Making Drip Irrigation Cost-effective
The Tomato Magazine
Feburary 2005
DELTA, Ohio - Looking for ways to make drip irrigating
field tomatoes more cost-effective, Jim, Jerry and Chris McDonnall of
McDonnall Farms have been experimenting with fertigation. The 2005 tomato
crop will be their second year experimenting with the process.
The McDonnalls grow approximately 250 acres of processing tomatoes in
the Delta, Ohio area each year, along with field corn and soybeans. The
tomatoes are contracted with Red Gold, out of central Indiana.
Jim and Jerry are brothers; Chris is Jim's son.
Dealing with Low Rainfall Years
In an effort to protect their tomatoes against short-rainfall years, the
McDonnalls are using supplemental irrigation. Seventy-five to 100 acres
of their tomato crop is under drip, an experiment that began four or five
years ago and has been a big help, especially during low-rainfall years.
A traveling unit is available for use in other fields. The growers prefer
the drip but have struggled to justify its cost-approximately $100 per
acre.
"After going to the expense of putting down tape, if we do get adequate
rain, it's hard to feel good about the added investment," Chris admits.
"You may only use the tape two or three times and, under such circumstance,
it is difficult to see any bottom line advantage."
Looking for ways to make the investment more cost-effective, the family
turned to their local supplier who suggested fertigating their crop through
their drip system. At the dealer's recommendation, they also used Rootfeed™
and Harvest More Urea Mate™, products from Stoller Chemical Company,
Houston, Texas.
The 2004 tomato crop was the first test for the experiment, and, despite
a learning curve, the McDonnalls are optimistic about future benefits.
The drip tape now plays an enhanced role in their production tool portfolio,
even when there is adequate natural moisture. There is no need for additional
trips through the field during the year to make sure the crop is adequately
fertilized.
Had Weed Challenge
The cultural practice in the past has been to plant the crop, wait a few
days, cultivate and then side dress with a fertilizer application, Chris
says. When fertilizing with drip tape, the recommended practice has been
to place the tape immediately after planting to ensure needed moisture.
However, the growers soon discovered that, under their circumstances,
there were good reasons to do things differently. The recommendations
they were following were based on fertigating through drip lines placed
under plastic mulches.
"Our hope was that we could use fertigation to replace the early
fertilizer side dressing applied in the past," Chris says, "however,
when the drip tape was put down immediately after planting, it became
impossible to cultivate between the rows."
Traditionally, the McDonnalls plant two rows of tomatoes, 18 inches apart,
on raised beds. They would then wait10 days and lay the tape, positioned
above ground, between the rows.
"For weed control, we like to cultivate between the rows with a shovel,
when the plants are still small," he explains. "Unfortunately,
last year, when we positioned the tape immediately after planting, we
discovered we were no longer able to cultivate between the rows. You can't
go after the weeds with a hoe for fear of cutting the tape. It was just
too early to place the tape. We ended up fighting weeds throughout the
season.."
Despite that learning experience, Chris says the family is optimistic
that this coming season they can tweak the system and make things work.
The first tomato plantings begin between the first and tenth of May, when
there is less danger of a serious frost. The balance are planted through
June 15 to insure the processor will have a continuous supply over the
six- to eight-week harvest season.
Having learned from their experiences in 2004, the McDonnalls currently
plan on planting the crop, according to the accustomed schedule, only
reverting back to side dressing the crop for its early fertilizer needs.
Following that, they plan to wait three weeks and then place the tape.
That way, they can take care of the early cultivation and fertigate the
crop through the tape through the balance of the growing season.
"Last year was not a wet year, but we still ended up with plenty
of moisture," Chris remembers. "While we did not have to use
the tape to augment moisture levels like you would during a dry year,
we were able to use it to fertigate the crop. We saw a definite increase
in yields in the fields fertigated, anywhere from four tons per acre to
as high as seven or eight tons."
Tomato yields on the farm also vary from field to field because of differences
in the soil as well as varieties grown, the growers note.
The McDonnalls acknowledge that 2004 was the first year in their on-going
trial with fertigation and the use of Rootfeed™ and Harvest More
Urea Mate™. The coming year brings with a new opportunity to see
if the gains hold up.
Always Some Rain
"Most years here, we are going to get some rain," Chris points
out, "and you may go two or three weeks without turning the pump
on at all. After that, it's important to add some fertilizer, so you turn
the pump on just long enough to push the fertilizer through the tape.
Under such conditions, we're not trying to saturate the ground. Other
years, however, especially if the ground is dry, we'll be putting water
on constantly. The system operates in zones, and you may finish covering
all of your zones only to find it's time to begin all over again."
Because there was good moisture in 2004, the tape lines were not used
for irrigation that frequently, but, when they were, they also were carrying
nutrients to the plants, Chris says.
With the use of irrigation, the McDonnalls typically see their tomato
yields in the high 30-ton range. With certain varieties, it is not uncommon
to achieve yields in the 50- and 60-ton range, but the overall average
is generally in the high 30s.
"Some of the varieties we plant are not big yielders," Chris
points out. "Most often, these are special varieties for whole packing,
where the tomatoes are harvested, peeled and then diced. While the yields
on these are lower, the processor compensates offering growers a higher
return per ton."
© 2005 Columbia Publishing
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