[255][256][257][258][259][260][261][262][263][264][265][266]. New canola cultivars have much higher yield potential than conventional canola cultivars and changes in production practices may be needed to achieve optimum yield from these cultivars. Studies were conducted to investigate the influence of seeding rates (2.8, 5.6 and 8.4 kg ha -1 ), fertilizer level (67% -low, 100% -medium, 133% -high of the commercial recommendation) and fungicide application on growth, dry matter accumulation, seed yield and seed quality using two high-yielding canola cultivars [cv. Quantum, open pollinated (OP), and cv. Invigor TM , hybrid (HYB)]. The studies were conducted from 1999 to 2001 at three sites in the Parkland region of the Canadian prairies. The two cultivars did not differ in their responses to seeding and fertilizer rates, or fungicide application. Plant density was lower for the HYB than the OP because the HYB had larger seeds, with fewer seeds per kilogram. Emergence declined slightly at high fertilizer levels in some site-years due to fertilizer induced seedling damage, but increased with seeding rate. Time to onset of flowering and maturity showed no consistent influence of cultivar, and tended to be somewhat prolonged with an increase in fertilizer levels, but reduced by an increase in seeding rate. On average, the HYB produced 822 kg ha -1 more biomass and 200 kg ha -1 more seed yield than the OP. Sclerotinia stem rot incidence was very low, except at Melfort in 2000, and fungicide application generally failed to benefit the crop. Seed yield was generally increased when seeding rate was increased, with the largest increase occurring from 2.8 to 5.8 kg ha -1 . Seed yield responses to the high rates of seeding or fertilizer only occurred where both inputs were at the highest level, indicating that the optimum level of one was dependent upon the level of the other input. Oil and protein concentration in the seed was higher for the HYB than the OP. High fertilizer levels generally increased the total yield of biomass and seed, and protein concentration in the seed, but usually reduced oil concentration in the seed. Increased seeding rate resulted in a small increase in oil concentration and a small reduction in protein concentration in the seed. Net returns were greatest and least variable for the HYB cultivar. Overall, the HYB performed better than the OP, and the full economic value of high-yielding canola cultivars was only realized when fertilizer and seeding rates were at or above the current recommended rates. . Les recherches se sont déroulées de 1999 à 2001, à trois endroits, dans la région des prairies-parcs des Prairies canadiennes. Les deux cultivars ont réagi de la même manière à la densité des semis, au taux de fertilisation et à l'usage du fongicide. Le cultivar PL a donné un peuplement plus dense que la variété HYB, les semences de ce dernier étant plus grosses, donc moins nombreuses par kilo. La levée a légèrement diminué aux taux de fertilisation les plus élevés à certains sites-années, l'engrai...

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, S. V. 2002. Yield and water use efficiency of pulses seeded directly into standing stubble in the semiarid Canadian prairie. Can. J. Plant Sci. 82: 681-686. In semiarid climates, appropriate management of the previous crop stubble in combination with seeding method is important to improve growing conditions for the subsequent crop. To determine the effects of standing stubble of various heights on the microclimate and on the growth and yield of pulse crops, we seeded desi chickpea (Cicer arietinum L. 'Cheston'), field pea (Pisum sativum L. 'Grande'), and lentil (Lens culinaris L. 'Laird') directly into cultivated, short (15 to 18 cm), and tall (25 to 36 cm) spring wheat (Triticum aestivum L.) stubble. Standing stubble changed the microclimate near the soil surface by reducing soil temperatures, solar radiation, wind speed, and potential evapotranspiration throughout the life cycle of these crops. Microclimate effects were much more pronounced for tall versus short stubble. The three pulses responded similarly to increasing stubble height. Vine length increased as stubble height increased, but the plants did not stand more erect. However, there was a tendency for plant height to increase as stubble height increased. Tall and short stubble increased the overall average grain yield by 13 and 4% compared to cultivated stubble. Crop water use was not affected by stubble height so the increased grain production was due to increased water use efficiency. Tall and short stubble increased the overall average water use efficiency by 16 and 8% compared to cultivated stubble. En climat semi-aride, il importe d'exploiter le chaume de la culture antérieure avec la méthode de semis appropriée si l'on veut améliorer les conditions de croissance de la culture subséquente. Afin d'établir l'incidence de la hauteur du chaume sur le microclimat ainsi que sur la croissance et le rendement des légumineuses à graines, les auteurs ont semé du pois chiche (Cicer arietinum L. 'Cheston'), du pois de grande culture (Pisum sativum L. 'Grande') et de la lentille (Lens culinaris L. 'Laird') directement sur un sol labouré ou couvert de chaume de blé de printemps (Triticum aestivum L.) court (15 à 18 cm) ou élevé (25 à 36 cm). Le chaume modifie le microclimat au ras du sol en réduisant la température du sol, le rayonnement solaire, la vitesse du vent et le potentiel d'évapotranspiration durant la vie des plantes. Les répercussions sur le microclimat sont beaucoup plus prononcées avec le chaume élevé que le chaume court. Les trois légumineuses réagissent de la même façon à la hauteur du chaume. Les vignes sont plus longues quand le chaume est plus haut, mais les plants ne sont pas plus dressés. La hauteur de la plante a néanmoins tendance à augmenter avec celle du chaume. Le chaume court ou élevé accroît le rendement grainier moyen de 13 % et de 4 % comparativement à celui obtenu sur le sol retourné. La hauteur du chaume ne modifie pas la quantité d'eau absorbée, de sorte que le relèvement de la production résulte d'une utilisation plus efficac...

. 2008. Adaptation of alternative pulse and oilseed crops to the semiarid Canadian Prairie: Seed yield and water use efficiency. Can. J. Plant Sci. 88: 425Á438. Diversification and intensification of the cropping systems in the traditional wheat-fallow area of the semiarid Canadian prairie is necessary to improve sustainability. Selection of alternate crops to include in cropping systems requires information on production risks with different climate regimes. To understand water use/yield relationships of alternate crops, three pulse crops (leguminous grain crops) [chickpea (Cicer arietinum L.), pea (Pisum sativum L.) and lentil (Lens culinaris Medik.)], three oilseed crops [canola (Brassica napus L. and B. rapa L.) and mustard (B. juncea L.)], and one cereal crop [wheat (Triticum aestivum L.)] were studied under varying water regimes: during 1996Á1998 under well-watered, rainfed, imposed drought conditions, and in 2001 under rainfed conditions. Generally, the relative ranking between crops for water use was maintained across water regimes, such that the crops separated into three general groups of water users (high: wheat, B. napus, mustard; medium: chickpea, B. rapa, lentil; low: pea) with pea using an average of 34 mm and 13 mm less water than high-and medium-water-using crop groups, respectively. The exceptions included desi chickpea, which tended to use less water and B. rapa, which tended to use more water relative to the other crops as water use decreased. Generally, pea and wheat produced the most grain and biomass, had the highest water use efficiency, and had moderately high to high harvest indices. Wheat and pea are well adapted to variable rainfall amounts inherent in semiarid climates. Desi chickpea and lentil produce good grain yields under dry conditions, and grain yields relative to those of other crops can be increased by some drought stress, especially mid-to lateseason stress. Therefore, because of their relatively good performance under water-stressed conditions, they are also well adapted to semiarid climates. Conversely, the Brassica oilseeds yielded relatively poorly compared with wheat and pulse crops under severe water-stressed conditions, so they are not as well adapted to the semiarid climate. In 2001, grain yield of wheat and pulses seeded on stubble was ]30% of the yield on fallow, whereas stubble-seeded Brassica oilseeds yielded only about 10% of that on fallow. Compared with stubble seeding, production of Brassica oilseeds on fallow will decrease the risk of very low yields under drought. We found little indication that mustard was more drought tolerant than B. napus.

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