Thoughts on establishing a prairie
Imagine you're looking out onto 3,000 acres of pasture land, and would like to complete a successful prairie restoration. This will be about a 7 year project to even get close to a fully established prairie that you can feel good about.
Take a walk through the tract of land, and do a thorough inventory. Seek out any native plants that may be hiding, and stake this area out. Chances are, if you find a few native plants, there may be more seed beneath the soil. This could potentially turn into a remnant of previous prairie plants naturally occurring.
Take the non marked existing land, and spray the vegetation with a non-selective herbicide. This is done late summer.
All vegetation you sprayed will be ready to burn after a couple weeks. The dead vegetation will act as fuel for the fire.
Burn breaks must be made around the possible remnant areas found to protect these plants as they will still be living when the fire is conducted.
Once the fire has run through, seeding may commence. DO NOT throw all of your eggs into one basket...
Install a cover crop such as Canada Wild Rye.
This article also states that side-oats grama is another fine cover crop for establishing a prairie: http://www.ag.iastate.edu/farms/06reports/w/NativeCoverCrops.pdf
The article also brings about another point of installing seeds of plants that will establish early in the spring. This is most notable for stabilizing the soil.
Remember More disturbance --> More opportunity for invasive/aggressive plants.
As the competition from the previous flora is diminished, and a fire sent through in the fall, the spring will have awakened any seed in the soil looking for a chance to emerge.
This point is exactly why you do not want to put all your eggs in one basket. With no forbs or fabaceae plants installed, you are given the upper hand to combat anything that emerges unwanted. Selective herbicides targeting broadleaf plants can be used in mass quantity. This will not harm your cover crop of rye or side oats, and will dramatically decrease the unwanted plants.
Something to take serious and to watch for on these herbicide labels is the ounce per acre, and how many applications per year you're allowed. If you're doing this by yourself with smaller equipment, and a little less low tech, this can be challenging. Luckily there's Ag equipment out there that utilizes GPS to know where to spray. On a 40' boom sprayer, if the rig crosses over an already sprayed area, the 7' or so of the boom that crossed will automatically shut off. The rate at which these machines put out is also much more effective and cost efficient that trying to do it yourself with an ATV and 10' boom.
Take a survey of problem areas, and reflect on whether or not the land would be ready for seeding. You may need another round of fire, and mass herbiciding before installing the rest of the seed in year 3. Achieving a successful prairie in accordance with time, is most beneficial to rid out the invaders first. This is getting the heavy lifting out of the way first.
Let's say you spend year 2 spraying selective herbicides, and decide not to install the prairie seed. Continue the same process of fire, and selective treatments until you believe you have exhausted the seed pool within the soil. Once this is accomplished, spray the cover crop again in late summer. Burn these areas to prep for seed. Install the prairie seed, and watch it emerge in the following spring.
Some say you can inter-seed amongst your cover crop, but I'd say just start from scratch again.
Identifying the plants as they come up can be seen as quite challenging as they're seedlings and a lot can look similar. Yet looking at a chart showing which plants emerge when, will cut down the number of plants substantially from your seed list you installed for identification.
As a side note to this installation, it is recommended to use a mycorrhizae inoculant with the seed mix. The science with this gets complex, as this is a difficult relationship to study. There are many factors that can go into the results. In essence, it acts as a performance enhancer that bolsters the surrounding soil. However, I would like to think that this can also feed any invasive plant seeds still within the soil (making them just as adventageous). There is also minor disturbance with the seed drill. This could provide enough of a window combined with the mycorrhizae to entice the invasives to emerge. Not to mention all competition has vanished from above ground. Just something to think about. We'll save the entire mycorrhizal association with plants for another day.
With all of that being said, there are numerous ways to go about restoring a prairie. I believe the learning curve is getting a lot better. If someone invents sort of a sonar detector (fishing) to inspect the soil before a seeding to determine what seed lies beneath the soil, we'd all be a lot better off.