Timing and Level of Nitrogen Fertility Effects on Spring Wheat Yield in Eastern Canada

Bread wheat (Triticum aestivum L.) produced in areas of higher rainfall, such as eastern Canada, are often low in protein. Our objective was to determine if N management could be used as a way to produce bread quality wheat in eastern Canada. An experiment was conducted for 2 yr at two Quebec sites. The effects of N fertilizer level and timing on grain yield, yield components, and lodging level of four hard red spring wheat cultivars with breadmaking potential were investigated. The soil type was Ste-Rosalie clay (fine, non-acid, frigid, typic Humaquept). The experiment was a four (cultivars) × four (N level) × two (N timing) factorial. Cultivars were Columbus, Katepwa, Max, and Hege 155-85. In both years, 0, 60, 120, and 180 kg N ha⁻¹ were applied at seeding or 60% at seeding and 40% at anthesis. Hege 155-85 had the highest gram yield, responded most to N fertilizer addition, and was the most resistant to lodging. Differences in N management effects and cultivar responses were observed among the four site-years. Grain yield, plant height, lodging, tillers per square meter, spikes per square meter and kernels per spike increased with increasing N fertility. When compared with application of all the fertilizer N at seeding, split application of N fertilizer (60% at seeding, 40% at heading) had little effect on yield (no effect at three site-years, small reduction at the fourth), reduced the risk of lodging at one site, caused a reduction in the number of tillers per square meter and spikes per square meter at one site-year, caused an increase in 1000-kernel weight at two site-years, and caused an increase in test weight at three site-years. Gram yield increases due to greater N application were largely due to increases in kernels per spike and tillers per square meter. The correct combination of N application level and timing of N application can increase yields and reduce the risk of lodging. However, under these experimental conditions, the most important management decision is the choice of cultivar.