It’s not just the drought hurting Georgia farmers this year. A University of Georgia expert said the way many water their
crops could cut $100 million from cotton yields alone.

Struggling to keep their crops healthy, Georgia farmers often declare that even in
irrigated fields, they need rain to get good yields.

But that’s not necessarily true, said Tony Tyson,
an Extension Service engineer with the UGA College of Agricultural and Environmental Sciences.

“For the most part, people have drawn that conclusion from past experience,”
said Tyson, an irrigation specialist. “But either their system was underdesigned or
the farmer was hesitant to run it long enough to supply the peak water demand.”

Usually, the problem isn’t the system. “Most systems less than 10 years old are
adequately designed,” he said.

The problem, he said, is that many Georgia farmers use supplemental irrigation. They
just fill in between rains. When their crop shows signs of moisture stress, they crank up
the irrigation.

That approach is costly, he said, in years like this, when dry spells are long and
temperatures high.

“If you wait until you see signs of stress, you’ve already hurt the yield
potential,” he said. “That’s especially true in the critical pollinating and
fruiting period.”

Losing any yield is costly. Georgia growers get up to 1,400 pounds of cotton from
irrigated fields. A loss of 230 pounds per acre would mean about $100 million over
Georgia’s 600,000 acres of irrigated cotton.

The Georgia Agricultural Statistics Service
rates 73 percent of Georgia’s 1.4 million acres of cotton as only “fair” or
worse. About 40 percent is irrigated.

Tyson figures most yield losses on irrigated acres could be avoided if the systems were
designed and used right.

“We recommend designs that will meet peak demand,” he said. “That means
that with no rainfall at all, the system will supply the highest demand of a given
crop.”

With most row crops, he said, the system must provide up to one and one-quarter inches
of water every three days.

Some systems can’t meet that demand. “In the late 1970s and early ’80s,
irresponsible or inexperienced irrigation contractors sometimes cut the system capacity to
come up with a competitive price,” he said. “Some of those systems can’t put out
enough water in conditions like this.”

Some farmers irrigate out of ponds they have already pumped dry. But Tyson said that
shouldn’t happen.

“That’s one of the things we look at in the design,” he said. “It’s hard
to justify making the kind of investment you have to make on irrigation if you don’t have
adequate water.”

Some strategies, though, avoid problems even with underdesigned systems. “We
recommend splitting the system,” he said, “and planting different crops under
them that don’t require peak irrigation at the same time.”

Most crops have a water-use curve, he said, that ranges from less than one-tenth to
about one-third of an inch per day. The peak water demand for corn and tobacco is in May
and June. For cotton and peanuts, it’s July and August.

Most farmers, though, have systems that can put out plenty of water. But for various
reasons, they hesitate until they’ve already lost valuable yields.

“Some of our farmers do a good job with irrigation management,” Tyson said.
“I can just about guarantee you somebody will make 1,400 pounds of cotton per acre
even this year.”

The ones who manage their irrigation well, he said, are committed to supplying water
whenever their crops need it.

“You’re not going to make peak yields with supplemental irrigation in stressful
conditions,” Tyson said. “You have to be committed to supplying the moisture
needs of the crop. Sometimes that means irrigating 24 hours a day. But you have to do
it.”