Des Moines Register
02/12/06
Precipitation is makin' us wait
By ANNE FITZGERALD
REGISTER AGRIBUSINESS WRITER
In portions of southern Iowa, the subsurface soil is as hard as a rock, not from
frost, but from lack of moisture. Streams have slowed to a trickle. Pond water
levels are low.
With spring planting due to begin in two months, some crop specialists and
farmers fear drought will develop this year.
"The creek that crosses my place has water standing in it, but you could walk
along it and not get your feet wet. . . . If you put a paper cup in it, it wouldn't go
anywhere," said Mark Carlton, an Iowa State University Extension field crop
specialist based in Albia.
Such signs of dryness are worrisome for Iowa, the nation's No. 1 corn- and
soybean-producing state. At today's cash market prices, Iowa's 2005 corn and
soybean crops would be worth about $6 billion. Federal farm subsidies, livestock
feeding and value-added ventures, such as ethanol production, add to crop
farmers' economic impact on the state, and crops diminished by drought would
have a direct and negative impact on the state's economy.
In addition, drought would hurt growers of fruits, vegetables, trees and other
horticultural crops — a small but growing niche in Iowa.
A year ago, most Iowa soil had adequate moisture. But during the growing
season, drought developed in southeastern and east-central Iowa, northern
Illinois and much of Missouri. Drought also hit portions of Texas and Oklahoma.
Genetic improvements have made crops such as corn more tolerant of drought.
That was evident last year when corn yields were better than had been expected
in some drought-stricken areas.
But crops still need soil moisture, and concerns are growing that drought could
revisit the U.S. Corn Belt this year. Unlike a year ago at this time, the southern
two-thirds of Iowa is short of soil moisture.
"That's the bad news," said Harry Hillaker, Iowa's state climatologist. "The good
news is fairly normal precipitation this spring would get . . . much of the state up
to normal before spring planting begins."
In addition, this winter has brought a bonus to Iowa, Hillaker said. Warmer-thannormal temperatures kept most farm ground unfrozen until recently, enabling
soils to absorb precipitation — melted snow in December and rainfall in late
January.
Even so, there is a deficit of soil moisture across much of Iowa, he and others
said. Lack of snowfall this winter is not to blame, Hillaker said, because it takes a
lot of snow to make an inch of moisture. Dryness is a problem in areas where soil
moisture was not recharged ahead of winter.
"Last year, we had a full soil moisture profile, and that's probably the thing that
saved us. . . . We had a bank account there, and this year we don't," said
Carlton, whose territory encompasses eight southeastern Iowa counties.
At this point, southwestern Iowa is the driest region in Iowa.
Conditions are similar to the winter of 2002-03, said Clark McGrath, an Iowa
State agronomist based in Lewis whose territory covers nine southwestern
Iowa counties.
"Some of the producers are nervous, and some are not," he said.
Lynn Gronborg, an Avoca row crop farmer and cattle producer, said it's hard not
to worry when the water level in his pond is five feet below normal and his tile
lines aren't running.
"It's really dry south and west of here," Gronborg said. "Our moisture comes from
that direction, and it can be a problem unless the weather changes and we get
some wet days in the spring."
On average, Iowa soil can hold about two inches of moisture per foot. Corn and
soybean plants typically tap the top five feet of soil. When soil moisture is
abundant, that means about 10 inches of moisture available to those crops. Iowa
State specialists estimate that southern Iowa has less than three inches of
moisture in that top five feet of soil.
Hay — after corn and soybeans, Iowa's largest crop — can tolerate drier
conditions than row crops, because hay's roots run deeper, said Steve Barnhart
, an agronomist and forage specialist with ISU Extension in Ames.
"At this point, I don't see any reason for concern," he said.
But if drought spreads next summer, second and third cuttings of hay will be
limited, Barnhart said.
Weather experts are of two minds.
It's too soon to tell whether drought will emerge this year, and conditions can
improve dramatically with spring rainfall, they said last week. But they also are
monitoring drought conditions in regions hard hit last year — from Texas to the
Upper Midwest.
"Drought likes company. If somebody else is dry in another part of the country,
it's always a little bit worrisome," Hillaker said. "It just can kind of feed on itself
and spread. . . . It is something to keep your eye on to see if it persists into the
spring."
"Things aren't hopeless, by any means," he said. "But you wouldn't want to put a
year like 2005 on top of the conditions we have right now and expect crop yields
to be so good."
Moisture requirements
Plants need varying amounts of moisture to grow. Soil composition, production
practices, type of crop, variety and root depth are key determinants. Here are the
moisture requirements of some crops raised in Iowa:
• CORN AND SOYBEANS: At least 25 inches to raise a full crop.
• FRESH MARKET TOMATOES: From 16 to 20 inches during the four-month
growing season.
• TREES AND SHRUBS: One inch every seven to 10 days.