A series of weather-related crop maladies could potentially threaten yields for the 2011 season, according to Iowa State Extension Field Agronomist Virgil Schmitt.

“If you’d asked me two weeks ago I’d tell you... (Iowa yields) could be above the trend line,” Schmitt said. “Now we’re trending to hedge back toward average yields.”

Strong, straight-line winds during a storm July 11 flattened acres of corn across Eastern Iowa, crops that were already stressed due to the lack of rain in recent weeks.

Now, high temperatures threaten to stress the crops and force rapid maturing, which could result in smaller kernels.

Luckily, according to Schmitt, the crops flattened in the windstorm, for the most part, did not break. Instead, the root lodging of the plants held, which gives them a chance to recover. Through a process agronomists call “goose-necking,” most of the plants will curve skyward and continue to be productive.

“If you’re going to have the corn flattened, that’s what you want to have,” Schmitt said. He added that corn that maintains root lodging after being knocked over only results in about a 20 percent yield loss, a far better survival rate than uprooted plants.

Unfortunately, the storm that knocked over the crops failed to produce significant amounts of rain, further depleting the soil of moisture crops need. Schmitt said he hasn’t seen crops showing signs of moisture stress yet, like curling of the leaves, but he expects to soon if the lack of rain continues.

The heat isn’t helping matters, according to Schmitt, as it increases a plants need for moisture and forces rapid maturing. A rapid maturity is ideal during the early stages of crop growth in May and June, but come mid-July, most crops are in the reproductive stage. If crops progress too rapidly through this stage, kernels don’t reach their ideal size.

He said that in an ideal world, temperatures would be higher in the early months of summer, but would cool off in July and August.

“The years that we’ve set our (crop yield) records, that’s typically the pattern that we’ve run,” Schmitt said.

However, given the relatively strong start to the season, Schmitt anticipates a decent, if unremarkable yield.

He added that the weather and its effect on crops is out of our control and very little can be done to counter it.

“Nothing (can be done), unless somebody’s gotta  good rain dance they can do,” Schmitt said.

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