Yield and moisture content of corn stover components in Québec, Canada.

Abstract

Over a three-year period (2008 to 2010), seven corn hybrids were sampled weekly from early September to mid-November. They had been planted on three different sites in climatic zones ranging from 2500 to 3100 crop heat units (CHU). Dry matter (DM) yields and wet basis moisture content (MC) were measured during 8 to 12 weeks for grain and six stover components: lower stalk (below the first ear), upper stalk, lower leaves, upper leaves, cob and husk. At the expected grain physiological maturity, total stover yield at the 2500 CHU site averaged 7.21 t DM ha-1 with a stover-to-grain mass ratio of 0.94. Total stover yield was higher at the 3100 CHU sites with 8.75 t DM ha-1 for a stover-to-grain mass ratio of 0.82. The average fractions of stover were: cobs 18%, husk 9%, upper leaves 15%, lower leaves 14%, upper stalk 11% and lower stalk 33%. Lower stalks were the wettest component with MC of 63 to 84%. MC of leaf and husk fractions was below 20% toward the beginning of November. From early September to late October, stover moisture declined gradually from 75 to 54% at the 2500 CHU site and from 70 to 45% at the 3100 CHU sites. Even by mid-November, average stover MC remained above 30% so direct harvest in the fall would not be feasible with dry storage. Stover above the ear (husk, cob, upper leaves and upper stalk) was drier than stover below the ear. Partial stover harvest above the ear may allow dry storage but would leave an average of 47% DM in the field.