Wntcur, A. T. 1990. Yield effect of pulses on subsequent cereal crops in the nofthern prairies. Can. J. Plant Sci. 70: 1023-1032. A study comparing the crop sequences pulse-barley-wheat and barley-barley-wheat, was conducted from 1982

. 1996. Seeding rate and row spacing affect flax yields and weed interference. Can' J. Plant Sci. 76: 537_544. Seedin!rate and row spacing aie management practices that affect flax seed yield. Two experiments were conducted from lggg to 1990 to determine the influence offlix seeding rates (300, 600, and 900 seeds m-2) and row spacings (9, 18, and 27 cm). One was a flax-weed inrerference study (three-sites) and the other was a weed-free study (13 sites

No abstract

A snow management system, which utilizes no‐till seeding into standing stubble immediately after harvest of the previous crop, has permitted the expansion of winter wheat (Triticum aestivum L.) production in western Canada. The effect of seed rate and row spacing on grain yield and yield components of no‐till winter wheat were evaluated in 21 trials conducted in Saskatchewan from 1986 to 1988. Two winter wheat cultivars were evaluated in eight of the trials. The relationship between grain yield (Y) and seed rate was best described by a modified inverse polynomial: Y = uSR(1‐SR/566)/(SR + u/104) where u represents the upper limit of yield when seed rate is not limiting. This curve accounted for 98% of the observed variation in grain yield. Optimum seed rate varied from 58 kg ha−1 at a very dry trial to 148 kg ha−1 in a trial with more favorable growing conditions. Grain yield increased as row spacing decreased and the effect of row spacing on pain yield was increased under more favorable growing conditions. Increased seed rate and decreased row spacing interacted positively to increase grain yield so optimum seed rate increased as row spacing decreased. Increased spikes per square meter was responsible for the increase in grain yield associated with high seed rate and narrow row spacing. In contrast, kernel weights were slightly higher with low seed rate and kernels per spike were higher with low seed rate and wide row spacing. Optimum seed rate was higher for the cultivar ‘Norstar’ than for ‘Norwin’ due to higher yield potential of Norstar under the conditions experienced in this study.

Management practices are required in rainfed agriculture of western Canada to reduce early season water evaporation from soil relative to loss by transpiraition. The objective of this study was to measure the effect of two seed rates and two row spacings on the pattern of water use and writer use efficiency (WUE) of no‐till winter wheat (Triticum aestivum L.). Nine field trials were conducted on Udic Haploboroll and Molllic Cryoboralf soils in Saskatchewan from 1987 to 1989. Higher dry matter production and more rapid early season plant ground cover associated with the 9 cm row spacing and 140 kg ha−1 seeding rate, compared to other row spacing‐seeding rate combinations reduced water loss from evaporation and increased the partitioning of evapotranspiration to transpiration during the pre‐anthesis growth period. Pre‐anthesis water use was 11% higher, post‐anthesis wateir use 6% lower, and growing season water use 4% higher for the 140 compared to the 35 kg ha−1 seeding rate, The 140 kg ha−1 seeding rate produced 40% more preanthesis dry matter than the 35 kg ha−1 rate, thus establishing a higher yield potential for the crop. A row spacing of 9 compared to the 36 cm resulted in water use that was 6% higher during the pre‐anthesis, growth period and 3% higher during the entire growing season. The combination of 140 kg ha−1 seeding rate and 9 cm row spacing ultimately produced a 21% higher grain yield and a 9 kg cm‐−1 higher WUE than the combination of 35 kg ha−1 seeding rate and 36 cm row spacing. Grain protein concentration increased from 13.1% with the 35 kg ha−1 seeding rate to 13.9% with the 140 kg ha−1 seeding rate. Grain protein yield increased from 198 to 227 kg ha−1 for the 35 compared to the 140 kg ha−1 seeding rate. The increase in grain protein concentration and yield associated with 140 kg ha−1 seeding rate was related to the pattern of water use by the crop. Even under conditions of high dronght stress, a larger number of more uniformly distributed plants associated with seeding rates higher than 35 kg ha−1 and row spacings narrower than 36 cm resulted in a higher WUE and a water use pattern that produced larger yields and higher grain protein concentration.