By Donna Fleury
Barley silage stubble provided good results and high yields with the following winter wheat crop. Photo courtesy of AAFC.
Winter wheat can have a good fit in many cropping systems across the Prairies; however, having suitable stubble ready for timely planting in the fall can be a challenge. Canola and barley silage stubble are typically looked to first, while pulses and others crops are thought to be less suitable. A recent research project conducted by Agriculture and Agri-Food Canada (AAFC) investigated the suitability of several alternative stubble options.
“Traditionally the most ideal stubble for winter wheat has been canola stubble because of its snow trapping ability,” says Dr. Brian Beres, research scientist with AAFC in Lethbridge, Alta. “Canola and winter wheat are also highly compatible in a no-till system. However, as genetics improve and both breeders and growers push for higher yields with canola, the cost has been an increase in growing degree-day requirements, to the point where canola varieties are up to 10 days later maturing in some regions compared to a decade ago. This means canola is no longer a timely stubble option for seeding winter wheat in some regions. The good news is cropping systems have diversified to include pulses and other crops, so alternative stubble types may be feasible.”
Led by Dr. Byron Irvine, with AAFC in Brandon, Man., researchers conducted a four-year study to investigate the suitability of ideal stubble types for winter wheat and select spring cereals grown in the Black soil zone across the Canadian prairies. Spring wheat, canola, pea, barley grain or silage, and oat stubble were established at four locations in Western Canada, including Brandon, Indian Head and Melfort, Sask. and Lacombe, Alta. In the year following establishment, winter wheat, hard red spring wheat, barley and oats were grown on each stubble type at each study area. Winter wheat was planted by the optimal date (August 30 to September 15) at each location.
“The four-year study results confirmed there are very good stubble alternatives for growing winter wheat beyond canola,” explains Beres. “On average, the yield of crops grown on canola, pea and barley silage stubble most often was greatest, and yield on wheat and barley grain stubble most often was least. Winter wheat and spring cereal crops often yielded best and had greater grain protein concentration on barley silage, pea and canola stubbles relative to other stubble types. The yield and grain protein concentration of spring cereals was best when grown on pea stubble.”
Although pea stubble and other pulses were assumed to not provide enough residue to be suitable, the data from this study showed pea stubble has a good fit and provided some of the highest yields. The study also showed that none of the snow depth differences among stubble types were related to any plant stand differences. Barley silage stubble provided good results and high yields, while barley grain and oat stubble provided significantly lower winter wheat grain yield. Factors such as heavy crop residues, competition from volunteers and nitrogen immobilization likely contributed to the lower yields. However, in some areas these may be the only stubble options for winter wheat plantings.
Stubble alternatives to canola exist
“The good news from the study is that growers can look to other stubble alternatives besides canola for growing high yielding winter wheat,” says Beres. “There are multiple environments and stubbles for planting winter wheat and if you are seeding on time with a high seeding rate and establishing a healthy crop stand in the fall, high yields are likely.”
With a competitive stand, inputs such as herbicides may be significantly reduced, with possibly only a fall 2,4-D application required. Winter wheat provides yield advantages, economic advantages and biological advantages for addressing weed, disease and other pest problems because of its competitiveness in cropping systems.
“The main challenge for growing winter wheat is the mindset around the operational logistics of planting in the same window as fall harvest. However, this is not as daunting as some would think,” says Beres. “In many situations, a good combining day likely doesn’t start until noon. I know some growers who have their seed drill ready to go to seed winter wheat in the morning and then harvest for the rest of the day, and with today’s size and scale of no-till air drills, you can cover a lot of ground in a morning of seeding.
“The longer-term gain is captured the following spring when there are less acres to plant, as most wheat acres are already established,” he adds. “Growers can then make oilseed and pulse crops their priority in what can often be a very short and wet window in the spring.”
Winter wheat provides other benefits to cropping systems such as capturing and utilizing snow melt and spring water that might otherwise run off or cause problems such as N leaching. Winter crops are more competitive early and make better use of early water resources than spring crops. Winter wheat also provides habitat for upland birds, such as nesting sites for ducks, and for other wildlife. There are ripple effects in a winter growth system that are more compatible with the ecosystem than just a spring cropping system.
Researchers are working to continually advance winter wheat system agronomics and have shown that factors such as higher seeding rates (450 seeds per square metre), new genetics and seed treatments are advantageous. Future directions will include nitrogen stability and growth regulators.
“Some growers, particularly those growing winter wheat under irrigation and in high production rain-fed areas, have had some problems with lodging with the taller and higher-yield winter wheat varieties,” explains Beres. “Although the yield potential is great with these varieties, the downside are the issues if the crop lodges.
“We now know that there are good alternative stubble options for winter wheat growers, and we are entering a time when winter wheat for a number of reasons, including marketing, deserves greater attention,” he adds. “Growers should be taking notice and really considering the benefits that winter wheat can provide to their operation and their business line.