bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of constructed wetlands to process agricultural wastewater
Authors: Peterson Hans G.
Published: April 2011

Constructed wetlands are emerging as a serious challenge to conventional wastewater treatment because of lower construction and operating costs, less requirement for trained personnel, more flexibility, and lower susceptibility to variations in waste loading rates. Water quality improvements can be achieved by removal of plant nutrients, such as N and P, organics (natural and manmade) as well as inorganic contaminants. Wetland treatment is now advocated by regulatory agencies and has been determined as the technology of choice by municipalities and industries required to meet stringent discharge regulations. These same regulations have not usually been imposed on the agricultural community, but deteriorating water sources will likely change this regulatory anomaly. Use of this technology in treating agricultural wastewater is still in its infancy with few, although rapidly expanding, applications. This paper aims to highlight different aspects of wetland treatment by exploring its use for the treatment of agricultural run-off as well as wastewater from the agri-food industry. It is concluded that natural wetlands will be quite limited in absorbing agricultural wastewater while constructed wetlands can be designed for optimum pollutant removal. Key words: Constructed wetlands, wastewater treatment, agriculture, food processing, nutrient removal, nitrogen, phosphorus, organics
Comparing the adaptation of sunola, canola and mustard to three soil climatic zones of the Canadian prairies
Authors: Miller P. R. , Johnston A. M. , Brandt S. A. , McDonald C. L. , Derksen D. A. , Waddington J.
Published: April 2011

Sunola (Helianthus annuus L.) emerged in the early 1990s as a new drought- and heat-tolerant oilseed crop option for prairie producers. This study was conducted to compare the agronomic performance of sunola with that of canola (Brassica napus L. and B. rapa L.) and mustard (B. juncea L.). In 1993 and 1994 a spring seeding date experiment comparing crop maturity and grain yield of sunola, canola and mustard was conducted at three locations: Swift Current and Scott in the semi-arid Brown and Dark Brown soil zones, respectively, and Melfort in the subhumid Black soil zone. Additionally, a tillage system experiment was conducted at Swift Current that compared grain yield and water-use-efficiency (WUE) of sunola and mustard grown in four tillage treatments: tilled, and untilled fallow, and tilled, and untilled wheat stubble. In the more typical 1994 season, the average thermal time to reach maturity for sunola was 1200 growing degree days (GDD), consistent for all locations, and was greater than that required for B. napus by 70 to 320 GDD (1–4 wk), depending on location. When compared with the seed yield of the Brassica spp. oilseeds, sunola averaged 59% at Swift Current, 54% at Scott, and 94% at Melfort. The WUE for sunola was 3.0 and 2.9 kg ha−1 mm−1 when grown on fallow and wheat stubble, respectively, compared with 5.6 and 4.8 kg ha–1 mm–1 for mustard. Due to its low seed yield potential and low WUE, sunola is not well adapted for production in the semi-arid Brown and Dark Brown soil zones. Key words: Sunola, canola, mustard, adaptation, seeding date, water-use-efficiency
Using height to adjust for interplot interference in spring wheat yield trials
Authors: Clarke F. R. , Baker R. J. , Depauw R. M.
Published: April 2011

Interplot interference can occur in yield trials when genotypes vary for height. We investigated the possibility of adjusting yield for interplot interference by using height measurements in an analysis of covariance. Computer simulation showed that genetic correlation between height and yield would have no impact on analysis of covariance, as well as showing that analysis of covariance would reduce precision in the absence of interference due to height difference. Sixty-five data sets from yield trials conducted in Saskatchewan in 1992, 1993 and 1994 were analyzed to see if analysis of covariance would improve precision of yield estimates. Forty percent of the historical data sets showed evidence of significant interplot interference. In those trials in which interference occurred, yield decreased an average of 0.39% for every centimetre by which the average height of the flanking plots exceeded that of the test plot. Using final height to adjust for interplot interference is effective when genotypes vary for height and when the regression coefficient is significant. Key words: Interplot interference, yield adjustment, height difference, covariate
AC ELK common bean
Authors: Park S. J. , Rupert T.
Published: April 2011

AC ELK is a high-yielding, light red kidney bean (Phaseolus vulgaris L.) cultivar with early-season maturity in Ontario. Its main advantages are high yield potential and an early maturity. Seed has acceptable cooking/canning quality. AC ELK is resistant to race 1 of bean common mosaic virus and anthracnose (Collectotrichum lindemuthianum) race alpha and alpha Brazil. Key words: Phaseolus vulgaris L., dry bean, cultivar description, bean common mosaic virus, anthracnose
AC OLE common bean
Authors: Park S. J. , Kiehn F. , Rupert T.
Published: April 2011

AC Ole is a high-yielding pinto bean (Phaseolus vulgaris L.) cultivar with mid-season maturity. It has high yield potential and an upright plant type, suitable for direct combine harvest. AC Ole seed has acceptable cooking/canning quality. It is resistant to races 1 and 15 of bean common mosaic virus. Key words: Phaseolus vulgaris, dry bean, cultivar description
Development of soybean brown stem rot in relation to infested residue size, density and depth of placement
Authors: Harikrishnan R. , Yang X. B.
Published: April 2011

Greenhouse experiments were conducted to determine the effects of infested soybean-residue placement, size and residue density on the development of brown stem rot caused by Phialophora gregata. Results showed that incidence and severity decreased significantly with decrease in residue size and with increase in depth of placement but the three residue densities used had no significant effects on the disease. Key words: Brown stem rot, Phialophora gregata, tillage
Potato response to crop sequence and nitrogen fertilization following sod breakup in a Gleyed Humo-Ferric Podzol
Authors: Li H. , Parent L. É. , Tremblay C. , Karam A.
Published: April 2011

Meadow soils could supply significant amounts of N for several years and reduce N requirements for the potato (Solanum tuberosum L.). We examined a combination of three crop sequences, three cultivars and six N rates in relation to tuber yield and quality. Superior, Kennebec and Snowden were grown as follows on a Tilly silty loam between 1993 and 1995: (1) 3-yr continuous potato cropping of Superior, (2) 3-yr continuous potato cropping starting with Snowden and followed by 2 yr of Kennebec, and (3) 3-yr sequence of Kennebec, oat (Avena sativa L. 'Marion') and Superior. There were six N treatments (0, 70, 105, 140, 175 and 210 kg N ha−1) and a split application of 140 kg N ha−1 (half at seeding and half before hilling). The seasons were either favorable to growth (1993), relatively wet (1994) or relatively dry (1995). In 1993 and 1994, total yield varied between 37 and 50 t ha−1. In 1995, continuous cropping of Kennebec and Superior produced 28 t ha−1 compared with 37 t ha−1 under crop rotation. The rotation increased total yield of Superior by 34% and graded yield by 42% in 1995. The N requirement was closely related to yield, rather than cultivar. Compared with continuous cropping of Superior, tuber-quality index was highest with the rotation for rhizoctonia (Rhizoctonia solani) (67 vs. 57) and common scab (Streptomyces scabies) (90 vs. 82). The incidence of both diseases decreased when at least 70 kg N ha−1 was applied. For common scab, skin coverages was higher at rates of 0, 175 and 210 kg N ha−1 than at intermediate rates of 70–140 kg N ha−1. Mineral N accumulated in the 0–60-cm layer in the interrow and increased rapidly when N rates exceeded 105 kg N ha−1. After sod breakup an N rate in the range of 70–100 kg N ha−1 and crop rotation with cereals sustained the productivity of the potato during 3 yr while minimizing the environmental impact of mineral N. Key words: Crop rotation, common scab, rhizoctonia, reduced N rates, Solanum tuberosum L.
A comparison of the yield response of solin (cv. Linola 947) and flax (cvs. McGregor and Vimy) to application of nitrogen, phosphorus, and Provide (Penicillium bilaji)
Authors: Grant C. A. , Dribnenki J. C. P. , Bailey L. D.
Published: April 2011

Field studies were conducted at three locations over three years with Linum usitatissimum L. to determine whether the solin cultivar Linola 947 and the traditional oilseed flax cultivars McGregor and Vimy, differed in seed yield, straw yield and harvest index response to N and P fertilizer and the phosphorus-solubilizing fungus, Penicillium bilaji, marketed as "Provide". While cultivars differed in seed yield, straw yield and harvest index, the relative performance of the cultivars varied with site and year and did not relate to whether the cultivar was solin or traditional oilseed flax. The degree and pattern of response of straw yield and harvest index to N and/or P fertilization varied with year and location. Where significant differences occurred due to P or Provide management, seed yield and harvest index were lower and straw yield higher with application of Provide than with application of P fertilizer, indicating that Provide was less effective than P in enhancing seed yield of flax. Solin did not generally differ from traditional oilseed flax in the response of seed yield, straw yield and harvest index to fertilizer applications. Response of seed and straw yield to N and response of harvest index to P each differed among cultivars in only one-site year, while an N-by-P-by-cultivar interaction occurred in only one site-year for seed and straw yield. Considering the limited occurrence of cultivar-by-fertilizer interactions, fertilizer recommendations produced for traditional flax cultivars should also be applicable to solin cultivars. Key words: Seed yield, harvest index, cultivar
Regrowth of crested wheatgrass (Agropyron cristatum [L.] Gaertn.) following defoliation
Authors: Romo J. T. , Harrison T.
Published: April 2011

Effects of defoliation of crested wheatgrass (Agropyron cristatum [L.] Gaertn.) on the amount of time required to reach peak regrowth, the lag period for regrowth to begin, regrowth biomass, tiller survival and replacement, and carryover effects of defoliation the following year were investigated. Regrowth of crested wheatgrass was determined during the summers of 1990, 1991 and 1992 in central Saskatchewan following a single defoliation to a 5-cm stubble height at eight stages of growth. Crested wheatgrass regrew 54–130 g m−2 of biomass when defoliated tillers had ≤3.6 leaves. Regrowth began accumulating within 3–53 growing degree-days (GDD) and peaked in 705–875 GDD. Rates of leaf development after defoliation (218–252 GDD phyllochron−1) equaled or were faster than control (218–330 GDD phyllochron−1). Regrowth biomass accounted for 35–76% of total annual production. Total annual production was greatest when plants were defoliated during vegetative growth or at peak growth. In 1991 and 1992, etiolated growth in the spring following defoliation was reduced by defoliation in the previous year. Tiller replacement was not affected by defoliation and averaged 1.2 tillers tiller−1 (SE = 0.1) in 1991 and 1.5 tillers tiller−1 (SE = 0.1) in 1992. Two periods of grazing can be expected from crested wheatgrass if it is grazed when tillers have ≤3.6 leaves; however, the impacts of a second grazing must be determined. If crested wheatgrass is grazed late in the growing season, only one period of grazing can be expected, and production will likely be less the following growing season, necessitating a rest period for plants to regain their production potential. Key words: Crested wheatgrass, defoliation, grazing management, growing degree-days, phyllochron, regrowth
Effect of seed-placed urea fertilizer and N-(n-butyl)thiophosphoric triamide (NBPT) on emergence and grain yield of barley
Authors: Grant C. A. , Bailey L. D.
Published: April 2011

Seedling damage from excess seed-placed urea fertilizer can be a major problem in one-pass seeding and fertilizing systems. Field studies were conducted on a clay loam and a fine sandy loam soil over 3 yr to evaluate the impact of seed-placed urea N, with and without the addition of the urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) on stand density and growth of barley. Seedling damage, as indicated by reduction in stand density, occurred on both soil types at rates of seed-placed N as low as 40 kg N ha−1. Addition of NBPT to the urea fertilizer increased stand density at N levels where damage occurred with the untreated urea. Dry matter yield at heading generally was unaffected by N application or use of NBPT; however, final yield was increased by use of NBPT in four of five site-years. Use of NBPT appears promising as a method of reducing the risk of seedling damage from seed-placed urea fertilizer, thus increasing the rate of urea-N that can be safely placed with the seed. Key words: Urease inhibitor, seedling toxicity, ammonia
Within-season grass herbage crude-protein- and nitrate-N concentrations as affected by rates and seasonal distribution of fertilizer nitrogen in a high yearly rainfall climate
Authors: Bittman S. , Kowalenko C. G.
Published: April 2011

An orchardgrass study in which three rates of N (100, 200 and 400 kg ha−1) each distributed in 1/0/0/0, 0.75/0.25/0/0, 0.50/0.25/0.25/0 and 0.25/0.25/0.25/0.25 proportions prior to four cut intervals examined crude-protein-N and nitrate-N concentrations in grass herbage at each cut in three trials. Crude-protein-N concentration frequently increased to a greater degree and in a different pattern (based on cut) than yield as the rate of N application increased. This showed that crude-protein-N by itself cannot be used as a method for determining the N sufficiency status of grass. Both rate and distribution of fertilizer N strongly influenced plant nitrate-N concentration; the degree of change varied considerably among cuts and trials. Plant nitrate-N concentration in the control did not correspond to yield responsiveness to N application, making it a poor indicator of the plant's need for fertilizer applications. Residual effects of N applications on plant nitrate-N were noted into the last cut of the season from a single spring application. The effect of N rate and distribution, then, was a function of immediate and residual effects of the applications. There was some evidence that N present in the soil in nitrate-N form enhanced the potential for high nitrate-N in the plant. Plant nitrate-N concentrations accounted for up to 29% of the total N in the plant with concentrations greater than 4000 mg N kg−1 at the highest N application rates. Plant nitrate-N did not exceed 1000 mg N kg−1, a concentration considered safe for ruminants, when 75 kg N ha−1 or less ammonium nitrate was applied as a single application prior to a growth interval for all cuts. Since grass protein- and nitrate-N concentrations respond differently than yield to N applications, a specific combination of rate and distribution of fertilizer will not necessarily produce maximum herbage quantity and quality simultaneously. Key words: Crude-protein-N, plant nitrate-N, residual effect, split applications
Effectiveness of elemental S fertilizers on forage grass
Authors: Malhi S. S. , Heier K. , Solberg E.
Published: April 2011

Two field experiments were conducted from 1993 to 1995 to compare the effectiveness of various cumulative elemental S and sulphate-S fertilizer applications in increasing dry matter yield (DMY) and S uptake of forage grass. In exp. 1, one sulphate-S (Na2SO4) and two elemental S (Agric-Grade 0-0-0-95 and Tiger 90) fertilizers were applied annually to grass in mid to late April at 10, 20, 30, 40 and 50 kg S ha−1 rates. The increase in DMY from S application was significantly lower with elemental S fertilizers than with Na2SO4 in the first and second years, but in the third year elemental S fertilizers had DMY increase similar to Na2SO4 In exp. 2, a number of elemental S and sulphate-S fertilizers were applied annually to grass in mid- to late April at 15 kg S ha−1 rate. There was a marked increase in DMY from S application in all the 3 yr with the three sulphate-containing S fertilizers (Na2SO4, K2SO4 and CaSO4). When elemental S fertilizers were used, only Turf-Grade 0-0-0-95 increased DMY in all the 3 yr and it produced DMY increase similar to the sulphate-S fertilizers in the third year. Elemental S Prills did not produce any significant increase in DMY in any of the 3 yr. Other elemental S fertilizers [e.g., Elemental S Powder, Agric-Grade 0-0-0-95 and Tiger 90] increased DMY in the third year only, but this increase was still less than the sulfate-S fertilizers. Turf-Grade 0-0-0-95 (with smaller granules) produced greater DMY increase than Agric-Grade 0-0-0-95 (with larger granules) in all the 3 yr (though significant in the third year only). The S fertilizers that contained small amounts of sulphate-S in addition to elemental S were generally more effective in increasing DMY than the similar fertilizers containing only elemental S. The increase in S uptake from applied S in grass showed usually similar trends as DMY increase. In conclusion, the results suggest that some elemental S fertilizers can be as effective in increasing forage DMY on perennial grass as sulfate-S fertilizers. However, depending upon soil type and climatic conditions two or more growing seasons may be needed for S in the elemental S fertilizers to become fully available to the plants. Key words: Elemental S fertilizers, forage yield, grassland, sulphate-S fertilizers, sulphur uptake
Weed communities associated with arable Saskatchewan farm management systems
Authors: Leeson J. Y. , Sheard J. W. , Thomas A. G.
Published: April 2011

The objective of this study was to determine the impact of a range of management systems on weed communities in cropped fields on farms in Saskatchewan. Farms (n = 28) with management systems defined by a combination of different cropping histories and chemical input levels were selected. Fields were surveyed on each farm in 1995, 1996, and 1997 after any post-emergent weed control to ensure that their weed communities reflected the impact of all agronomic management practices typical of the management system. Canonical correspondence analysis was used to determine whether weed communities were significantly correlated with management system after removal of variance due to ecoregion and year. The largest difference in weed communities attributable to farming system was between the systems with annual cropping histories and those that included perennials in the cropping history. Thus, the life history of the weeds reflected the life history of the crops. Herbicide use was correlated with the next largest difference between systems. A significant association between weed communities and different management systems indicates that weed species are being selected for by these systems. If such selection pressure continues, these species may become a threat to the system's sustainability. Key words: Weed communities, chemical input level, cropping history, canonical correspondence analysis, correspondence analysis, farming system
Canopy architecture, row spacing and plant density effects on yield of dry bean (Phaseolus vulgaris) in the absence and presence of hairy nightshade (Solanum sarrachoides)
Authors: Blackshaw R. E. , Muendel H. H. , Saindon G.
Published: April 2011

A field study was conducted to determine the combined effects of cultivar growth habit, row spacing and plant density on weed management and dry bean yield. In the absence of weeds, upright and viny cultivars expressed similar yield potentials and greater yields of both cultivars were attained by increasing density from 24 to 48 plants m−2. A reduction in row spacing from 69 to 23 cm apart increased dry bean yield in all years when grown at a density of 48 plants m−2 but only increased yield in 1 of 3 yr when grown at 24 plants m−2. In the presence of hairy nightshade (Solanum sarrachoides Sendt.), the upright cultivar always attained a greater yield than the viny cultivar. Upright dry beans were often 15–20 cm taller than viny beans, and this resulted in their being more competitive for light with hairy nightshade. Regardless of cultivar, an increase in plant density resulted in greater suppression of hairy nightshade and greater dry bean yield. Narrow compared with wide rows always resulted in less hairy nightshade biomass, and a concurrent increase in dry bean yield occurred in 2 of 3 yr. Despite the advantages conferred by an upright cultivar, narrow rows and high plant density, yield of weedy beans was always much less than that of weed-free beans. Further studies are required to integrate these desirable agronomic practices with herbicides or other weed control tactics to develop an improved weed management program for dry bean. Key words: cultural control, hairy nightshade, integrated weed management, upright dry beans, weed suppression, Solanum sarrachoides
Enhancing pasture productivity with alfalfa: A review
Authors: Popp J. D. , McCaughey W. P. , Cohen R. D. H. , McAllister T. A. , Majak W.
Published: April 2011

Alfalfa has been recognized for its superior yield and quality in seeded pastures. However, when grazing immature alfalfa there is a risk of animal losses due to frothy bloat in some ruminant livestock. Inclusion of at least 50% grass in the pasture mixture is commonly recommended to reduce the risk of bloat. Two decades of plant breeding have resulted in the release of AC Grazeland, an alfalfa cultivar that reduces the incidence of bloat. Other bloat control agents such as pluronic detergents and ionophores can also be of value. Development of grazing-tolerant alfalfa varieties is solving some of the problems associated with lack of persistence of alfalfa in mixed stands; however, they are not bloat-safe. Animal productivity commonly increases when alfalfa is included in pasture mixtures. Improvements in cattle rate of gain are observed when alfalfa contributes as little as 35% to the sward. Grazing management is the principal method for controlling pasture yield and quality as well as animal performance and bloat incidence. When grazing management is used to optimize pasture production and nutrient intake, yearling steers can gain as much as 1.5 kg head−1 d−1 and liveweight production ranging from 107 kg ha−1 (on dryland) to 1946 kg ha−1 (under irrigation) can be expected. Limiting utilization of alfalfa-based pasture to ≤70% may be more important for maximizing gain per head than managing herbage quality. Key words: Alfalfa, beef production, forage, grazing
A review of the effects of forage condensed tannins on ruminal fermentation and bloat in grazing cattle
Authors: McMahon L. R. , McAllister T. A. , Berg B. P. , Majak W. , Acharya S. N. , Popp J. D. , Coulman B. E. , Wang Y. , Cheng K.-J.
Published: April 2011

Condensed tannins (CT) are polyphenolic secondary plant products that are widespread in the plant kingdom. By definition, CT bind to protein and are regarded as "antinutritional" compounds which reduce protein digestibility. Variations in CT chemistry alter protein binding capacities among polymers from different plant species and developmental stages. Condensed tannins interact with proteins in feed, saliva and microbial cells, with microbial exoenzymes, and with endogenous proteins or other feed components, which alters digestive processes as compared with diets free of CT. Tannin levels exceeding 40 to 50 g kg−1 DM in forages may reduce protein and DM digestibility of the forages by ruminants. At low to moderate levels, CT increase the quantity of dietary protein, especially essential amino acids, flowing to the small intestine. Unlike alfalfa, legumes that contain CT do not cause bloat. Dietary CT may provide a means to beneficially manipulate protein digestion and/or prevent pasture bloat in ruminants. Research efforts are also currently being directed to genetically modify alfalfa to de-repress its CT biosynthetic pathway, or to move genes encoding steps of this pathway into alfalfa from other legumes. The effects of CT in forage legumes on digestion in ruminants and the potential use of tannin-rich forages for preventing bloat in grazing systems are discussed. Key words: Tannins, bloat, by-pass protein, cattle, grazing, alfalfa
Linola™ '1084' low-linolenic acid flax
Authors: Dribnenki J. C. P. , Mceachern S. F. , Green A. G. , Kenaschuk E. O. , Rashid K. Y.
Published: April 2011

LinolaTM '1084' is a yellow seeded, low-linolenic acid (solin) flax (Linum usitatissimum L.) cultivar. It is higher yielding than LinolaTM '989' and LinolaTM '947' and has higher oil content and lower total saturated fats than LinolaTM '989' and LinolaTM '947'. It is immune to North American races of rust and is moderately resistant to Fusarium wilt. Key words: Flax, low linolenic acid, cultivar description, solin
Field evaluation of dual inoculation of alfalfa with Sinorhizobium meliloti and Penicillium bilaii
Authors: Rice W. A. , Lupwayi N. Z. , Olsen P. E. , Schlechte D. , Gleddie S. C.
Published: April 2011

Field experiments were conducted at five sites to evaluate the effects of dual inoculation of alfalfa (Medicago sativa L.) with Sinorhizobium meliloti and Penicillium bilaii, a phosphorus-solubilizing fungus, on the yield and quality of alfalfa hay. Dual inoculation with S. meliloti strain NRG-34 and P. bilaii strain PB-50 increased nodule number and occupancy, but resulted in only small increases in hay yield and total nitrogen and phosphorus concentrations of hay compared with inoculation with S. meliloti alone. There was little response of alfalfa to phosphorus fertilizer at the sites, and this may partly explain the small effects of dual inoculation of the two microorganisms. There were no significant differences in nodulation, hay yield or hay nutrient concentrations between alfalfa inoculated with separate NRG-34 and PB-50 inoculant products and that inoculated with a co-cultured inoculant. This similarity in response supports use of a single effective delivery system for the two different rhizosphere microorganisms, which is of great practical relevance as producers are more likely to adopt technology that requires a single inoculation procedure than one requiring two separate inoculation procedures at planting time. Key words: Co-cultured inoculant, Medicago sativa, phosphorus-solubilizing microorganisms, Penicillium bilaii, Sinorhizobium meliloti
Comparing nondestructive measures of forage structure and phytomass
Authors: Olson B. E. , Wallander R. T. , Beaver J. M.
Published: April 2011

Nondestructive radiative transfer and canopy volume methods were compared with the destructive hand-clipping method to determine forage structure and phytomass. On a native range site, fifteen 1-m2 circular plots were located at each of five microsites. On a crested wheatgrass site, thirty 1-m2 plots were located in grazed and in ungrazed areas. At peak standing crop, all plots were measured with a LI-COR Plant Canopy Analyzer to determine leaf area index (LAI), diffuse non-intercepted radiation (DNIR), and mean tilt angle (MTA) of leaves. Then, plants within plots were measured with a ruler to determine volume. Finally, all phytomass within plots was harvested. At the native range site, plant volume was related with LAI and DNIR on four of five microsites. Phytomass was related with LAI and DNIR on two microsites. At the crested wheatgrass site, volume and phytomass were related with LAI, DNIR, and MTA on grazed plots. Only phytomass was related with LAI and DNIR on ungrazed plots. The Plant Canopy Analyzer measures canopy structure and phytomass; it is fast, and its data are transferred directly to a computer. Measuring plant volume is inexpensive and requires minimal training. Determining phytomass by clipping is accurate and requires minimal training, but it is time-consuming and destructive. Key words: Leaf area, canopy, volume, phytomass, radiative transfer
A review of the development of a bloat-reduced alfalfa cultivar
Authors: Coulman B. , Goplen B. , Majak W. , McAllister T. , Cheng K.-J. , Berg B. , Hall J. , McCartney D. , Acharya S.
Published: April 2011

The studies that led to the development of a bloat-reduced alfalfa began in 1970. Initial work focused on the causes of bloat, the characteristics of bloat-safe and bloat-causing legumes and the development of screening methodologies. The characteristics that were examined as causal factors of bloat in legume species included soluble proteins, saponins, absence of condensed tannins, and rapid breakdown of cells in the rumen. The factor or combination of factors responsible for causing bloat in animals grazing legumes have not been clearly identified; however, of the above, rapid cell breakdown was considered to be the most promising line of research to pursue in selecting a bloat-safe legume. A 4-h nylon-bag rumen digestion technique was developed, which was used to assess the initial rate of digestion (IRD) of fresh leaf material in large numbers of alfalfa genotypes. Using this technique on a population of four alfalfa cultivars, four cycles of recurrent selection for low initial rate of digestion (LIRD) were carried out over an 11-yr period. The resulting selected population, LIRD-4, had a vegetative stage initial rate of digestion that was approximately 85% of that of unselected alfalfa. To determine whether this reduction in IRD would reduce or eliminate bloat, grazing experiments comparing LIRD-4 and unselected cv. Beaver were conducted at three locations over 3 yr. Over all grazings, LIRD-4 caused significantly fewer incidences of bloat than Beaver; thus it is a bloat-reduced, rather than a bloat-safe cultivar. LIRD-4 was released in 1997 and named AC Grazeland Br. Key words: Bloat, cattle, alfalfa, low initial rate of digestion, grazing, bloat-reduced alfalfa
In vitro ruminal undegradable proteins of alfalfa cultivars
Authors: Tremblay G. F. , Michaud R. , Bélanger G. , McRae K. B. , Petit H. V.
Published: April 2011

The quality of alfalfa would be greatly improved by an increase in its ruminal undegradable protein (RUP) concentration. Protein degradation rate (PDR), in vitro dry matter digestibility (IVDMD), leaf weight ratio (LWR), dry matter yield (DMY), total nitrogen (TN), in vitro RUP (expressed on both TN, RUP-TN, and dry matter basis, RUP-DM), acid detergent fiber (ADF), and neutral detergent fiber (NDF) concentrations were determined in 27 alfalfa cultivars. Cultivars were seeded in triplicate on 2 consecutive years and evaluated during the 2 subsequent production years with two harvests per year. Protein degradation rate and RUP-TN were determined using a ruminal inhibitor in vitro system. Data were averaged for spring growth, summer regrowth, and both harvests across 2 production years. Each of the three data sets was analyzed by ANOVA followed by a principal component analysis (PCA) on the ANOVA means. For the four-harvest data, cultivar differences were highly significant (P < 0.001) for all variates except for PDR (P = 0.07) and RUP-TN concentration (P = 0.10). The first PCA axis was largely defined positively by RUP-DM, IVDMD, TN, LWR, and RUP-TN, but negatively with ADF, NDF, PDR, and DMY. The second PCA axis defined a contrast between PDR versus RUP-TN, DMY, ADF, and NDF. Five cultivars were distinctive with high or low PCA scores in all three PCA. Rangelander and Heinrichs, along with Ultra, had low PDR; the first two cultivars had low DMY whereas Ultra was a medium-yielding cultivar. In contrast, Algonquin and Oneida VR had high PDR and medium DMY. While the first principal component (PC) indicated a general trend that low PDR and high RUP were associated with low-yielding cultivars, the second PC identified specific cultivars with both low PDR and high DMY. Therefore, selection for low PDR and high DMY is feasible. Key words: ruminal protein escape, dry matter digestibility, alfalfa
Isolation of protoplasts from viable sperm cells of common buckwheat (Fagopyrum esculentum Moench.)
Authors: Woo Sun Hee , Adachi Taiji , Jong Seung Keun , Campbell Clayton G.
Published: April 2011

Protoplasts from sperm cells were isolated. Sperm cells from germinated pollen placed in solution were released, sieved and removed after sucrose density gradient centrifugation. The isolated cells were spherical and approximately 5.0–6.0 µm in diameter. Cytological observations confirmed that sperm cells of common buckwheat are true protoplasts. Key words: Common buckwheat (F. esculentum Moench.), sperm cell isolation, osmotic shock
Merits of native and introduced Triticeae grasses on semiarid rangelands
Authors: Asay K. H. , Horton W. H. , Jensen K. B. , Palazzo A. J.
Published: April 2011

Experiments were conducted on four semiarid range sites to compare stand establishment, productivity, and persistence of several introduced perennial Triticeae grasses with that of their native counterparts. On Intermountain sites with severe water limitations (< 300 mm), native grasses were more difficult to establish, less productive, and less persistent than the introduced grasses. Stands of native grasses declined most rapidly under defoliation. At locations where moisture conditions were more favorable, particularly where more summer precipitation occurred, native Triticeae grasses established and persisted relatively well compared with the introduced entries. Although difficult to establish, stands of the rhizomatous native, western wheatgrass [Pascopyrum smithii (Rydb.) A. Löve] in creased during the seasons after establishment. Choice of plant materials to be used in range seeding programs should be based on objective criteria. To do otherwise will perpetuate degradation of soil resources, especially on sites that are dominated by weedy annual species such as cheatgrass (Bromus tectorum) and medusahead rye (Taeniatherum asperum). It is proposed that adapted introduced grasses be equally considered along with native grasses as a component of seed mixtures on environmentally harsh sites that have been burned, infested with competitive weedy species, or otherwise degraded. Key words: Grass breeding, revegetation, introduced grasses, Triticeae, cheatgrass, seedling vigor, plant persistence
Effects of photoperiod on the phenological development of redroot pigweed (Amaranthus retroflexus L.)
Authors: Huang Jian Zhong , Shrestha Anil , Tollenaar Matthijs , Deen William , Rahimian Hamid , Swanton Clarence J.
Published: April 2011

Mechanistic weed models focus on determining the outcome of weed and crop interference. An understanding of weed phenology is essential for simulation model development. Phenological development is a major factor determining the outcome of weed–crop competition. Growth cabinet studies were conducted to characterize the influence of photoperiod on the phenological development of redroot pigweed (Amaranthus retroflexus L.). Results indicated that redroot pigweed is a quantitative short-day species. Four development phases of redroot pigweed were described according to its response to photoperiod: (1) a juvenile phase of 1.1 d; (2) a photoperiod-sensitive inductive phase of 7.9 d; (3) a photoperiod-sensitive post-inductive phase of 39.9 d; and (4) a photoperiod-insensitive phase of 2.2 d. This information is useful for the development of mechanistic models and for comprehending the distribution and competitive ability of redroot pigweed with crops. The utilization of these results could help in predicting the phenological development of redroot pigweed. Key words: Phenology, mechanistic weed models, juvenile phase
The biology of Canadian weeds. 8. Sinapis arvensis. L. (updated)
Authors: Warwick Suzanne I. , Beckie Hugh J. , Thomas A. Gordon , McDonald Tracey
Published: April 2011

An updated review of biological information is provided for Sinapis arvensis L. Native to the Old World, the species is widely introduced and naturalized in temperate regions around the world. The species occurs in all the provinces, the Northwest Territories, and the Yukon. It is an important weed of field crops in the Canadian prairies. A strongly persistent seedbank, competitive annual growth habit and high fecundity all contribute to its weedy nature and ensure that it will be a continuing problem. Several cases of herbicide resistance have been documented for natural populations of S. arvensis in Canada, including biotypes resistant to: i) Group 2 herbicides, which inhibit acetolactate synthase (ALS), from Manitoba in 1992 and Alberta in 1993; ii) Group 4 herbicides or synthetic auxins from Manitoba in 1991; and iii) Group 5 herbicides, which inhibit photosynthesis at photosystem II, from Ontario in 1983. The species is a close relative of Brassica nigra (L.) Koch, black mustard, and is capable of limited genetic exchange with the Brassica crop species under laboratory hybridization conditions either by conventional crossing or with the aid of ovary/embryo recovery techniques. Key words: Wild mustard, Sinapis arvensis, weed biology, herbicide resistance, risk assessment
AC Parkhill barley
Authors: Ho K. M. , Choo T. M. , Martin R. A. , Rowsell J. , Guillemette L.
Published: April 2011

AC Parkhill is a two-row, spring feed barley (Hordeum vulgare L.) cultivar developed by the Eastern Canada Barley Breeding Group, Agriculture and Agri-Food Canada. It has high yield and resistance to powdery mildew. AC Parkhill is well adapted to Ontario. Key words: Barley, Hordeum vulgare L., two-row barley, yield
Response of three Brassica species to high temperature stress during reproductive growth
Authors: Angadi S. V. , Cutforth H. W. , Miller P. R. , McConkey B. G. , Entz M. H. , Brandt S. A. , Volkmar K. M.
Published: April 2011

The effect of short periods of high temperature stress on the reproductive development and yield of three Brassica species were studied in a growth chamber experiment conducted for 2 yr. Two genotypes from Brassica juncea L. and one each from B. napus L. and B. rapa L. were grown under day/night temperatures of 20/15 °C till early flowering or early pod development, subjected to high temperature stress of 28/15 °C or 35/15 °C for 7 d and then allowed to recover at 20/15 °C. Species differed in optimum temperatures, with B. juncea and B. rapa having higher optimum temperature than B. napus. Dry matter was unaffected by moderate temperature stress, while it was reduced by high temperature stress. The 35/15 °C treatment was injurious to reproductive organs at different developmental stages of all three species. High temperatures at flowering affected yield formation more than high temperature at pod development. On the main stem, mean seed yield reduction due to heat stress was 89%, but partial compensation by pods on the branches reduced mean per-plant seed yield decrease to 52%. Reduction in fertile pods (not total pod number), thousand seed weight and seeds per pod were responsible for the reduced seed yield. Brassica rapa was more sensitive to heat stress than B. napus and B. juncea. Although observation did not indicate the exact developmental phase when the reproductive organs were susceptible to heat stress, pods that passed a critical threshold developmental phase tolerated heat stress, which explained the smaller effect of high temperature stress at pod development. A direct temperature effect on reproductive organs appeared to be responsible for the reduction in yield. All genotypes began to recover from the stress by continuing flowering after returning to 20/15 °C. Brassica napus was least able to recover from severe stress at flowering, as evidenced by the formation of many abnormal pods during recovery. Per-plant yield response of canola-quality B. juncea line J90-4316 was similar to oriental mustard Cutlass. Thus, heat stress effect depends on the growth stage of canola and mustard and Brassica species differ in heat stress response. Key words: Brassica species, napus, rapa, juncea, heat stress, yield, pod number
Effects of root inoculation and fungicide soil drenches on sclerotinia blight of coneflower
Authors: Wang H. , Chang K. F. , Hwang S. F. , Turnbull G. D. , Howard R. J.
Published: April 2011

Greenhouse studies showed that root inoculation had significant effects on sclerotinia blight (Sclerotinia sclerotiorum) of coneflower (Echinacea sp.). Seedling wilt and root rot symptoms caused by S. sclerotiorum were most severe when inoculum was placed in direct contact with seedling roots, and diminished as the distance of the inoculum from the roots increased. When colonized agar disks, colonized oat grains and sclerotia as inoculum sources were evaluated on E. angustifolia, grain inoculum was the most virulent and sclerotia the least. An in vitro bioassay was conducted, and a logistic dose-response model was developed for the fungicides benomyl, vinclozolin, iprodione and dicloran. The first three fungicides were further evaluated in greenhouse experiments. Benomyl was the most effective in controlling S. sclerotiorum in both bioassay and greenhouse evaluations. The same three fungicides were evaluated in two field experiments in Alberta, where all were effective in reducing disease incidence. Key words: Echinacea sp., Sclerotinia sclerotiorum, dose-response model
Morphological and cytological characters associated with low-temperature tolerance in wheat (Triticum aestivum L. em Thell.)
Authors: Limin A. E. , Fowler D. B.
Published: April 2011

Attempts to associate morphological or cytological characters with low-temperature (LT) tolerance in wheat (Triticum aestivum L. em. Thell.) and other members of the Triticeae group have met with ambiguous or contradictory results. Consequently no single character has emerged that can be considered a reliable predictor of LT tolerance. Twenty-six winter wheat cultivars of diverse origin were analyzed to determine the association among leaf length, width, area and cell size (guard cell length) and their association with LT stress tolerance. Measurements were made on plants grown at 4 °C and at 17 °C to determine if expression of LT tolerance associated characters was temperature dependent. At 4 °C, all individual leaf characters measured, including cell size, were very highly correlated with LT tolerance and with each other. Undisturbed plant height was not significantly correlated with LT tolerance until 5 wk of growth at 4 °C and reached its highest correlation at 10 wk when the plants were on average at their most prostrate state of growth. Growth at 17 °C resulted in much weaker relationships among all characters. At 4 °C short narrow leaves and small cell size were the best indicators of LT stress tolerance. Prostrate growth habit of plants grown at LT was also a good indicator of plant LT tolerance, but measurements of this character did not improve prediction equations based on leaf characters and cell size. Key words: Low-temperature tolerance, plant morphology, cell size, leaf characteristics, Triticum aestivum
Rhizospheric P and K in forest soil manipulated with ammonium sulfate and water
Authors: Clegg Stephen , Gobran George R.
Published: April 2011

This study shows how the stress manipulations, ammonium sulfate, drought and irrigation changed the P and K status of three soil fractions (bulk soil, rhizosphere and soil-root interface) from E, Bh and Bs horizons of a Norway spruce stand in southwestern Sweden. The results indicate that dynamic linkages exist between the three soil fractions and tree growth. Accumulation rather than depletion of P and K were observed in the vicinity of the roots which we attribute primarily to accumulated organic matter and high rates of mineralization. Relative depletion of P and K around roots resulted from treatments that stimulated tree growth and P and K uptake. The ratio of organic P, the largest extractable P fraction, to inorganic P indicated that organic P is an important P resource when inorganic P is heavily utilized in treatments where growth has increased. There are indications that K supply was reduced by stimulating growth with ammonium sulfate and irrigation, suggesting that K rather than P can become the second limiting factor to growth at this site after N. Key words: Organic matter, available P and K, relative depletion, Norway spruce, ecosystem manipulation, conceptual model, environmental stress
The effects of diverse cropping systems on aggregation of a Luvisolic soil in the Peace River region
Authors: Broersma K. , Robertson J. A. , Chanasyk D. S.
Published: April 2011

Aggregate distribution and stability of surface soil were determined for different cropping systems of a Luvisolic soil in the Peace River region of Alberta. Gray Luvisolic soils have inherent problems that include weak platy structured surface horizons which are underlain by compact sub-soils. The cropping systems consisted of (i) continuous barley (CB) (Hordeum vulgare L.); (ii) barley/forage (BF), 3 yr of barley followed by 3 yr of forage (mixture of bromegrass [Bromus inermis Leyss] and red clover [Trifolium pratense L.]); (iii) continuous grass (CG) (bromegrass); and (iv) continuous legume (CL) (red clover). The barley/forage rotation consisted of two phases, the barley phase (BF) and forage phase (BF). Each phase was present every year. Aggregate separation by dry-sieving with a rotary sieve indicated that the CL cropping system had fewer large aggregates and more small aggregates than the other cropping systems. The CG, BF and CB cropping systems had more larger aggregates and were similar to each other. Wet-sieving, by contrast, resulted in the CG cropping system having greater amounts of large aggregates while the CL, BF phases, and CB cropping systems were similar with more smaller aggregates. Wet-sieving of the different aggregate size fractions from the rotary dry-sieve indicated that the cropping system aggregate stability was in the order of: CG > CL > BF ≥ BF ≥ CB. The stability of the BF cropping system was greater than that of the BF as it had recently come out of the BF phase (3 yr of forage production). Aggregate stability for the cropping system soils was consistent among the evaluation method of wet-sieving and the McCalla water-drop method. Inclusion of forage crops are important in maintaining or improving soil structure of Luvisolic surface horizons.

Key words: Luvisolic soil, cropping systems, aggregation, aggregate stability, Peace River region
Proceedings of the Quebec City Symposium on Greenhouse Gas Emissions from Soil Ecosystems
Authors: Simard Régis R. , Angers Denis A. , Bordeleau Lucien M. , N'dayegamiye Adrien
Published: April 2011

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