• Authors:
    • Felton, W.
    • Haigh, B.
  • Source: Update of research in progress at the Tamworth Agricultural Institute 2002
  • Year: 2003
  • Summary: Crop growth rate and weed competition were studied in New South Wales, Australia during 2002 using reflectance sensors. Seeds of wheat cv. Sunstate, chickpea cv. Howzat, faba bean cv. Fiord and rape cv. Oscar were sown at 40, 70, 100 and 3 kg/ha, respectively. Two reflectance sensors mounted on a small tractor were used to collect data across each plot every two weeks (45-129 days after sowing). Wheat recorded the greatest biomass, yield and water consumption, whereas chickpea recorded the highest harvest index and lowest water consumption. The rate of crop development was greatest in wheat and lowest in chickpea. The number of days required to produce 1000 kg/ha of shoot dry matter was 92, 100, 102 and 11 days after sowing for wheat, faba bean, rape and chickpea, respectively. Reflectance measurements were also used to evaluate the potential of wheat, triticale and barley as 'mimic weeds' against wild oat [ Avena fatua] in chickpea. Reflectance estimates were made at 51, 62, 84, 100 and 120 days after sowing. The 'mimic weeds' established faster than wild oat. The density of wild oat was lower than that of the mimic weeds, although none of the weeds achieved the target density of 81 weeds/m 2. The similar linear relationships with regard to the effects of weed biomass on crop yield for wild oat and 'mimic weeds' indicated that the latter can be used in weed studies instead of the actual weed. At low densities, wheat and barley were the most competitive. Triticale and wild oat exhibited similar competitive ability.
  • Authors:
    • Blackshaw, R. E.
    • Clayton, G. W.
    • Harker, K. N.
    • O'Donovan, J. T.
    • Stevenson, F. C.
  • Source: Canadian Journal of Plant Science
  • Volume: 83
  • Issue: 2
  • Year: 2003
  • Summary: Implementing a favourable agronomic practice often enhances canola production. Combining several optimal practices may further increase production, and, given greater crop health and competitiveness, could also improve weed control. A field experiment was conducted at Lacombe and Lethbridge, Alberta, from 1998 to 2000, to determine the optimal combination of glufosinate-tolerant cultivar (hybrid In Vigor 2153 or open-pollinated Exceed), crop seeding rate (100, 150, or 200 seeds m(-2)) and time of weed removal (two-, four-, or six-leaf stage of canola) for canola yield and weed suppression. At equal targeted seeding rates, the hybrid cultivar had greater seedling density (8 plants m(-2) higher) and seed yield (22% higher) when compared with the open-pollinated cultivar. Combining the better cultivar with the highest seeding rate, and the earliest time of weed removal led to a 41% yield increase compared with the combination of the weaker cultivar, the lowest seeding rate and the latest time of weed removal. The same optimal factor levels also favoured higher levels of weed control and lower weed biomass variability. Managing these factors at optimal levels may help increase net returns, reduce herbicide dependence and favour the adoption of more integrated weed management systems.
  • Authors:
    • Crawford, M.
    • Ransom, K.
    • Hirth, J.
    • Harris, R.
    • Naji, R.
  • Source: Solutions for a better environment: Proceedings of the 11th Australian Agronomy Conference, Geelong, Victoria, Australia, 2-6 February 2003
  • Year: 2003
  • Summary: Companion cropping (also known as intercropping) of lucerne involves sowing an annual crop into an existing lucerne stand. A sample of eight farmers from north central Victoria, Australia, who currently companion crop, were interviewed to document the impact of this practice on grain production, and to determine why and how they used this approach in their farming system. All eight farmers companion cropped lucerne to produce grain for either human or livestock consumption. Wheat, barley, oat and triticale were most commonly sown into lucerne stands, with rape less frequently companion cropped. Most companion-cropped stands of lucerne were either winter-active or highly winter-active cultivars and most had densities of 10-30 plants/m 2. They were commonly 9-12 months old, although some stands up to 10 years old were successfully companion cropped. Sowing rates of the annual crop were generally greater than those used in conventional monoculture cropping, and most farmers sowed diagonally across existing lucerne rows. Most interviewed farmers adopted companion cropping because of perceived better economic returns from cropping rather than grazing their second-year stands of lucerne, which then became more persistent and productive stands for future grazing. Farmers who companion cropped into mature stands aimed to maintain year-round plant transpiration to minimize the impact of their cropping practices on local groundwater systems, through a better hydrologic balance between the rainfall and their vegetation. Decreased grain yields from companion-cropped crops were common, and were estimated to be 10 to 80% of those obtained in the absence of lucerne. The magnitude of the yield decreases appeared to be most strongly influenced by seasonal conditions. The use of herbicides for in-crop lucerne suppression was perceived to enhance grain quality by slowing lucerne growth over the late winter-spring period, thereby reducing lucerne seed and herbage contamination at harvest. As seasonal and soil water conditions critically influenced the success of herbicide applications, specialist advice was often sought.
  • Authors:
    • UK, National Institute of Agricultural Botany (NIAB)
  • Source: Pocket guide to varieties of cereals, oilseeds & pulses for autumn 2003
  • Year: 2003
  • Summary: This edition presents information on the autumn sown varieties of wheat, barley, oats, triticale, rye, durum wheat, oilseed rape, linseed, peas and beans. Individual information on each variety is given, including variety notes, yield performance, relative ranking position in different environments and a summary of the important character ratings from the Recommended Lists.
  • Authors:
    • Fielding, D. J.
    • Begna, S. H.
  • Source: Journal of Economic Entomology
  • Volume: 96
  • Issue: 4
  • Year: 2003
  • Summary: We characterized the type and extent of grasshopper injury to above- and below-ground plant parts for four crops, i.e. barley ( Hordeum vulgare), oats ( Avena sativa), wheat ( Triticum aestivum), and canola [turnip rape] ( Brassica campestris [ B. campestris var. oleifera]), commonly grown, or with potential to grow, in central Alaska, USA. Cages were placed on 48 pots containing plants in second to third leaf stages and stocked with 0, 2, 4, and 6 first-instar Melanoplus sanguinipes pot -1. Plants were harvested 22 days after planting. Stem growth of barley and oats was not affected except at the highest grasshopper treatment. In rape, stem biomass was reduced at the medium and high grasshopper treatments, when most of the leaves had been consumed. The highest grasshopper treatment reduced leaf area in barley and oats by ~55%, and caused a significant reduction in dry weight of leaves, stems, and roots (41-72%). Wheat and canola plants were smaller than barley and oats across all treatments and, at the highest grasshopper density, above-ground portions of wheat and canola were completely destroyed. Length and surface area of roots of barley and oats were reduced by 20-28% again at the highest grasshopper density, whereas the reduction for wheat and canola ranged from 50 to 90%. There was little or no difference among all grasshopper densities for C:N ratio in leaf and stem tissues of all crops. The results suggest that wheat and canola are more susceptible than barley and oats and that densities ≥2 pot -1 (~≥50 m -2) of even very small grasshoppers could cause significant damage in small-grain and oilseed crop production.
  • Authors:
    • Azooz, R.
    • Soon, Y.
    • Arshad, M.
  • Source: Soil & Tillage Research
  • Volume: 65
  • Issue: 1
  • Year: 2002
  • Summary: In recent years, crop rotation and no-till farming have become common practices in Alberta, Canada, and are widely recommended to maintain and/or enhance soil quality for sustained crop production, and improve environmental quality. This study was undertaken to evaluate the effects of rape ( Brassica rapa [ B. napus var. oleifera]) and field pea ( Pisum sativum) as replacements for summer fallow on wheat ( Triticum aestivum) production, and to determine the role of tillage (no-till versus modified no-till) on crop production on an Albright silt loam (Mollic Cryoboralf) near Beaverlodge, Alta. Spring wheat was grown for 2 years of the 3-year cropping cycle. Crop sequences studied were: rape-wheat-wheat (RWW), field pea-wheat-wheat (PWW) and fallow-wheat-wheat (FWW). The control was continuous wheat, i.e. wheat-wheat-wheat or monoculture wheat (MW). In modified no-till, sweeps attached to the seed drill pushed crop residues aside from the centre 7.5 cm of the seed row. Wheat yield following field pea increased by an average (1997-99) of 10.5% compared to monoculture wheat. Our data showed no measurable effect of rape on succeeding wheat yields compared to monoculture wheat. Wheat yields following fallow were intermediate between the RWW and PWW cropping systems. Residue management through the modified no-till system resulted in a warmer seedbed during spring and improved wheat production in all crop rotations studied, especially the first succeeding wheat. Modified no-till also resulted in higher yields of rape but not pea. Our data indicate that in a 3-year rotation with wheat, the preferred break crop would be field pea for the cold semiarid region of Alberta.
  • Authors:
    • Riveland, N.
    • Lafond, G.
    • Nielsen, D.
    • Brandt, S.
    • Miller, P.
    • Tanaka, D.
    • Johnston, A.
  • Source: Agronomy Journal
  • Volume: 94
  • Issue: 2
  • Year: 2002
  • Summary: Oilseed crops are grown throughout the semiarid region of the northern Great Plains of North America for use as vegetable and industrial oils, spices and birdfeed. In a region dominated by winter and spring wheat ( Triticum aestivum), the acceptance and production of another crop requires that it both has an agronomic benefit to the cropping system and improve the farmers' economic position. In this review, we compare the adaptation and rotational effects of oilseed crops in the northern Great Plains. Rape ( Brassica sp. [ Brassica napus var. oleifera]), mustard ( B. juncea and Sinapis alba), and flax ( Linum usitatissimum) are well adapted to cool, short-season conditions found on the Canadian prairies and northern Great Plains border states of the USA. Sunflower ( Helianthus annuus) and safflower ( Carthamus tinctorius) are better adapted to the longer growing season and warmer temperatures found in the northern and central Great Plains states. Examples are presented of how agronomic practices have been used to manipulate a crop's fit into a local environment, as demonstrated with the early spring and dormant seeding management of rape, and of the role of no-till sowing systems in allowing the establishment of small-sown oilseed crops in semiarid regions. Continued evaluation of oilseed crops in rotation with cereals will further expand our understanding of how they can be used to strengthen the biological, economic and environmental role of the region's cropping systems. Specific research needs for each oilseed crop have been recommended.
  • Authors:
    • Lajeunesse, J.
    • Pageau, D.
    • Legere, A.
    • Simard, M.
    • Warwick, S.
  • Source: Weed Technology
  • Volume: 16
  • Issue: 2
  • Year: 2002
  • Summary: The presence of volunteer rape ( B. napus [ B. napus var. oleifera]) is becoming a significant agroecological concern, given the large-scale use of herbicide-tolerant varieties in some areas. Our goal was to estimate the frequency and persistence of volunteer rape in Quebec cropping systems by surveying fields that included a single rape crop since 1995 in Quebec, Canada. A survey was conducted in 131 fields in the main rape-growing areas of Quebec: in the Saguenay-Lac Saint-Jean region and the Quebec City-La Pocatiere area, Canada, during June-August 2000. Volunteer rape plants were counted in 0.25-m 2 quadrats every 10 m along a W pattern, and every 15 m along the margins of 88 fields. Volunteer rape plants were found in 90% of the fields surveyed and in a wide range of crops, including cereal, maize, and soyabean. Average densities of 4.9 and 3.9 plants/m 2 were found a year after rape production in fields and field margins, respectively. Volunteer rape densities decreased significantly over time. However, volunteer plants were still present at low densities 4 and 5 years after production. Dense stands of volunteer rape were found before postemergence herbicide application in no-till fields (9.84.1 plants/m 2), suggesting that, contrary to what was suggested in the literature, seeds could become dormant in no-till as well as in tilled systems. A small proportion of the volunteer rape plants observed in no-till fields near Quebec City and Ottawa included plants that had overwintered, either originating from autumn-germinated seedlings, harvested adult plants that had grown new leaves before the onset of winter, or spring regrowth from the base of unharvested adult plants from experimental plots. The presence and persistence of low densities of volunteer rape may not have been a cause of concern until now. However, producers should be made more aware of the potential short-term and long-term problems associated with potential gene flow between different herbicide-tolerant rape (HT rape) varieties and also between HT rape and related weed species.
  • Authors:
    • Ulrich, D.
    • Brandt, S. A.
    • Malhi, S. S.
    • Lemke, R.
    • Gill, K. S.
  • Source: Journal of Plant Nutrition
  • Volume: 25
  • Issue: 11
  • Year: 2002
  • Summary: Cropping systems can influence the accumulation and distribution of plant nutrients in the soil profile, which can affect their utilization efficiency by crops and pollution potential in the environment. A field experiment was conducted on a Dark Brown loam soil at Scott, Saskatchewan, Canada to assess the effects of input level, cropping diversity and crop phase on the accumulation and distribution of nitrate-nitrogen (N) and extractable phosphorus (P) in the soil profile at the end of 1995 to 2000 growing seasons. The 54 treatments were combinations of three input levels (organic-ORG, reduced-RED and high-HIGH), three cropping diversities (low diversity-LOW, diversified annual grains-DAG, and diversified annual and perennials-DAP), and six crop phases chosen from fallow (tillage-fallow or chemfallow), green manure [lentil-Lens culinaris Medicus or sweet clover-Melilotus officinalis (L.) Lam], spring wheat (Triticum aestivum L.), canola (Brassica napus L. and Brassica rapa L.), fall rye (Secale cereale L.), field pea (Pisum sativum L.), spring barley (Hordeum vulgare L.), flax (Linum usitatissimum L.), oats (Avena sativa L.), and bromegrass (Bromus inermis Leyss), alfalfa (Medicago sativa Leyss) mixture hay. Soil was sampled from the 0-15, 15-30, 30-60, and 60-90cm depths in each crop phase from 1995 to 2000, with additional depths 90-120, 120-150, 150-180, 180-210, and 210-240cm taken from the wheat phase in 2000. In general, there were greater amounts of nitrate-N with HIGH input compared to ORG or BID inputs, especially under LOW diversity. The nitrate-N in various soil depths suggested some downward movement of nitrate-N to the deeper soil depths when HIGH input was compared to ORG input. In LOW cropping diversity, green manure or fallow usually had more nitrate-N in soil than other crop phases. In DAG and DAP cropping diversities, nitrate-N varied with crops and on average it had maximum concentration after wheat or canola in DAG and after hay followed closely by wheat in DAP. The ORG input level had greater nitrate-N than RED or HIGH inputs in some instances, most likely due to relatively low extractable P in soil for optimum crop growth under ORG input. Extractable P in the 0-15 and 15-30 cm soil depths tended to be greater under HIGH or RED inputs compared to the ORG input level in many cases. In summary there was no consistent effect of cropping diversity on extractable P in soil under ORG input, but LOW diversity tended to show more extractable 13 compared to DAG and DAP diversities in some cases of RED and HIGH inputs. The green manure/fallow, HIGH input and LOW diversity treatments tended to result in higher nitrate-N and extractable P levels compared to the corresponding treatments, and the effects were more pronounced on nitrate-N than extractable P and in shallow compared to deeper soil layers.
  • Authors:
    • Chanasyk, D. S.
    • Mathison, M. N.
    • Naeth, M. A.
  • Source: Canadian Journal of Soil Science
  • Volume: 82
  • Issue: 2
  • Year: 2002
  • Summary: The longevity of deep ripping effects on Solonetzic soils was investigated at 11 field sites in east-central Alberta after a period of 15 to 20 yr. Select soil properties and crop yield of deep-ripped and non-ripped control plots were analyzed. Dryland yield data of wheat, barley, oats and canola were assessed for 10 of the 11 sites over a 16-yr time period. Select soil properties were analyzed once in 1998 with penetration resistance (PR) evaluated again in 1999. A significant difference in penetration resistance was found between the deep ripped versus control treatments ( P≤0.05). There were no significant treatment differences for soil texture, bulk density (Db), pH, electrical conductivity (EC) or sodium adsorption ratio (SAR). A significant yield difference between the deep ripping and control treatments (for all crop species) was found for 6 of 10 sites ( P≤0.10), with all sites having an increase in mean yield for the majority of years evaluated. Generally, sites in the drier ecoregions had smaller yield increases than those in the wetter ones. Hence some beneficial effects from deep ripping remain for a long time period.