Corn Stover Fractions during Extended Harvest

摘要

Two corn hybrids were sampled weekly at each of three research farms in Quebec, Canada between September 4 and November 19. The Saint-Augustin site (AUG) was in a 2500 crop heat unit (CHU) zone while the two other sites, Sainte-Rosalie (ROS) and Sainte-Anne-de-Bellevue (ANN), were in 2900 CHU zones. At AUG, grain yields of hybrids 46T07 RR and 30A27 RR were 3.35 and 4.25 Mg of dry matter (DM)/ha in early September and reached 7.69 and 7.55 Mg DM/ha by the end of October, respectively. Meanwhile, stover yield declined to 7.71 and 7.04 Mg DM/ha by the end of October, with an average loss rate of 25 and 12 kg DM/ha/d, respectively. At ROS, grain yield of hybrids 46707 RR and 25T19 RR were 4.41 and 4.72 Mg DM/ha in early September and reached 9.85 and 10.88 Mg DM/ha by mid-November, respectively. Meanwhile, stover yield declined to 8.29 and 8.33 Mg DM/ha by mid-November, with an average loss rate of 41 and 40 kg DM/ha/d, respectively. At ANN, grain yields of hybrids 39D85 and 38M59 were 7.59 and 9.27 Mg DM/ha in early September and reached 8.59 and 14.44 Mg DM/ha by mid-November. These hybrids had less stover loss (2 and 6 kg/ha/d) and less total stover yield (5.76 and 6.74 Mg DM/ha, respectively, at the end of sampling) than the other hybrids. At a standardized harvest time (171 d after planting), grain, cob, husk, leaf and stalk averaged 55, 10, 4, 12 and 19% of the overall plant biomass, respectively. On average at 171 d after planting, 56 % of the corn fibre was located above the point of junction between the first ear and the stalk. The average moisture content of fibre ranged between 68 to 76 % during September and declined to as low as 28 % by mid-November.