By Keith Robinson, Purdue University
Frequent and heavy rains have kept most Indiana farmers out of their fields during corn planting season so far this month, and the weather outlook for the next two weeks portends continued wet conditions.
But that doesn’t mean yields at harvest time are in danger of dropping off yet.
Forecasters expect precipitation to be above normal through the first week of May, following a pattern of rain that has swelled rivers and streams and flooded fields.
"The rain over the next couple of weeks shouldn't be as heavy as it has been, but the frequency of rewetting of topsoils is the problem," said associate state climatologist Ken Scheeringa, based at Purdue University.
As of the week ending April 21, farmers had planted just 1% of the state's corn crop, compared with the five-year average of 16% by the same time, the U.S. Department of Agriculture's National Agricultural Statistics Service reported. Last year, when an unusually dry spring was a precursor to drought, farmers had 43% of the crop in the ground by this time.
Heavy rains and cool temperatures prevented most fieldwork last week, when some areas received nearly 7 inches of rain and temperatures dropped to 21 degrees.
Temperatures finally are warming, a trend that typically would help to dry out fields so farmers could work in them. But more rain would negate that effect.
"We're in a wet pattern that isn’t going to change in the immediate future," Scheeringa said.
State climatologist Dev Niyogi earlier this year had said planting could be delayed because of a wetter-than-normal trend and that Indiana could be in for some drying in the growing season, leading to a return to mild to moderate drought conditions across the state. He said that possibility has not changed.
"We don’t have a dominant El Niño or La Niña this year, so the patterns we are seeing from wet to dry could become the highlight of the growing season," Niyogi said.
Although Indiana farmers are two weeks behind the five-year average pace in planting corn, statewide statistical data suggest that planting date accounts for only 23% of the variability in yields from year to year, said Purdue Extension corn specialist Bob Nielsen. Tillage and use of herbicides and nitrogen fertilizer are among many yield-influencing factors, or YIFs.
"The good news is that planting date is only one of many YIFs for corn," Nielsen wrote in his online "Chat 'n Chew Café," which contains crop production information compiled from universities and public websites across the United States.
Nielsen noted that last year 94% of the corn crop was planted by May 15, but it yielded 38% below trend, largely because of the drought - a disastrous YIF. Conversely, farmers in 2009 planted only 20% of the crop by that date because of wet conditions, yet their harvest was 9% above trend.
He said if planting delays continue, farmers still would have until mid-May to decide whether to switch to seeds that would take the crop to maturity faster.
"Let's not succumb quite yet to fear-mongering triggered by the prospects of a delayed late start to corn planting in 2013," Nielsen wrote.
Read more about the planting date conundrum for corn.
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