Corn Motion in the Wind during Senescence: 11- Effect of Dynamic Plant Characteristics
Lodging in corn (Zea mays L.) is often the result of wind-induced motion, which creates a strain on the stalk and root system. In elastic theory, motion is defined by static characteristics (stiffness) and dynamic characteristics (damping Coefficient [ζ] and natural frequency [fn]). A study was conducted to determine the relationship of plant ζ, fn, and stiffness (K) to total plant motion in the wind. The ζ,fn and K were calculated from stalk motion measured on 23 plants in the field durini OFtober, 1988, at West Lafayette, IN. Interrow contact was eliminated, and plants were grouped according to whether the ear was upright or had fallen to a hanging position. With the ear upright, ζ,fn, and K averaged 0.11, 1.54 Hz, and 2.44 N m deg−, respectively. Plant resonant oscillations corresponded with fn. The fn was well above the frequencies of highest wind energy. In theory, total plant motion will decrease as ζ and fn, increase. Field measurements showed that with the ear upright, and fn were uncorrelated with total motion, but when the ear dropped to a hanging position, there was a 54% increase in fn accompanied by a 15% reduction in motion. The results indicate that dynamic plant characteristics do affect the characteristics of plant motion. However, the plant motion was relatively insensitive to the range of ζ and fn we observed because fn, was well above the frequencies of high wind energy.
Copyright © . .