- Ian Thompson
Taking Prairie Restoration Experiments Up a Notch
Today, we tried out a more intensive approach to restore native grassland on the farm. As we mentioned in earlier posts, quite a bit of information is available on prairie restoration if you're starting with bare soil. If you're working with a piece of land that already has a lot of native plants, and want to increase plant diversity and soil health without detonating a nuclear bomb, it can be harder to find good information. The first step in restoration is proper landscape management, but once that is in place, what are the most effective ways for re-introducing and increasing important species in damaged prairies? We're trying out some different approaches and posting the results for those who might be interested. If you're keeping score, so far we've tried mixing seeds in bison winter feed, raking seeds into bare patches of soil, pushing seeds into the soil, broadcasting seed and letting the animals trample it into the ground, seeding in wild hog wallows, seeding on top of buried compost, and we're currently on our second year of experiments with seed bombs.
For the present experiment, we followed some sage advice offered by Chris Helzer of the Nature Conservancy, who restores and manages tallgrass prairie for a living. He kindly reminded us that in order for a seed to make a plant, it has to have sunlight, nutrients, and water. The amount of these that it gets is based, in part, on competition with other plants. For a new plant to take hold, often it needs a little break in the competition from the established plants. Chris sometimes accomplishes this by grazing an area heavily with cattle, broadcasting seed, and then continuing to hit it pretty hard with grazing through the growing season.
This winter, we chose one of our poorest spots of ground to feed hay. In the past, this area had its topsoil eroded away, leaving fine sand with almost no organic matter. During the growing season, a patchy cover of sandbur and woolly croton forms on this soil, along with a few more interesting plants like prairie cottonweed. We fenced off about two acres of this damaged land and fed hay on it all winter. The animals helped us add literally tons of organic matter, trampled it into the soil, and did a pretty fine job of setting back the established plants.
We'll take a moment here to make a confession. Ideally, the hay we fed this winter should have been 100 percent native prairie plants, so that any seeds in it that later came up would have helped us towards our goal. In reality, we could only acquire a few native hay bales and the rest was not. There was just no other option. We've seen pastures in southern Oklahoma converted even from established, tenacious Bermuda grass into native prairie plants without chemical control. Under the right management conditions, the taller plants from the tallgrass prairie can out compete shorter invasives. If something undesirable does come up from seeds in the hay, our plan is to hit it with some heavy grazing, as Chris recommended.
Our good friend Tom helped us figure out how to make a drag (by chaining some heavy metal trusses to our 1952 model tractor). After moving the herd on to a greener pasture, we ran the drag over the ground and were ready to plant. The bulk of our seed mix was of native tallgrasses that we had hand-gathered in local prairies, mixed with a nice bunch of compass plant seed that we had scored on a nearby roadside this fall. To this, we also added locally purchased seed of about 30 species of grasses and wildflowers that do well in sandy soil. The three of us hand-broadcasted literally millions of prairie seeds over the two acres, letting the light breeze help distribute them out over the ground. Successful praire seedings need about 100 seeds per square foot, and that's what we shot for. With the seeds disbursed, we pulled the drag around the pasture one more time to help cover as many of the seeds as possible in about 1/4 inch of soil. It's supposed to rain tomorrow.
It's probably obvious that we're more invested in these experiments than just as an interesting challenge. The tallgrass prairies is full of such amazing life. Walking through a stretch of it is a completely different experience spiritually than going through a Bermuda grass pasture. We want to give people who come to visit the farm more of that experience. We want to give the web of life that is native to this place a fighting chance to improve the soil and support the animal life in the way that it was meant to. When we share or sell bison meat, we want the meat to be a healthy, sustainable harvest of that healthy prairie and soil. For these and many other reasons, restoring native prairie is an integral part of our operation.
With the growing season gearing up, and the herd just moved out to spring pasture, its time to work on some more cross fencing. Later this spring, and for the next few years, we'll periodically cross that new fence to have a look at what has germinated from our plantings. For the soil and prairie nerds out there, stay tuned for updates on the progress of this and other restoration experiments from time to time.