OMAHA, Neb. (DTN) -- Improved grazing management not only can help increase the amount and quality of rangeland grasses, but can lower the carbon footprint as well.
Ruminants, particularly beef cattle, are perceived by many as a problem since they are a source of greenhouse gas (GHG) due to the methane produced by rumen fermentation.
Richard Teague, professor of ecosystems science and management at Texas A&M University, and colleagues Seong Park and Tong Wang examined the possibility of reducing the net carbon footprint of ruminants using improved grazing.
According to Teague, adaptive multi-paddock grazing is a more effective form of rotational grazing in which one paddock is grazed at a time while other paddocks recover and livestock numbers are adjusted as needed to match available forage as conditions change.
This method of grazing has been shown to sequester more soil carbon than the traditional continuous and rotational grazing used in the past by researchers and many farmers.
"The adaptive multi-paddock grazing concentrates on very short periods of grazing. You graze for a short period, and then you move on to the next paddock," Teague said. "This is good for both the animals and for the grasses, as the plants can recover more quickly."
Shorter grazing periods allow for sufficient recovery for plants, although that recovery time changes according to how good or bad the weather is. In good growing conditions, recovery is relatively quick, but for drier or colder conditions, longer periods of recovery are needed, he said.
CARBON FOOTPRINT WITH DIFFERENT GRAZING METHODS
The research Teague worked on was to calculate net greenhouse gas (GHG) emissions for cow-calf farms grazing only rangeland under three grazing strategies:
1. Continuous grazing with light stocking, representing the best-case scenario for continuous grazing;
2. Traditional heavily stocked, continuous grazing, representing the most commonly used grazing management; and
3. Adaptive multi-paddock grazing, representing the best-case rotational grazing.
In the end, the adaptive multi-paddock grazing resulted in the production of more grass, resulting in more carbon in the ground, he said.
Teague said that each of the grazing methods measured still take reasonable management.
"If you have really bad management, then you would not be able to increase soil carbon," he said. "But the better the grazing management, the more net carbon sequestration results, and that offsets the emissions from the cows."
Most of the research so far is done in Texas, since that is where the researchers are located, but the GHG emission and sources in the Southern Great Plains region are higher than other regions of the U.S.
Teague explained that the forage quality in the Southern Great Plains is lower than farther north, since the climate is hotter and the plants have to contend with more dry periods.
"Since we can show in principle that this good grazing works with greater greenhouse gas emissions, it should work even better with fewer emissions," he said.
This grazing method would also work in other areas, such as the Midwest and Northern Great Plains, Teague said. He and other researchers have been measuring carbon sequestration with improved grazing farther north and into Canada and east of the Mississippi River with great success.
"The amount of carbon they are putting in the soil up there is substantial" he said. "With the cooler temperatures further north, you lose a lot less carbon through natural means. It just stays in the ground. In the wetter areas to the east of the Mississippi, the better growing conditions combined with improved grazing management results in considerably more carbon sequestration."
CARBON SEQUESTRATION IMPROVED
The adaptive multi-paddock grazing is more environmentally friendly, because it results in more carbon sequestration in the soil. In fact, the higher-quality grass produced by using this method actually reduces the methane gas emitted from the cows.
Teague explained that by using this method of grazing and keeping the plants leafy, it results in a higher quality of nutrition for cattle. The cattle can digest the higher-quality grass more quickly, which lowers the amount of methane gas they emit.
Teague explained that by managing rangeland in this way, the amount of bare ground is also reduced. Since bare ground causes loss of carbon from the soil into the air, more living plants covering the ground minimized carbon losses.
"If you've covered the ground and the plants are growing well, that causes the microbes to improve the soil. So more rain enters the soil, increasing your productivity. Increasing the productivity causes a greater amount of carbon to be put into the soil," he explained.
Teague said that one of the major reasons for the grazing research was because cattle are viewed by many environmentalists as the source of major problems.
"They arrived at these conclusions because they stick a cow in a small, airtight, little box and feed her, water her and measure her emissions," he said. "Then they deduce this is what's causing all the problems in the world without taking into account the whole environment cows live in."
Teague explained that if a cow is in a natural environment, grazing on a range that is under good management, much more carbon is captured and put it into the ground than the amount the cow is emitting.
Cows or calves fed corn have a greater GHG footprint, he explained. Animals fed corn inherit the footprint that comes from growing the corn. But if you're just grazing, you are creating a negative carbon footprint.
"That's one of reasons, apart from human health reasons, why so many people are going to finish animals on grass," he said. "Grass-fed beef produces a low greenhouse gas footprint."
IMPLEMENTING ADAPTIVE MULTI-PADDOCK GRAZING
Teague said there are no set rules for how many head of cattle to graze per acre in each paddock and for how long, because the factors change with each soil, topography, rainfall, temperatures, etc.
"Weather changes all the time, so that means you can't just use the same number of days of grazing and the same number of days of recovery in just a mechanical, non-thinking way," he said. "You have to change things, but the principles are the same. Recovery periods will take longer the drier it is."
For the adaptive multi-paddock rotational grazing, a minimum of 20 paddocks are needed, although Teague said that 30 paddocks is an optimal number and much easier to manage, and also results in more positive results. For a farm with four to five paddocks, Teague recommended that farmers sub-divide the existing paddocks into six or eight paddocks each, being careful to ensure there is access to a reliable water source from each paddock.
"The more paddocks you have, the shorter you can keep the grazing, while having a very long, adequate recovery period," he said.
Teague commented that once the multi-paddock grazing system is used, the cows learn quickly how to move. Often, all the farmer has to do is open the gate and the cows move quickly into the new paddock, because they know they are going to get into fresh grazing and better grass.
The only expenditure in dividing up additional paddocks is simply putting in a single-strand electric fence and providing a reliable livestock watering system, he said.
As for the length of time to leave the herd in each paddock, Teague said to work toward just a moderate defoliation, especially on the plants valued the most, then move on and let them recover.
He added that by taking care of the valued plants, farmers don't need to worry as much about weeds and other plants cropping up.
"You take care of the good plants and they can dominate the bad plants," he said.
Teague said the most important thing if a farmer wants to convert to the multi-paddock grazing method is to get educated on how to do it. He advised farmers to seek out other farmers who do it well, as most farmers prefer to learn from other farmers.
He added that he has seen how many farmers have turned around their operation by doing so, or attending better grazing courses.
"I've seen some people who have been almost to the point of bankruptcy, farming with the same sort of grazing that their grandfathers did," he said. "But then they implemented new things and many reversed their whole economic situation and are doing very, very well."
Cheryl Anderson can be reached at firstname.lastname@example.org
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