Organic Farmer June 2019

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Multispecies Grazing: Integrating Ecological Processes and Biodiversity to Promote Regenerative Agriculture By LEE RINEHART | NCAT Agriculture Specialist Cattle and sheep are natural complementary grazers. Photo courtesy of Linda Coffey, NCAT. ORGANIC FARMS ARE based on diversity, from wide variation in plant species composition above ground to the billions of microbes that make up the soil microbiome. Ensuring diversity in the pastures we manage fosters resilience and productivity, and is a natural application of our fundamental organic, agrarian values. Producers who combine perennial pasture, cover crops in rotation on annual fields, and good grazing management with high species diversity will see benefits to soil health and increased revenue due to reduced inputs and higher productivity. This is particularly important for organic farmers, who apply nature’s design to make animals and pastures more resilient and productive. “The presence of multiple species of large herbivores is the typical condition of grassland and savanna ecosystems,” says John Walker, a range ecologist who wrote on the subject more than two decades ago (Multispecies grazing: The ecological advantage, by John Walker, 1994). Early in my career I was taught to plant one or two species of pasture forages and graze them continuously with a single livestock species. This practice is still evident if you drive around the countryside and look critically at pastures. Most often you see a closely grazed landscape peppered with the mature stalks from less-palatable plants. Cattle and sheep that graze continuously easily select the newest growth and cause selection pressure that results in the eventual demise of the best forages. This picture, however, can change. There has long been an interest in grazing multiple species together, either sequentially or at the same time. More producers are adding diversity to their farms, not only by adding diverse pasture mixes and cover crops, but with multiple species of livestock. There are some very good reasons for doing this. A well-managed farm with abundant diversity is generally healthier, has greater carrying capacity, fewer weed problems, and higher net income. Multispecies grazing takes full advantage of biological diversity. Those farmers who work hard to increase pasture-plant diversity will also see an even greater advantage by adding diversity of livestock to the mix. In fact, these ideas go hand in hand. Multispecies grazing works best, and excels, when a multitude of forage species make up the pasture composition. As vegetation of pastures becomes more diverse, multispecies grazing tends to improve composition and utilization. Multispecies Grazing Increases Carrying Capacity This management practice “may be one of the most biologically and economically viable systems available to producers, especially on landscapes that support heterogeneous plant communities” (Managing livestock using animal behavior: Mixed-species stocking and flerds, by Dean Anderson, E. L. Fredrickson, and Rick Estell. Animal, 2012). Studies have shown that when you add sheep to a cattle herd, you get 20 to 25 percent greater productivity and carrying capacity over cattle alone, and 8 to 9 percent greater productivity and carrying capacity over sheep alone (Walker, 1994). Ecological Resiliency and Better Pasture Health Grazing, when controlled and matched to the pasture resource, is known to increase pasture health. Diversity is key here, and just as diversity of plant species leads to greater soil health, having diverse animal species on the landscape adds a multiplier effect. Proper grazing increases soil aggregation, enhancing soil structure and allowing for better water-holding capacity and nutrient exchange. Grazing also contributes soil organic matter and rumen microbes to the soil that help to increase biodiversity, buffer soil temperature, escalate nutrient cycling, and minimize soil compaction and disturbance. Because different animal species have different grazing habits and select various forages and combinations of forages, pastures that are grazed with multiple species have more uniform defoliation. Defecation patterns affect nutrient cycling, and whereas cattle prefer not to graze around their dung, sheep generally do not have any bias about foraging near cow patties. Better forage utilization and uniformity of grazing contributes greatly to forage quality and resiliency by keeping forage growth constant; resetting the plants to the same stage of growth with each grazing event and preventing weedy or unpalatable plants from taking over. 16 Organic Farmer June/July 2019
Vegetation Management Pastures that have infestations of weeds or brush can be grazed with species appropriate to the plants present. This reduces the ability of any one species to dominate the landscape. Grazing managers must understand the growth habits of weeds and desirable plant species and know what animals graze them, in order to target-graze the weeds, and allow palatable plants enough rest to recover. This is especially important where invasive plants are involved. One species may eat what another will reject and, by using the correct livestock, managers can suppress and reduce a weed problem in a cost-effective and ecologically responsible way. With knowledge of plant response to grazing and timing of grazing events, grazing managers can alter the landscape to a healthy, diverse, quality pasture. Goats can be used to control weeds and brush in diverse pastures. Photo courtesy of Lee Rinehart, NCAT. Parasite Control One of the biggest benefits of multispecies grazing is its effect on parasite management. Cattle will consume parasite larvae such as the Barber Pole Worm (a sheep and goat parasite) and because this worm is incompatible with cattle, the worms will die. The same thing happens when small ruminants consume parasites that are indigenous to cattle. Because of parasite larval incompatibility between species, cattle can be grazed after or with small ruminants to reduce the incidence of larval infection. Continued on Page 18 Annual cover crops provide excellent forage while adding diversity, building soil organic matter, and feeding soil microbes. Photo courtesy of Lee Rinehart, NCAT. June/July 2019 www.organicfarmermag.com 17
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Organic Farmer June 2019

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