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Warm season grasses – a useful alternative

Millet is one of the most moisture efficient of all crops and where good moisture is available, sorghum-sudangrass produces more biomass.


November 20, 2007
By Helen McMenamin

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Millet is one of the most moisture efficient of all crops and where good moisture
is available, sorghum-sudangrass produces more biomass.

Millet does not come with the extravagant claims made of most novel crops,
perhaps because it was tried on the prairies and generally rejected about 60
years ago. But, in the last few years, some cattlemen who have tried it like
what they see.

"It may look good because we seem to be in a warm weather cycle,"
says Corny Van Dasselaar of Bench Mark Seeds in Lethbridge, Alberta. "Or,
maybe we're looking for something different these days."

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The benefits Van Dasselaar sees are based on the rapid growth of millet and
other warm season grasses. The growing season for millets is 60 to 80 days,
so the decision to seed or not seed can be delayed without losing yield. In
some areas, millets fit after winter cereal silage harvest, after cutting alfalfa
terminated early in the season or when seeding is delayed for some reason.

Millets and sorghum-sudangrass thrive in hot weather. Millet is also extremely
moisture efficient, producing more biomass per inch of water than any other
crop. The Southern Applied Research Association, based in Lethbridge, has been
looking at the fit of these crops in a variety of situations in southern Alberta.

For the last three years, Ken Chernoff of Kamsack, Saskatchewan, has grown
Golden German millet for his cows to swath graze in early winter. This is one
of the most widely recommended uses for millet because its heavy stems can be
very slow to dry sufficiently for baling. "We get more grazing days per
acre from millet than barley," says Chernoff. "And it's more palatable
than oats."

He moves an electric fence every day, limiting the cows to a few swaths. On
his light land, Chernoff can put in rebar posts fairly easily, but some of his
neighbours use a cordless drill for putting in posts. He has found the cows
will graze through 10 or 12 inches of snow – up to their eyes. "Sometimes
we have to kick open the swaths for them," he says. "One year though,
we had to leave some millet swaths out all winter. We got too much snow early
in the year for the cows to graze. We turned them out again at the end of April
and they cleaned up everything. The millet didn't deteriorate much over the
winter.

"We seed millet after all our other crops, around the second week in June
and fertilize it the same as cereals. It's slow to get started, but once it
gets started, even in a dry summer we'll get a little rain and the millet will
grow three or four inches in a matter of days."

Early in the year, the warm season grasses are poor competitors with weeds.
Chernoff uses a pre-seeding burnoff and Buctril M in-crop.

"All warm season grasses are poor competitors early in the year,"
says Van Dasselaar. "Corn is the same. I like to see millet seeded into
soil that's 20 degrees C, so the plants emerge and grow quickly."

Vern and Vivienne Pancoast of Redcliff, near Medicine Hat, seeded Siberian
millet on some newly rented land at the end of June. They harvested almost three
tonnes of hay per acre. "I was really surprised," says Vern. "That's
poor land and the crop had no rain, apart from a little shower as we finished
seeding.

"It made wonderful hay with good green colour and fine stems, even though
we only seeded about 12 pounds per acre. The cows really liked it. They ate
the millet before any other hay or greenfeed. We had a lot of grasshoppers because
that field is beside rangeland, but they didn't damage the millet."

The Pancoasts tried some sorghum-sudangrass in the same field. It yielded more
than the millet, but did not seem as palatable to the cattle. Van Dasselaar
has not seen this in other situations.

After harvesting winter triticale as silage, Lethbridge area cattle feeder,
Duane Vandenberg seeded several varieties of sorghum-sudangrass and millet alongside
oats under pivot irrigation. All the warm season grasses out-produced the oats
by 10 percent or more.

"The sorghum-sudan seems to be less of a gamble on the weather,"
he says. "But, last year wasn't really a year for oats. It was too hot
and oats could have used more water. All the warm season crops did well. Our
winter triticale went about 12 tonnes (67 percent moisture) and then we got
six or seven tonnes more silage in September. We were able to get three crops
in two years."

"A lot of people are underseeding silage crops with annual ryegrass,"
says Van Dasselaar. "In that situation, two tonnes of dry matter is an
excellent yield. In our trial, all the millets and sorghum-sudangrass yielded
10 or 20 percent more dry matter."

Once they are headed, millets and sorghum-sudangrass become woody very quickly.
They must be cut as soon as the head emerges. Some newer varieties do not set
seed at prairie latitudes. Sorghum-sudangrass can cause prussic acid poisoning,
but once the plants are more than 18 inches tall, the chemical is sufficiently
diluted and there is no risk to cattle. Like any lush, rapidly growing forage,
warm season grasses are susceptible to frost damage and should be tested for
nitrates.

Warm season grasses provide rotational benefits: late seeding and species differences
can reduce the pressure of weeds and disease in following crops. Their shallow
roots allow summer moisture to accumulate at depth in the soil profile.

Millet may bring flexibility into a system that includes fallow. It can be
seeded after a chemical application and, if there is sufficient moisture, harvested
for forage. If the summer is dry, the crop can be sprayed out and provide cover
to protect soil and trap snow.