 Mg ha−1 in clear-cut landscapes) occurred due to clear cutting at the research sites in the Mixedwood forest. The dominant soil type at these sites, Gray Luvisolic soils developed in glacial till, experienced a 11% loss in SOC storage; higher losses (36% loss) occurred from sandy Brunisolic inclusions in the sites. Changes in SOC storage at the research sites in the Black soil zone landscapes varied with texture and parent material: sandy glacio-fluvial landscapes experienced slight gains of SOC (from 54.1 to 60.1 Mg ha−1); silt and clay glacio-lacustrine landscapes experienced a 15.3% decrease in SOC (from 145.2 to 122.9 Mg ha−1); and loamy glacial till landscapes underwent a major decrease in SOC storage (from 116.2 to 75.2 Mg ha−1) Our results indicate that attempts to increase SOC storage in Saskatchewan soils should concentrate on agricultural landscapes, especially those dominated by glacial till. Key words: Landscape, soil organic carbon, Chernozemic, Mollisol
The European bison as seed dispersers: the effect on the species composition of a disturbed pine forest community
Authors: Jaroszewicz Bogdan , Pirożnikow Ewa , Sagehorn Ruth 
Published: April 2011

We studied the process of change in plant species composition in a pine–spruce forest influenced by endozoochorous seed dispersal by the European bison Bison bonasus L. The intensity of endozoochory was 3.4 times higher in the open tree stand than in the surrounding undisturbed forest (t = –3.0836, df = 50, P = 0.003). Over 1578 individuals/ramets belonging to 23 vascular plant taxa developed on 114 bison dung piles. The process of colonization included two plant species that have never before been recorded in the studied forest community. Seven out of 14 species transferred by bison were small-seeded herbaceous plants without morphological adaptations for long-distance dispersal. The majority of plant species recorded on the bison dung (55.9%) occur in deciduous forests. In contrast, over 50% of the plants surrounding bison faeces represented species of coniferous forests. The PCA analysis revealed the existence of two distinct groups of plant species: within bison faeces and on random systematic samples. The Jaccard coefficient of species composition similarity between them was 0.28. Our results demonstrate that the European bison is an effective vector of plant propagules between plant communities. This fact could have great importance for the restoration of degraded habitats, and could also introduce the risk of invasion by alien species.