MASS AND MOISTURE DISTRIBUTION IN ABOVEGROUND COMPONENTS OF STANDING CORN PLANTS

Abstract

Corn stover mass and moisture properties were identified to aid decisions regarding collection of standing corn stover dry matter with least moisture, and to aid development of moisture prediction tools for applications including harvest, transport, size reduction, and storage. Vertical distributions of mass and moisture in standing stalks and aboveground components such as leaf, husk, and ear in standing corn plants were evaluated over time. Stalks were cut into 254 mm long sections to facilitate analysis, and to correspond with billet length collected for cane-type crops. Stalks had the greatest wet mass (72.6%) followed by leaf (20.7%) and husk (6.8%) during the normal harvest period. Moisture profile in aboveground plant components exhibited two separate, sequential linear relationships when plotted with time. The first zone was rapid moisture reduction prior to the normal harvest period. The second zone, corresponding with but not the result of grain harvest, had slow, gradual moisture reduction and stabilization. Geometrical analyses of stalk cross-sectional area, volume, and lateral surface area to volume ratio documented physical properties for future moisture prediction tools. Considering stalks only, the bottom 1 to 4 stalk sections had 60.6% of total dry matter, although that was the last portion of the stalk to dry, thereby increasing the liability of added moisture on transportation and storage. An apparent drying front moved downward through the plant over time and may be explained by reduced the lateral surface area to volume ratio from stalk top to stalk bottom. Dry matter and moisture content of stalks were not significantly influenced by the observed soil and environmental parameters, including rainfall. It was hypothesized that standing stalks readily shed rainfall and allowed less opportunity for moisture penetration. Mass and moisture content of discrete stalk sections were normalized using plant height to facilitate multiple regression equations applicable to other crop heights. Results pertain to assessment of mass and moisture status of standing stalks in the field before and after grain harvest, identity of moisture factors related to the supply of uniform-quality feedstock, and discovery of relevant biomass properties needed for design and management of efficient biomass processes and equipment.