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Drip irrigated garden conserves water, labor compared to furrow system

LOS LUNAS - Drip irrigated gardens save water and labor, according to a study done at the New Mexico State University Agricultural Science Center in Los Lunas. Plus there was significant increase in yield for some produce over the traditional furrow watered garden.

Manuel Reyes, field hand at NMSU's Agricultural Science Center in Los Lunas, harvests okra during a drip irrigated garden study during the summer of 2007. The study showed that less water was used in a drip irrigation system compared to the tradition furrow system with the produce yield being equal or better. (NMSU Photo by Jane Moorman)

"The study proved that you can save water and labor time and have a general higher yield with the drip irrigation system," said Ron Walser, urban small farm specialist at the Los Lunas facility, of the research conducted during the summer of 2007 that compared vegetables grown in both drip irrigation and furrow fields.

The study compared the exact same variety of vegetables and flowers in two gardens, one watered by traditional furrows where the water flows down small trenches running beside the plants, and the other with drip irrigation tape uncovered and covered with either black or silver plastic where the water is delivered through pipes to each row of crops and released through emitters or drip holes positioned near each plant. In drip irrigation, only the area around the plant is watered and in furrow irrigation, the whole row is watered.

Plant varieties studied included cucumber, squash, tomato, artichoke, basil, beets, broccoli, brussel sprouts, cabbage, carrot, green beans, lettuce, cantaloupe melon, Crenshaw melon, okra, pea, bell pepper, green chile, dried red chile, jalapeno, radish, spinach, swiss chard and various cut flowers including sunflowers.

"I didn't expect the difference in the water usage to be as drastic as it was," Walser said. "Furrow irrigation was 300 percent greater than the drip irrigation, with drip using 12 acre inches to the furrow using 39 acre inches."

With the concern for conserving water, Walser said this study shows that people can garden and still conserve water.

The second advantage of the drip irrigation system was the time saved weeding. The plastic covered areas of the drip irrigated garden took only 14.75 hours of labor compared to the 46.25 hours in the same space of furrow watered garden.

It was also determined that most of the varieties of vegetables raised had better yield on the drip irrigation. Some of the greater differences were the cucumbers with 30.13 pounds per plant from drip irrigation compared to 18.13 pounds in the furrow garden and tomatoes with 28 pounds per plant compared to 15.28 pounds. Basil, beets, green beans, swiss chard and bell peepers also did better in drip irrigation.

Swiss chard had a double success. It produced more under drip irrigation, 156.75 pounds per 100 feet of plants, compared to 69.95 pounds in the furrow garden. It also out produced spinach that yielded 17.95 pounds under drip and 13.05 in the furrow garden.

"Swiss chard is a good greens substitute for spinach. I recommend it to backyard gardeners, plus it really sold at the farmers market," Walser said. "Both are in the spinach family, but swiss chard grows all summer and is much larger. It can take the heat unlike a lot of greens that wilt."

Another vegetable that had significant greater yield under drip irrigation was green bean. In a 100 foot row of plants, 166.03 pounds were produced under drip, while the furrow garden produced 64.33 pounds.

Vegetable varieties that did not have better yield under drip irrigation were broccoli, brussel sprouts and carrots. Brussel sprouts produced 116.09 pounds in a 100 foot row of furrow irrigation, compared to 76.99 pounds under drip irrigation.

Those having similar yield were cabbage, cantaloupe, Crenshaw melons, okra, jalapeno and radish.

"The difference in the cantaloupe was slightly skewed because the drip irrigation didn't work properly for a 10 day period and the plants were put into stress. It caused the melons which had set to not develop in size like the furrow garden," said Lorraine Swanick, NMSU research assistant at the Los Lunas facility. "But a second crop came on after the irrigation issue was resolved so the total weight yield was close."

Besides demonstrating the impact of water conservation, the study's goal was to determine if a drip irrigation garden would be profitable.

"Our Valencia County Master Gardener volunteers sold the vegetables at Albuquerque's Saturday Farmer's Market. We got a good idea what really moves and the prices that the market would bare. To keep things simple during our research we sold everything for $1 a pound, except squash that was 50 cents a pound, green beans at $1.50 a pound and peas at $2 a pound," Walser said. The harvest was sold twice a week by staff members at the Los Lunas facility under the direction of Tom Plant, farm superintendent.

From that income, Walser and his staff calculated that drip irrigation produced a gross combined income of $3,068.01 based on 100 feet rows of each crop except cucumber, squash and tomato. The furrow garden's income was $2,641.26.

The only down side of the drip irrigation garden is a higher startup cost with the installation materials costing $365, plus the cost of equipment to lay the irrigation tape and plastic down. The furrow garden had no materials cost and its labor cost was less.

Walser said the equipment that installed the irrigation tape and plastic costs from $1,500 to $10,000 to purchase, depending on the accessories and task it can accomplish, plus a tractor is needed.

A publication with a complete list of produce yield and gross income will be available during the summer. For further information about the study contact Stephanie Walker, NMSU Extension vegetable specialist at (575) 646-5280.