Corn Greensnap from Extreme Wind is Influenced by Several Factors
2003
Elmore, Roger W. | Hoffmeister, George | Klein, Ralph | Marx, David B.
Severe storms with downdrafts and straight-line wind speeds up to 100 miles per hour (mph)in Nebraska resulted in widespread mid-season corn (Zea mays) stalk breakage (greensnap), in July 1993 and 1994. These weather events reduced grain yields up to 90%. Nebraska was again affected by winds up to 70 mph associated with thunderstorms in July 1998 and June and July 2000. We evaluated plants from several hybrids in small plot trials as well as in producers' fields in order to determine if leaf orientations (azimuths) affect a corn plant's tolerance to greensnap. Although hybrids differ greatly in their susceptibility to greensnap, leaf orientations of hybrids were similar and thus do not appear to affect susceptibility to greensnap. However, for plants broken at the node, the orientations of leaves attached to broken nodes were most often parallel to the direction of the damaging wind and pointing leeward while for the majority of plants broken at the internode, orientations of leaves attached to the broken internode were oriented into the direction of the damaging wind (windward). Leaf orientations of standing plants were often in a somewhat symmetrical, bimodal pattern and more uniformly distributed than broken plants. Those who simulate greensnap would best attempt to imitate these breakage patterns with mechanical stalk breakage simulators. Rows perpendicular to extreme winds suffer the most damage. We have not often seen both east-west and north-south rows affected in the same area from the same storm. Since predicting extreme winds is difficult we suggest producers choose tolerant hybrids and alter row direction among fields to reduce the risk of an extreme wind from damaging several fields. A range of planting dates and hybrid maturities may also reduce risk.
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