Purple Prairie Clovers

In the environmental debate, some rank cattle up there with smokestacks and auto emissions. But Canadian researchers are discovering Mother Nature has developed her own mitigation strategy for bovine burps, flatulence, and excrement — and showing that grazing cattle has major environmental benefits. In 2000, concerns over cattle and greenhouse gases prompted Allan Iwaasa of Agriculture and Agri-Food Canada’s Swift Current research centre to launch a study to see what happens when cropland is seeded to pasture. The fields, which had been cropped since the 1920s (despite having marginal soils) were seeded to two different native perennial mixes. There was a simple mix of seven species of cool-season grasses and a complex one with 14 species of
“So five years ago we looked to see if there were some benefits from the purple prairie clover in regards to having condensed tannins. We then, with the help of (colleague) Yuxi Wang, started looking at how the purple prairie clover condensed tannin levels compared to sainfoin. The purple prairie clover had some of the highest levels of condensed tannins that we were able to find for any of the tame or native species that we were evaluating.” Sainfoin’s condensed tannins protect against bloat, and many Alberta producers have been anxiously awaiting the commercial availability of AC Mountainview, developed by Ag Canada forage breeder Surya Acharya in Lethbridge and currently being increased for seed sales by Northstar Seed. (It’s expected to be available for sale next year.) Older sainfoin cultivars, such as Nova and Melrose, were generally single-harvest-type sainfoins; did not persist long in alfalfa mix stands; and didn’t regrow at the same rate as alfalfa after grazing or cutting. However, Mountainview has better regrowth potential and Iwaasa is conducting research comparing the Canadian Mountainview sainfoin to the U.S. Delaney sainfoin which also has traits for multiple
coli shedding in the animal dung,” said Iwaasa. “We are trying to quantify the amount of purple prairie clover in the mixture that will give us the most bang for our buck.” Another potential benefit of condensed tannins being studied is their potential to reduce methane emissions. The researchers have also looked at carbon sequestration in pastures and are studying a mix of alfalfa — a.k.a. ‘the queen of forages’ — and sainfoin. “Currently we are looking at the different sainfoin germplasms that were used in the development of AC Mountainview, and some of these sainfoin germplasms and U.S. cultivars may be better suited to grow in southwest Saskatchewan and arid areas of the Prairies,” he said. Although alfalfa fixes more nitrogen, sainfoin is very palatable and preferred by grazing cattle. By utilizing the new cultivars there may be opportunities for the animals to select the sainfoin and reap the benefits of the condensed tannins over a long period of time. But Iwaasa’s ongoing research also has a big-picture focus — not just the performance of the sainfoin-alfalfa mixture itself, but also nitrogen fixation and carbon sequestration back into the