bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of parent and temperature during pollination on alfalfa seed weight and number of seeds per pod
Authors: Katepa-Mupondwa F. M. , Smith Jr. S. R. , Barnes D. K.
Published: April 2011

Alfalfa seed weight and number of seeds per pod are important characteristics which have been associated with seed yield and seed quality. The objective of this research was to investigate the relative influence of seed and pollen parents and temperature during pollination on individual seed weight and number of seeds per pod. The relative influence of seed position in the pod on seed weight was also investigated. Twelve diverse clones were designated as seed (4) and pollen (8) parents. They were grown in the greenhouse at 24/18 day/night temperature and then transferred to growth chambers which were maintained at either 18 or 27 °C during and 24 h after pollination. Seed weight and number of seeds per pod were influenced by temperature during pollination, and also by both seed and pollen parents. The position of the seed in the pod influenced seed weight. The largest seed occurred at the base of the pod, which may have resulted from a differential nutrient supply from the base to the top of the pod. The number of seeds per pod was greatest at 27 °C. This was attributed to enhanced pollen fertility and fertilization success at the higher temperature. Both seed and pollen parents influenced seed weight and number of seeds per pod, and there were significant seed × pollen parent interactions for both traits. Environmental influence and pod position effects on seed weight and number of seeds per pod were small when compared with genetic effects. Selection for seed characteristics in seed and pollen parents could improve alfalfa seed production and seed quality. Key words: Alfalfa, Medicago sativa L., seed weight, number of seeds, temperature during pollination
Soil pH effects on growth and mineral concentration of birdsfoot trefoil
Authors: Kallenbach Robert L. , McGraw Robert L. , Beuselinck Paul R.
Published: April 2011

Birdsfoot trefoil (Lotus corniculatus L.) accessions G 31276 and G 31272 exhibit rhizomatous growth and were collected from alkaline soils (pH 8.0–8.5). Nothing is known about the adaptation of rhizomatous birdsfoot trefoil to more acid soil. Our objective was to determine the effects of soil pH on plant growth and mineral concentration of rhizomatous and domestic non-rhizomatous birdsfoot trefoil. Three entries, Norcen AU Dewey, and RBRC (a bulked reciprocal cross of G 31276 and G 31272), were grown at soil pH levels of 5.0, 6.0, 7.0 and 8.0 in a glasshouse. Dry-matter (DM) production and concentrations of Al, Ca, K, P, Mg, Mn and Zn in tissues were determined. No significant entry × soil pH interaction was found for either DM accumulation or mineral concentration, indicating the RBRC responded to acidic soil pH like the domestic entries Across entries, total DM was lower at soil pH 5.0 than at a higher pH. Concentration of Al and Zn in leaves and stems was greatest at soil pH 5.0 and declined with increasing PH. Calcium concentration in leaves and stems was highest at soil pH 8.0. Magneisum concentration was not affected by soil pH. Phosphorus concentration in leaves was lowest at soil pH 5.0 and tended to increase with increasing pH, whereas P concentration in stems was highest at pH 5.0 and not significantly different at pH 6 0 7 0 or 8 0. Leaf K concentration was not affected by soil pH, but K concentration in stems was highest at pH 5 0. Manganese concentrations in leaves and stems followed an irregular pattern. Similar responses to soil pH among entries suggest that birdsfoot trefoil populations derived from accessions G 31276 and G 31272 will not likely be limited by soil pH. Key words:Lotus corniculatus, nutrient concentration, rhizomatous growth, dry-matter distribution, pH tolerance
Influence de l'indice foliaire et des réserves en hydrates de carbone au moment de la coupe sur la croissance foliaire de deux graminées fourragères (Dactylis glomerata L. et Festuca arundinacea Schreb.)
Authors: Duru M. , Calviere I.
Published: April 2011

Leaf growth of two forage grasses (Dactylis glomerata L. and Festuca arundinacea Schreb.) was studied as a function of the sward state after a cut. Two heights of cut (3 and 6 cm) and a variable number of previous cuts were used to reach different residual leaf area index (IFr), and non-structural carbohydrate (CNS) concentration and quantity. For both species, four treatments were studied in 2 consecutive years. In mid-May for each of the species, the IFr ranged from 0 to 1, and the quantity of CNS varied from 12 to 25 g 100 g−1 DM according to the treatments. Over the 3 wk of regrowth, the IF reached values ranging from 1 to 7 and its increase depended on the IFr and the quantity of CNS. Among the three components of the quantity of CNS (weight of sheath per tiller, tiller density and CNS concentration), only the first two had a significant effect on the IF increase. Tiller mortality occurred when the quantity of CNS or the IFr were the lowest and it contributed little to the growth of lower leaves. No significant differences were found between the two species. Key words: carbohydrates, leaf area index, tiller, cut
Influence of previous crop type on yield of spring wheat: Analysis of commercial field data
Authors: Bourgeois Luc , Entz Martin H.
Published: April 2011

Although rotational benefits of non-cereal crops have been observed in small plot research trials few quantitative data are available on a field scale. In this study, field data of farmers from the Manitoba Crop Insurance Corporation were analysed to compare yield of wheat (Triticum aestivum L.) following different crops. The yield of wheat following wheat was used as a basis of comparison among crop sequences. The yield data were collected between 1982 and 1993 from fields 64 ha in size, located throughout the province of Manitoba. During this period, the yield of wheat following flax (Linum usitatissimum L.), peas (Pisum sativum L.), and canola (Brassica napus L.), on average was 16%, 11%, and 8% higher, respectively, than wheat following wheat. In one year, the yield of wheat was increased by as much as 41% following a field pea crop. Key words: Crop rotation, barley, canola, flax, field pea, wheat
AC Walton spring wheat
Authors: Nass H. G. , Johnston H. W. , Blatt C. R. , Atlin G. , Walton R. B.
Published: April 2011

AC Walton is a hard red spring milling wheat (Triticum aestivum L. em. Thell.) with high grain yield, lodging resistance, and excellent loaf volume and gluten strength. It is resistant to powdery mildew, and moderately resistant to septona leaf and glume blotch, and fusarium head blight. AC Walton is suitable for production in Eastern Canada, particularly in the Atlantic region. Key words:Triticum aestivum, wheat (spring), cultivar description
AC Skipper navy Bean
Authors: Saindon G. , Huang H. C. , Mündel H.-H. , Kozub G. C.
Published: April 2011

AC Skipper is an early-maturing navy bean (Phaseolus vulgaris L.) cultivar with good canning characteristics. It was developed at the Lethbridge Research Centre from a complex three-way cross of Kentwood, Swan Valley and Redkloud. AC Skipper has a short determinate bush growth habit, matures almost 3 d before OAC Seaforth, and is adapted to all bean growing regions of western Canada. Key words:Phaseolus vulgaris, navy bean, cultivar description, early maturity
The gynoecial infection pathway of Monilinia vaccinii-corymbosi in lowbush blueberry (Vaccinium angustifolium)
Authors: Shinners T. C. , Olson A. R.
Published: April 2011

Monilinia vaccinii-corymbosi (Reade) Honey is an economically important pathogen of lowbush blueberry (Vaccinium angustifolium Aiton) which causes blighting of leaves and flowers and mummification of fruits. This study was conducted to determine if infection of lowbush blueberry gynoecia occurs through colonization of the stigma. Sections of gynoecia inoculated with conidia were examined by brightfield microscopy. Conidia germinated on the stigmatic surface 1–3 d following inoculation to form hyphae winch invaded the stylar canal and other tissue down to the ovules. The infection pathway observed was identical to that of pollen tubes following pollination. After invasion of the ovary fungal colonization continued until the entire fruit wall was colonized with mycelium. Key words: Mummy berry, stigma colonization, pseudosclerotium
Effect of cultivar selection on metribuzin efficacy in field pea (Pisum sativum)
Authors: Wall D. A.
Published: April 2011

Field studies were conducted at Morden, Manitoba from 1993 to 1995 to investigate the effect of cultivar selection on the effectiveness of metribuzin {4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one} for wild mustard control in field pea. In check plots, Titan, a cultivar with long vines, suppressed wild mustard growth more than Trump, a cultivar with short vines Wild mustard control with metribuzin was more consistent in Titan than in Trump. Metribuzin at 140 g ha−1 (half the full label rate) reduced wild mustard dry weight by 75 to 99% in plots seeded to Titan and by 38 to 88% in plots seeded to Trump. Results suggest that less herbicide is required for weed management in more competitive field pea cultivars. Key words: Cultivars, competitiveness, metribuzin, wild mustard, Sinapis arvensis, yield
Long-term animal research in genetic improvement of livestock and poultry
Authors: Burnside E. B.
Published: April 2011

In animal experimentation, long-term studies have contributed substantially to our knowledge of genetics in particular, and of nutrition, physiology, and reproduction, to lesser extents. Long-term genetic selection experiments have yielded information on selection limits, dissipation of genetic variance over time, and created unique lines which may be utilized as consumer demands shift. Costs of long-term experimentation are not inordinately high in comparison to other experimentation, if economic animal species are used and returns from animal products are recovered to help finance the experiment. Government finance is, however, required for long-term experimentation, as private industry has little motivation for this work. The paper outlines recent significant contributions of long-term experimentation, and provides guidelines for planning experiments. Key words: Selection response, animal genetics, long-term experimentation, experimental design
Management and modification procedures for long-term field experiments
Authors: Poulton P. R.
Published: April 2011

Long-term experiments like those at Rothamsted in southeast England offer the best practical means of studying the effects of land management or global change on soil fertility, sustainability of yield or wider environmental issues. For the data from such experiments to be of use, farmers, scientists and policy makers must be certain of their validity. This is best assured by the rigorous management of the experiment, by ensuring that any changes are carefully considered and that all operations are well-documented. A steady flow of well-interpreted, published data is also essential. This paper gives examples of how the long-term field experiments at Rothamsted have been managed and how modifications have been made to ensure their relevance to modern agriculture. Key words: Rothamsted, sustainability, long-term experiments, global change
Design and planning of long-term experiments
Authors: McRae K. B. , Ryan D. A. J.
Published: April 2011

Long-term experiments (LTE) are extremely varied in form, and scientists who undertake this type of experiment face many challenges. Aspects of management, design layout, the role of the coordinator and statistician, and computer use are discussed. The important statistical ideas for LTE are reviewed and related to single perennial crops such as wild blueberries, fruit trees and permanent pastures. Key words: Long-term experiments, planning of experiments, experimental design, REML, residual maximum likelihood
Economics of conservation tillage in the semiarid prairie
Authors: Zentner R. P. , McConkey B. G. , Campbell C. A. , Dyck F. B. , Selles F.
Published: April 2011

Concerns about environmental sustainability and economic survival have changed tillage practices significantly in western Canada. This study examined the effects of conventional (CT), minimum (MT), and no-tillage (NT) management on the economic performance of hard red spring wheat (Triticium aestivum L.) or durum wheat (Triticum turgidum L.) production when grown in fallow–wheat (F–W) and continuous wheat (Cont W) rotations, over a period of up to 12 yr (1982–1993) on three soil textures in southwestern Saskatchewan. Our results show little short-term economic incentive for producers to adopt NT management practices. Production costs were similar on the three soil textures, averaging $141 ha−1 for F–W and $224 ha−1 for Cont W. Total costs for Cont W systems averaged 10 to 13% higher for NT compared to CT. For F–W systems total costs for NT averaged 29% higher than for CT on the silt loam, and 14% higher on the heavy clay. Also for F–W systems costs for NT averaged 23, 12, and 17% higher than for MT on silt loam, sandy loam, and heavy clay soils, respectively. Although conservation tillage (MT and NT) provided savings in labor, fuel and oil, machine repair, and machine overhead (compared to CT), these savings were more than offset by greater expenditures for herbicides. On the silt loam, net returns were highest for Cont W (CT) and lowest for F–W (NT) at wheat prices greater than $147 t−1; at lower wheat prices, F–W (CT) and Cont W (CT) provided the highest and about equal net returns. On the sandy loam, F–W (MT) consistently earned the highest net return; F–W (NT) ranked second highest, while Cont W systems ranked lowest. On the heavy clay, F–W (MT) and Cont W (CT) provided the highest net return at wheat prices greater than $147 t−1, while at lower wheat prices F–W (MT) ranked highest. In our study, the relatively poor economic performance of conservation tillage, particularly NT, for monoculture wheat production was due to a combination of higher input costs and the lack of significant yield advantages with MT and NT management. Key words: Minimum tillage, no-tillage, net returns, production costs, riskiness
Comparison of field methods for selection of protein and oil content in soybean
Authors: Pazdernik D. L. , Hardman L. L. , Orf J. H. , Clotaire F.
Published: April 2011

Soybean [Glycine max (L.) Merr.] is known for its high protein and oil content but a gradual decline has been reported in protein content of soybeans grown in the northern latitudes during the past 10 to 15 yr. Due to this decline, research investigating breeding methods aimed at improving protein content in soybean is needed. The objectives of this study were to compare soybean protein and oil content of: (i) row vs. hill plots, (ii) sampling at the end vs. center of the row, (iii) short, one-row plots at one location vs. long, four-row plots at two locations, and (iv) to assess the heritability of these two traits. Protein and oil content were measured among eighteen cultivars planted in 30-cm × 30-cm hill plots and 1.8-m row plots, and among four cultivars planted in separate experiments aimed at comparing the end vs. center of the row in 1.8-m row plots. Four F5 and F6 populations were planted in 1.8-m and 3.6-m row plots at five MN locations over 2 yr to determine the effect of plot size and the heritability of protein and oil content. Protein and oil content were not affected by plot type, supported by a high correlation between row and hill plots for both protein and oil content (r = 0.82, P > 0.01). Sampling position in the row had a large effect, with higher protein and lower oil content in seed collected at the end of the row. Selection for protein and oil content in short, single-row plots at one location appears to be equivalent to selection for protein and oil content from long, multiple-row plots at multiple locations, although year effects may have an impact. The heritability estimates for protein and oil content were 0.47 to 0.54 and 0.44 to 0.46, respectively. Our results support the continuation of short, single-row evaluation tests for protein and oil content with the consideration of using hill plots as an alternative to row plots. Key words:Glycine max (L.) Merr., protein, breeding methodology
Row spacing and seeding rate effects in wheat and barley under a conventional fallow management system
Authors: Lafond G. P. , Derksen D. A.
Published: April 2011

Varying seed row spacing had no effect on the yield of spring wheat (Triticum aestivum L.) or barley (Hordeum vulgare L.) when grown under a conventional-tillage fallow-management system. Grain yields were improved with increased seeding rates by 14% in wheat and 32% in barley. The absence of a row-spacing-by-seeding-rate interaction suggests that adjustments in seeding rates are not required with changes in row spacing. The presence of surface residues and standing stubble cannot explain the lack of a row-spacing effect when using a zero-tillage stubble-cropping system, since similar results were obtained with a conventional-tillage fallow management system in this study. Key words: Yield, yield components, plant density
Influence of root age on the concentration of ginsenosides of American ginseng (Panax quinquefolium)
Authors: Court William A. , Reynolds L. Bruce , Hendel John G.
Published: April 2011

The influence of root age on the ginsenosides and root weight of Panax quinquefolium was investigated. Root weight, and the ginsenosides Rb1, mRb1, Re and Ro increased with the age of the root. Differences obtained for the ginsenosides Rb2, mRb2, Rc, mRc, Rd, mRd, Rg1, and gypenoside XVII with the age of the root were small. It was found that ginseng harvested after only 3 yr contained lower amounts of ginsenosides than ginseng harvested after 4 yr. Keywords: Ginseng, ginsenosides, root age, root weight
Sporulation of Bipolaris sorokiniana on the crowns of crop plants grown in Saskatchewan
Authors: Duczek L. J. , Jones-Flory L. L. , Reed S. L. , Bailey K. L. , Lafond G. P.
Published: April 2011

Production of conidia by B. sorokiniana was determined on crowns of field-grown annual crops in the fall of each year from 1991 to 1993. Sporulation was highest on crowns of the annual cereal crops, barley, canary seed, rye, triticale, oat, and wheat. Sporulation varied from year to year with the highest numbers in 1992 and the lowest in 1993. There were differences between cultivars of wheat and of barley, but the differences were not consistent from year to year. Significantly lower conidial numbers occurred on annual pulse crops (fababean, field pea, lentil), and oilseed crops (canola, flax, mustard, safflower, sunflower) than on cereal crops. In 1992 and 1993, sporulation was assessed on perennial forage legumes and grasses. Sporulation was significantly higher on wheatgrass species (crested, intermediate, northern, slender, streambank, tall, and western wheatgrass) than on other forage grasses (smooth bromegrass, meadow bromegrass, reed canarygrass, Altai wildrye, Dahurian Wildrye, and Russian wildrye) and forage legumes (alfalfa, alsike clover, birdsfoot trefoil, cicer milkvetch, red clover, and sainfoin). The low sporulation on crowns of annual pulse crops, annual oilseed crops, forage legumes, and forage grasses other than on wheatgrass species indicates their suitability in crop rotations designed to reduce the inoculum density of B. sorokiniana. Growing annual cereal crops and wheatgrass forage grasses will likely maintain or increase the inoculum levels of B. sorokiniana in soil. Key words:Bipolaris sorokiniana (Sacc. in Sorok.) Shoem., sporulation, annual and perennial crops
Fungicidal control of powdery mildew in field pea
Authors: Warkentin T. D. , Rashid K. Y. , Xue A. G.
Published: April 2011

The efficacy of sulfur (Kumulus S) and myclobutanil (Nova 40W) fungicides for control of powdery mildew (Erysiphe pisi Syd) in field pea (Pisum sativum L.) was investigated in field trials at two locations in Manitoba in 1994 and 1995. Both fungicides were effective in reducing disease seventy and increasing seed yield and seed weight of the susceptible cultivar Radley. Fungicide treatments were economically beneficial when disease pressure was high. Key words: Field pea, Pisum sativum L., powdery mildew, Erysiphe pisi Syd., sulfur, myclobutanil
Long-term trends in the greenhouse gas emissions from the Canadian dairy industry
Authors: Dyer J A , Vergé X. P. C. , Desjardins R L , Worth D.
Published: April 2011

Estimates of the efficiency of mitigation measures on reducing greenhouse gas (GHG) emissions from the agricultural sector are required. In this paper, recently calculated dairy GHG emissions for 2001 were extrapolated back to 1981 for census years using an index. The index was verified by comparing it with estimates based on the Intergovernmental Panel on Climate Change (IPCC) methodology for 1991. The index agreed with the IPCC estimates within 1% for methane and 4% for nitrous oxide on a national scale with no region having a difference of more than 5% for methane. For nitrous oxide, all regions were within 10%, except British Columbia, where the index was 19% too high. The index indicates that GHG emissions from primary milk production within the Canadian dairy industry have decreased by about 49% since 1981, mainly due to a 57% reduction in the dairy cow population during that period. The GHG emissions per kilogram of milk decreased by 35%, that is from 1.22 kg CO2eq kg-1 milk to 0.91 kg CO2eq kg-1 milk. Because this study took into account the energy-related CO2 emissions from all the major farm inputs (fertilizer and fossil fuel), there was little risk of hidden GHG emissions in the emission intensity calculation. This study demonstrates that where lack of input data restricts historical application of simulation models, a semi-empirical index approach can yield valuable results. Key words: Greenhouse gas, dairy industry, index, intensity indicator
Mercury transfer from watersheds to aquatic environments following the erosion of agrarian soils: A molecular biomarker approach
Authors: Caron S. , Lucotte M. , Teisserenc R.
Published: April 2011

Lake St. Pierre, an important freshwater location for sports and commercial fisheries in Canada, is composed of a 120 km2 stretch of the St. Lawrence River, located at the center of the St. Lawrence Lowlands. Receiving its waters from the St. François, Yamaska, Ottawa, and St. Lawrence Rivers, it is subjected to important inputs of mercury (Hg) and suspended particles eroded from its watershed. This study aims at tracing back the origin of terrigenous Hg loadings to Lake St. Pierre. The specific phenol signatures yielded by a mild oxidation of the terrestrial organic matter (TOM) carried in the water column was used as a tracer to identify the different sources of terrigenous Hg to the lake. Our results demonstrate that most of the Hg bound to suspended particulate matter (SPM-bound Hg) found in Lake St. Pierre is associated with TOM. We were also able to distinguish the relative influence that forested soils, mainly drained by the Ottawa River, and agrarian soils, located on nearby watersheds, exert on the lake's Hg burden. Our data strongly suggest that the erosion of vast areas of agrarian soils, drained by the Yamaska and St. François rivers to Lake St. Pierre, greatly facilitates the transfer of Hg from the watersheds to the lake. This study stresses the need to improve the management of agrarian soils and protect them from extensive erosion in order to preserve the integrity of the fish resources harvested in Lake St. Pierre. Key words: Mercury, soil erosion, Lake St. Pierre, lignin biomarkers
Model prediction of soil drainage classes based on digital elevation model parameters and soil attributes from coarse resolution soil maps
Authors: Zhao Z. , Chow T L , Yang Q. , Rees H W , Benoy G. , Xing Z. , Meng F -R
Published: April 2011

High-resolution soil drainage maps are important for crop production planning, forest management, and environmental assessment. Existing soil classification maps tend to only have information about the dominant soil drainage conditions and they are inadequate for precision forestry and agriculture planning purposes. The objective of this research was to develop an artificial neural network (ANN) model for producing soil drainage classification maps at high resolution. Soil profile data extracted from coarse resolution soil maps (1:1 000 000 scale) and topographic and hydrological variables derived from digital elevation model (DEM) data (1:35 000 scale) were considered as candidates for inputs. A high-resolution soil drainage map (1:10 000) of the Black Brook Watershed (BBW) in northwestern New Brunswick (NB), Canada, was used to train and validate the ANN model. Results indicated that the best ANN model included average soil drainage classes, average soil sand content, vertical slope position (VSP), sediment delivery ratio (SDR) and slope steepness as inputs. It was found that 52% of model-predicted drainage classes were exactly the same as field assessment observations and 94% of model-predicted drainage classes were within ±1 class. In comparison, only 12% of maps indicated drainage classes were the same as field assessment observations based on coarse resolution soil maps and only 55% of points were within ±1 class of field assessed drainage classes. Results indicated that the model could be used to produce high-resolution soil drainage maps at relatively low cost. Key words: Soil drainage, artificial neural network model, ANN model, high-resolution soil maps, DEM, hydrology model
Framework for evaluation of sustainable land management: A case study of two rain-fed cereal-livestock farming systems in the Black Chernozemic soil zone of southern Alberta, Canada
Authors: Gameda S. , Dumanski J.
Published: April 2011

The Framework for Evaluation of Sustainable Land Management (FESLM) was used to assess the sustainablility of two land-use systems in the Canadian Prairies. The FESLM provided a means of identifying the factors impacting on sustainability, the processes by which these factors operate and interact, and the indicators and thresholds by which they could be measured to attain an assessment end point. On the basis of the framework, it was possible to expand sustainability assessment beyond traditional factors of productivity and economic viability to include ones pertaining to production risk, protection of the natural resource base, and social acceptability. In conducting the FESLM-based analysis, the decision-making characteristics of the producer were identified as important components of sustainability. Preliminary indications are that substantially greater amounts of farm-specific and regional data are required to make a conclusive FESLM-based sustainability assessment. Nevertheless, application of the framework suggests that, for the farming systems and the type of producer under consideration, the conservation-based land-use system is more sustainable than the conventional land-use system. Key words: Sustainable land management, Black Chernozemic soil zone, livestock farming
Détermination par méthode électromagnétique de la concentration en sel d’un sol irrigué
Authors: Job J. O. , Tabbagh A. , Hachicha M.
Published: April 2011

A prerequisite for the control of salinity in soils is the determination of the salinity of the upper first metre of the soil with the greatest accuracy. This is commonly done from saturated paste extracts but on too small a volume and too restricted a number of samples. This must be done without modification of the soil structure and on a sufficiently narrow grid. Electromagnetic conductivity meters of Slingram type are convenient to indirectly determine the salinity by measurement of electrical conductivity. However the depth of investigation commonly exceeds the first metre and the saturated salted zone beneath significantly influences the results. A theoretical study together with a complete calibration test on the border of Chott El Guettar (Tunisia) confirms that short coil separation (60 cm) increases the sensitivity of the apparatus to conductivity variations in the first metre of soil. Key words: Saline soils, electrical conductivity, electromagnetic apparatus
Micromorphological evidence of pedogenetic pathway of a Podzolic Gray Luvisol (Falmouth series) in Nova Scotia
Authors: Wang C. , Brewster G. R. , Webb K. T.
Published: April 2011

A catena of Podzolic Gray Luvisols (Falmouth series) – Gleyed Gray Luvisols (Queens series) – Orthic Gleysols (Kingsville series) is commonly found on fine loamy, weakly calcareous parent materials in Nova Scotia, with Podzolic Gray Luvisols occupying the best drained landscape positions. The hypothesis that podzolic B horizons of Podzolic Gray Luvisols were developed on degraded Bt horizons was investigated by micromorphological characterization of one Podzolic Gray Luvisol pedon. Although not visible in field examinations, argillans were common in thin sections of the Bf and Bm horizons. These argillans were not associated with the walls of voids or the surface of grains. Argillans of the Bt horizons, however, were associated with features such as cracks, vughs, and channels. The upper Bt horizon (i.e., Bt1gj) showed signs of degradation. The pale brown matrix color was more like the Bm horizon above than the dark brown Bt2gj horizon below. The strongly acidic nature of the Bt1gj horizon may have triggered degradation. It is concluded that the Bf and Bm horizons were developed on degraded Bt horizons through the translocation of amorphous Fe and Al and organic matter. Key words: Pedogenesis, micromorphology, Luvisols, bisequal soils
Effect of 20 annual applications of excess feedlot manure on labile soil phosphorus
Authors: Dormaar J. F. , Chang C.
Published: April 2011

Concentrations were measured of various forms of soil P in the Ap horizon of a Lethbridge loam (Dark Brown Chernozemic) brought about by 20 yr of feedlot manure loading or 14 yr of feedlot manure loading + 6 yr of no further additions under both nonirrigated and irrigated conditions. Depth of cultivation affected the concentrations of the various P fractions. Although total P and phosphatase activity increased with manure additions, these increases diminished at triple the recommended loading rates. Increased phosphatase activities never rose above those of the soil from ungrazed native prairie. Irrigation increased the phosphatase activity of the control treatment. Concentrations of total P remained well above those of the control plots, even after 6 yr without any additional manure loading. New approaches to the estimation of P fractions are needed to understand P in land used for manure disposal. Key words: Phosphatase activity, labile phosphorus, pollution, phosphorus harvesting, cultivation depth
Industrial organic compounds in selected Canadian soils
Authors: Webber M. D. , Wang C.
Published: April 2011

Studies were conducted to determine the concentrations of a large number of industrial organic compounds in selected Canadian agricultural soils and to assess the potential for land application of municipal sludges to cause significant polynuclear aromatic hydrocarbon (PAH), organochlorine pesticide (OC) and polychlorinated biphenyl (PCB) contamination of agricultural land. Twenty-four Agriculture and Agri-Food Canada, Soil Quality Evaluation Program (SQEP) benchmark soils and six intensively cropped southern Ontario soils exhibited similar small concentrations of a few base-neutral and acid (BN&A) extractable industrial organic compounds (seldom >1 mg kg−1 dry wt), PCBs (<200 μg kg−1 dry wt) and organophosphorus pesticides (OPs). Fonofos, the only OP detected, was observed at concentrations <100 μg kg−1 dry wt. Neutral and phenoxy acid herbicide analyses for 13 soils (seven SQEP and six intensively cropped) indicated infrequent detection of these compounds. There was no detection of carbamate herbicides. In most soils, only trace amounts (<10 μg kg−1 dry wt) of OCs were observed but in one intensively cropped soil, DDT exceeded 70 mg kg−1 dw. A greater incidence of compounds such as alpha chlordane, dieldrin, aldrin and DDT in intensively cropped than in other soils is assumed to reflect increased use of these compounds for intensive crop production. Soils treated with sludge according to recommended practice exhibited minor increases in PAH, OC and PCB concentrations. There is no risk to human health or the environment from industrial organic conpounds, except possibly DDT, in Canadian agricultural soils that have received no sludge or from PAHs, OCs and PCBs in soils that have received southern Ontario sludges according to recommended practice. Key words: Municipal sludge, industrial organic compounds, organic contaminants, agricultural sustainability, soil
Calculation of organic matter and nutrients stored in soils under contrasting management regimes
Authors: Ellert B. H. , Bettany J. R.
Published: April 2011

Assessments of management-induced changes in soil organic matter depend on the methods used to calculate the quantities of organic C and N stored in soils. Chemical analyses in the laboratory indicate the concentrations of elements in soils, but the thickness and bulk density of the soil layers in the field must be considered to estimate the quantities of elements per unit area. Conventional methods that calculate organic matter storage as the product of concentration, bulk density and thickness do not fully account for variations in soil mass. Comparisons between the quantities of organic C, N, P and S in Gray Luvisol soils under native aspen forest and various cropping systems were hampered by differences in the mass of soil under consideration. The influence of these differences was eliminated by calculating the masses of C, N, P and S in an "equivalent soil mass" (i.e. the mass of soil in a standard or reference surface layer). Reassessment of previously published data also indicated that estimates of organic matter storage depended on soil mass. Appraisals of organic matter depletion or accumulation usually were different for comparisons among element masses in an equivalent soil mass than for comparisons among element masses in genetic horizons or in fixed sampling depths. Unless soil erosion or deposition had altered the mass of topsoil per unit area, comparisons among unequal soil masses were unjustified and erroneous. For management-induced changes in soil organic matter and nutrient storage to be assessed reliably, the masses of soil being compared must be equivalent. Key words: Soil carbon, soil nitrogen, soil phosphorus, soil sulfur, carbon cycle, carbon storage, bulk density effects, Gray Luvisol, soil erosion
Effect of plant age on water content in crowns of fall rye and winter wheat cultivars differing in snow mold resistance
Authors: Gaudet D. A. , Laroche A. , Puchalski B.
Published: April 2011

Resistance to snow molds in winter wheat increases with plant age, and older plants express higher levels of resistance than young plants. Experiments were conducted to study the effect of plant age on percent crown water content (%CWC) and dry weights in fall rye and winter wheat cultivars grown under controlled environments and in the field at Lethbridge, AB. Under controlled environments, the oldest (6 wk of pre-hardening growth at 20°C) treatments accumulated the greatest dry weights following exposure of plants to 1 to 6 wk hardening conditions at 2°C, compared with younger (1 to 4 wk pre-hardening growth) treatments. Exposure of plants to hardening temperatures had the greatest effect on %CWC values, which decreased, gradually, from 82–89% (4.95–8.67 g H2O g–1 DW) in unhardened treatments to 67–72% (2.05–2.65 g H2O g–1 DW) in plants receiving the 6 wk pre-hardening and 6 wk hardening growth. However, the oldest treatments (4 to 6 wk pre-hardening growth) always exhibited the lowest %CWC values among all hardening treatments. The %CWC in the oldest (6 wk) unhardened plants was also lower ([Formula: see text] = 80.8% or 4.24 g H2O g–1 DW) than in the youngest (1wk) unhardened plants ([Formula: see text] = 91.2% or 11.31 g H2O g–1 DW ), demonstrating that water loss occurs in older plants in the absence of low hardening temperatures. In a field study at Lethbridge during the autumn, winter, and early spring of 1997–1998 and 1998–1999, different seeding dates were employed to obtain plants differing in age and developmental state. The %CWC in early-seeded treatments was lower during the autumn, and remained lower in early spring, compared with later seeded cultivars. The %CWC in crowns was negatively associated with the snow mold resistance rating of a fall rye and five winter wheat cultivars under controlled environment conditions, and among a fall rye and 13 winter wheat cultivars in the field; the highest correlation values in the field were observed from mid-November to mid-March during 1997–1998 (r = –0.84), and 1998–1999 (r = – 0.76). These results indicate that the type of snow mold resistance that increases with plant age is related to the accumulation of crown dry matter and the ability of wheat and rye plants to lose crown water in response to both extended growth at warm temperatures and hardening at low, above freezing temperatures. Key words: Carbohydrates, fructans, low temperature basidiomycete, Coprinus psychromorbidus
Physiological and morphological traits of lowbush blueberry (Vaccinium angustifolium Ait.) plants in relation to post-transplant conditions and water availability
Authors: Hicklenton Peter R. , Reekie Julia Y. , Gordon Robert J.
Published: April 2011

Experiments were conducted with the lowbush blueberry (Vaccinium angustifolium Ait.) to investigate 1) changes in leaf water potential (ψ1) of transplanted seedlings, and rhizome development under various surface mulches, and 2) the water relations of mature plants subjected to irrigation or water withholding. Pre-dawn ψ1 for seedlings in bare-ground, sand and bark mulch treatments was > −0.2 MPa for most of the season following transplant. Dusk ψ1 was lower than predawn ψ1 for the first 2 wk after transplant under mulch and for the first 3 wk in bare ground, but these differences were not sustained. Rhizome numbers were 40% and 120% greater under bark and sand mulch, respectively, when compared with bare ground after three growing seasons. Mature (15-yr old) plants of cultivars Fundy and Brunswick were grown for one season under either rain-sheltered, rainfed or irrigated conditions. Pre-dawn ψl showed little or no difference between treatments until early August when, with volumetric soil water content below 8%, ψ1 of sheltered plants was reduced to about −0.3 MPa as compared with −0.1 MPa in rainfed and irrigated plants. Similarly, midday ψl and stomatal conductance (gl) were lower in sheltered, than in irrigated plants during August. Irrigated plants produced more large (>12-mm diameter), and fewer small (<10 mm) fruit than those under shelter where size distribution was about equal (Fundy), or showed a predominance of medium and smaller fruit (Brunswick). Fundy and Brunswick differed in the degree to which reduced soil water affected ψ1, g1 and fruit size distribution. Both Fundy and Brunswick possessed deep penetrating root networks with 35 and 60% of roots, respectively, terminating below 40 cm. This suggests that mature plants can resist drought by accessing water resources well below the soil surface. Key words: Mulch, water potential, stomatal conductance, wild blueberry, root architecture
Crop and weed response to nutrient source, tillage and weed control method in a corn-soybean rotation
Authors: Perron F. , Légère A. , Tremblay G. , Simard R. R. , Angers D. A. , Hamel C.
Published: April 2011

The integration of various sustainable management techniques in cropping systems can potentially reduce agro-environmental problems, but may warrant a new approach to weed management, due to changes in weed communities. A 3-yr experiment was conducted to determine the effects and interactions of tillage (moldboard plow or chisel plow), weed control method (chemical or mechanical), and nutrient source (mineral fertilizers or liquid hog manure supplemented with mineral fertilizers) on crops and weeds in a corn (Zea mays L.)–soybean (Glycine max (L.) Merr.) rotation on two soils (a Sainte-Rosalie clay and a Duravin clay loam, Orthic Gleysols), at Saint-Hyacinthe, Québec. In most cases, weed density and biomass were more important with mechanical than with chemical control. Nutrient source did not affect weed density, but weed biomass was higher in the manure than the mineral treatment in 1997. Weed populations on both soils were greater with chisel plow tillage combined with mechanical weed control. The presence of crop residues in chisel plow systems may have hindered the efficacy of mechanical weed control operations, particularly when corn was the previous crop. Soybean populations, mid-season biomass and yields were reduced in chisel plow compared with moldboard plow tillage. Corn populations and mid-season biomass were not affected by any of the factors, whereas corn yields showed variable responses over the years. Efficacy of mechanical weed control would need to be enhanced or complemented with other weed control methods, in order to reduce the risks of weed infestations and lower crop yields, particularly in conservation tillage systems. Liquid hog manure would have little effect on weed populations, but would need to be adequately balanced in order to ensure proper crop nutrition and optimum yields. Key words: Chisel plow tillage, mechanical weed control, liquid hog manure, conservation tillage
MillenniUM 03 summer rape
Authors: McVetty P. B. E. , Scarth R. , Rimmer S. R.
Published: April 2011

MillenniUM 03 summer rape (Brassica napus L.) is a high erucic acid, low glucosinolate (i.e., canola quality meal) cultivar. It has an average 26% yield advantage over Reston high erucic acid, low glucosinolate summer rape, is 25 g kg−1 higher in seed oil content than Reston, 21 g kg−1 higher in meal protein content than Reston, and is adapted to the southern B. napus growing regions of western Canada. Key words: Rape (summer), high erucic acid, low glucosinolate, cultivar description
TR4 summer turnip rape
Authors: Hutcheson D. S. , Falk K. C. , Rakow G. F. W.
Published: April 2011

TR4 summer turnip rape (Brassica rapa L.) is a breeding population with a total (aliphatic and indole) glucosinolate content of 4.2 µ mol g−1 oil free meal. It was derived from selections among segregating progeny of a cross between the low aliphatic glucosinolate breeding population BC86-18, and the low indole glucosinolate breeding population DLY. Key words: Glucosinolates, aliphatic, indole, canola, germplasm
Partitioning of 35S in ryegrass grown in sulfur-deficient soils
Authors: Banerjee M. R. , Yesmin L.
Published: April 2011

A pot study was conducted in a growth chamber using 35S labelled gypsum to study the fate of applied 35S fertilizer in a soil-plant system. The distribution among plant parts and soil fraction of applied 35S was investigated with ryegrass grown in sulfur-deficient soils. Of the applied 35S, 19–35% was recovered in the shoot and 4–16% in root tissues. Within the soil, extractable 35S accounted for 41–55% of applied S, microbial biomass 35S accounted for 2–6%, and the remaining 4–14% was unrecoverable. In addition to the available soil S fraction, it was concluded that S in the unharvested plant residue could be an important supplementary S source for succeeding crops. Keywords: Radioactive sulfur, soil sulfur, plant sulfur, ryegrass
Canada’s plant hardiness zones revisited using modern climate interpolation techniques
Authors: McKenney D. W. , Hutchinson M. F. , Kesteven J. L. , Venier L. A.
Published: April 2011

Canada’s plant hardiness zones are well known to Canadian gardeners. The original hardiness indices and zones were developed in the early 1960s through regression models of several climatic parameters and plant survival data from numerous locations across the country. Since that time Canada’s climate has changed and climate interpolation techniques have improved. We have remapped Canada’s plant hardiness zones using data from the period of the original analysis (roughly 1930–1960) and for the 1961–1990 period using thin plate spline interpolation methods. Trials of bivariate and tri-variate splines were undertaken and evaluated using withheld data. A trivariate function of position (longitude and latitude) and elevation performed best. Standard errors of the surfaces were about 0.5°C or less for temperature variables and 5 to 28% for rainfall depending on the month (winter months being the worst). The creation of a new digital elevation model (a regular grid of position and elevation) of Canada enabled the mapping of each variable required for the plant hardiness formula at spatial resolutions of 1 km to 10 km. These models better capture the spatial variation in climate than previously possible and hence should provide a stronger basis for applications such as the determination of plant hardiness zones. Comparisons of the zones between the two time periods are consistent with what is known about climate in Canada. The hardiness index has declined or has stayed stable in eastern Canada and has increased in western areas. The results also suggest that more station data are required in western Canada to better capture the inherent spatial variability of climate, particularly precipitation, in mountainous terrain. Key words: Plant hardiness, thin plate splines, climate mapping, spatial analysis
AC Medallion oat
Authors: Duguid S. D. , Brown P. D. , Chong J. , Harder D. E. , Haber S. , Menzies J. , Noll J. S.
Published: April 2011

AC Medallion is a high-yield ing, white hulled oat cultivar possessing the crown rust resistance gene combination Pc38, Pc39, and Pc68, which is highly effective against the crown rust population on the Canadian prairies at the time of registration. It has very good resistance to loose and covered smut, good resistance to stem rust, and moderate tolerance to Barley Yellow Dwarf Virus (BYDV). AC Medallion has good kernel characteristics including good protein and oil content. AC Medallion is well suited for the oat-growing areas of western Canada and in particular the Black Soil zone of Manitoba and Saskatchewan and the Brown soil zone of Saskatchewan and Alberta. Key words: Oat, Avena sativa L., cultivar description
AC Assiniboia oat
Authors: Brown P. D. , Duguid S. D. , Haber S. , Chong J. , Harder D. E. , Menzies J. , Noll J. S. , McKenzie R. I. H.
Published: April 2011

AC Assiniboia is a high-yielding, tan hulled oat cultivar possessing the crown rust resistance gene combination Pc38, Pc39, and Pc68, which is highly effective against the crown rust population on the Canadian prairies at the time of registration. It has very good resistance to loose and covered smut, good resistance to stem rust, and excellent tolerance to Barley Yellow Dwarf Virus (BYDV). AC Assiniboia has good kernel characteristics, including good protein and oil content. AC Assiniboia is well suited for the oat-growing areas of western Canada and in particular the Black soil zone of Manitoba and Saskatchewan. Key words: Oat, Avena sativa L., cultivar description
CO429 corn inbred line
Authors: Reid L. M. , McDiarmid G. , Parker A. J. , Hamilton R. I.
Published: April 2011

CO429 is a short-season corn inbred line with good combining ability, average to superior lodging resistance in hybrids, and excellent emergence and early season vigour. Key words: Corn, maize, Zea mays, cultivar description