Harvesting System Design and Performance - Engineering and Science of Biomass Feedstock Production and Provision - page 123

Fig. 5.36 Functional processes in harvest and transport of agricultural residue

5.4.4.1 Corn Stover

Cornstoverconsistsofthestalk,leaf,cob,andhuskofthecornplantandexcludes
thegrain.TheestimatedcornstoveryieldinNorthAmericaisabout130Tg,which
canproduce38.4GLofethanol[ 31 ].Cornstoverhasaconsiderableadvantage
compared to switchgrass and small-grain straw because of its current availability as
a by-product of corn grown as a food and fuel source. However, corn stover removal
results into loss of soil cover and nutrients, which could potentially increase soil
erosion and water pollution.
Typically, dried corn stover is baled. Traditionally, after grain harvesting, a flail
shredder shreds the stalks, the sunlight dries the spread stover, a rake forms wind-
rows,andaroundbalerbalesthewindrowsatabout20-25 %moisture.InNorth
America, it takes several days to weeks before the stover reaches baling moisture
because of low ambient temperature and rains. Sometimes stover is harvested wet
(>45%moisture)andpreservedbyensiling[ 32 ].Wetharvestingeliminatesield
drying and improves timeliness. After a combine has harvested the grain, a shredder
shreds and windrows the stover in a single pass. A forage harvester with a windrow
pickup head gathers and chops the stover. Table 5.9 shows the results of a study in
North America on the performance of a precision-cut forage harvester for corn sto-
verharvesting.Thewet throughputratevaried from40to55 Mg ha −1 and dry