Companion crops show promise in moist soil

A research study concluded seeding annual ryegrass and festulolium with common perennial forages could be a good choice as a companion crop in moist prairie soils.

“The use of annual ryegrass at a very low seeding rate was usually beneficial in the sense that it increased the forage production in the seeding year,” said Bruce Coulman, emeritus professor in the department of plant sciences at the University of Saskatchewan.

“The most important reason is to provide a bigger return in that year of establishment when perennial forages are really not that vigorous.”

Experiments were conducted in two different years at the Agriculture Canada research centres at Saskatoon and Melfort.

The soil types were a dark brown chernozem at Saskatoon and a thick black chernozem at Melfort. At both sites, trials were seeded on fallowed land and no fertilizer was applied at seeding.

In May, crested wheatgrass, meadow bromegrass and alfalfa were seeded at a depth of about 1.25 centimetres at a rate of 100 seeds per metre in rows spaced 30 cm in plots of 1.2 x 6 metres. Mixtures of alfalfa-meadow bromegrass and alfalfa-crested wheatgrass were seeded at a rate of 50 seeds per metre of row of each species.

Two separate trials were seeded in each site-year. One included Westerwolds ryegrass as a companion crop, which was mixed with the seed of the perennial species at varying rates.

The other trial included festulolium as a companion crop at different rates.

The cultivar Perun contains about 80 percent annual ryegrass and 20 percent meadow fescue.

Fertilizer was applied to the pure grass plots and on the pure alfalfa and alfalfa-grass mixtures in the fall of each year.

Coulman said seeding annual ryegrass depressed the establishment of the perennial forage, which was not quite as thick as on its own, but overall there was really no difference in total dry matter yield whether the companion crop was used or not.

“It (annual ryegrass) did have some suppressive effect on the forages, particularly in the year after establishment, but by the third year they’d recovered and if you look at the total dry matter yield over the three years, it’s about the same for whether you use the annual ryegrass companion crop or didn’t use it,” he said.

When seeding a forage crop such as a mixture of alfalfa and bromegrass, farmers will often plant a companion annual crop like wheat and barley, which gives the ability to harvest the spring cereal or take it off as silage.

“What that does is it provides a good economic return in the year of establishment, whereas if they didn’t include it there wouldn’t be much to harvest that year,” he said.

Weed control is one of the other key advantages of using companion crops, which will compete against weeds more successfully than forages on their own. As well, forages seeded on land that is prone to erosion will get a helping hand from the faster establishing companion crop.

Of course, the issue, he points out, is companion crops are in direct competition with the establishing forage, which is a much smaller seed compared to the faster developing cereals.

He said annual ryegrass seeds are about the same size as perennial forage seeds, but the seed germinates and develops faster.

It’s not recommended to use companion crops in brown soil zones because it considerably reduces the stand as well as yield for several years compared to no companion crops.

However, it’s not an issue in the black soil zone and companion crops are generally highly recommended in higher moisture areas.

“You can get a good return from that companion crop and it won’t suppress the yields of the forage in the following years,” he said.

Coulman said that annual ryegrass is an aggressive species and will not become a standard companion crop on the Prairies even though it develops faster than the perennial forage and helps increase the amount of forage in the year of establishment.

“Annual ryegrasses are not planted here very much because to get highest yields, it generally needs more moisture than we have here,” he said.

As a result, during their experiments, researchers played with seeding rates and considerably cut rates down within different soil types.

Unlike Europe, where ryegrass is common and it can behave as a perennial, Saskatchewan researchers found ryegrass was winter-killed between the first and second year of the stands.

He said currently there’s probably no one planting ryegrass as a companion crop, but it may be a possibility for prairie producers living in the right soil zones, who normally receive enough moisture. It can provide good quality hay production in the first year of establishment without compromising forage yields over the life of the stand.

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