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.
Special herbicide treatment 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 has 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.) Using the co-op for this task made lots of sense, because their spray rig is very efficient and the job can be accomplished in very little time.
Getting the timing
of the spraying correct was a little tricky. The co-op recommended that the field be sprayed at the time that the exotic grasses were about 4 inches tall. Thus, close monitoring was important, and when the grass was getting close to the right height we alerted the co-op that we would need them soon.
week of April in 2005 was quite warm, so that small shoots of some of the prairie species
were above ground and were partly affected. However, this was not a permanent effect
and the 2006 observations showed that they were all present
and growing well.
Spraying the Barn Prairie April 2005
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.