Locations In Alberta Research Articles

Influence of fuel data assumptions on wildfire exposure assessment of the built environment

Background Land cover information is routinely used to represent fuel conditions in wildfire hazard, risk and exposure assessments. Readily available land cover data options that vary in resolution, extent, cost and purpose of collection have become increasingly accessible in recent years. Aim This study investigates the sensitivity of community-scale wildfire exposure assessments to different land cover information products used to identify hazardous fuel. Methods Ten versions of a community wildfire exposure assessment were conducted for each of five case study locations in Alberta, Canada, by varying the input land cover data. Proportional and spatial distribution of hazardous fuels and classified exposure are compared across datasets and communities. Key results We found proportional and spatial variation of exposure values between datasets within each community, but the nature of this variation differed between communities. Land cover classification definitions and scale were important factors that led to inconsistencies in assessment results. Conclusions Readily available land cover information products may not be suitable for exposure assessments at a localised scale without consideration of unique context and local knowledge of the assessment area. Implications Results may inform fuel data selection considerations for improved results in various wildfire applications at localised scales.

Development of a qPCR and a Lamp Assay for Verticillium longisporum Detection and a Triplex qPCR Assay for Simultaneous Detection of V. longisporum, Leptosphaeria biglobosa, and L. maculans from Canola Samples

Verticillium wilt, Verticillium stem striping, and Verticillium stripe are common disease names that all denote infection caused by Verticillium longisporum on canola or other brassica crops. In this study, a quantitative PCR (qPCR) and a loop-mediated isothermal amplification (LAMP) assay were developed for the detection of V. longisporum from canola stem samples. Both assays are specific to V. longisporum at the species level and ubiquitous at the strain level across all whole-genome sequenced strains. The low limit for positive detection of the two assays is 1 pg fungal DNA in a 20-µl reaction or 700 fungal cells in 100-mg plant tissue. The qPCR assay was combined with the duplex qPCR assay for the two blackleg pathogens, Leptosphaeria biglobosa and L. maculans, to constitute a triplex qPCR system for simultaneous detection of all three pathogens. The usefulness of this triplex qPCR system was verified on canola samples collected from various locations in Alberta, Canada. Using this triplex qPCR system, V. longisporum was detected from one sample, while the two blackleg pathogens were detected at higher frequencies. Since it is sometimes difficult to differentiate Verticillium stripe and blackleg on Alberta canola samples based on visual symptoms, the triplex qPCR system is an important tool for the detection of V. longisporum, especially when its presence is masked or obscured by symptoms of blackleg. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Determining adaptability of farmer bred spring wheat (Triticum aestivum L.) genotypes to Canadian organic production using stability analysis

AbstractParticipatory plant breeding (PPB) is a collaborative process between farmers, plant breeders and researchers to create germplasm specifically bred for target environments. We sought to examine the yield performance and adaptability of genotypes from an organic PPB wheat programme under organic management across the Canadian prairies. We evaluated 25 farmer genotypes and 6 commercial cultivars in locations in Alberta, Saskatchewan and Manitoba, totalling 12 organic environments. The top performers most responsive to higher yield environments were three farmer genotypes (BL34‐SW, BL43C‐TM and BJ13‐GW) and one check cultivar (Vesper). Genotype plus genotype by environment (GGE) biplot analysis indicated that one farmer genotype (BL23‐AS) and one check cultivar (Vesper) demonstrated high yield and greater organic adaptation than other genotypes tested. Two registered cultivars (AAC Brandon and Jake) had low yield and poor adaptation, as did one farmer genotype (PWA10B‐LD). Yield was positively and strongly correlated with height, anthesis and mature biomass and kernel number per unit area. The results provide evidence that early generation farmer selection is an effective breeding strategy for discovering wheat genotypes with high yield and excellent adaptability to organic production systems in Canada.

Examination of the correlation between SPT and undrained shear strength: Case study of clay till in Alberta, Canada

In this study, we introduce a novel method for estimating undrained shear strength (Cu) by incorporating SPT depth. A comprehensive dataset of 328 data groups from locations in Alberta was employed to investigate the correlation between Cu and various factors such as Atterberg limits, moisture content, sampling depth, and both field SPT numbers (N) and modified SPT numbers (N60), utilizing Pearson Correlation Analysis. The performance of the new approach was evaluated using metrics such as mean absolute error (MAE), mean square error (MSE), root mean square error (RMSE), mean absolute percentage error (MAPE), and coefficient of determination (R2). Comparative assessments of the new approach were made with existing approaches for Cu estimation. Furthermore, the proposed approach was applied to calculate Cu based on borehole information and moisture content data from 702 projects in Alberta, and its validity was verified against published information. The results demonstrate that the new approach yields Cu calculations with comparatively small discrepancies. This paper presents a reliable tool for estimating the average Cu of clay till in Alberta in a preliminary design state, with potential applicability to other regions as well.

The effects of pre-harvest glyphosate rate and timing on yield and pre-malt quality of malting barley

The production of barley cultivars with malting and brewing quality characteristics is subject to strict grading and technical standards for the end-use market. Environmental and management factors can significantly alter grain quality, and the qualities required for malting. Crop and kernel uniformity are critical factors where variability can exceed the tolerance for meeting malt quality. A practice to address variations in crop maturity is the application of pre-harvest glyphosate. Pre-harvest glyphosate applications can, however, alter malting characteristics in barley, and, if mis-timed, can also reduce yield. A 4-year study at five locations in Alberta and Saskatchewan from 2013 to 2017 was conducted to determine the effects of pre-harvest glyphosate applications on malting barley characteristics. Glyphosate was applied at 900 and 1125 g ae ha−1 on malting barley cultivars ‘CDC Meredith’ and ‘AC Metcalfe’ malting barley at soft dough, hard dough, and physiological maturity growth stages. Yield reductions of up to 12% were observed from glyphosate applications at soft dough, and yield was maximized with applications at physiological maturity. Glyphosate application, at two rates, reduced percentage plump kernels, but did not affect kernel weight or protein concentration. The growth stage of barley plants did not provide an accurate indicator of seed moisture levels at the time of application, which motivated our conclusion that glyphosate applications can be mistimed by inaccurate indicators. The results motivate our questioning of the utility of pre-harvest glyphosate applications, given the adverse effects to barley yield and quality observed, even when applied according to the label instructions.

Queen quality, performance, and winter survival of imported and domestic honey bee queen stocks

Canadian beekeepers have faced high colony mortality each winter over the last decade. Frequently citing “poor queen quality” as a top contributing factor to colony loss, Canadian beekeepers report needing to replace half their queens each year. Domestic queen production exists throughout Canada but is limited due to the short season and can be further limited when colony mortality is high. Consequently, Canadian beekeepers import over 260,000 queens annually, primarily from locations with warmer climates. In this study, newly mated imported queens from Hawaii (USA) and New Zealand were compared to domestic Canadian queens produced in British Columbia; these stocks were evaluated on their morphological and sperm storage characteristics. Stock quality was also evaluated in the field at two locations in Alberta, Canada over two production seasons. Our results show initial variation in queen morphology and fertility among imported and domestic queen stocks. Most striking, the New Zealand queens weighed 10–13% less than the Hawaii and British Columbia queens, respectively upon arrival. Colony performance over a two-year field study suggests: (1) brood pattern solidness has a positive nonlinear correlation with honey production regardless of queen stock and environment; (2) environment (i.e., apiary location) and queen stock variably predict colony health and productivity depending on year; specifically, apiary site appears to be a stronger predictor of colony health and productivity than queen stock in year one, but in year two, queen stock appears to be a stronger predictor than apiary site; (3) high clinical symptoms of chalkbrood may explain the prevalence of poor brood patterns in colonies headed by queens from New Zealand; (4) domestic queens are 25% more likely to survive winter in Alberta than imported queens. Therefore, it is important to consider possible mismatches in disease immunity and climate conditioning of imported queen stocks heading colonies in temperate regions that face drastically different seasonal climates and disease ecology dynamics.

Identifying optimal geographic locations for hybrid concentrated solar biomass (HCSB) power plants in Alberta and Ontario, Canada

ABSTRACT Solar thermal and biomass hybridization combine two energy sources that complement one another seasonally and diurnally, overcoming their respective disadvantages. In the current research, the feasibility of locating a new medium capacity (5–150 Mwe) hybrid concentrated solar biomass power plant is investigated in Alberta and Ontario. To address the above-mentioned goal, three critical criteria are considered to find the most suitable region. The amount of direct normal irradiation and the biomass feedstock in 50 km and 100 km radii are analyzed in different regions in Ontario and Alberta. The third factor is the distance to the substations. According to the results, although it is difficult to justify developing a hybrid concentrated solar biomass power plant in Ontario, at least five locations in Alberta meet the aforementioned criteria. By concentrating on substations located near natural gas power plants, Calgary, with four natural gas power plants, can be regarded as the most suitable region. According to the findings, we identified that by establishing a 100 Mwe hybrid concentrated solar biomass power plant that requires 359,478 tons of forestry biomass and costs between 3.7 and 4.9 mCAD/Mwe, about 5% of Calgary’s total electricity consumption would be met while reducing CO2 emissions by 32 tons.

Assessment of Wood Chips and Agricultural Residues as Denitrifying Bioreactor Feedstocks for Use in the Canadian Prairies

Highlights Performance of denitrifying bioreactors in Alberta was evaluated. Barley straw was more effective in reducing nitrate compared to wood chips. Hydraulic retention time, feedstock, and season are the primary factors affecting nitrate removal. Abstract. This study evaluated the performance of pilot-scale denitrifying bioreactors (LWD: 6 × 0.6 × 1m) filled with different carbon substrates, including barley straw, hemp straw, and woodchips, for removing dissolved nitrogen from simulated subsurface drainage at two representative geographic locations in Alberta. In this study, the bioreactors were tested under varying hydraulic retention times (4, 8, and 12 h) in the spring, summer, and fall of one year. Tracer studies were conducted to evaluate flow and dispersion characteristics. The mean of nitrate removal efficiency ranged from 19% to 87% during the spring, 44% to 95% during the summer, and 21% to 68% during the fall. We found that barley straw was more effective in reducing nitrate (45% to 95%) compared to wood chips (19% to 54%). This study is the first testing of the effect of different biomass types and hydraulic residence times on bioreactor performance in the Canadian prairies (Alberta) and will allow agricultural producers and regulators to assess the suitability of these systems within the region. Keywords: Bioreactor, Denitrification, Water quality, Wood chips, Agricultural residues, Subsurface Drainage.

Abstract WP43: Modeling The Decay In Probability Of Receiving Endovascular Thrombectomy Based On Time From Stroke Onset

Introduction: Large-vessel occlusion (LVO) stroke patients with infarct core volumes greater than 70 mL do not meet current AHA guidelines for thrombectomy eligibility. Therefore, it is important to understand how time-dependent infarct core growth translates to a patient’s declining probability of thrombectomy eligibility. Modeling the probability that a suspected LVO patient would qualify for thrombectomy can help inform the optimal prehospital emergency transport strategy which maximizes the likelihood of an excellent patient outcome. Methods: We determined the time from stroke onset required for an infarct core to grow to 70 mL as a function of penumbra volume and collateral score. After applying a series of numerical interpolations, our framework outputted the probability a suspected LVO patient qualifies for thrombectomy (based on core volume threshold) as a function of time from stroke onset to imaging. We then incorporated this function into an existing model of prehospital emergency transport, which previously assumed all patients were thrombectomy-eligible, in order to assess the impact that considering treatment eligibility had on optimal transport decisions. Results: An exponential decay curve best fit the numerically-generated probability function. We found that after integrating this eligibility model into the emergency transport decision tool the optimal transport strategy changed from drip and ship to mothership in 8.5% of possible patient pickup locations in Alberta, Canada. Conclusions: This methodology provides a novel, mechanistic approach to deriving a thrombectomy eligibility curve. As a result, we are able to better optimize prehospital transport decisions to improve outcomes of suspected LVO patients.

Epidemiology of Nosema spp. and the effect of indoor and outdoor wintering on honey bee colony population and survival in the Canadian Prairies.

The epidemiology of Nosema spp. in honey bees, Apis mellifera, may be affected by winter conditions as cold temperatures and differing wintering methods (indoor and outdoor) provide varying levels of temperature stress and defecation flight opportunities. Across the Canadian Prairies, including Alberta, the length and severity of winter vary among geographic locations. This study investigates the seasonal pattern of Nosema abundance in two Alberta locations using indoor and outdoor wintering methods and its impact on bee population, survival, and commercial viability. This study found that N. ceranae had a distinct seasonal pattern in Alberta, with high spore abundance in spring, declining to low levels in the summer and fall. The results showed that fall Nosema monitoring might not be the best indicator of treatment needs or future colony health outcomes. There was no clear pattern for differences in N. ceranae abundance by location or wintering method. However, wintering method affected survival with colonies wintered indoors having lower mortality and more rapid spring population build-up than outdoor-wintered colonies. The results suggest that the existing Nosema threshold should be reinvestigated with wintering method in mind to provide more favorable outcomes for beekeepers. Average Nosema abundance in the spring was a significant predictor of end-of-study winter colony mortality, highlighting the importance of spring Nosema monitoring and treatments.

Primary care physicians’ perceptions of the role of alternative payment models in recruitment and retention in rural Alberta: a qualitative study

Background:Despite well-documented challenges in recruiting physicians to rural practice, few Canadian studies have described the role physician payment models may play in attracting and retaining physicians to rural practice. This study examined the perspectives of rural primary care physicians on the factors that attract and retain physicians in rural locations, including the role that alternative payment models (APMs) might play.Methods:This was a qualitative study involving in-depth, open-ended interviews with rural primary care physicians practising under fee-for-service (FFS) models and APMs in Alberta, Canada. Participants were recruited from the Rural Health Professions Action Plan member list (consisting of physicians practising in rural or remote locations in Alberta) and the College of Physicians and Surgeons of Alberta online database. Interviews were conducted April to June 2020, and data were analyzed using a thematic framework approach.Results:Fourteen physicians were interviewed. There were 5 themes identified: factors that attract physicians to rural practice, barriers and challenges associated with rural practice, the potential role of APMs in recruitment and retention, factors that physicians consider in deciding to change payment models, and physician perceptions of APMs compared with FFS models. Participants expressed that APMs may have some role to play in retaining rural physicians but identified professional challenges, and family-related and personal factors as key determinants. Most FFS physicians indicated that they were interested in exploring APMs provided specific concerns were addressed (e.g., clear and adequately compensated APM contracts, and physician involvement in the development of APMs).Interpretation:Primary care physicians practising in rural regions in Alberta view payment models as one consideration among many in their decision to pursue rural practice. Alternative payment model contracts designed with the input of physicians may have a role to play in attracting and retaining physicians to rural practice.

Spatial and temporal variation of epigaeic beetle assemblages (Coleoptera, Carabidae, Staphylinidae) in aspen-dominated mixedwood forests across north-central Alberta.

Epigaeic beetle assemblages were surveyed using continuous pitfall trapping during the summers of 1992 and 1993 in six widely geographically distributed locations in Alberta’s aspen-mixedwood forests prior to initial forest harvest. Species composition and turnover (β-diversity) were evaluated on several spatial scales ranging from Natural Regions (distance between samples 120–420 km) to pitfall traps (40–60 m). A total of 19,885 ground beetles (Carabidae) representing 40 species and 12,669 rove beetles (non-AleocharinaeStaphylinidae) representing 78 species was collected. Beetle catch, species richness, and diversity differed significantly among the six locations, as did the identity of dominant species. Beetle species composition differed significantly between the Boreal Forest and Foothills Natural Regions for both taxa. Staphylinidae β-diversity differed significantly between Natural Regions, whereas Carabidae β-diversity differed among locations. Climate variables such as number of frost-free days, dry periods, and mean summer temperatures were identified as significant factors influencing beetle assemblages at coarse spatial scales, whereas over- and understory vegetation cover, litter depth, shade, slope, and stand age influenced beetle assemblages at finer spatial scales. Significant interannual variation in assemblage structure was noted for both taxa. Because composition of epigaeic beetle assemblages differed across spatial scales, forest management strategies based only on generalized understanding of a single location will be ineffective as conservation measures. In addition, site history and geographic variation significantly affect species distributions of these two beetle families across the landscape. Thus, we underscore Terry Erwin’s suggestion that biodiversity assessments focused on species assemblages at different spatial scales provide a sound approach for understanding biodiversity change and enhancing conservation of arthropod biodiversity.

Effects of simulated hail damage and foliar-applied recovery treatments on growth and grain yield of wheat, field pea, and dry bean crops

Hailstorms can be responsible for significant economic loss to the agricultural sector in Alberta, Canada. Foliar applications of certain fungicides and nutrient blends have been advocated to promote recovery and yield of hail-damaged crops. Proper understanding of different crop and hail-related factors is required for an accurate assessment of hail damage to crops and for evaluations of hail-recovery product claims. This study was undertaken at three locations in Alberta during three growing seasons (2016–2018) to determine the effects of two levels of simulated hail severity at three different crop developmental stages, including the early growth (BBCH 30 for wheat; BBCH 14–16 for pulses), mid-growth (BBCH 39 for wheat; BBCH 60 for pulses), and late growth (BBCH 60 for wheat; BBCH 71 for pulses) stages. Plant growth and yield parameters of wheat (Triticum aestivum L.), field pea (Pisum sativum L.), and dry bean (Phaseolus vulgaris L.) crops were measured. Simulated hail damage led to reductions in height, biomass, NDVI, grain yield, and kernel weight of all three crops. Average yield decreased by 24% and 35% for wheat, 17% and 35% for dry beans, and 37% and 45% for field peas for light and heavy hail severity, respectively. Hail timing was a critical factor influencing the extent of crop damage, with hail damage during the early growth stage leading to a lesser yield reduction compared with hail damage at the mid-growth and late growth stages. Fungicides and nutrient blends applications did not significantly improve crop recovery, grain yield, or kernel weight for any of the crops in this study.

Pasture rejuvenation using sainfoin and cicer milkvetch in western Canada

AbstractSod‐seeding of depleted pastures with non‐bloating legumes can be a low‐cost pasture rejuvenation strategy for ranchers in the North American prairies. A study was conducted to determine if sainfoin (Onobrychis vicifolia subsp. vicifolia) or cicer milkvetch (CMV) (Astragalus cicer L.) populations or cultivars (hereinafter populations) can be used to rejuvenate alfalfa (Medicago sativa L.) or grass pastures. The study included sainfoin populations with increased fitness to grow with alfalfa and CMV cultivars that were selected for early emergence and rapid seedling growth. These populations were seeded using three seeding methods: traditional re‐seeding, drilling seed with Great Plains drill, or Pan drill, using split‐plot randomization at three locations in Alberta in 2015 or 2016. Lethbridge had pre‐existing alfalfa while Ponoka and Red Deer were predominantly grass pastures. The sod‐seeded rejuvenation, as indicated by percentage dry matter (DM) contributed by newly planted species succeeded at Lethbridge (≥15), failed at Ponoka (∼1), and partially succeeded at Red Deer (≥9). Successful establishment of new plants did not increase the total forage mass of the rejuvenated pasture. Sainfoin populations established better and contributed greater forage mass compared to CMV cultivars when sod‐seeded on alfalfa pasture, but the improvement was not consistent on grass pasture. Forage nutritive values were not different among populations within species, but pasture seeded with CMV cultivars had greater crude protein than unseeded plots. Sod‐seeded grass–legume pasture had greater crude protein than unseeded plots at Red Deer. Sod‐seeding alfalfa pasture with sainfoin populations can be an efficient pasture rejuvenation strategy.

Modelling PAH Degradation in Contaminated Soils in Canada using a Modified Process‐Based Model (DNDC)

Core Ideas A novel process‐based model for degradation of soil PAHs is proposed. Model is based on dynamic interactions between water, soil, vegetation and climate. Model effectively simulates biogeochemical processes of PAH degradation in soils. Simulated results agree well with data from remediation sites in Alberta. Polycyclic aromatic hydrocarbons (PAHs) are persistent pollutants of concern. A process‐based model of the PAH degradation can improve our understanding of ecological drivers and processes. In this paper, a process‐based biogeochemistry model, DeNitrification‐DeComposition (DNDC) is modified to simulate the dynamics of PAHs degradation in soils at abandoned oil and gas well sites. This new version of DNDC‐Organic Pollutants, called DNDC‐OP, coupled the rates of PAH degradation with dynamics of soil, vegetation and climate, such as soil moisture and temperature. The model was parameterized and validated against datasets of four soil PAHs: pyrene, fluorene, chrysene and anthracene, at three different abandoned oil and gas well site locations in Alberta, Canada. The sensitivity of the parameters was analyzed and tested. The simulated results were in good agreement with the measured data with a coefficient of determination (R2) of 70 to 97%, and the root mean square error (RMSE) of 4.5 to 9.1 at all three sites. We also evaluated the influence of environmental factors, such as soil temperature and moisture, on the degradation of PAHs. An increased degradation of all four PAHs occurred with increasing soil moisture content. An increase of soil temperature from 10 to 20°C and subsequently to 25°C resulted in a decreased appearance of all four PAHs from the three well sites. The result shows that this model can be used as a tool for evaluating PAH degradation for effective reclamation strategies.

Spatial and Seasonal Variations of Water and Salt Movement in the Vadose Zone at Salt-Impacted Sites

Oilfield-produced brine is a major source of salt contamination in soil and groundwater. Salt transport in the upper soil layers is controlled by the atmospheric interactions via infiltration of meteoritic water. In lower layers, it is controlled by fluctuations in the groundwater table, which are also linked to atmospheric interactions via groundwater recharge. Therefore, climate is an important factor in the movement of contaminants in the unsaturated zone. A one-dimensional variably saturated flow and transport model with soil atmospheric boundary conditions was used to estimate the effect of climate type and soil texture on soil water and salt dynamics in variably saturated soils. Numerical simulations were run with Hydrus-1D, using daily climate data. Simulations were run for nine-year climate datasets for different ecoclimatic locations in Alberta, Canada. Results indicated that coarse-grained materials are good evaporation barriers, resulting in water gain conditions at the ground surface, irrespective of the climate type. However, the quantity of water gain and associated advective fluxes are a function of climate. Results also indicated that flow and transport in fine-textured soils is more dependent on the climate type. For fine-grained soils in arid climatic conditions, net water loss at the ground surface and upward migration of salt can be expected. For wetter climates, the upward migration of salt is less probable.

Factors influencing overyielding in young boreal mixedwood stands in western Canada

Mixtures of trembling aspen (Populus tremuloides Michx.) and white spruce (Picea glauca (Moench) Voss) are a prominent component of the boreal forests of western Canada. Overyielding, indicating higher productivity in mixtures than in monocultures, has been observed in mature stands but has not been examined in young stands (<30 years old) in this region. We used data collected between 2006 and 2015 at 7 locations in Alberta and Saskatchewan for the Western Boreal Growth and Yield Association (WESBOGY) Long Term Study to examine whether overyielding occurs in young mixtures of these species and to identify factors (species composition, stand density, tree size, species proportion, site quality, and climate) that influence overyielding. Our results show that overyielding is occurring in these young boreal mixedwood stands in western Canada. Relative productivity total (RPT), indicating mixing effect (RPT > 1 indicates overyielding), varies from 0.921 to 1.537 among mixedwood treatments, and thinned aspen stands show higher production than unthinned aspen stands. Initial stand density (basal area) and initial aspen size (QMD at the start of the measurement interval) positively influence mixing effect while initial spruce size (QMD) negatively influences mixing effect. The magnitude of overyielding declines with increasing growing season length (DD5) and the relative productivity of aspen decreases with increasing site quality. Species mixtures support higher stocking than pure stands due to differences in growth rate and shade tolerance of the two species. Tree size is also important since productivity will decline when two species compete with each other for space and resources. Consequently, a mixed species stand that has space partitioning and size inequality between species, which reduces competition and favours expression of the functional traits (e.g., shade tolerance) of each species, tends to have better productivity.

Investigating Genetic Progress and Variation for Nitrogen Use Efficiency in Spring Wheat

Improved N use efficiency (NUE) increases wheat (Triticum aestivum L.) yields and reduces N losses in the environment. We investigated genetic variation and correlations among agronomic and NUE traits in Canada Western Red Spring wheat cultivars to further improve NUE. Trials were conducted for 3 yr at two locations in Alberta, Canada, under two levels of N (200 and ~50 kg ha−1). Genotype × environment interaction was significant for traits associated with vegetative growth, and genotype × N fertilizer treatment interaction was significant for important yield and NUE traits. There were significant positive correlations between total dry matter and N uptake efficiency (NUpE) in the high (r = 0.74, P &lt; 0.05) and low (r = 0.83, P &lt; 0.05) N treatments. The effect of dwarfing Rht‐1b allele was more prominent under high N treatment in increasing NUE. However, cultivars with Rht‐1b allele showed inconsistent results for NUpE, indicating that Rht alleles might have pleiotropic effects on N uptake. Grain yield, NUE, and N utilization efficiency (NUtE) exhibited genetic improvement over time only under high N treatment. Our results indicated that grain yield increased mainly due to improved harvest index (HI), suggesting improvement in C assimilation rather than N partitioning efficiency. Nitrogen use efficiency may further be improved by intercrossing cultivars with high HI, N harvest index, and NUtE and those with good NUpE, while using total dry matter production as a selection criterion.

Influence of tillage, vertical seed distribution, and pyroxasulfone application timing and rate on control of wild oat (Avena fatua L.)

Tillage and new herbicide options may be necessary for the control of herbicide-resistant wild oat. The efficacy of soil-applied herbicides such as pyroxasulfone can be influenced by edaphic factors and weed seed recruitment depth, which varies with tillage system. We investigated the effect of tillage and pyroxasulfone rate when applied in the fall and spring on wild oat biomass at three locations in Alberta in 2014–2015. The vertical position of wild oat seeds, with and without tillage, was examined at each site. Wild oat biomass was greater in untilled plots compared with plots with fall tillage at all locations. In two out of three locations, pyroxasulfone efficacy was superior when applied in the fall compared with spring, possibly influenced by low spring rainfall. A single tillage pass at the Edmonton and Kinsella locations did not affect wild oat seed distribution, but there was an increase in seeds present in the surface layer in the untilled treatment at Lacombe. Tillage, used in combination with soil-applied herbicides, may be an option to achieve acceptable control of herbicide-resistant wild oat.

Investigation of the factors affecting the consistency of short-period traffic counts

The main intent of this study is to investigate the accuracy of short-duration traffic counts conducted during winter months. The investigation is based on 11-year sample data collected using permanent traffic counters at various locations in Alberta, Canada. Four types of road sites: commuter, regional commuter, rural long-distance, and recreational sites are studied. The sample data constitute six different durations of counts (12-, 24-, 48-, 72-, 96-h, and 1 week) taken during summer and winter months. The coefficient of variation (CV) is used as the relative measure of deviation for counts of different durations to measure the accuracy of short-period traffic counts. The study results indicate that 48-h count seems to be the most cost-effective counting interval during both summer and winter months. It is also found that the lowest values of CV result for counts taken at commuter sites, and the highest values are observed for recreational sites. Frequent changes in temperature and other weather events cause significant variation in traffic volume, which results in an increase in CV values for counts taken during winter months. The application of an adjustment factor to remove the effect of cold and snow from short-period counts is also included in this study. Introduced adjustment factors can reduce the values of CV for all counts taken during winter months. The findings of this study can lead highway agencies to improve the cost-effectiveness of their short-period traffic counting programs.