SPRING HARVEST OF CORN STOVER

In spring 2009, a quantity of 42.1 Mg of corn stover, on a dry matter basis (DM), was harvested over 11.4 ha under no-till or minimum tillage management. The average harvested biomass (3.7 Mg ha(-1)) represented a recovery of 44% considering previous fall stover yield of 8.3 Mg ha(-1) just prior to grain harvest. Corn stover was harvested with traditional hay making tools operated under two different sequences. The first sequence, called the fall plots, included mowing and raking in the fall, and raking once more and baling in the spring. The second sequence, called the spring plots, consisted in mowing, raking, and baling in the spring. Stover was packaged with three types of balers. Large square bales (LSB) were denser (150 kg DM m(-3) from fall plots; 128 kg DM m(-3) from spring plots) than large round bales (RB; 91 kg DM m(-3) from fall plots; 98 kg DM m(-3) from spring plots) and small square bales (SSB; 87 kg DM m(-3) from spring plots only). The moisture content of spring harvested stover was very low, ranging from 5% to 18% (wet basis). Average values and standard deviation showed that moisture content was lower and more uniform from spring plots. The operating speed averaged 6.3 km h(-1) for LSB, 4.4 km h(-1) for RB, and 2.0 km h(-1) for SSB. These speeds were slower than standard operating speeds in traditional crops such as hay and straw. Field efficiencies to harvest stover were also lower than standard values, from 43% to 60% for LSB and 52% to 54% for RB. Spring harvest of corn stover produced a very dry biomass which can be more useful than wet stover typical of fall harvest for some applications such as bedding and combustion. The fact that more than 50% of the original stover was not collected can be viewed positively for erosion control and soil protection.