Source: Saskatchewan Agriculture and Food
Inputs now comprise such a large share of farm production costs that producers are starting to rethink their approaches to production, according to Saskatchewan Agriculture and Food (SAF) Forage Development Specialist Trevor Lennox.
“One of the tools cattle producers have is legumes," he says. "I work with cattle producers, and alfalfa is by far the best resource we can work with because it fixes its own nitrogen and produces such good quality forage."
Insufficient nitrogen is the main factor limiting forage production potential on the prairies, he says.
“Water is your number one driving factor; next is nitrogen. With legumes, we have a plant that can provide a lot of its own nutrition. Meanwhile, our atmosphere contains 78 per cent nitrogen. It is a huge, vast resource of nitrogen. We just need to harness the power of legumes to pull nitrogen out of the air and fix it in the soil.”
Nitrogen fixation occurs mainly in the roots of legumes that form a symbiotic association with a bacteria species called rhizobia.
“Nitrogen fixation is directly related to the ability of legumes to accumulate energy through photosynthesis. Thus, leaf removal decreases nitrogen fixation, and leaf regrowth increases the potential for nitrogen fixation. Legumes not only fix nitrogen for their own needs, they are also able to supply nitrogen for non-nitrogen-fixing forage crops. In fact, they primarily supply nitrogen to forage plants following decomposition."
While legumes are still growing, mycorrhizal fungi can form a bridge between the root hairs of legumes and nearby grasses. This bridge facilitates the transport of fixed nitrogen from legumes to linked grasses. Depending on the nitrogen content of the soil and the mix of legumes and grasses in a pasture, legumes can transfer between 20 and 40 per cent of their fixed nitrogen to grass during the growing season.
Think of it this way: a pasture composed of at least 20 to 45 per cent legumes—on a dry weight basis—can provide the majority of the nitrogen needed by the forage stand.
When alfalfa constitutes a significant portion of the forage stand, it has the potential to fix 70 to 198 pounds of nitrogen per acre per year. Under irrigation conditions in southern Alberta, a pure stand of alfalfa has been shown to fix up to 267 pounds per acre per year. It is far cheaper to include a legume in a forage mix than to plant a grass and make annual applications of nitrogen fertilizer.
On another level, Lennox believes including legumes as part of the forage mix is necessary if nitrogen fixation is to provide a source of nitrogen for the pasture system.
“Rotational grazing is a management tool that has been shown to help maintain the proportion of alfalfa in mixed pastures,” he says.
But can cattle graze safely on pure alfalfa?
“When grazing cattle on pastures with a high component of alfalfa, bloat is a very real management problem," says Lennox. "However, a product called Alfasure is now available to control bloat. It has been on the market for a couple of years. In a series of grazing trials conducted across Western Canada, Alfasure has been almost 100 per cent effective at eliminating bloat in cattle.”
According to reports from those trials, yearling heifers grazing alfalfa gained an average of 1.5 to two pounds per day, and steers gained between two and 2.5 pounds per day. Stocking densities were two to three times higher on straight alfalfa than on grass and grass/legume pastures.
“When applied at the recommended rate, Alfasure costs 15 to 25 cents per head per day, depending upon the weight of the animal," says Lennox. "The drawback is that it needs to be applied through water, which requires restricting livestock access to only one watering source.”
To find out more about this product, contact your local veterinarian or the manufacturer (Rafter 8) in Calgary at 1-800-461-8615.
Fort more information, contact:
Trevor Lennox
Forage Development Specialist
Saskatchewan Agriculture and Food
(306) 778-8294
Inputs now comprise such a large share of farm production costs that producers are starting to rethink their approaches to production, according to Saskatchewan Agriculture and Food (SAF) Forage Development Specialist Trevor Lennox.
“One of the tools cattle producers have is legumes," he says. "I work with cattle producers, and alfalfa is by far the best resource we can work with because it fixes its own nitrogen and produces such good quality forage."
Insufficient nitrogen is the main factor limiting forage production potential on the prairies, he says.
“Water is your number one driving factor; next is nitrogen. With legumes, we have a plant that can provide a lot of its own nutrition. Meanwhile, our atmosphere contains 78 per cent nitrogen. It is a huge, vast resource of nitrogen. We just need to harness the power of legumes to pull nitrogen out of the air and fix it in the soil.”
Nitrogen fixation occurs mainly in the roots of legumes that form a symbiotic association with a bacteria species called rhizobia.
“Nitrogen fixation is directly related to the ability of legumes to accumulate energy through photosynthesis. Thus, leaf removal decreases nitrogen fixation, and leaf regrowth increases the potential for nitrogen fixation. Legumes not only fix nitrogen for their own needs, they are also able to supply nitrogen for non-nitrogen-fixing forage crops. In fact, they primarily supply nitrogen to forage plants following decomposition."
While legumes are still growing, mycorrhizal fungi can form a bridge between the root hairs of legumes and nearby grasses. This bridge facilitates the transport of fixed nitrogen from legumes to linked grasses. Depending on the nitrogen content of the soil and the mix of legumes and grasses in a pasture, legumes can transfer between 20 and 40 per cent of their fixed nitrogen to grass during the growing season.
Think of it this way: a pasture composed of at least 20 to 45 per cent legumes—on a dry weight basis—can provide the majority of the nitrogen needed by the forage stand.
When alfalfa constitutes a significant portion of the forage stand, it has the potential to fix 70 to 198 pounds of nitrogen per acre per year. Under irrigation conditions in southern Alberta, a pure stand of alfalfa has been shown to fix up to 267 pounds per acre per year. It is far cheaper to include a legume in a forage mix than to plant a grass and make annual applications of nitrogen fertilizer.
On another level, Lennox believes including legumes as part of the forage mix is necessary if nitrogen fixation is to provide a source of nitrogen for the pasture system.
“Rotational grazing is a management tool that has been shown to help maintain the proportion of alfalfa in mixed pastures,” he says.
But can cattle graze safely on pure alfalfa?
“When grazing cattle on pastures with a high component of alfalfa, bloat is a very real management problem," says Lennox. "However, a product called Alfasure is now available to control bloat. It has been on the market for a couple of years. In a series of grazing trials conducted across Western Canada, Alfasure has been almost 100 per cent effective at eliminating bloat in cattle.”
According to reports from those trials, yearling heifers grazing alfalfa gained an average of 1.5 to two pounds per day, and steers gained between two and 2.5 pounds per day. Stocking densities were two to three times higher on straight alfalfa than on grass and grass/legume pastures.
“When applied at the recommended rate, Alfasure costs 15 to 25 cents per head per day, depending upon the weight of the animal," says Lennox. "The drawback is that it needs to be applied through water, which requires restricting livestock access to only one watering source.”
To find out more about this product, contact your local veterinarian or the manufacturer (Rafter 8) in Calgary at 1-800-461-8615.
Fort more information, contact:
Trevor Lennox
Forage Development Specialist
Saskatchewan Agriculture and Food
(306) 778-8294
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