Switchgrass and Giant Miscanthus Agronomy - Engineering and Science of Biomass Feedstock Production and Provision - page 49

work well, provided they are fresh or have been stored properly under moist
conditions at temperatures of 4 °C [ 81 ]. Plugs should be planted so that the soil level
at the planting site is at approximately the same level as the soil in the container.
Rhizomes have commonly been planted at densities of 1-4 m −1 [ 57 ]. Currently,
University of Illinois, Urbana-Champaign, stands are planted at approximately
17,200 plugs or rhizomes per hectare (approximately 76 cm between rows and
76 cm between rhizomes or plugs within a row) because this density works well
with existing farm equipment and surrounding plants can fi ll planting skips more
readily than when using larger spacing. Attempts to replant skips with rhizomes or
small potted plants during the second and third growing seasons have had limited
success, as well as being labor intensive (authors' observations).
Planting sites are commonly rotary tilled to a depth of approximately 15 cm prior
to planting rhizomes or plugs. In temperate regions, it is recommended that rhi-
zomes and plugs be planted in early-to-mid spring. In the University of Illinois,
Urbana-Champaign, research and production fi elds, four-row planters, similar to
types used to transplant nursery or vegetable transplants, are used, which allows
2.4-3.2 ha per day to be planted and requires fi ve or six laborers. Currently, there
are several different commercial planters used in the USA and Europe that allow 12
or more hectares to be planted per day and require fewer laborers. Herbicides are
necessary during the planting season and often during the second year. Harness
(acetochlor) and Harness Xtra (acetochlor + atrazine), both produced by Monsanto
Company (St. Louis, MO), are labeled for grass control in M . × giganteus grown for
bioenergy. Broadleaf weeds are commonly controlled using 2,4-D. Additional
chemical weed controls have been successfully tested [ 82 ], but have not been
labeled for application to this crop.

3.3.3 Managing Established Giant Miscanthus

Managing established giant miscanthus is relatively easy due to the minimal inputs
it requires—in many years, the only necessary management activity in established
giant miscanthus occurs when the grass is harvested. First, while giant miscanthus
responds to moisture, it is the authors' opinions that energy crops should be pro-
duced without irrigation. Irrigation adds a production expense and also uses a
resource perhaps better used for human consumption or livestock and food crop
production. As a C4 grass, M . × giganteus is drought tolerant once established, but
production is commonly limited by water availability. Next, established giant mis-
canthus grows rapidly and develops a closed canopy early in the season, making it
extremely competitive with weeds, which typically makes chemical weed controls
unnecessary after the second growing season. In addition, while US researchers
have identifi ed several potential insect, disease, and virus problems on giant mis-
canthus [ 83 - 87 ], none of the identifi ed pests have been shown to reduce biomass
production. Moreover, there have not been reports of signifi cant pest problems on
commercially produced M . × giganteus in Europe.