ESN Effects On Canola Establishment, Weed Competition, and Canola Yield in a Four-Year Study.

A four-year field experiment was conducted at five sites on the Canadian prairies to determine the merits of using polymer-coated urea (ESN) fertilizer in spring canola cropping systems. Treatments included a) open-pollinated (OP) and hybrid canola, b) ESN and urea applied as a side-band 5 cm from the seed row, c) 100% and 150% of soil test N fertilizer rates, and d) 50% and 100% of recommended herbicide rates arranged in a factorial design with four replications. Canola was grown in rotation with barley in a zero-tillage production system and both phases of the rotation were present each year. Canola density was unaffected by treatments in this study. Weed tissue N concentration and biomass were often lower with hybrid compared with OP canola. Additionally, weed N concentration was usually lower with ESN than with urea. Canola yield was greater with hybrid than OP cultivars in 15 of 20 site-years. Both hybrid and OP cultivars expressed a positive yield response to the 150% N rate in 10 of 20 site-years and there were three additional site-years where this occurred with hybrid canola. ESN compared with urea increased canola yield in four site-years and in one additional site-year with hybrid but not OP canola. Canola seed oil concentration was usually similar with ESN and urea. An economic analysis of these study results is being conducted to better advise canola growers on more cost-efficient canola production practices.