Old Pasture Seeding
By Carl Kurtz
Learn how you can establish a prairie ecosystem on old pasture land.
A Practical Guide to Prairie Reconstruction (The University of Iowa Press, 2013), by Carl Kurtz, is a step-by-step guide to implementing a diverse and thriving prairie ecosystem. Kurtz is a naturalist and teacher whose professional writing and experience on his own acreage of prairie has informed a revival in preserving prairie tallgrasses. The following selection explains how to reestablish a diverse prairie on old pasture land.
What is the procedure for seeding an old pasture? Are there any benefits?
If you’re thinking about establishing prairie in an old pasture, here are some recommendations. Before doing anything to the site, take an inventory of what is growing there. We purchased an eighty-acre pasture fourteen years ago, and during the summer before we took possession we were able to make a list of nearly one hundred native species that were growing on the site. Generally it is best to allow the pasture vegetation to grow for at least a year after a history of heavy grazing to see what shows up. Burning the area may activate bonsai prairie plants. Our site had been so overgrazed that it took three years before we had enough vegetation to do the first burn.
Here is a procedure that we used that you might try if parts of your pasture are extremely degraded. First, we mowed the area in October and waited until new green vegetation appeared. We then sprayed it with Roundup in early November.
If the site had been smooth enough to drive over with a mower the next summer, we would have fall-seeded in late November. Instead, in early April, we burned off the dead vegetation. A few weeks later, remnant stands of big bluestem, side-oats grama, prairie violet, and sedges came up green and lively. They had been untouched by the spraying since they were in a dormant state. We tilled the soil lightly where there were native plants. We used a field cultivator in the rest of the area to uproot the rhizomes in patches of reed canary grass and an extensive area of smooth brome. Once the ground was leveled, we rolled it with a cultipacker and spread the seed mix.
Through the summer following the seeding, we mowed the area several times to a height of three or four inches to control weed growth. In reality weeds make a good cover crop if you keep them short enough that they do not smother the new prairie seedlings.
In other parts of our pasture site, we did fall overseeding without any ground preparation. No mowing, no herbicide, and for the most part no fire. The seed that we spread consisted primarily of early successional species such as gray-headed coneflower, saw-tooth sunflower, cup plant, ox-eye, and small amounts of native grasses. The results have been phenomenal. Many weedy species such as Queen Anne’s lace have nearly disappeared. The bands of color from the overseeded species follow the line of the meandering stream across a rich bottomland.
We did a considerable amount of overseeding on the site in the winter months. In the spring of our thirteenth year of ownership, a wildfire burned a large portion of it. That summer we saw numerous prairie plants that had never been visible before.
In some cases, it may have been seven or eight years before plants in the seeded area bloomed for the first time. Remember that your goal is to displace the bad stuff with the good stuff. In every case, try to be patient; prairies are largely composed of perennial plants. They are long-lived with full root development and succession occurring gradually over a decade or longer. Persistent attention will be needed for years to come.
What kinds of equipment will work best? How much seed should you plant? Is there a best time to seed?
There is no perfect time to seed tallgrass prairie. Successful plantings have been done in spring, summer, and fall. For many years we planted in mid to late June and found that we had fewer weed problems than we encountered with early spring seedings. There is also less chance of erosion from very heavy spring rains after mid June.
Since some species of forbs need cold-wet stratification to germinate, they may not germinate until the following spring. Cold-wet stratification means that the seed needs to be moist and just above freezing for a period of thirty to ninety days to break its dormancy. This process occurs over winter when you seed in late October and early to mid November and appears to give a wider variety of species an equal start. On some occasions we have planted the first half of the seed in the fall and overseeded the second half, without tillage, the following fall. Seed harvested from native stands usually varies considerably in quantity, quality, and species diversity from one season to the next. To increase diversity in your planting, use seed that is harvested in two different crop years.
Seed about ten to fifteen pounds of mixed forbs and grasses per acre using at least twice the weight of forbs compared to that of grass seed. Use a ten-pound rate for certified seed and a fifteen-pound rate for hand-collected seed. We use a rate of fifteen pounds for seed harvested from virgin sites. Certified seed that has been tested for germination and purity is more reliable. It is, however, more expensive if you are planting for high species diversity.
Depending on the management of the native site, the viability of seed harvested from virgin stands can range from less than 10 to more than 70 percent. In any case, we have never had a planting failure when using a rate of fifteen pounds per acre.
Regular burning on the harvest site is extremely important if you want to maintain seed quality and quantity from one year to the next. Sites that have not been burned for many years are generally poor seed producers.
Truax and Great Plains drills work very well for clean seed; however, they may not work well with seed that contains broken leaves, large stems, and other debris larger than an inch. We have found that dry fertilizer spreaders work well for seed mixed with heavy trash, but the material must be agitated by a person riding in the back of the spreader or it will bridge up and fail to deliver a uniform quantity. Fertilizer spreaders distribute seed over an area about six feet wide. Ezee Flow spreaders work very well for seed that contains heavy trash. Three-point broadcast seeders such as the Vicon are also being used by many individuals with good results. After the seed is broadcast or drilled, harrow lightly if the soil has been cultivated and roll until the soil is very firm. Remember that rolling is your best defense against water erosion when the soil is not protected by vegetation. If you are planting on a soybean or corn stubble field, leave the seed on the surface and let natural weather conditions plant it.
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