Vegetable growers find over-irrigating leaves profit, environment “all wet”
Editor’s note: This article is from the archives of the MSU Crop Advisory Team
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Editor’s note: This article is reprinted from Issue>Action>Impact Vol. 1, No.3, Summer 2007.
When MSU researchers decided to evaluate grower irrigation practices in
southwestern Michigan, they discovered that some growers were running
their drip irrigation systems upwards of eight hours per day. Producers
were employing this practice as insurance that crops were receiving
enough moisture, however costly nutrients were being washed away – not
an efficient use of water or nutrients.
Realizing the importance of helping growers identify the economic and
environmental consequences of their irrigation practices, researchers
secured funding from Project GREEEN to develop a system for measuring
soil moisture. After installing a series of monitoring tubes in test
fields, soil moisture levels were measured by putting a probe attached
to a monitor and data logger into the tube. Information from the data
logger is downloaded into a computer, which generates a printout
graphing how the past week’s irrigation application has affected the
soil moisture level – too much, not enough or just right.
Upwards of 50 sites on 15 vegetable operations were studied in the first
year of the two-year project. Data indicated that some growers
irrigated too much too early in the season – there were times when
moisture levels were off the chart topping more than 100 percent field
capacity. Researchers also found that regardless of the grower or soil
type examined moisture levels dropped off significantly at harvest time
when irrigation took a back seat.
“Harvest time is probably the most important time for maintaining
adequate moisture levels because this is when it contributes most to
fruit size,” says Ron Goldy, MSU Extension vegetable educator. “By and
large we found that the soil was drying out when water was the most
critical.”
Over the course of the two-year project, study results were presented to
growers at winter meetings. When funding for a third year of research
was not guaranteed, growers stepped up and volunteered to pay for the
program. Four growers signed up to continue; last year there were five
growers and this year there are seven. The program has expanded beyond
vegetable crops and now includes apples and blueberries.
Goldy believes the reason growers embraced the system was because it directly involved the producers on their own land.
“The project wasn’t done on campus, in the laboratory or at a research
station,” he says. “It appealed to them because it was conducted right
on the farm in their own fields.”
“Before this, growers have never been able to readily see or measure the
moisture level in the field,” Goldy says. “We’ve been able to show the
water level where the plant roots are working in and whether it’s too
wet or too dry.”
Goldy says the reports help producers know how long to operate their
irrigation systems each day based on weather and plant stage. As an
example, he cites that one grower has been able to reduce his water use
by 50 percent since starting to use the system.
“It helps when growers have an opportunity to apply the technology on
their own farm,” Goldy says. “They tell us that this helps them
understand the usefulness of the system and that it’s not that
expensive, especially when they pencil out how much money they save by
cutting irrigation use. This is one additional piece of information to
help growers make their final decision.”
Future plans include continuing to expand the irrigation program to include more commodities.
“Growers don’t realize what they have until they have it,” Goldy adds.
“Growers have recommended the system to others so they must find it
valuable. Word of mouth is the most effective sales tool.”