Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/1/2008
Publication Date: 1/2/2009
Citation: Shinners, K.J., Boettcher, G.C., Hoffman, D.S., Munk, J.T., Muck, R.E., Weimer, P.J. 2009. Single-Pass Harvest of Corn Grain and Stover: Performance of Three Harvester Configurations. Transactions of the ASABE. 52(1):51-60. Interpretive Summary: The non-grain portion of the corn plant (stover) is potentially useful for producing ethanol. However, current systems for harvesting corn stover are costly and involve many trips across the field to accomplish. A corn grain combine was modified in three different configurations to study potential ways to harvest corn stover simultaneously with the grain. The system that harvested just the cob and husk in addition to the grain had the least effect on harvest rate and fuel use but resulted in the least biomass harvested per acre. All three configurations could be set to leave sufficient residue to prevent excessive soil erosion. While further research is needed to refine the modified combine, it appears that simultaneous harvesting of corn grain and stover should be possible for farmers in the future when biorefineries will be producing ethanol from stover as well as corn grain.
Technical Abstract: Corn stover was harvested with a modified combine that simultaneously harvested grain and stover in separate streams. The harvester was used to collect the following stover fractions using three different heads: cob and husk (ear-snapper head), stalk and leaves (stalk-gathering head), and stalks, leaves, husk and cob (whole-plant head). Cob and husk were also collected when using the stalk-gathering head, but in a separate stream from the stalks and leaves. Material harvested with the ear-snapper, whole-plant or stalk-gathering head had average moisture of 38.2, 45.0 and 46.7% (w.b.); particle size of 14, 22 and 90 mm; and density in the transport container of 98, 64 and 40 kg DM/m3, respectively. Area productivity was 3.4, 1.9 and 1.5 ha/h; fraction of available stover DM actually harvested was 18, 64 and 49%; total harvester specific fuel use was 1.46, 1.83 and 2.07 L/Mg DM or 17.0, 27.4 and 33.4 L/ha for the ear-snapper, stalk-gathering and whole-plant head configurations, respectively. The untilled ground cover in the fall and spring was greater than the minimum requirement of 30% with all three heads. Chisel plowing in the fall with twisted shovels buried too much residue no matter which harvester configuration was used. Chisel plowing in the spring with sweeps left sufficient residue when either the ear-snapper or stalk-gathering head was used. Material harvested with the ear-snapper, stalk-gathering or whole-plant head had an average density in a bag silo of the transport container of 261, 111 and 160 kg DM/m3, respectively. Average loss in a bag silo was less than 4.3% of total stover DM after nine months of storage. Based on estimated cellulose and hemicellulose content, ethanol yield was 868, 1474, and 2804 L/ha from materials harvested with this ear-snapper, stalk-gathering and whole-plant heads, respectively.