Vertical partition of corn stover fractions prior to harvest

Abstract

The goal of this study was to determine the vertical partition of corn stover components in eastern Canada, and to consider fractional harvest. Four corn hybrids in two climatic zones were monitored over a twelve-week period for stem length, ear height, total dry matter (DM) and moisture content (MC). Hybrids with low crop heat units (CHU) were shorter; their ears were at 0.96 m above the ground on average. Hybrids with high CHU were taller and their ears were 1.21 m above the ground. At the end of the study, the average DM yield partitioned in seven components was: 54% grain, 14% bottom stalk (below the ear), 6% top stalk , 5% bottom leaves, 7% top leaves, 5% husk and 9 % cob. During the harvest period, the total mass of fiber decreased from 8.9 to 6.6 t DM/ha for a low CHU hybrid and from 9.3 to 8.3 t DM/ha for a high CHU hybrid. Compared with U.S. data, the MC of stover was much higher in Quebec. At the end of October, stover MC remained at 60% in Quebec compared to 50% in Wisconsin and less than 20% in Tennessee. For industrial end-uses (pellets, wood paneling), the MC of fiber should be as low as possible to minimize artificial drying. This research suggests collecting stover later in the season and mainly from the upper half of the plant to reduce drying costs. Natural field drying to reduce stover MC should also be considered.