Aspects of intensive management practices such as high N fertilization inputs and plant growth regulator use could potentially increase cereal yields in regions with a short crop‐growing season and occasionally dry and hot weather. A field experiment was carried out for four years (1987 to 1990) at Agronomy Research Centre of McGill University, Canada to evaluate the response of spring barley (Hordeum vulgare L.) cv. Cadette, Laurier and Leger to N rates (0, 70 and 140 kg N ha−1) and ethephon (2‐chloroethyl phosphonic acid) growth regulator treatment. The application of higher than conventional N level (70 kg N ha−1) did not increase barley yields under dry weather conditions and when the soil N resources were high. The high levels of N did increase the grain crude protein concentration by 2 to 10 g kg−1, as did ethephon treatment. The feed quality of spring barley was improved. Ethephon treatment reduced grain yield due to a severe reduction in the number of grains spike−1, and/or 1000‐grain weight, although the number of spikes m−2 was increased. Thus, the overall effect of ethephon treatment on yield was inconsistent and was influenced to a large extent by the prevailing weather conditions.

(1987)(1988)(1989)(1990)

Aspects of intensive management practices such as high‐yielding cultivars, narrow‐row spacings and fungicide treatments could potentially increase cereal yields in regions with a short crop‐growing season and occasionally dry and hot weather. A field experiment was carried out at McGill University, Canada for three years (1987 to 1989) to test the effects of triadimefon (1‐[4‐chlorophenoxy]‐3,3‐dimethyl‐1‐[1H‐1,2,4‐triazol‐1‐yl]‐2‐butanone, or Bayleton, a trade name) fungicide (0 vs. 140 g a.i. ha−1) and row spacing (10 vs. 20 cm) on the yield components, yield and other agronomic traits (spike emergence, days to maturity, leaf disease and plant height) of spring barley (Hordeum vulgare L.) cv. Cadette, Laurier and Leger. A cultivar by row spacing interaction resulted in a 11 to 13.5 % increase in grain yield due to narrow rows for Laurier in two out of the three years and up to 16 % for Leger in one year. Over the three years grain yields were on average increased 6 to 12 % due to use of the narrower row spacing. Fungicide application to barley at the early heading stage effectively controlled leaf diseases without influence on yield components or grain yield. Our results indicate that some components of intensive management such as narrow row spacing can be applicable in regions with a short crop‐growing season.