Objectives
The objectives were to determine how flax grain yield is established; how agronomic factors affect the expression of grain yield and how environmental conditions during the various stages of plant development influence the expression of final grain yield. This can provide producers with more insight into the production potential of flax and tools to help them make better informed management decisions about the crop. The study also established the performance of flax relative to canola when an optimum management program is used. This was to demonstrate to producers the full potential of flax when the correct management program is used and highlight more explicitly some of the agronomic and economic benefits of flax relative to canola and how to manage them within the same cropping system.
Project Description
For seeding date, it would appear that the yield depression is greater in canola than flax when planting is delayed and canola responds more to nitrogen than flax. The N recommendations for canola are appropriate based on the results from this study but could be lowered for flax. With flax, there does not appear to be benefits to using high rates of N to try and capture more economic yield. There may actually be merit for higher than recommended rates of N for canola. The risk would be much lower than in flax. Based on just these two observations, one would conclude that canola should be seeded first.
The main interest in this study was to examine closely how yield formation in flax is influenced by some of the more important agronomic factors. Given the large number of factors included in the study, there was also interest in determining any interactions between factors that could be of agronomic interest. An example was the seeding date x nitrogen rate interaction where the nitrogen rate response disappeared at the later seeding date. Other important interactions were discussed and their agronomic importance noted. It is interesting to note that overall, the three cultivars performed the same, on average, despite site x cultivar interactions for grain yield.
Pasmo and powdery mildew were the most common and severe diseases observed in a descending order of severity, respectively, at Morden, Brandon, Melfort, Indian head and Saskatoon. Lodging, heavy stand and seeding rates, high nitrogen and vigour, were always associated with significantly high pasmo. Pasmo was more severe at the early seeding dates in all locations. Powdery mildew was not generally affected by seeding rates or nitrogen levels but most likely by the humidity and temperature prevailing from mid-season onward to the end of the season. The recommendation of seeding recommended rates of resistant cultivars (in this case to powdery mildew and pasmo) and avoiding very early seeding and high nitrogen rates will result in a less dense canopy which is less favorable for pasmo and perhaps avoid high powdery mildew severity. The reduction in disease levels with the later seeding dates in snot always consistent with the observations for yield.
