Agriculture Reference
In-Depth Information
fallow break year during which new coppice growth, red fescue, and weeds
were killed with glyphosate, in May 2009 trees were replanted as stem
cuttings on a 1.5 × 2.4 m (5 ft × 8 ft) row spacing. For this third rotation,
the variety
Populus nigra × P. maximowiczii
“NM6” was planted with no
cover crop; weeds were controlled with herbicides applied in the first 2 years
of establishment and fertilizer was applied once, in the third year of the
rotation, at 156 kg N ha
-1
.
• The Coniferous Forest (CF) includes three small long-rotation tree
plantations established in 1965 and sampled as part of the MCSE beginning
in 1993. One of the three sites is dominated (>10% of total biomass) by
red pine (
Pinus resinosa
Aiton); a second is a mixture of Norway spruce
(
Picea abies
[L.] Karst), red and white (
Pinus strobus
L.) pines, and now
with significant black cherry (
Prunus serotina
Ehrh.) and large-tooth aspen
(
Populus grandidentata
Michx.); and the third is dominated by white pine.
The conifer stands have been periodically thinned and understory vegetation
removed by prescribed burning as recommended by MSU Extension Forestry
personnel.
Four successional ecosystems, either minimally managed or unmanaged, pro-
vide valuable reference communities for comparisons of specific processes and
populations:
• Early Successional communities (T7) were allowed to establish naturally
on land abandoned from row-crop agriculture in 1989 and have been left
unmanaged but for annual spring burning (begun in 1997) to prevent tree
colonization. Currently, the dominant plant species (>10% biomass) include
Canada goldenrod (
Solidago canadensis
L.), red clover (
Trifolium pratense
L.), timothy grass (
Phleum pratense
L.), and Kentucky bluegrass (
Poa
pratensis
L.).
• A Mown Grassland (never tilled) community (T8) that has never been in
agriculture was established naturally following the removal of trees from a
10-ha woodlot in ca. 1959. The site has been mown annually in the fall since
1960 to inhibit tree colonization, with biomass left to decompose on site. At
times between 1960 and 1984 the site may have received manure additions
during winter months. Because the site has never been plowed, it retains
an undisturbed, presettlement soil profile. KBS LTER sampling began in
1989. Plant community dominants (>10% biomass) include smooth brome
grass (
Bromus inermis
Leyss.), tall oatgrass (
Arrhenatherum elatius
L.),
and blackberry (
Rubus allegheniensis
Porter). Sampling occurs within four
replicated 15 × 30 m plots randomly located within a portion of the field.
• Mid-successional communities (SF) occupy three sites that were abandoned
from agriculture in the 1950s and 1960s (Burbank et al. 1992). Since that
time they have been allowed to undergo succession, which is occurring at
different rates across the replicates, possibly reflecting differences in soil
fertility. One site (SF-1, abandoned in 1951) has limited overstory growth
and is dominated (>10% biomass) by tall oatgrass, Canada goldenrod,
quackgrass (
Elymus repens
L.), timothy grass, and Kentucky bluegrass.
