Which of these pastures appears the healthiest?
How is each pasture contributing to climate change?
Which pastures have experienced the heaviest impact from animal grazing, and which have been least affected?
Let’s analyze and compare the pastures based on their health, contribution to climate change, and animal impact. These four photos were taken within a two-mile radius and over two consecutive days, implying similar soil types and growing conditions.
Most people would agree that Photo #1 depicts the healthiest grass based on appearance, but determining the healthiest pasture may seem subjective. We should explore what “healthiest” truly means and what management practices have contributed to this difference. Additionally, actively growing grass in soil rich in microbes acts as a proven carbon sink, making Photo #1 the top choices in regards to its impact on climate change.
The most interesting question is perhaps ranking the pastures based on their animal impact. Surprisingly, there is a virtual tie for both first and last place: Photos 1 and 4 display similar levels of high grazing impact, while Photos 2 and 3 represent fields with almost no grazing, except for occasional deer or elk. Delving into managing animals to achieve pastures that look like Photo #1 is an essential part of understanding why properly managed grazing is an excellent tool for maximizing carbon sequestration.
For some context on these photos:
- Photo #1 shows my field at Terra Farma, where we have been practicing multi-species rotational grazing for nearly two decades.
- Photo #2 portrays a field at Ello Farm, where we have been renting pasture for our beef cattle and meat goats for the past two years. However, this particular section has not yet been grazed and has been used for hay production for many years. We have an exciting new grazing plan for this property, which we can discuss in a future post.
- Photo #3 represents another nearby property where we recently started grazing our sheep. There has been no grazing or mowing on this field for at least five years.
- Photo #4 displays a field next to the sheep property, where cattle have unrestricted access to the entire field.
Fields 1 and 4 have a similar number of animals per acre when considering the entire property. However, the crucial distinction lies in the animals’ access to the pasture. In Field 1, the animals have access to only about 2-3% of the pasture at any given time, while in Field 4, the cows have continuous access to 100% of the pasture. Consequently, the cows in Field 4 graze the fresh, tender grass as soon as it emerges, preventing the plants from developing a robust root system and perpetually stunting their growth. In contrast, we move our animals to fresh grass every day in Field 1, ensuring that they won’t revisit the same spot for at least 40 days. This rotational grazing approach allows the grass to recover and develop strong roots, which play a vital role in combating climate change with cattle.
Surprisingly, healthy grass like that depicted in Photo #1 forms a symbiotic relationship with the microbial community living in the soil. As the actively growing grass photosynthesizes carbon dioxide from the air, it converts it into glucose and sends approximately one third of its production through its roots to the microbes. These microbes then supply nutrients from the soil to the plant. When the microbes and fungi utilize this glucose, they excrete carbon-rich waste into the soil, a substantial portion of which remains sequestered if the soil remains undisturbed. Studies have demonstrated that the amount of carbon sequestered in such systems is several times higher than what is emitted by the cows.
Frequent tillage or plowing can harm this microbial community and disrupt fungal pathways, leading to an increased reliance on artificial inputs like fertilizers and pesticides. Without any grazing impact, as seen in Photos 2 and 3, no nutrients are added to the soil. In the case of hay production, when the hay is sold off the farm, the nutrients are exported away from the field. Additionally, with no mowing or grazing, the tall grass from previous years accumulates and acts as a mulch, blocking sunlight from reaching the new grass shoots. Over time, this can result in a situation where opportunistic invasives dominate, and little else grows.
In summary, careful management practices can improve even degraded pastures with minimal additional inputs apart from planned animal impact. By implementing rotational grazing systems, such as the one demonstrated in Photo #1, we can promote healthier grass, carbon sequestration, and combat climate change effectively. Properly managed grazing, with controlled animal impact, plays a vital role in maximizing the potential of our pastures to combat the negative effects of climate change.
Mike Guebert earned his B.A. degree in geology from Humboldt State University and recently retired from Metro as a Program Manager at the former St. Johns Landfill in North Portland. Mike and his wife own and operate Terra Farma in Corbett, where they raise a variety of pasture-based livestock including dairy cows, goats, chickens, and turkeys. Their goal is to improve soil and water quality by practicing intensive rotational grazing, using chicken tractors (a portable chicken coop structure without a floor) to spread their fertility around the property, and excluding livestock from riparian areas. Mike is very active in the small farm community, serving on several committees and panels, often testifying to the state legislature in support of bills to help family farmers, and is always willing to offer assistance and advice to beginning farmers. Mike joined the Oregon Pasture Network Advisory Committee in 2022.