Hybrid Sunflowers and Brassica juncea Canola Need Nitrogen to Achieve Consistent Yields
Hybrid oilseed sunflowers and the recently developed Brassica juncea canola are gaining popularity in Western Canada, but little is known about their economic adaptation to the Prairie climate.
A study led by Bill May at Agriculture and Agri-Food Canada, with support from the Agriculture Development Fund, compared the nitrogen response of these crops to B. napus canola and flax in sites at Melfort, Redvers, Swift Current and Indian Head. In this study, nitrogen required for each treatment was applied along with P, K, and S standardised for each location.
When analysed collectively, the highest yield gain response to nitrogen occurred at Indian Head and Melfort. Crops grown at Swift Current were less responsive to nitrogen application than crops grown at Indian Head or Melfort, and crops grown at Redvers showed a minimal yield gain in response to nitrogen.
Averaged over all locations, B. juncea canola reached a maximum yield of 1.4 tonnes (T) per ha (22.3 bu per ac) at 144 kg per ha of applied nitrogen. The largest yield gain for B. juncea canola occurred up to 70 kg per ha of applied nitrogen, which was similar to sunflower’s largest yield. Sunflower reached a maximum yield of 1.25 T per ha (19.9 bu per ac) at 151 kg per ha of applied nitrogen.
For both B. juncea canola and sunflower, optimal economics occurred between 50 and 73 kg per ha of applied nitrogen. Flax reached a maximum yield of 1.9 T per ha (30.3 bu per ac) at 169 kg per ha applied nitrogen, with the largest yield gain up to 90 kg per ha of applied nitrogen. B. napus canola reached a maximum yield of 2.3 T per ha (36.7 bu per ac) at 200 kg per ha applied nitrogen, the highest application rate in the study. The largest yield gain of B. napus occurred up to 120 kg per ha of applied nitrogen and the optimal balance between yield potential and financial risk was between 90 and 120 kg per ha of applied nitrogen.
The researchers found that these nitrogen application rates were appropriate across a wide area of Saskatchewan. They noticed that there was variability in sunflower yield in response to nitrogen application rate, but the cause of this variability is unknown. The total days to flowering in the examined crops was affected by the growing location, crop and nitrogen application rate. The length of the flowering period was not affected by nitrogen application rates.
Even though B. juncea canola is targeted towards hot and dry locations, the yield of this crop was lower than B. napus canola at Swift Current, the hottest and driest location of the study. Sunflower yield at Swift Current was similar to that of B. napus canola and flax; however, in the other locations sunflower yield lagged behind B. napus canola and flax yield in this study. In general, the researchers found that at least 50 kg per ha nitrogen is required to improve grain yield stability in all crops examined.
The Agriculture Development Fund provides funding to help institutions, companies and industry organizations carry out research, development and value-added activities in the agriculture and agri-food sector. The results produce new knowledge, information and choices in technologies, techniques and varieties for farmers, ranchers, processors and input suppliers, to improve the competitiveness of Saskatchewan’s agriculture sector.
In 2011, the Saskatchewan Ministry of Agriculture committed $14.5 million in new funding for 71 ADF research projects.
Source: Saskatchewan Ministry of Agriculture