Pasture management

Cow

On this page, we suggest some key management techniques to ensure high quality forage, while preventing GHG creation:

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The key to preventing GHG creation (and ensuring a healthy herd) is to maintaining healthy, high quality pastures. High quality feed, whether in the form of pasture grazing or baled hay, means higher feed efficiency and more nutrients absorbed by the animal.

The rate of consumption by cattle is improved with high quality forage, increasing the efficiency of digestion and reducing the amount of time needed to graze. Faster digestion and greater feed use efficiency means less creation of GHG emissions.

Pastures also have numerous indirect benefits to reduce GHG production from animal production. Perennial forages trap atmospheric CO2 with their extensive roots systems, storing carbon (C) meters below ground.(1) Grasses and alfalfa not only improve the soil by increasing organic C, but are capable of absorbing excess water, lowering the water table and helping to control soil salinity.(2) Reducing soil moisture also limits the risk of N losses by denitrification, cutting down the amount of nitrous oxide (N2O) creation. Pastures also provide soil cover, protecting against erosion, and maintain or improve water quality.

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Promote high quality forages & legumes

The type of plants grown will have a big impact on pasture health. A diversity of native, deep-rooted, and productive plant species are needed for good quality pastures. These vigorous plants will ensure adequate vegetative cover to protect against erosion, will be able to handle frequent grazing, and will sequester atmospheric CO2 to store as C in their roots.(3) Using multi-species crop mixtures, such as alfalfa-brome grass,(4) will help the pasture mimic a natural system. A natural ecosystem will be able to use soil nutrients more efficiently and reduce the potential of loss to the environment.(5)

Integrating perennial legume forages, such as clover or alfalfa, into pasture mixes can help improve overall plant and pasture health.(6) The carrying capacity (amount of animals a system can support) of a pasture was increased by 28 percent when alfalfa was grown with the grass stand. When combined with fertilizer, the grazing system was able to support 57 percent more animals.(7)

Younger forage stands provide better feed value and tend to have lower methane (CH4) emissions than more mature stands. Methane emissions were reduced by half when grazing animals had access to high quality feed, when compared to reduced quality pastures.(8)

Legumes also help to increase the nitrogen (N) and C content of the soil. Although perennial legumes can help sequester soil C, perennial grasses have been found to store more C than legumes in a pasture setting.(9)

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Adopt rotational or bale grazing

Grazing allows animals to harvest their own feed during the summer months, reducing GHG emissions emitted from fuel use (created when making and using hay bales).(10) Grazing is natural for cattle and helps spread manure around a paddock,(11) limiting the CH4 and CO2 created by manure storage.

Manure nutrient build-up occurs around water troughs and bale feeders when animals are brought feed, increasing likelihood of nutrient loss and GHG creation.

Compared to continuous grazing, where livestock graze uncontrolled in one big paddock, rotational grazing divides a paddock into several small ones, with animals strategically moved every few days between paddocks.(12) Alternating between periods of grazing and rest helps maintain forage health by reducing weed competition and allowing plant recovery. Any excess N left behind in the manure and urine can be utilized by the plants or lost as ammonia or nitrous oxide.

Rotational grazing is more efficient and productive because livestock are only in the paddock for a short period of time. Cattle are selective eaters and rotational grazing encourages animals to consume all plant material, preventing under- or over-grazed areas and reducing wastage.(13) Rotational grazing is also environmentally friendly by limiting soil compaction and reducing soil erosion through the presence of continuous ground cover. Benefits for the producer include a longer grazing season because of shorter forage recovery periods, improved animal productivity and better nutrient distribution.(14)

Here is an inspiring 12-minute video. called “Soil Carbon Cowboys“. It shows the success that ranchers in Saskatchewan and North Dakota have had in improving soil carbon, increasing nutritional value of their forage, and improving the moisture handling of their land by using rotational grazing.

SOIL CARBON COWBOYS from Peter Byck on Vimeo.

Grazing can be extended into the cold winter months using ‘bale grazing’. Bale grazing is similar in concept to rotational grazing. Feed bales are set in the pasture and livestock allowed access to new bales every 2 to 5 days throughout the fall and winter.(15) This grazing technique allows the animals to feed themselves, reduces GHG emissions and distributes nutrients around a paddock.(16) Though this type of grazing does reduce the amount of manure that is concentrated in one area of the pasture, nutrient management is still necessary to remove excess manure from the feeding areas.

Although grazing limits GHG production by lowering fuel consumption, grazed cattle are found to emit more emissions than feedlot cattle. Grains fed to feedlot livestock are digested easier and more efficiently than grass.(17) The downfalls of grazing for the farmer include more active livestock management, such as labour for rotating livestock, paddock set-up planning and bale placement.(18) Despite a few minor disadvantages, almost all cattle farmers, with the exception of feedlot operations, graze their cattle during the summer months. Community pastures are still frequently used during the summer when a farmer does not have enough acres to support his grazing herd.(19)

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Avoid overgrazing pastures

It is important to avoid overgrazing a pasture. Overgrazing may expose the soil, increasing the risk of soil C mineralization or erosion. Overgrazing occurs when a plant is not given adequate time to re-grow or replenish its root reserves before it is grazed again. Livestock demands should be balanced with the available forage supply, so that enough plant material is left between grazing periods or over winter to keep plants healthy and limit soil erosion. Short grazing phases provide rest periods and allow plants to recover from the stress of grazing and reduce the likelihood of plant death.(20Removing cattle from pastures in early fall is another way to maintain high quality forage pastures.(21)

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Fertilize tame pastures

CCC_Livestock_Guide_2013_cover_smLivestock return between 25 and 60 percent of consumed C to the soil in their feces and urine.(22) When the natural distribution of nutrients is not enough to maintain pasture health, it may be necessary for farmers to supplement with fertilizer. Pasture fertilization can be done with synthetic fertilizers, manure or compost. These nutrient forms encourage vegetative growth and improve pasture productivity. Fertilizers also encourage C sequestration in the soil. Using legumes in a pasture mixture is a natural method of improving feed quality and increasing soil N and C levels.(23)

For more information, download our publicationFarming in a Changing Climate in Manitoba – Livestock Edition (2013)

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