The effect of pulse crop rotation and controlled-released urea on the nitrogen accumulation and end-use quality of Canada Western Red Spring wheat
Przednowek, David William Andrew
The main goal of this study was to evaluate the effect of pulse crop rotation and controlled-release urea (CRU) on soil nitrogen (N) status and N accumulation of Canada Western Red Spring (CWRS) wheat. Spring wheat (Triticum aestivum L. cv. AC Barrie) was grown at Carman and Brandon, MB, on field pea (Pisum sativum L.) and flax (Linum usitatissimum L) stubble at three rates (0, 30, and 90 kg N ha-1) of N from two fertilizer N sources, ammonium nitrate (AN) and CRU, a polyurethane-coated urea with an N content of 43 per cent. Wheat was grown at Swift Current, SK, on field pea and durum wheat stubble at three rates of N (34, 50, and 78 kg N ha-1) based on soil test recommendations. The effect of previous crop on N uptake pattem was more consistent than the effect of fertilizer N source. Significantly higher soil NO3-N at planting on field pea stubble at two of three Manitoba sites resulted in higher wheat plant and grain N yield. Contrary to a number of similar western Canadian studies, apparent net mineralized N during the growing season and per cent post-anthesis N uptake were higher for what grown on flax stubble (F-W) compared to wheat grown on field pea stubble (P-W) at the two sites; the result was attributed to rapid N mineralization following field pea harvest. Wheat end-use quality was assessed with the Mixograph, dough micro-extension tests, and the Canadian Short Process bake test. At the same flour protein content (FPC), flour from wheat grown on field pea stubble had significantly lower Mixograph work input-to peak and dough strength index, as well as shorter dough development time at FPC < 14 per cent. Samples from Swift Current in 2001 produced much weaker, more extensible dough than samples from the other four site years, indicating that growing season conditions can have a pronounced effect on end-use quality...