Open Gate Rotational Grazing

An alternative approach to facilitating wildlife and plant diversity in grazed prairie.

Based on the last 20 years of experience and data collection, the shifting mosaic approach to habitat management seems to support plant and animal diversity and foster ecological resilience in our prairies.  One of the most important parts of our shifting mosaic management is that each patch of prairie goes through a progression of season-long intensive grazing, followed by a multi-year recovery period.  At any time, only part of a prairie is in each phase of the system (intensive grazing, early recovery, late recovery), so there is always a variety of habitat structure available (short, “weedy” and tall) for wildlife.  In addition, as that grazing/recovery progression occurs, plant species experience a different set of growing conditions each year.  Regardless of its competition ability or strategy, each plant is ensured favorable conditions for its growth and reproduction at least once every few years.  Based on our long-term data sets, our management has sustained plant species richness, and both conservative and opportunistic plant species are persisting in our prairies.

A fenceline contrast at our family prairie shows the kind of habitat heterogeneity found in a shifting mosaic approach to prairie management.

Patch-burn grazing is one way to create a shifting mosaic, but it’s certainly not the only way.  While patch-burn grazing has some attributes that make it easy to implement (no need for cross fences or moving animals during the season), it does require regular application of prescribed fire, which can be difficult for some landowners.  In addition, patch-burn grazing is very different from the kinds of rotational grazing systems many ranchers are comfortable with and have set up their pastures for.  We’ve been experimenting with an approach to creating a shifting mosaic that keeps many of the wildlife and diversity-friendly attributes of patch-burn grazing but might fit better within the comfort zone and logistical framework of many ranchers.

For lack of a better idea, I’m currently calling this approach “Open Gate Rotational Grazing”.  It is not a rigid prescribed grazing system, but rather a general and adaptable way of managing multiple grazing paddocks within a prairie.  It’s similar to a traditional deferred grazing strategy, but with one big difference.  In most rotational grazing systems, cattle are moved from one pasture to the next, closing the gate behind them to allow the previous paddocks to rest.  In the open gate system, when cattle are presented with their next paddock, the gate behind them remains open – allowing the cattle to continue grazing the initial paddock even as they have access to new grass.

In a traditional rotational grazing system, cattle are progressively moved through a series of paddocks, closing the gate behind them.  In a deferred rotational system, at least one paddock is usually rested for the season.
Under an open gate approach, gates are left open when new paddocks are made available, allowing cattle to graze both the new paddock and the one(s) they had been grazing before.

The idea started one year when we weren’t able to get a burn done in a prairie under patch-burn grazing management.  Since we didn’t have a burned patch to focus cattle grazing, we instead used electric fence to concentrate the cattle in the area we’d hoped to burn.  We kept them in the enclosure until they had it grazed pretty short.  Then we removed the electric fence and allowed cattle to access to the whole site.  For the remainder of the season, the cattle continued to focus most of their grazing in that former enclosure, attracted by the tender regrowth.  As a result, the overall grazing pattern was fairly similar to what we’d expect with patch-burn grazing.  Seeing how strongly cattle were drawn back to where they’d grazed earlier provided the seed for the open gate rotational system.

On my family prairie, I’ve been using the open gate approach for the last several years.  I have four paddocks, and I basically think of the gates between those paddocks as relief valves.  We start with the cattle in one paddock, and when they have grazed most of the grass down in that pasture, I open the gate to an adjacent paddock so they have more options.  The cattle can keep grazing the regrowing plants in paddock #1, but they aren’t forced to eat more than they want to in that paddock because they have another whole paddock available to them.  If the cattle graze down most of the plants in the second paddock, I can open a gate to a third paddock and provide them with even more options.  I keep the fourth paddock closed off for the entire season so it can rest.  I choose a different paddock to start with each year.

The result of an open gate approach is that one paddock is grazed all season long, one is rested all season, and the others have intermediate levels of grazing.  This results in heterogeneity of habitat structure as well as a wide range of growing conditions for plants.  Each year, grazing starts in a different place, shifting the disturbance regimes among the various paddocks.

The open gate approach can be used with just about any rotational grazing system, as long as there are adjacent paddocks that can be opened up.  One key component of the open gate approach is that paddocks grazed early in the season continue to receive grazing pressure for the rest of that season without forcing cattle to eat progressively lower quality forage as the season goes on.  Instead, cattle can regulate their diet freely, choosing between previously grazed areas and those they haven’t yet grazed.  Typically, when cattle are given that kind of choice, they eat very little other than grasses.  This works out well for pollinators because it means many wildflowers are allowed to grow and flower amongst grazed grasses.

At our family prairie, the open gate approach seems to be helping with our continuing quest to increase plant diversity in areas formerly dominated by grasses.  New plants are introduced via overseeding (after a season of intensive grazing), and then persist under our grazing management.

In the open gate system, there is great flexibility about when, and how intensively, each paddock is grazed each year, though some of that flexibility depends on how the paddocks are arranged.  Ideally, all the paddocks would be connected through a single hub so the manager can choose to open any gate to any pasture, as needed.  However, my family prairie doesn’t provide that amount of flexibility (the four paddocks are arrayed in a donut-like loop, with no way to connect them through the donut hole) and the approach still works.  Most of the time, the paddock grazed most intensively one year gets complete rest the next.  However, the pattern of grazing each year always depends upon how I think recovery from previous years’ grazing is going.

I think there are great benefits to longer grazing periods and longer rest periods than are typically found in rotational grazing systems.  Certainly, those prolonged grazing and rest periods can provide a greater variety of wildlife habitat conditions, especially on the shorter and taller ends of the vegetation structure spectrum.  In most rotational grazing systems, cattle are moved out of a pasture before grasses are grazed very short, allowing them to recover quickly.  In addition to reducing habitat heterogeneity, that approach can favor strong grass dominance at the expense of wildflowers and plant diversity.

Even when grazing pressure is intense within each paddock of a traditional rotational system, short duration grazing may not foster habitat heterogeneity.  For example, if a paddock is grazed hard in May, it might suppress cool-season grasses, but warm-season grasses won’t be much affected, and once cattle are removed, summer vegetation will fill in quickly, resulting in vegetation structure of moderate to tall height.  The same can happen with summer grazing bouts followed by fall growth of cool-season grasses.  By maintaining grazing pressure for the entire growing season, two things happen.  First, there is sustained short vegetation structure for wildlife that need it.  Second, and perhaps more important, all dominant grasses are weakened by that long term grazing, leading to a fairly long recovery period (1-3 years, depending upon grazing intensity and geographic location), during which wildflowers and other plant species are temporarily released from that grass competition.  That long recovery period creates terrific wildlife habitat and also helps sustain plant diversity.

While prescribed fire isn’t necessary in open gate rotational grazing, it can certainly be incorporated.  The paddock to be grazed all season could be burned before the season starts, for example, which would further add to its attractiveness to livestock (and remove eastern red cedar trees, excess litter, etc.).  At my own prairie, I haven’t been using fire for a variety of reasons, including that I’m so busy burning for work I don’t have time/energy to burn my own place.  So far, I’ve been happy with the way the prairie is responding in the absence of fire, but if I can get myself better organized, I wouldn’t mind doing some burning.  If nothing else, it would mean less time cutting little cedar trees with loppers.

Prescribed fire is not a strategy all ranchers are willing or able to include in their operations.  The open gate approach provides options for creating a shifting habitat mosaic without relying on regular prescribed fire.

I don’t have many years of experience with this open gate approach, or much data to help me understand all the nuances of its impacts on flora and fauna.  However, what I’ve seen from early experiments seems promising.  I’m sharing the idea and our experiences so far, not because I’m endorsing the open gate approach as the next big thing, but because I hope others might find ways to try it and report back.  Because the basic idea is as simple as not closing a gate when opening a new paddock, it can be employed in many different scenarios if people see potential for it.  Also, I’m not trying to claim or patent the idea, and I’d be shocked if there aren’t people reading this that have already tried it in various forms.  If so, I’d love to hear about it.

How I Manage My Own Prairie

One of our major objectives at the Platte River Prairies is to experiment with and demonstrate various prairie management techniques and strategies.  All those strategies are aimed at creating and maintaining plant diversity, ecological resilience, and a wide range of wildlife habitat types.  We hope that our work can be useful to private landowners and other grassland managers looking for ideas to incorporate into their own management.  However, we don’t expect anyone to replicate exactly what we’re doing because every land manager has their own set of objectives for their land.  As an example of how others might incorporate some of the lessons we’re learning into a different setting, I thought I’d share how I’m doing that at my family prairie.

My family prairie is very different from the Platte River Prairies in several respects.  First, the Helzer prairie is on hills of loess (pronounced “luss”) soils, whereas the Platte River prairies grow in sandy loam.  In addition, most of my prairie was farmland until my grandpa seeded it back to grass in the early 1960’s.  There are a few small areas of remnant (unplowed) prairie embedded within the previously farmed area, and some plant species have spread from those.  However, plant diversity is still fairly low, so I’ve been supplementing that by adding seed of more plant species over time.

This is one of the more diverse portions of our prairie - a part that was never plowed.  It still has plants such as leadplant, stiff sunflower, and many others.
This is one of the more diverse portions of our prairie – a part that was never plowed. It still has plants such as leadplant, stiff sunflower, and many others.

The most important difference between my prairie and the Platte River Prairies, though, has to do with my objectives.  At the Helzer prairie, I want plant diversity and wildlife habitat, but I also need strong and steady income from my prairie to cover the taxes and contribute to our family’s finances.

Objectives for the Helzer family prairie:

  1. Increase plant diversity.
  2. Create a wide range of grassland habitat types each year (short/sparse to tall/dense and intermediate stages).
  3. Provide a place my family and I can enjoy.  I want my kids to hike, explore, camp out, and learn about prairies and agriculture.
  4. Make money.

Recreation is part of our objectives for the prairie, but income is also very important.

Recreation is one of our objectives for the prairie, but income is also very important.

Challenges:

  1. Poor soils – much of the organic matter in the soil, especially on slopes, eroded away when it was farmed and even more then 50 years of grassland cover has not rebuilt what was lost.
  2. Soil erosion.  Because loess soils are easily erodible, heavy rain can wash exposed soil from both the crop fields and heavily grazed areas of our pasture, causing a number of problems.  No-till farming techniques on the crop fields reduce erosion from them, but we also have to be careful about how we graze the prairie to avoid losing soil from the steeper slopes.
  3. Invasive species – smooth brome and Kentucky bluegrass are the big ones, and they can become dominant enough to swamp out plant diversity if left unchecked.
  4. Tree encroachment.  Eastern red cedar trees are constantly trying to colonize the prairie.  We’ve removed all the big cedar trees from our own property, but others nearby produce seed that birds helpfully carry into our prairie.  Deciduous trees such as honey locust, white mulberry, and green ash also spread into the prairie unless we beat them back.
  5. Habitat fragmentation.  Our prairie is truly an island of prairie in a sea of cropland.  We own about 160 acres of land, about 50 of which is in crops.  That leaves us roughly 110 acres of prairie on which we have to support populations of prairie plants and animals, and we can’t rely on the surrounding landscape as a source of recolonization if we accidentally wipe any of them out.

So, what to do?

Trees

Controlling the encroachment of trees, especially cedar trees, is pretty straightforward – we just cut them down as they come in.  We use herbicide on the stumps of deciduous trees, but with the cedars, my kids and I just roam around with loppers and snip the little ones off.  As long as we don’t get behind, it doesn’t take too much time, and it’s not hard work.

My son John, when he was 9, helping us clear cedar trees.
My son John, when he was 9, helping us clear cedar trees.

Of course, controlling cedars would be even easier if we were using fire, but we’re not.  (Surprised?)  I’d love to burn my prairie, but there are a two big reasons I don’t.  First, I don’t have any equipment for conducting my own burns – not even a drip torch.  I could probably borrow some equipment and find some people to help me burn if I really tried.  However, the bigger reason I don’t burn is that there are only so many days a year when weather conditions are appropriate for burning, and on those days I’m burning at work!  Maybe someday when I retire…  In the meantime, we’re getting by with loppers and cows.

Grazing Plans

This is the real heart of our management, and the part that takes the most thought and adjustment over time.  The first consideration every year is drought.  We live in a part of the country where droughts are frequent, and drought impacts our prairie particularly strongly because we have so little organic matter (which helps hold soil moisture) in the previously farmed portions.  As a result, I assume every year will be a drought year until I’m proven wrong, and my stocking rates are based on that assumption.  If we have a wet year, I can increase our stocking rate the next year to take advantage of the bonus root reserves produced by “undergrazed” grasses.  However, by stocking relatively conservatively, I can usually get through very dry years without overgrazing or putting an undue burden on my renter by making him pull his cattle off early.

A map of our 160 acres of land, including both cropland and grassland.  The prairie is split into four main pastures.  The blue dots show water tanks that we recently installed.
A map of our 160 acres of land, including both cropland and grassland. The prairie is split into four main pastures. The blue dots show water tanks that we recently installed.

Apart from drought, my main grazing strategy is to incorporate the concept of a “shifting mosaic of habitat types” across my prairie.  In the Platte River Prairies, we often accomplish this with various patch-burn grazing techniques, but I don’t use fire on my own prairie.  Instead, we have the prairie split up into four main pastures (and a couple smaller sites in and around the pond/wetland that are rarely grazed).  The way we utilize those four pastures changes every year based on what happened the year before and on short-term objectives, but there is a basic framework (shown below) I’ve been using for the last several years.

TEMPLATE GRAZING PLAN FOR THE HELZER PRAIRIE

Year 1                                                                              Year 2

Late April – Early May: Pasture #1                       Late April – Early May: Pasture #2

Early May – June 1: Pasture #2                             Early May – June 1: Pasture #3

June 1 – July 15: Pasture #3                                   June 1 – July 15: Pasture #4

July 10 – October 1: Pasture #’s 1, 3, and 4       July 10 – October 1: Pasture #’s 1, 2, and 4

A graphical illustration of my grazing plan framework.  In Year 1, pastures 1 and 2 are grazed early to knock back brome.  Then pasture 3 is grazed for a month by until mid-July.  For the remainder of the season, cattle have access to three pastures, but continue to graze pasture 3 most intensively because of the attractive regrowth of the grasses there.  This creates a system fairly similar to a patch-burn grazing system, but uses a grazing enclosure, rather than fire, to create attractive forage and concentrate grazing.
A graphical illustration of my grazing plan framework.

 

During Year 1 in the above example, pastures 1 and 2 are grazed early to knock back brome. Pasture 3 is then grazed until mid-July. For the latter half of the season, cattle have access to three pastures, but will continue to graze pasture 3 most intensively.  This is because the vegetation in pastures 1 and 4 was ungrazed during June/July and reached a later stage of maturity (and is less palatable) than that in pasture 3, which is still relatively young and tender because of the grazing.  In other words, the earlier season grazing stimulates later season grazing.

This creates a system somewhat similar to a patch-burn grazing system, but without the use of fire.  Pasture 3 gets grazed intensively for most of the season in Year 1, but pastures 1 and 4 provide “overflow” grazing to help ensure that pasture 3 isn’t grazed excessively.  That overflow also seems to limit wildflower grazing because the cattle aren’t forced to eat only from one pasture and can wander more broadly to find what they really want – mostly grass.

In Year 2, pasture 3 is rested (after a brief spring grazing bout to suppress brome) and pasture 4 has a year of intensive grazing.  The pattern continues in Year 3 and Year 4 and then (probably) starts over.  When everything works as planned, there’s always one pasture that’s short, one that’s got fairly tall vegetation, and another one or two in various phases of recovery from being grazed in previous years.  Even plants strongly sought after by cattle get a chance to bloom and reproduce at least once every four years, and most bloom much more often.

I’ve had to adjust my approach to grazing over time to be sure I don’t overexpose the prairie to soil erosion.  As a result, I graze a little less intensively than we do in our (mostly) flatter/sandier Platte River Prairies.  I really like the plant diversity and habitat results I get from season-long intensive grazing and multi-year recovery periods, but have had to moderate that somewhat as I’ve learned more about what the soils can take.  I still take the grass pretty short, but limit the length of time it’s kept that short – especially in parts of the prairie most prone to soil erosion.

Overseeding

Introducing seed to increase plant diversity over time is an important part of our restoration/management process.  My grazing management is facilitating the spread and survival of the plant species we have, but there’s limited abundance and diversity to work with.  My kids (sometimes) help me harvest seeds from around the county during the summer and fall.  During the winter, we broadcast those seeds in the pasture most heavily grazed during the previous year – where they can make contact with the soil where they fall.  That pasture is typically grazed the next spring, and then rested for the remainder of the year.  As a result, seedlings have a decent chance of survival because the surrounding vegetation was weakened by grazing, but they are not exposed to (much) grazing during their first season of growth.  So far, results from overseeding have been encouraging – we’re just limited by the time we have to harvest seed.

Here's Daniel, throwing seeds into an area that was grazed intensively the previous season.
Here’s Daniel, throwing seeds into an area that was grazed intensively the previous season.

By far, the most critical aspect of my management is adaptability.  While there is a basic framework for our grazing management, I don’t hesitate to stray from it in order to react to drought or invasive species concerns, or because it just looks like we need to try something different.  The pasture that gets the most intensive grazing each year is the one that has recovered most fully from its last intensive grazing bout.  That recovery time depends upon the stocking rate when it was grazed and the weather during and after that grazing period.  Most importantly, I try to ensure that all the plant species in the prairie are allowed to bloom at least once every few years (without getting their flowers nipped off) and that we always have a wide range of habitat structure (short, tall, and recovering vegetation) across the prairie.  If I see issues with either of those conditions, I adapt my grazing management accordingly.

There is no cook book for how to manage a prairie because every prairie and every prairie manager’s objectives are different, and those unique conditions require unique strategies.  However, I do think there are broad lessons about how to facilitate wildlife habitat and plant diversity (such as the “shifting mosaic of habitat patches” idea), and those lessons can be applied to almost any situation.  The trick is to figure out how to adapt them for an individual site and set of objectives, and to continue adapting them as weather and other conditions change.  In my case, I’ve come up with a system that works pretty well for my particular prairie and objectives, as well as with the time and equipment I have.

As I said earlier, I don’t want people to replicate the management we’re using in the Platte River Prairies.  Instead, I am always thrilled to hear that other land managers have picked up ideas from us and incorporated them into their own grassland management.  Hopefully, those ideas have helped those land managers increase plant and wildlife diversity on their land, while still meeting their other objectives.  That would make me very happy.