- Ian Thompson
Rebuilding Prairie in Pastures: What We're Learning
Updated: Nov 22, 2020
America's native grasslands are amazing places. They provide nutrition for grazing animals that is perfectly synced to the animals' natural rhythms. Extensive roots protect the soil from erosion while trapping thousands of pounds of C02 per acre in the form of drought-fighting organic matter. These landscapes support almost numberless native species of pollinators, other insects, and native birds, some of which are rapidly disappearing from the face of the earth. Native prairies embody an inherent beauty that is tied to countless stories and important human connections. For these and other reasons, they have a value that goes beyond dollars. Yet, the tallgrass prairies of the American heartland have been reduced by 98%. Today, this ecosystem is among the most threatened in the world.
Efforts, spear-headed largely by private individuals and non-government organizations, have seen some of the best remaining pieces of tallgrass prairie preserved. Tens of thousands of acres of cropland and roadsides have also been replanted to native prairie. Practical information about how to manage an existing prairie or about how to replant one from scratch is out there if you look for it. However, today, many prairies exist as damaged remnants on private land, often within active cattle pastures. Information about how to restore these working prairies, arguably a much more difficult challenge than either of the tasks above, is a little harder to come by (for two of the best sources see here and here). In this post, we'll share some practical things that we have learned about restoring a working prairie through 5 years of trial and error at Nan Awaya Farmstead. What we have yet to learn could fill a library. Nevertheless, we hope that sharing some of the things we wish we'd known earlier may be useful to other people looking to do something similar. Most of our readers are not pasture managers, and this is a long, somewhat information-dense post. If land management discussions don't give you goosebumps, you certainly have permission to sit this one out and come back to our next post, which will be about something different. For those who are inclined to read on, let's add to the conversation about restoring prairie in working pastures...
Usually, the restoration of a damaged prairie seems to happen when a conservation group purchases a tract of land for that explicit purpose. One of the first things that they often do is to remove grazing animals, if there are any, because perpetual overgrazing is one of the forces that damages prairies in the first place. The price of land is insane, and buying a tract for the sole purpose of prairie restoration is a pretty rare and special thing. Most private individuals cannot afford to buy or own a good-sized piece of land if that land doesn't help pay for itself. The number of prairies in active cattle pastures outnumber the conservation prairies by many magnitudes. Some of these grazed prairies are healthy and well managed. Many more of them have been degraded. If grazing animals have to be completely removed for restoration to occu, then most of these prairies never will be restored. There is no question that, if managed properly, grazing can be beneficial to a healthy, well-established prairie, but could it be possible for a rancher to restore prairie while animals are still grazing it?
As a kid growing up in the suburbs, I once thought ranchers just put their cattle on a pasture; the cattle ate the grass, maybe some hay in the winter, and that was basically it. In reality, managing grazing animals in a way that maintains those grassy pastures is a real skill. In our area, most ranchers have too many animals on their land to sustain them naturally. After a grass plant is grazed, it draws resources from its roots to rebuild. If it doesn't have enough time to rebuild its roots before it gets grazed again, the roots weaken. If this happens too many times, the plant dies. In overgrazed pastures, the tastiest plants disappear first. In this part of the world, these include Big Bluestem, Little Bluestem, Indian Grass, Switchgrass, and Eastern Gamagrass, the dominant grasses of the southern tallgrass prairie. Their absence leaves big holes, which are filled by other plants like Ragweed that are not palatable to the animals. This is how the land balances itself. In our area, ranchers most often disrupt this balance by spraying their "weeds" with poison that kills a wide swath of beneficial native broadleaf plants. Then, they plant foreign grasses like Bermuda and Bahia that can survive a lot of abuse. They fertilize these pastures, which gives the non-native plants an additional advantage over the native ones. Ultimately, the prairie is replaced with a crop of non-native grass that has to be maintained with costly spray and fertilizer, while providing almost none of the prairie's ecological benefits. If the land is ever plowed in this process, it destroys the roots and seed bank in the soil, and the prairie is gone for good. However, if pastures are not plowed, and if only some areas are planted in invasive grass, big parts of the prairie may survive underground for quite some time.
When we purchased what is now the Nan Awaya Farmstead, the upland pastures were almost completely covered in a blanket of Ragweed, Goatweed, and Horsemint, the legacy of having been overgrazed for many years. There were only a few tiny patches of unpalatable native grasses on the 160 acres, and none of the more palatable ones. Fortunately, the soil has apparently never been plowed, and only a minority of the farm had been planted in introduced grasses.
Just before we bought this farm, we took a holistic pasture management class. After we bought the farm, we invested in hiring the instructor to come visit the land and advise us. He wisely told us that before we moved our animals onto it, we should allow the land to go ungrazed for a year to see what plants would come up on their own. He advised us to set up a system to regularly monitor the changing condition of the land. He also advised us to cross fence the farm into 15 separate pastures. A year later when we moved our grazing animals to the farm, rotating our animals through those pastures would provide each pasture with more than 10 times as much rest time as grazing time, allowing the grasses and other palatable plants to continue to rebuild. Our consultant felt that in three years of this management, the land would likely support a good stand of grass and be able to feed a profitable herd of 30 bison...
One of the most important things 5 years of experience has taught us is that it takes time to restore damaged pasture grasses, particularly if the soils are sandy, like on our farm. If you're a new producer, planning to use intensive rotational grazing to flip a worn out pasture to profitability over just a few years - don't bet the farm on it. Take the time to directly observe how many years the soils and grasses on your land really need to recover, rather than making a leap of faith. If we had jumped into full-time bison ranching, relying on improved management to rapidly increase the number of animals this land can support, we would have gone bankrupt within a couple of years. That would have been a costly lesson in what it takes to restore damaged land.
Under reasonable expectations, intensive rotational grazing can be an effective technique for ranchers who want their operation to be sustainable and profitable. Designed to prevent palatable plants from getting overgrazed, the technique seems well matched to rebuilding prairies that have been damaged by overgrazing. However, using this technique does require patience. We began rotating a herd of 6 bison through our pastures as the plant communities continued to rebuild. Besides bringing some income, and in the case of bison drawing public interest, grazing animals can directly help with prairie restoration. They can eat up patches of invasive annual grasses before they seed, destroy cedar trees, trample down last year's growth so new plants can get sunlight, and their grazing helps to keep the grass vegitative and growing. As forage production and carrying capacity have gone up, we've been able to increase our herd size to match. Under this management strategy, we are seeing real, concrete improvements on our land. As noted in our previous post, at least 27 species of native grasses and 151 species of native forbs and wildflowers have reemerged in our pastures just from what survived in the soil. This is quite a remarkable change, given what this land looked like a few years ago, and the change is still happening.
Currently, we're at 10 bison and 2 Choctaw ponies, or about 13 acres per animal. We'll likely be able to expand more in the coming years, but our herd size will eventually be constrained by the potential productivity of our soils. It may never reach 30 animals. If we had plowed everything under, planted Bermuda grass, and fertilized, our herd might be at 30 or more animals right now - This is how the prairie has disappeared - but there are advantages, including financial ones, to doing something different. By matching our herd size to the natural carrying capacity of the land, we receive less income from the land. However, we're also saving a fortune on the costs of trying to prop up a higher level of production than our land can naturally support.
Although they have made their reappearance, the most important native tall grasses have been slow to take back over our pastures. We've learned that the answer for how to create the right conditions for them to do this comes in two parts. The first part is to make sure that the animals do not graze the leaves of these plants down below half of their original height. Once that point is reached, the animals need to be moved, even if the other grasses nearby are still tall. These then have to be mowed (and essentially wasted) so that they don't gain a competitive advantage over the grasses that we want to spread. The second part of the answer is, to the greatest extent possible, do not graze these grasses between July 4th and mid-November when the seeds fall off. This gives the plants the best opportunity to produce a full seed crop. Achieving either one of these, let alone both can be a tall order for an active grazing operation. We are able to accomplish them in different areas of the farm in different years because our herd size is matched to the land's current carrying capacity, and the land has now been cross fenced into 23 pastures. Every year, we can afford to exclude several of these pastures from grazing for 5 months at a time on a rotating basis. Even in the pastures that are grazed during this interval, the damage to the palatable tallgrasses is limited, because we are moving our herd on a fast rotation (no more than 5 days in a pasture at a time). We also still have a few pastures of previously planted Bermuda and Bahia (seen in the before and after shot above), which can take some of the pressure off as the native pastures rest. We've still got a long, long way to go for the dominant native grasses to begin dominating our pastures, but we're seeing movement in the right direction. 5 years ago, there were none of these grasses visible above ground; 2 years ago some clumps were present; since then, their coverage has more than doubled.
It's still a little hard to picture, but under the right management (with the appropriate monitoring and making adaptions to our management based on what we see), native tallgrasses will eventually dominate our pastures. At that point, we'll be less in the prairie restoration phase and more in the prairie maintenance phase. Chris Helzer, of the Nature Conservancy has taught us that on healthy prairie, the tallgrasses can become so dominant that they smother the native wildflowers and other plants that contribute significantly to the ecological benefits that the prairie provides. In the past, this was negated by fire. Fires burned down the dominant grasses. When they regrew, the tender foliage was particularly nutritious, attracting herds of bison, which sometimes camped out, grazing and regrazing the new growth for an extended period. "Bison carpet", is a good descriptor of the effect on the plant community. Short vegetation opens the ground up to sunlight. That and the reduced grass competition gives native wildflowers and other forbs that are present in the soil an opportunity to shine, while providing habitat to animal species that need short vegetation (see here). As these less palatable species come up, the grazing animals move on; the grasses reestablish their dominance after a season or two, and the cycle can repeat. The tallgrasses won't be dominant on our land for a while. When they begin to be, we'll try changing up our management strategy to incorporate fire followed by more extended grazing periods in different pastures each year, and see how the ecosystem responds.
The above management techniques can only restore those plants that have roots or seeds already present in the soil. If important species are rare or absent in the seed bank (as Eastern Gamagrass, Switchgrass and a few important forbs still are on our farm), they will be extremely slow to reestablish. We have experimented quite a bit to find low cost planting techniques that can work to efficiently reintroduce such plants without destroying the desirable plants that are already there. Rather than overseeding the whole farm - something we can't afford to do- our goal has been to learn how to reintroduce colonizing populations of the missing plants, which will be able to spread across our pastures under favorable management conditions. In past posts, we've tentatively weighed the merits of 8 different techniques, including broadcasting small seeds onto sparsely vegetated areas, mixing hard-shelled native grass seeds with our animal's winter feed, broadcasting native seeds in a winter feeding area and letting the animals trample / fertilize them all season, broadcasting seeds on a winter feeding area at the end of the season, directly hand-planting seeds, trying out two different recipes for seed bombs, planting in wild hog wallows, and finally planting young bare-root plants. We have found that some of these techniques are more efficient than others.
After two previous posts on seed bombs, here is our final analysis of the technique - final at least for now. The seed bomb recipe that seems to be the most logical combines 1 part clay, 4 parts compost, 1 part native soil from where the seeds originated, and about 20 seeds. This mixture is formed into quarter-sized balls, which are allowed to dry, and then pushed half-way into the ground in spots within pastures where young plants will face limited competition from established plants. We planted 1,000 seed bombs in 2019, and another 1,000 this spring. Annual Sunflower is a highly visible native plant that has not survived in our soil. We used it as a marker in our mixture to gauge the effectiveness of the seed bombs. Out of 2,000 seed bombs planted in our pastures, only 5 Annual Sunflower plants bloomed in 2019, and 0 bloomed in 2020. This year, close observation showed that after planting, the seed bombs did soften in the spring rain, as hoped, and many of them germinated 2, 3, or even 6 plants, which started to send down roots into the surrounding soil. It all looked good until May when animals picked through many of these small, unprotected clumps of rich soil, destroying the seeds and young plants.
As Chris pointed out to us, while seed bombs sound good in theory, each bomb represents only a tiny point of contact between seed and soil, only a small chance at a plant reaching maturity. On the other hand, seeds broadcast onto a square foot of bare soil represent a hundred contacts and a hundred chances. To test this out, we picked a patch of our very worst soil, bare sand, and spent the winter burying our accumulating kitchen compost about 18 inches underneath the surface to provide a moisture source for roots to grow towards. This spring, we made a rectangular plot in the sand on top of the buried compost and planted half of it with seed bombs on a 1ft grid. On the other half, we broadcast the same seed mixture that was in the seed bombs and covered it in 1/8" dry soil. Only the rain watered the plot. Although many plants from the seed bombs initially germinated, not a single one had made it to maturity by the end of the growing season. On the side where the seeds were broadcast, Annual Sunflowers and several bunches of Sand Lovegrass (a desirable native grass) had come up and gone to seed.
Before we count the seed bomb technique out for good, I will say that this year Laura Jackson of the Tallgrass Prairie Center taught us that large, perennial prairie plants will sometimes germinate and then remain in a tiny state, maybe an inch in height, for an extended period of time until the right growing conditions emerge. This year, we did start to see some big, healthy tallgrass plants appear in a few of the locations we had planted seed bombs back in 2019. Maybe more are still on their way. We're not fully decided on whether seed bombs can be a viable tool for restoring missing parts of the prairie to our pastures, but for now we're going to focus on techniques that are producing more reliable results.
Interestingly, what has proven to be the most effective planting technique up to this point, is shallowly raking seeds into the rooting areas left by the wild hogs that often visit our land. Like a plowed field, plant competition is temporarily removed in these areas, opening up a chance for young seedlings to make it. Unlike a plowed field, the affected areas are usually small enough and the level of disturbance varied enough that it doesn't permanently remove the desirable plants from the area.
The technique of feeding grazing herd in a concentrated area for a winter and then over-seeding with prairie plants seems to hold a lot of promise. Our experiment last year definitely improved the biology (and growing potential) of the soil, but what came up was mostly non-native grasses from the seeds in the hay, rather than the native seeds we had broadcast. This technique would have probably been very effective if we could have gotten our hands on native hay. This year, we were again unable to get native hay, but we did get hay cut from cool season rye grass that goes dormant before the main native grasses are really taking off. We'll let you know how this goes. Hopefully one of these years, we'll be able to find a native hay source and try it.
This spring, we experimented with planting young, bare-rooted plants in the ground for the first time. Our technique was to dig a small hole in the ground, mix some compost in with the loose soil, put the plant in, and place colored mulch around it to hold in moisture, limit competition, and to help us re-locate the plant. We returned to water every day until we figured the roots were well established. This technique was extremely labor intensive, but also quite effective at reintroducing Eastern Gamagrass and Switchgrass to some small, protected corners of our pastures, from which they may expand. We learned that for these plantings to have the highest chance of success, they need as much root mass as possible. This means that when grass seedlings are small, they are much more likely to survive when several of them are planted in the same hole together, rather than being separated.
Three winters ago, we accidentally burned 27 acres of our bottom land pastures. The grasses and native flowers that came back were impressive. Too wet to mow, these bottom land areas have again grown up in brush to the point that they are not making as much food for our animals as they once did. It's time to burn them again (in a controlled way this time). Seeding over the burned areas may provide our best and lowest-cost opportunity to reintroduce native grasses across some big areas. We'll let you know how it goes.
There is such a small amount of good, practical information about rebuilding native prairies in working pastures available on the internet. We hope that the above can encourage conversation. Please feel free to write into the comments or email us directly. Let's start talking.