By Darrin Pack
July 17, 2015
Indiana’s flood-ravaged grain crops could still produce a modest yield, but the chances for recovery are becoming increasingly slim with more rain forecast for parts of the state over the next two weeks, Purdue Extension experts say.
“I have been optimistic with my assessment, based on the possibility that the weather would moderate,” said corn expert Bob Nielsen. “But every subsequent downpour pushes a few more fields off the cliff.”
Prospects are not much brighter for soybeans.
“It’s very similar to what we are experiencing with corn,” said soybean specialist Shaun Casteel. “Some plants have been in standing water for up to three weeks.”
According to the latest U.S. Department of Agriculture Crop Progress report, released Monday (July 13), 25 percent of Indiana’s corn crop and 26 percent of the state’s soybean crop was rated as poor or very poor.
Waterlogged plants desperately need a stretch of dry weather to allow roots to regenerate, the experts said.
Heavy rains and flooding across much of the Midwest since early June has left many corn and soybean fields saturated or flooded, depriving plants of much-needed oxygen. The lack of oxygen causes roots to deteriorate and ultimately die.
When the soil starts to dry out, new root growth begins near the surface.
“It is the rate and extent of that fresh root development that largely determines whether a waterlogged field will recover ‘strongly’ or not,” Nielsen said.
Root growth is strongest in bright sunlight and warm temperatures. Overcast or rainy conditions delay drying and threaten the recovery.
“Unfortunately, most of Indiana has not yet had a significant string of days with favorable growing conditions and so cornfield recovery has been exceedingly slow and frustrating for growers,” Nielsen said.
Knowing their crops’ chances of recovery is vital to farmers who are trying to decide whether to invest in an initial or additional application of potentially costly nitrogen-based fertilizer.
“It’s hard to know whether you need a lot of nitrogen for these little corn plants,” said soil fertility specialist Jim Camberato. “It’s hard to tell if the return on investment is there.”
Casteel said applying nitrogen to soybeans that are struggling and nitrogen stressed in early reproductive development could be “a shot in the arm that could go a long way.” He cautioned that some areas of the field might have to be written off.
Nielsen’s most recent article, “Salvageability of Waterlogged Fields of Corn: That’s the $64 Question,” appears in the latest issue of Purdue’s Pest & Crop online newsletter. Casteel’s most recent videos on assessing soybeans and nitrogen stress after wet conditions are in the same issue. To download the newsletter, go to http://extension.entm.purdue.edu/pestcrop/2015/Issue15/.