Waterloo Cedar Falls Courier, IA
08-28-07
Standing water hurts yields
By MATTHEW WILDE, Courier Staff Writer
DECORAH --- Fields resembling lakes won't fare well at harvest, crop experts
say, but all isn't lost.
Monday's U.S. Department of Agriculture Crops and Weather Report said the
state averaged 8.78 inches of rain so far in August, eclipsing the previous record
for the month set in 1993 at 8.24 inches.
It's also the fifth wettest month in Iowa's history, dating back to 1873. The record
is July 1993 at 10.5 inches.
Record rain --- especially in a short period --- doesn't bode well for record yields.
Excess water limits the ability of soybean pods and corn ears to properly fill out
and promotes disease problems and stem rot. Plants under water for 24 hours
most likely won't survive, as well as those partially submerged for three days or
more.
Northeast Iowa has its share of drowning plants, though no acreage estimates
were provided in the report. Palle Pedersen, Iowa State University Extension
soybean specialist in Ames, said low-lying fields near creeks and rivers will
lose out while the majority of crops will benefit from the rain.
"Some areas gained yield and some lost. Overall, I don't think it will hurt
production statewide," Pedersen said. "However, it never looks good to see a
nice field turn into a lake. It will cost those farmers."
Government predictions in early August called for a 180-bushel corn harvest in
Northeast Iowa and soybeans averaging 50 bushels per acre.
The Iowa Soybean Association said crop scouts are worried continuous overcast
skies and rainy weather promote diseases, such as sudden death syndrome,
white mold, frogeye leaf spot and many others.
"It is becoming more and more evident now, even from roadside observations,
that 2007 is one of the more significant seasons for SDS (sudden death
syndrome). Nothing can be done for the disease this season, but you should
document these areas or fields for future management decisions (crop rotation,
tillage, select resistant varieties, etc.). Also, consider that where there is SDS
there is often also soybean cyst nematode," the association wrote in a weekly
crop update to ag professionals.
As of Sunday, the state's soybean crop is rated 2 percent very poor, 4 percent
poor, 19 percent fair, 52 percent good and 23 percent excellent.
The reports said strong winds last week blew down many corn fields and
damaged buildings and grain bins in some areas.
Eighty-five percent of the state's corn is in the dough stage, while 58 percent is
dented. Both are slightly behind last year's progress, but ahead of the five-year
average of 82 percent and 45 percent, respectively.
The crop is rated 3 percent very poor, 7 percent poor, 20 percent fair, 48 percent
good and 22 percent excellent.
Brian Lang, ISU Extension crop specialist based in Decorah, said the corn
silage harvest will likely begin as soon as the soil dries sufficiently to handle field
equipment.
On the bright side, ISU Extension agronomist and soil fertility expert John
Sawyer said water-logged fields planted to corn next year should respond better
to spring nitrogen applications. As tile lines run, there will be less residual nitrate
left in the soil profile.
Farmers shouldn't count on extra carryover nitrogen.
"The (corn) crop should see a significant yield boost ... it will be more reliant on
the fertilizer. Farmers will get more bang for their buck," Sawyer said.
Harvest of the third hay cutting statewide has been slowed by wet days, with only
52 percent complete. The five-year average is 70 percent.
Contact Matthew Wilde at (319) 291-1579 or matt.wilde@wcfcourier.com.