It takes a good deal of time to develop a new forage variety and determine the best way to manage it but in the case of AC Saltlander green wheatgrass the timing couldn’t be better for Prairie producers growing anxious about future droughts.
AC Saltlander is a perennial green wheatgrass with a high tolerance for salinity originally developed by Dr. Harold Steppuhn in 2004. Commercial seed has been available since 2008 from Miller Seeds of Milk River, Alta., the North American distributor. Crop Production Services markets it in its Salinemaster blend.
Fortunately, Dr. Alan Iwaasa, a grazing research scientist with Agriculture and Agri-Food Canada at the Swift Current Research and Development Centre, has been researching the grazing performance and best management practices of AC Saltlander since its inception and his work is now reaching the point where it can start to help producers make the most of this forage.
The percentage of the Canadian Prairies affected by salinity is hard to pin down since it varies with the level of soil moisture. But Iwaasa says a rough estimate puts the amount affected by slight to severe salinity at five to 10 million acres.
Affected areas are less productive and more likely to be overrun by weeds such as foxtail barley and kochia, both of which have degrees of tolerance to salinity.
With the Prairies experiencing dry conditions after a decade of relatively good moisture, salinity has increased in parts of Western Canada, often related to a rising water table bringing salts to the surface.
It’s expensive and time-consuming to rehabilitate saline soils. While there have been various efforts to do so in the past, Iwaasa says the causes of salinity are associated with many different environmental and soil moisture conditions that it’s not always very easily prevented or solved by engineering practices.
Seeding a perennial forage like AC Saltlander has the potential to be a more cost-effective means. It can capture moisture, preventing the water table from rising and bringing salts to the surface, or it can use groundwater to drive the water table farther down, thus pushing salts further into the ground. When this successfully reduces salinity in a certain area, it becomes easier to establish other forage varieties.
However, it isn’t a miracle cure. “If you have a very severe saline area, chances are you will need to seed AC Saltlander at higher seeding rates and have patience for it to grow. It will take longer,” says Iwaasa. “But if you’re able to start on the peripheral area and gradually mitigate or help to reduce some of the salinity, you can gradually adapt or have the AC Saltlander expand…into those other areas that eventually may decline over time in salinity concentration.”
New research shows possible cost benefit
With considerable producer interest in AC Saltlander, Iwaasa and his team turned their attention to further examining the best methods for establishing this cultivar. They began a new study in 2015, funded by the Saskatchewan Ministry of Agriculture. The focus was to determine the ideal seeding rates and methods, explore its nitrogen fertility needs and how well it survives during waterlogging.
“When we first tried this in 2015, that unfortunately was a very dry year and we didn’t have very successful establishment,” recalls Iwaasa.
It wasn’t until 2016 that they established some stands, which allowed for preliminary results to start rolling in the following year. This year’s work will allow researchers to further examine the production values.
Six different seeding methods were tried in slight to moderate and moderate to severe saline soils — conventional spring seeding, direct no-till spring seeding and direct, no-till fall seeding, each at seeding rates of five and 10 pounds per acre.
“We have seen some advantages as far as the conventional seeding,” says Iwaasa. “We can’t really say definitively if the fall direct or the spring direct seeding has an advantage as of yet; we really have to evaluate that over several years.”
Another study compared seeding rates of 2.5, 5.0, 10 and 15 lbs. per acre. “The recommendation has been using around 10 pounds per acre, and we wanted to see how these other seeding rates would compare as far as forage production, as well as the ability to outcompete foxtail barley,” says Iwaasa.
They found forage yields at five pounds were comparable to the higher rates in moderate salinity soils. “When it comes to being able to compete with foxtail barley and still maintain a good forage biomass yield, the five pounds per acre can do just as well as 10.”
“This has a huge implication for producers because the AC Saltlander green wheatgrass seed can be quite expensive. If you were able to cut your seeding rate in half, then this would allow you some great benefits.”
“At higher salinity rates, you definitely may have some advantages by seeding at higher rates. Just like anything else, the higher salinity soil ranges are going to have more challenges for the establishment of AC Saltlander,” he says.
In terms of palatability, AC Saltlander proved comparable to smooth brome. “We did that under a grazing regime in which the animals were allowed to graze the two forage species at the heading stage and just as it set seed,” says Iwaasa. “The AC Saltlander green wheatgrass was grazed to the same extent as the smooth brome, and the average daily gains and the total livestock production were very similar.”
This spring, the Canadian Journal of Plant Science will publish a paper on AC Saltlander written by Steppuhn, retired AAFC technician Ken Wall and Iwaasa, which illustrates the cultivar’s ability to outcompete weeds such as foxtail barley and downy brome in areas affected by different levels of salinity.
The work on AC Saltlander is ongoing, and within two to three years Iwaasa hopes to be able to provide producers with a set of best management practices on how to seed, when to seed and what’s the best seeding rate to successfully establish AC Saltlander.
Another area of study will be it’s value in mixtures, such as a saline-tolerant alfalfa blend, with the intention of creating a new blend that “has a very deep-rooting ability and also can go after some of that additional water table.”
“A legume grass mixture will be a lot more productive as well as having the nitrogen-fixing ability (and) providing some potential benefits as far as animal performance on that type of grass and legume system. So that will be something else we’ll be looking at in the next probably five to six years.”