A small (0.8 acre) CRP field near the barn and wetland
has been planted to prairie in a different manner. Instead of killing
all existing vegetation with glyphosate, we started with a combination
of burning and overplanting, using wet-mesic and wetland species.
This experiment was begun in 2001 and was partially successful.
However, by the fall of 2004 we realized that we were not going
to get rid of smooth brome simply by waiting for prairie vegetation
to outcompete it (at least not in our lifetimes). Herbicide treatment
was added to the operation, but with a different approach. Below
a brief summary.
The first burn was carried out in April 2001. The fuel was primarily
exotic smooth brome, which had moved into the field during the mid-1980s,
when it was last cropped. After the burn, the field was planted
with wetland and wet-mesic prairie species that had been collected
elsewhere on the property. During the summer of 2001 wild parsnip
was removed by hand, and Canada thistle was treated with glyphosate
(spot foliar treatment with 2%). The field was also mowed in mid-summer
and the crop removed (used by a local beef-cattle farmer). This
whole process was repeated in 2002: burning, seeding, mowing, weed
control. |
In 2003 the field was burned again, followed by overseeding.
This time it was mowed early in the season (late May). Weed control
by hand pulling continued. At the end of the season, a species check
list showed 26 prairie species, including Indian grass, several
asters, Joe-pye weed, ironweed, and all four Silphium species (none
of which flowered). However, there was still a lot of exotic grasses,
including smooth brome and quackgrass.
In 2004 the field was burned again, followed again by overseeding,
but it was not mowed at all. A check list showed 52 prairie species,
all flowering and many setting seed.
Because the west end of the field had a lot of quack-grass, and
smooth brome was still present throughout, we used a technique suggested
to us by Jim Sime. This involved spraying with glyphosate in early
spring, after the exotic grasses were up but before any prairie
(warm-season) plants were visible. Since glyphosate is inactivated
when it comes in contact with soil, it should have no effect on
the prairie plants (which have not have yet appeared above the surface).
To this end, we burned this prairie in early December 2004 so that
we would be able to see and treat the bad grasses as soon as they
appeared. In early April, the local co-op (Premier; Black Earth)
came with their boom sprayer and sprayed the whole field. (Because
this little field was well below the level of the co-op's minimum
charge, we also had them spray some other fields on the same trip.)
Getting the timing of the spraying correct was a little tricky,
since the first week of April was quite warm in 2005 and some prairie
species were partly affected. However, this was not a permanent
effect and the 2006 observations showed that they were all present
and growing well..
The results for the summer of 2005 were quite satisfying. Prairie
dock, ironweed, cup plant, bottle gentian, glade mallow, several
Rudbeckias, prairie blazing star, wild bergamot, wild quinine, golden
Alexanders, Indian grass, and many other species were present and
flowering (see list below). The smooth brome and quack grass were
greatly reduced in amount, and their space was occupied extensively
by fox tail grass, an annual that did not persist.
Noteworthy in 2006 was big bluestem, Indian grass, and an additional
Silphium species, compass plant, all of which flowered this year
for the first time. |
