For some, a cool beverage on a warm summer evening is not a bad way to end the day. Your cows agree, and they extend the thought to the pasture as well. That’s a good thing all the way around. Using a cocktail mix of summer annuals can extend the grazing season and reduce production costs.
In dry climates, for instance, ranchers are often short on summer and fall pasture, especially when productivity of cool-season perennial grasses wanes during heat of summer. In 2008, the University of Idaho’s Nancy Cummings Research, Extension and Education Center at Salmon, began looking at ways to extend grazing with summer annuals.
“We looked at species that grow well in dry corners of pivot-irrigated ground, to increase hay yield or pasture,” says John Hall, Extension beef specialist. “This evolved into a project to increase forage production for fall grazing.”
The test plots were continued for three years. When irrigation was available during the 60-day growing season, production was 2 to 3 tons per acre with some species. Part of the plot was given only a month of irrigation, with water turned off Aug. 1, to simulate what happens on many ranches in this part of the country when water is no longer available.
5 species analyzed
The first plots contained five species of warm-season annuals, including sudex (sorghum-sudan grasses), teff, German foxtail millet, pearl millet and grazing corn planted July 1. Production varied from 0.5 ton per acre for pearl millet with no irrigation after early August, to 5.6 tons per acre for sudex with full-season irrigation. The most promising species that first year were sudex, German foxtail millet and teff; all produced more than 2.5 tons per acre in less than 60 days.
The next two years, Extension personnel irrigated the entire plot. “We planted the same species, but changed from grazing corn to a short-season silage type of corn because we got more tonnage with it,” explains Hall.
In all three years, the plots were planted about the first of July. “Part of the reason for planting that late was to avoid any possibility of frost, and for the purpose of fall grazing. Timing of planting would depend on your grazing needs. Some annuals, planted earlier, could be grazed once and then left to grow again for fall. This would depend on the length of your growing season,” he says.
“One of our reasons for planting late, since we planned to graze them just once in the fall, is so these plants would reach the stage where they provide maximum yield and still have good nutrient quality for fall grazing. Corn is usually producing tassels and silk by then, but not much grain formation. Sudex has headed out but is not mature — and the same with most of the other species,” Hall says. The frost hits it at that stage, and it doesn’t become overly mature.
“With corn, instead of grazing stalks, you are grazing frosted standing corn, with more nutrients in the total plant. Over the three years, the nutrient analyses — with frost hitting these plants at their maximum growth stage, but before they become overmature — showed crude protein levels between 9% and 10% on the low side, and on the high side between 13% and 14%. Energy values exceed what a dry cow would need after weaning her calf,” says Hall.
“Our top-yielding species was corn. Sorghum-sudan grass was a close second, followed by the German foxtail millet. If you have the opportunity to graze twice, you can use teff. It produces a crop so quickly that you can graze it several times. We had to take a hay crop off because it grew so fast, and then got regrowth for fall grazing,” Hall explains. Teff is an annual grass used for grain in Sudan, but it doesn’t have much of a seed head and is better for grazing, he says.
“German foxtail millet can be grown on totally dry land, producing 1 to 1.5 tons per acre in country that gets about 14 inches of annual precipitation. Actual production may depend on your pattern of rainfall during summer,” he says.
“We followed normal seeding rate on all species, and strip-grazed them in the fall. On the sudex and the corn, we were getting about 70 animal grazing days per acre. The German foxtail millet gave us about 60 animal grazing days per acre,” he says.
“The sudex and corn work nicely if you want to graze after snowfall. They stand up well, and cattle can get to it and root it out of the snow.” Hall says. If you graze other species after snow, you might have to put it in windrows, which adds more cost.
Producers need to be aware of risks for prussic acid poisoning from sudex with drought and frost. “We wait at least two weeks after a hard, killing frost before we graze it. This allows prussic acid to dissipate,” he says.
Cover-crop cocktail mixes
Cover crops have traditionally been used to help hold the soil and prevent erosion when transitioning between different types of crops, and are often plowed under before planting the next crop — to add organic material and fertility to the soil. Farmers with livestock often select cover crops that can be grazed, adding another benefit and the advantage of animal manure.
Nora Paulovich at the North Peace Applied Research Association (NPARA) in Alberta has been trying various blends of crops to see what works best in that area. A mix of plants creates a good diet for cattle, providing different nutrients to help balance what they need, as well as taking advantage of moisture and growing conditions at different times of year. This can produce better yield as well as a better-quality product that’s available through the entire summer. If one type of plant doesn’t do well, some of the others might.
“Our work with cover crops is still in its infancy, however. We are still trying various things, and a dozen producers in our area are trying different combinations and species as well. We are experimenting with seeding rates, and include species from warm- and cool-season grasses as well as legumes,” Paulovich says.
If there is more diversity aboveground, there is also more diversity belowground. Paulovich was interested in this concept when she started the NPARA in 2007, trying to figure out what producers could accomplish with plants versus commercial inputs to improve the soil.
“We tried green manure without tillage, trying to just roll the crop rather than till it in. We struggled with getting good plant-to-soil contact because our soils were quite hard. But the crops following our green manure were better and didn’t need the inputs that were required without the green manure,” she says.
Then she started working with cocktail cover crops. “We started with just turnips, then used a cocktail mix the past three growing seasons. The shovel test — trying to put a spade in the ground — was easy where our cocktail cover crop had been growing for two years. By contrast, the land adjacent, with a monoculture [one species], was harder. It was like night and day, the difference in the soil,” she says.
Measurements are taken on water infiltration, yield data and other metrics. “One producer said to me, ‘I have hope now. If I had to rely on commercial inputs and fertilizer, I would give up farming, but I see that we can improve our soils this way.’ We are now trying to mimic nature again,” Paulovich says.
Heather Smith Thomas is a rancher and freelance writer based in Salmon, Idaho.
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