Biomass Feedstock Production and Provision: Overview, Current Status, and Challenges - Engineering and Science of Biomass Feedstock Production and Provision - page 7

Even for digging up the rhizomes of mature plants for propagation, a potato
harvester is often used. The seeding for switchgrass and rhizome planting for
Miscanthus will typically be done in late spring or early summer when possibility
of frost is minimal.
The irrigation and fertilization practices for dedicated energy crops have not yet
been optimized. Although these crops can produce good yields even without fertiliza-
tion, some fertilization will be done, especially in the fi rst year to improve yield. For
example, the application of nitrogen fertilizer on switchgrass monoculture increased
the yield signifi cantly [ 18 , 19 ]. The impact of fertilization on Miscanthus yield has
been found to be less pronounced. The application of pesticides and herbicides may
also be done, and the optimal application rates are being currently investigated.
A major issue for these perennial crops is survival during winter, also known as
overwintering, especially in the temperate and cold regions. Excessive cold may
damage the seed and rhizome, which may lead to lack of emergence during the next
growing season. In the fi rst season itself, some seeds and rhizome may fail to
emerge. Consequently, some reseeding will be required at the beginning of the
second and possibly third growing season.

1.3.2 Harvesting, Packing, and Handling

The crop residue is generated during the harvesting of the primary crop, such as
corn and wheat. The residue left on the fi eld after the primary harvesting operation
is over will be collected and baled. The equipment and associated technology are
well developed and available. Crop residue, if left on the fi eld, enriches soil nutri-
ents and moisture and reduces soil and water erosion. Therefore, the fraction of resi-
due that is collected will have to be carefully decided. It has been reported in the
literature that only up to 30 % of corn stover can be sustainably collected after
accounting for these factors [ 20 ]. For dedicated energy grasses, the collection will
depend on the type of harvesting system being employed. The two-pass collection
system appears to be the one that will most often be used for energy crops. The
harvester or mower will harvest the biomass crop in the fi rst pass, while a baler will
later pick it up and bale it in the second pass. The collection effi ciency will be lower
because all biomass cannot be picked up by the baler. Moreover, there is the possi-
bility of soil contamination. To overcome these issues, and also to speed up the
overall process, a single-pass operation is being proposed. The harvested biomass is
directly sent to a baler without being dropped on the ground. This ensures that all
the biomass is baled without any soil contamination. However, this technology is
still at the demonstration stage. For baling, a round baler normally has a lower
throughput rate and output bale density than a square baler [ 21 ]. However, it might
still be used more often because it is cheaper than a square baler. Moreover, round
bales shed water more readily than square bales. This means that if the bales are to
be stored in the open without protection, biomass in round baled form would be
better protected against rain. Another option that has been implemented, especially