• Authors:
    • Ma, B.
    • Strachan, I.
    • Zhou, X.
    • Mabood, F.
    • Almaraz, J.
    • Smith, D.
  • Source: Journal of Agronomy and Crop Science
  • Volume: 195
  • Issue: 5
  • Year: 2009
  • Summary: Climate change will alter temperature and rainfall patterns over North American agricultural regions and there will be a need to adapt crop production systems to the altered conditions. A set of field experiments were conducted in south-western Quebec, Canada, with soybean ( Glycine max L.), corn ( Zea mays L.), sorghum ( Sorghum bicolor L.) * sudangrass ( Sorghum sudanense Piper) hybrid and switchgrass ( Panicum virgatum L.) under two tillage and three nitrogen fertility regimes, to study their performance in three successive growing seasons (2001-2003), two of them with unusually warm and dry conditions. The annual crops were established in two tillage systems: conventional and no-till (NT). All crops except soybean were fertilized with three levels of nitrogen: corn - 0, 90 and 180 kg N ha -1, sorghum-sudangrass - 0, 75 and 150 kg N ha -1, switchgrass - 0, 30 and 60 kg N ha -1. The 2001 and 2002 seasons were hotter and drier than the 2003 season, which was the most favourable for crop growth. The capacity of the crops to yield in dry seasons was as follow: switchgrass > sorghum-sudangrass > corn > soybean. The corn and sorghum-sudangrass responses to nitrogen fertilizer were low in 2001 due to the combined effect of dry growing season and coarse soil texture. Soybean did not perform well under NT. Corn yielded better at the highest nitrogen fertilizer rate under NT when the early season was warmer than the normal. Our results show that switchgrass and sorghum-sudangrass could be an option in south-western Quebec if the frequency of hot and dry seasons increase in the future, because of climate change.
  • Authors:
    • Darbyshire, S.
    • Clements, D.
    • DiTommaso, A.
    • Dauer, J.
  • Source: Canadian Journal of Plant Science
  • Volume: 89
  • Issue: 5
  • Year: 2009
  • Summary: Hemp dogbane, Apocynum cannabinum (Apocynaceae), is a perennial herb with white to greenish flowers in terminal clusters that produces pencil-like pods 12-20 cm long. A highly variable plant, A. cannabinum may be distinguished from spreading dogbane ( Apocynum androsaemifolium) by its shorter corolla (2-6 mm compared with 5-10 mm), erect greenish-white petals (compared with recurved or spreading pinkish petals), seeds more than 3 mm long (compared with seeds less than 3 mm), and more erect leaves (compared with spreading or drooping leaves), although frequent hybridization between the two species obscures the identity of some individuals. Hemp dogbane is native to the United States and southern Canada, but most abundant in the upper Mississippi River Valley and east to the Atlantic coast. It has been increasing in other areas, and becoming more of a problem where conservation tillage is adopted. It infests crops such as corn ( Zea mays), soybeans ( Glycine max), wheat ( Triticum aestivum), sorghum ( Sorghum bicolor) and forages, and may cause livestock poisoning due to cardiac glycosides within its milky sap (but livestock generally avoid it). Potential medicinal uses of these compounds have been investigated, and the roots are a source of fibre. Control of A. cannabinum with various herbicides is difficult due to a thick cuticle, and one solution may be to target susceptible stages, such as seedlings or early spring growth. Cultivation may also control A. cannabinum, but care must be taken not to promote the proliferation of the plant through regrowth from fragmented roots and rhizomes. Rotation with alfalfa also reduces populations of A. cannabinum.
  • Authors:
    • Walker, A. M.
    • McKinnon, J. J.
  • Source: Canadian Journal of Animal Science
  • Volume: 89
  • Issue: 3
  • Year: 2009
  • Summary: McKinnon, J. J. and Walker, A. M. 2009. Comparison of canola and mustard presscake from biodiesel production as protein sources for growing cattle. Can. J. Anim. Sci. 89: 401-408. Two studies were conducted to examine in situ rumen degradation kinetics of biodiesel presscake from canola (CPC) (Brassica napa) and mustard (MPC) (Brassica hirta) relative to regular canola meal (CM) and to compare the performance of cattle fed these meals as protein supplements in backgrounding diets. In the in situ trial CPC and MPC had similar (P > 0.05) rates of DM, CP, fibre and crude fat disappearance relative to canola meal. However, CPC and MPC exhibited greater (P 0.05) in effective degradability of crude fat were observed. The feedlot trial involved 391 steers (323 +/- 24 kg) that were fed one of three experimental diets: a control diet consisting of barley silage (213 g kg(-1)) oat hulls (306 g kg(-1)), chopped straw (63 g kg(-1)), rolled barley (255 g kg(-1)) and CM (101 g kg(-1)), ora diet containing either CPC or MPC in place of CM as the protein supplement. Backgrounding performance was unaffected by treatment as no differences in DMI (P = 0.127), ADG (P = 0.679) or feed:gain (P = 0.792) were observed. Composition of gain estimated by ultrasound measurement of longissimus dorsi area and subcutaneous fat depth was unaffected by dietary treatment. It is concluded that biodiesel presscake from both canola and mustard seed provides a superior source of rumen degradable nutrients relative to CM and can be used as a protein supplement for growing cattle without any adverse affects on performance at levels up to 10% of the diet DM.
  • Authors:
    • Deen, W.
    • Earl, H.
    • Queen, A.
  • Source: Agronomy Journal
  • Volume: 101
  • Issue: 6
  • Year: 2009
  • Summary: Red clover (Trifolium pratense L.) use as an underseeded cover crop in winter cereals has declined due to inability of growers to consistently establish uniform stands. The objective of this study was to assess the effect of light and soil moisture competition on underseeded red clover establishment and end of season dry matter production. Field trials were conducted at multiple locations in 2005 and 2006 in Ontario, Canada. Wheat (Triticum aestivum L.) N rate (67 and 135 kg N ha(-1)) and row thinning treatments (19-cm rows, every third 19-cm row removed at the 4-5 leaf stage) were used to alter light penetration and soil moisture competition. The high N rate and row thinning treatments consistently reduced light penetration, beginning as early as wheat stem elongation initiation, but had no effect on soil gravimetric moisture content. Soil moisture was primarily affected by location and year. Red clover dry weight in 2005, a relatively dry year, ranged from 688 to 1184 kg ha(-1), and in 2006, a relatively wet year, ranged from 2336 to 2805 kg ha(-1). Average final red clover stand count was 23 plants m(-2) in 2005 and 55 plants m(-2) in 2006. In 2005, plant mortality occurred before wheat anthesis. In both years, and at most locations, red clover final dry weight was positively correlated with light penetration, again beginning as early as initiation of wheat stem elongation. Final red clover dry weight in both years and red clover stand count in 2005 were correlated with soil gravimetric water content during wheat anthesis, but this was primarily due to location and year effects. Although both light penetration through the wheat canopy and soil moisture influence biomass production of underseeded red Clover, soil moisture has the greater influence and is altered very little by wheat management.
  • Authors:
    • Christensen, D. A.
    • McKinnon, J. J.
    • Gozho, G. N.
    • Racz, V.
    • Mutsvangwa, T.
  • Source: Journal of Animal Science
  • Volume: 87
  • Issue: 10
  • Year: 2009
  • Summary: Ruminal fermentation, nutrient digestion, and flows to the duodenum in growing cattle fed differently produced canola protein supplements were studied in a 4 x 4 Latin square design using Speckle Park heifers (initial BW = 451 +/- 26 kg). Canola protein supplement treatments consisted of the following: 1) 8.78% regular canola meal (RCM); 2) 9.25% RCM plus 1.80% canola oil (RCMO); 3) 11.1% canola press-cake from biodiesel oil extraction (CPC); and 4) 8.14% high ruminally undegradable protein (RUP) canola meal (RUCM) plus 1.32% canola oil (RUCMO). Experimental diets also contained 39.9, 40.2, 39.9, and 39.9% barley grain; 31.7, 31.4, 31.2, and 31.4% barley silage; and 17.5, 15.2, 15.6, and 16.5% oat hulls for the RCM, RCMO, CPC, and RUCMO diets, respectively. Feeding the CPC, RCMO, and RUCMO diets decreased (P
  • Authors:
    • Swanton, C. J.
    • Tardif, F.
    • Hamill, A. S.
    • Sikkema, P. H.
    • Gulden, R. H.
  • Source: Weed Science
  • Volume: 57
  • Issue: 6
  • Year: 2009
  • Summary: Glyphosate-resistant (GR) crops have been adopted rapidly since their commercial introduction, and with the increase in commercially available crops resistant to glyphosate, continuous use of the same herbicide mode of action is now possible in some crop rotations. A 6-yr study was initiated to investigate the effects of conventional herbicides compared with continuous use of gyphosate in GR or Roundup Ready corn and GR soybean in a corn-soybean and a corn-soybean-winter wheat rotation. Individual experiments were fully phased and established at three locations under conventional tillage (CT) and at two locations under no-tillage (NT). Results indicated that midseason weed ground cover was lower when weeds were controlled with glyphosate; however, in most cases, this did not result in improved corn or soybean yields. Within locations, species richness, which strongly influenced other diversity indicators, was most affected by the herbicide treatments. Including winter wheat in the crop rotation had little effect on corn and soybean weed ground cover, density, and community structure and only affected soybean yield. Moreover, no effects of herbicide system used in previous corn and soybean were observed in winter wheat, with the exception of species diversity in NT, where species diversity tended to be greater when weeds in previous corn and soybean were treated with conventional herbicides. After 6 yr, the effects of continuous use of GR crops in rotation were similar to those reported in previous Studies; however, continued monitoring and longer-term investigations of these systems are necessary to detect the early stages of development of herbicide-resistant biotypes.
  • Authors:
    • Clayton, G. W.
    • Turkington, T. K.
    • Irvine, R. B.
    • O'Donovan, J. T.
    • Harker, K. N.
  • Source: Weed Science
  • Volume: 57
  • Issue: 3
  • Year: 2009
  • Summary: Wild oat causes more crop yield losses and accounts for more herbicide expenditures than any other weed species on the Canadian Prairies. A Study was conducted from 2001 to 2005 at four Canadian Prairie locations to determine the influence of repeated cultural and herbicidal management practices on wild oat Population density, biomass, and seed production, and on barley biomass and seed yield. Short or tall cultivars of barley were combined with normal or double barley seeding rates in continuous barley or a barley-canola-barley-field-pea rotation under three herbicide rate regimes. The same herbicide rate regime was applied to the same plots in all crops each year. In barley, cultivar type and seeding rate were also repeated on the same plots year after year. Optimal Cultural practices (tall cultivars, double seeding rates, and crop rotation) reduced wild oat emergence, biomass, and seed production, and increased barley biomass and seed yield, especially at low herbicide rates. Wild oat seed production at the quarter herbicide rate was reduced by 91, 95, and 97% in 2001, 2003, and 2005, respectively, when call barley cultivars at double seeding rates were rotated with canola and field pea (high management) compared to short barley cultivars at normal seeding rates Continuously planted to barley (low management). Combinations of favorable cultural practices interacted synergistically to reduce wild oat emergence, biomass and seed production, and to increase barley yield. For example, at the quarter herbicide rate, wild oat biomass was reduced 2- to 3-, 6- to 7-, or 19-fold when optimal single, double, or triple treatments were combined, respectively. Barley yield reductions in the low-management scenario were somewhat compensated for by full herbicide rates. However, high management at low herbicide rates often produced more barley than low management in higher herbicide rate regimes.
  • Authors:
    • Tabil, L. G.
    • Adapa, P. K.
    • Schoenau, G. J.
  • Source: Agricultural Engineering International: the CIGR Ejournal
  • Volume: 11
  • Year: 2009
  • Summary: Agricultural biomass such as barley, rape, oat and wheat straw has the potential to be used as feedstock for bioenergy. However, the low bulk density straw must be processed and densified in order to facilitate handling, storage and transportation. It is important to understand the fundamental mechanism of the biomass compression process, which is required in the design of energy efficient compaction equipment to mitigate the cost of pre-processing and transportation of the product. Therefore, a comprehensive review of various compression models was performed and the compression behaviour of selected ground agricultural biomass was studied. Five compression models were considered to determine the pressure-volume and pressure-density relationship to analyse the compression characteristics of biomass samples, namely Jones (1960), Heckle (1961), Cooper-Eaton (1962), Kawakita-Ludde (1971) and Panelli-Filho (2001) models. Densification studies were conducted on four selected biomass samples at 10% moisture content and 1.98 mm grind size using four pressure levels of 31.6, 63.2, 94.7 and 138.9 MPa. The mean densities of barley, rape, oat and wheat straw increased from 907 to 977 kg/m 3, 823 to 1003 kg/m 3, 849 to 1011 kg/m 3 and 813 to 924 kg/m 3, respectively. The Kawakita-Ludde model provided an excellent fit having R 2 values of 0.99 for selected agricultural straw samples. It was also concluded that the ground oat and rape straw had the highest level of porosity and failure stress, respectively. The parameters of Cooper-Eaton model indicated that the ground straw samples were densified easily by the particles rearrangement method and Jones model indicated that canola and oat straw were more compressible as compared to barley and wheat straw.
  • Authors:
    • Schoenau, G.
    • Tabil, L.
    • Adapa, P.
  • Source: Biosystems Engineering
  • Volume: 104
  • Issue: 3
  • Year: 2009
  • Summary: Agricultural biomass has the potential to be used as feedstock for biofuel production. However, crop residue after harvest must be gathered, processed and densified in order to facilitate efficient handling, transportation and usage. in this study compacts were prepared by densifying material against a base plate (representing the specific energy required to overcome friction within the straw grinds) as opposed to the process that occurs in a commercial operation where compacts are formed due to back-pressure effect in the die. Densification was measured using four selected biomass samples (barley, canola (oilseed rape), oat and wheat straw) at 10% moisture content (wb) and 1.98 mm grinder screen size using a compaction apparatus which applied four pressure levels of 31.6, 63.2, 94.7 and 138.9 MPa. The specific energy required to extrude the compact was measured; this will closely emulate the specific energy required to overcome the friction between the ground straw and die. The mean densities of barley, canola, oat and wheat straw compacts ranged from 907 +/- 31 to 988 +/- 26 kg m(-3), 823 +/- 73 to 1003 +/- 21 kg m(-3), 849 +/- 22 to 1011 +/- 54 kg m(-3) and 813 +/- 55 to 924 +/- 23 kg m(-3), respectively; while the mean total specific energy for compaction of grinds ranged from 3.69 +/- 0.28 to 9.29 +/- 0.39 MJ t(-1), 3.31 +/- 0.82 to 9.44 +/- 0.33 MJ t(-1), 5.25 +/- 0.42 to 9.57 +/- 0.83 MJ t(-1) and 3.59 +/- 0.44 to 7.16 +/- 0.40 MJ t(-1), respectively. Best predictor equations having highest coefficient of determination values (R(2)) and standard error of estimate or root mean square error were determined for both compact density and total specific energy required to compress the ground straw samples. The resulting R 2 for pellet density from barley, canola, oat and wheat straw were 0.56, 0.79, 0.67 and 0.62, respectively, and for total specific energy the values of R 2 were 0.94, 0.96, 0.90 and 0.92, respectively. (C) 2009 IAgrE. Published by Elsevier Ltd. All rights reserved.
  • Authors:
    • Shirriff, S.
    • Lozinski, C.
    • Holzgang, G.
    • Hall, L.
    • Brenzil, C.
    • Thomas, A.
    • Leeson, J.
    • Beckie, H.
  • Source: Weed Technology
  • Volume: 22
  • Issue: 3
  • Year: 2008
  • Summary: Weed resistance monitoring has been routinely conducted in the Northern Great Plains of Canada (Prairies) since the mid-1990s. Most recently, random surveys were conducted in Alberta in 2001, Manitoba in 2002, and Saskatchewan in 2003 totaling nearly 800 fields. In addition, nearly 1,300 weed seed samples were submitted by growers across the Prairies between 1996 and 2006 for resistance testing. Collected or submitted samples were screened for group 1 [acetyl-CoA carboxylase (ACCase) inhibitor] and/or group 2 [acetolactate synthase (ALS) inhibitor] resistance. Twenty percent of 565 sampled fields had an herbicide-resistant (HR) wild oat biotype. Most populations exhibited broad cross-resistance across various classes of group 1 or group 2 herbicides. In Manitoba, 22% of 59 fields had group 1-HR green foxtail. Group 2-HR biotypes of kochia were documented in Saskatchewan, common chickweed and spiny sowthistle in Alberta, and green foxtail and redroot pigweed in Manitoba. Across the Prairies, HR weeds are estimated to occur in fields covering an area of nearly 5 million ha. Of 1,067 wild oat seed samples submitted by growers and industry for testing between 1996 and 2006, 725 were group 1 HR, 34 group 2 HR, and 55 groups 1 and 2 HR. Of 80 submitted green foxtail samples, 26 were confirmed group 1 HR; most populations originated from southern Manitoba where the weed is most abundant. Similar to the field surveys, various group 2-HR biotypes were confirmed among submitted samples: kochia, wild mustard, field pennycress, Galium spp., common chickweed, and common hempnettle. Information from grower questionnaires indicates patterns of herbicide usage are related to location, changing with cropping system. Two herbicide modes of action most prone to select resistance, groups 1 and 2, continue to be widely and repeatedly used. There is little evidence that growers are aware of the level of resistance within their fields, but a majority have adopted herbicide rotations to proactively or reactively manage HR weeds.