- Ian Thompson
Every day, right under our feet, there is a war going on that we had never even noticed until recently. During the growing season, different species of grasses are constantly battling each other in a turf war for the right to collect as much solar energy as possible. Under certain conditions, one type of grass dominates; when those conditions change, another grass or a forb species will literally take the field in victory.
Thanks to the holistic pasture management class, and two years of rumination since we took that class, we can't look at a pasture anymore without assessing the types of plants growing on it and thinking about what conditions led to them being in that pasture. This might well be some type of diagnosable neurotic condition, but it has given us an entirely different awareness of the land around us.
Historically, tallgrass prairie and cross timber (which included tangled oak forest interspersed with tallgrass prairie meadows) covered the landscape where we live. Made up of 700 different plant species, the diversity and inter-specific relationships of that ecosystem were too complex for a human mind to fully comprehend. Over thousands of years, the plant communities of the tallgrass prairie had adapted to regular fire, periodic grazing by herds of bison, and sporadic drought. Tallgrass prairie dominated a 240 million acre landscape stretching along the eastern margin of the Great Plains. Then, the conditions changed. The fires were stopped. The prairie-sod-busting steal plow arrived on the scene. Bison herds were slaughtered to the brink of extinction. Pastures were fenced in and grazed continuously by cows.
After 200 years under these new conditions, the tallgrass prairie has shrunk to just 2% of its original extent, and a number of non-native pasture grasses have moved in. In our area, the best tallgrass prairie remnants are located in the narrow rights of way between pasture fences and highways. Here, cows can't continually munch the grass, while bi-annual mowing destroys the competition from young trees. The disappearance of the tallgrass prairie from its once dominant position on the landscape has global implications tied to the loss of biological diversity and the loss of a major carbon sink.
Where does our land fit into this? When we purchased our new farm, it had very little grass on it except for some grazed-short Bahia and Bermuda (introduced pasture grasses) and a few stocks of native grass finding protection from the cows where they could. Due to finite time and resources, our strategy has been to let the bulk of the land go fallow, while we fence in one pasture at a time. Each completed pasture is grazed and then mowed with our family heirloom 1952 model Ford 8N tractor to cut down the thickets of curly cup gumweed and woolly croton. These two woody forbs, a legacy from years of continuous grazing, create a tall canopy that can completely kill out the grass. Under our new management conditions, the existing patches of grass remain vegetative (i.e. tasty for the buffalo), and the grasses are slowly retaking turf from the forbs.
Early on, one of our management goals was to encourage native grass species. Currently, our most dominant pasture grass is Bahia. Introduced from South America, the roots of this grass extend only 6 inches into the soil. Conversely, the roots of the native tallgrass prairie grasses extend down 6-12ft! Guess which grass does better in a drought? Guess which type of pasture can produce better forage without chemical inputs? We're also guessing that the deep-rooted native grasses, if properly managed can be much more efficient at rebuilding topsoil than the short-rooted invasive grasses. Then of course there's the fact that, all else being equal, 6-foot tall native grasses tend to produce more food for the animals than 12-inch tall Bermuda.
A key in bringing back tallgrass prairie is to recreate the conditions that it thrived under to begin with. Our practices of rotational grazing with bison, mowing the forbs, and long rest periods come close to imitating those original conditions. This year, we have been thrilled to see stands of native grasses moving out from the fence rows and forest edges into our pastures all over the farm. This is happening both in the pastures that are with in our grazing rotation and in the area that is still fallow. Just in the last two years, some of our small pastures have become dominated by native tall grasses. These areas would now be considered degraded tallgrass prairie. Degraded or not, we're ecstatic, because two years ago there was nothing on the property that could have been considered prairie, period.
Before we got too excited, we thought it would be wise to take a close look. Last week, Ian was sick at home for a few days and took the opportunity to study the online FFA videos about identifying pasture grasses. Then, we did a native grass survey of the whole property. One piece of good news is that we have well over fifteen grass species from the original tallgrass prairie living on our land.
As for the less-good news; the forage on the original tallgrass prairie was dominated by four main grass species, Little Bluestem, Big Bluestem, Indian Grass, and Switch Grass. We have some small, but expanding stands of Little Bluestem in several pastures. We do have Indian Grass, but all of it on the entire probably would barely cover the footprint of a small house. We're very proud of our majestic Big Bluestem, because we didn't have any a year ago, but all of it together would hard-pressed to cover a large dining room table. We haven't been able to find any Switch Grass at all. We do have fair amounts of other good-grazing native grasses like Priarie Junegrass and Sand Dropseed. However, our most abundant native grasses are Broomsedge Bluestem and Splitbeard Bluestem. Both of these grasses have come to dominate the field in the picture above, which was covered by a thick carpet of Bahia two years ago. We and the buffalo are thrilled to have these two beautiful species growing in abundance. However, adapted for disturbance and poor soils, their dominance among our natives is another indicator of how much this land has been abused.
For now, we're going to leave our stands of Bermuda and Bahia. They are keeping the soil from eroding in many areas, while providing grazing for our animals. It looks like under the current grazing conditions, the native forage grasses will continue to expand year-by-year, even into the strongholds of the introduced grasses. To speed up that transition, we're considering collecting some seeds from healthier local stands of tallgrass prairie and planting them strategically on our land. We lack the resources to plow or drill, but once some of these grasses are established, they will expand if given favorable conditions. That's it for this growing season. We'll be sure to keep you posted on the Grass Wars.