Crop Conditions a Concern; Corn Height Noticeably Short

BY DAN GRANT

The old adage of corn reaching “knee-high by the Fourth of July” seems outdated, as many fields are shoulder-high or even tasseling by the holiday in recent history, as was the case at some locations again this year.

But corn height is an issue this season as stands currently range anywhere from just ankle-high to 6-plus feet tall.

Emerson Nafziger, University of Illinois crop systems specialist, discussed the situation in a recent issue of The Bulletin.

“One notable feature of the corn crop as we approach the critical pollination period is the short plant height in most fields,” Nafziger said. “Plants in some fields are only 5 feet tall or so as tassels begin to emerge.”

Normal height for corn at this stage in recent years hovers at closer to 6 feet.

Nafziger recently noted shorter corn was widespread in central Illinois and less of an issue in southwest Illinois. Fields in northern Illinois are a little further behind, but have more time before pollination.

“Is below-normal plant height in corn a problem?” Nafziger noted. “If the plant has a normal amount of healthy leaf area, high yields would be possible with plants only 6 feet tall or so after pollination.”

Unfortunately, though, leaves must compete for water to enlarge, and the leaf area on short plants is often less than that of taller plants.

Nafziger, therefore, believes it can be much harder for short corn to achieve very high yields (250 bushels per acre or more), compared with plants that reach 8 or 9 feet in height.

The extreme range in corn height so far this season resulted from a multitude of factors, including a wide range of planting dates, cool and wet soils in May that slowed plant growth, hot and dry conditions in early June that caused leaf rolling, and high evaporative rates followed by low temperatures during vegetative growth in the second half of June.

Crop prices rallied in late June and early July due to some of the concerns.

“Yield is challenging to predict due to the difficult start to the growing season in many locations,” said Todd Hubbs, U of I ag economist. “Potential (corn) yield is likely at or below USDA’s June assessment of 170.7 bushels.”

Favorable growing conditions the rest of the season could result in an average bean yield close to USDA’s estimate of 48.2 bushels per acre, the economist noted.

But the trade is probably “skeptical of trend yield in soybeans being attainable at this point,” Hubbs said.

The trade is focused on a heat dome building over the west and the possibility of dry conditions in the Midwest during corn pollination, according to Paul Georgy of Allendale, Inc.

“The weather forecast remains the feature focus for traders,” Georgy said.

Crop conditions remain well below year-ago levels. The portion of crops rated good to excellent, as of July 5, totaled 68 percent for corn (down 7 percent from last year) and 64 percent for beans (down 2 percent from the previous week and 6 percent lower than last year).