- Ian Thompson
Practical Prairie Rehabilitation - Little Bluestem
Updated: Jan 16, 2022
After record-warm temperatures in December, we're finally enjoying our first taste of real winter weather this weekend. First thing this morning, I just had to go out for a walk in our pastures to be a part of the frozen landscape. I eventually found myself sitting on a hillside in a wind-protected opening looking at the dormant Little Bluestem plants in front of me.
Little Bluestem is a native part of this land. This grass was one of the most dominant ground covers in the prairies and savannas of southeastern Oklahoma in the early 1800s. The plants that I was looking at were not planted by human hands; they are a remnant of what has been on the land now comprising Nan Awaya Farm since time beyond memory. Little Bluestem is part of a lineage that goes back to the oldest-known grass fossils, which date from 100 million years ago, during the time of the dinosaurs. Little Bluestem or its ancestors provided food for the Columbian mammoth during the Ice Age. The grass has been a favorite food of buffalo for millennia, and it is a favorite of our buffalo and horses today.
Little Bluestem is adapted to fire and periodic heavy grazing by animals. In the absence of these, it and the other native grassland plants founder in their own shade and eventually get out competed by brush. Without a controlled burn (try as we might), some places on this farm are growing up into a thick, tangly, thorny, thicket so dense that you can't even crawl through on your belly. With a determined effort since summer, we've cleared about 6 acres of it and counting. By removing the vines and underbrush, but leaving selected trees, we're catching these areas up from years of fire suppression and restoring them to native savanna - basically prairie with a few trees growing in it. Oklahoma savanna is ecologically diverse and drought-resistant, a productive place for grazing animals, and a beautiful, pleasant landscape to be on.
With the vines and thick underbrush removed, the native grassland plants still surviving in the soil will get a chance to grow. It will be interesting to see what pops up in these cleared areas during the next several years. To help things progress, we also hand-planting thousands of patches of native seed, including seed from Little Bluestem that we've harvested elsewhere on the farm.
Little Bluestem grows in all but three of the lower 48 states. Across this wide range, it has adapted the ability to thrive drought-prone, infertile soils. Its main strategy is to focus on the long game. After a Little Bluestem plant germinates, it will spend at least the first year growing fibrous roots deep into the soil. The above-ground portion of the plant may stay tiny for years until favorable conditions for growth come along. Fully grown Little Bluestem plants on the farm range anywhere from about 1 1/2 to 5 feet tall. Their roots go 6ft deep into the soil. Science is just beginning to uncover the truly fascinating details of how the plant uses these roots, for lack of a better term, to farm microorganisms in the soil. Like other plants, Little Bluestem leaves pull in energy from the sun and CO2 from the air. The plant transforms these into sugars, carbon and other substances. It uses its roots to exchange these with the microorganisms in the soil for substances that the plant needs to thrive. Over time, this process removes carbon from the air and deposits it deep into the soil. Other plants do this too, but grasslands are more efficient at it than just about any other type of landscape. The implications of this can be seen by looking back in time. During the Miocene (23-5 million years ago), newly forming grasslands spread at the expanse of forests and deserts worldwide. The global transition towards grassland pulled enough CO2 out of the atmosphere that it diminished a natural greenhouse gas effect and significantly cooled the planet's climate. Obviously, the carbon-sequestering abilities of Little Bluestem and other native grasses can play a role in combating modern, human-caused climate change too. As an added benefit, the carbon-rich soils that they build are resilient against the drought and erosion exacerbated by today's climate situation.
Like other native plants, Little Bluestem is finely tuned to the rhythms of the life around it. It grows most of its leaf mass around the beginning of summer. The structure of the plant is designed to intercept and slow raindrops as they fall in a way that helps the rain soak into the soil. This increases plant productivity, while also helping to limit both drought and flooding. Little Bluestem plants contain their highest protein content right at the time of year when bison herds are calving and need the highest level of protein in their diet for new life. The plants lose protein content and gain carbohydrates in time with the animals' need to put on fat reserves for winter. In addition to feeding bison, Little Bluestem provides forage for a wide variety of native insects including several species of butterfly caterpillars. Little Bluestem seeds are food for a number of birds. When winter comes, Little Bluestem sends its energy reserves into its deep roots, while the above-ground part turns the prairie a reddish color. Even this dormant, clumpy foliage provides ideal winter habitat and escape routs for a number of mammals and birds, including the increasingly threatened prairie chicken.
Little Bluestem is a decreaser species. This means that grazing animals, like bison and cows like to eat it, so its abundance generally decreases when they are present. If grazed too severely and too often, entire meadows of Little Bluestem die out. 5 years ago, there was almost no Little Bluestem to be seen at Nan Awaya Farm. Due to years over overgrazing, it could be found growing only along a few protected edges of the woods. Over the past 3 years, we've seen the number of Little Bluestem plants in our pastures increase by an estimated 500%. Although we are now planting Little Bluestem in pastures where it is still rare or missing, few of these young plants have grown up to a visible size yet. Most of the current 500% increase is solely due to management changes.
Through practical experience, we've found that if a working pasture is not already dominated by invasive plants, it is possible to rebuild remnant populations of Little Bluestem and other palatable natives though careful, observant management. The keys we've found are: 1) Realistically balance the size of the herd to the amount of available forage; 2) Graze Little Bluestem and other warm season native forage species only one time during their growing season. They can be grazed again during the dormant season, and again during the cool season. (We accomplish this by using a 20+ pasture rotation system). 3) Don't allow animals to graze the plants down below half of their full height during the growing season (we rotate the herd between pastures every 4 days to prevent this); 4) If you want to have a full seed crop for warm season grasses, defer grazing between July 4 and November when the seeds fall off, and finally, 5) It's helpful to have a "pressure relief" pasture where you can take animals when forage is in short supply, so that the native areas don't get overgrazed (In our case, we have several pastures of Bermuda and Bahia grass, planted by the previous owners, where we can take our herd when times are tough). As noted above, we also harvest seeds from Little Bluestem and other prairie plants and use them to reestablish new patches in areas of a pastures that are still dominated by more weedy species.
The above management practices can reestablish palatable native grasses and forbs on chronically overgrazed native range lands. Once that is accomplished, the pendulum can swing the other direction with these plants becoming so dominant that they limit ecological diversity. When that happens, all you have to do is overgraze, and you'll see an explosion of forbs the next year. Then, the cycle can repeat itself.
This strategy of rehabilitating native habitat in working pastures can be beneficial not only for the ecosystems and soil, but also for a producer's bottom line. Today as we start into a new year, we calculated our grazing statistics for 2021 and compared them with previous years. In 2018 (the first year we were able to graze all of Nan Awaya Farm) we received 56.79 inches of rain, compared with only 37.96 inches this year. Despite less 19 inches of rain in 2021, our forage production was a whopping 59.5% higher than it had been in 2018. Thought of another way, every 1 inch of rainfall in 2018 produced 31.96 animal grazing days. In 2021, that same inch produced 76.26 grazing days. The difference is like adding 94 acres to our original farm size. Bottom line- as the soils and native grassland communities improve at Nan Awaya, so is forage production.
In a day and age when there seem to be so many challenges in the relationship between people and the land, it's sometimes desirable to find things that can tackle multiple problems at once. As Little Bluestem and other native prairie plants expand in the pastures at Nan Awaya Farm, the soil, the water use, the local ecosystem, the pasture forage, and economics are all improving. That's not to mention the quality of life that comes from interacting with a landscape that is becoming more vibrant year-by-year. We're still a long way from where we would like to eventually be, but we're definitely learning. I look forward to what the land has to teach in 2022.