High-tech Drip System

NWU Radio Script

3-5-01

Micro-management isn't always associated with positive outcomes in the business world. But when it comes to irrigation, micro-management is exactly how some farmers are producing positive results in California.

In an article written for the Westlands Irrigator by Liz Hudson of the Westlands Water District, the concept of high-tech drip irrigation is discussed and how it is helping increase yields and profits.

Tom Stefanopoulos of Stamoules Packing Co., a long-time Mendota-area grower-packer-shipper of fresh produce, has invested in a state-of-the-art drip irrigation system on 1,500 acres of high-valued vegetable crops. He says use of subsurface drip tape has produced better quality produce, high yields and less production costs - results most farmers want to achieve.

The system consists of an array of computers, sophisticated pumping stations, filters, plastic tubing and radio frequency.

Chuck Dees, who oversees Stamoules' irrigation program, notes the computer-driven drip irrigation system provides more flexibility and efficiency in irrigating the 1,500 acres currently under drip. The equipment is located both in the field and in the office. In the field the flat plastic drip tubing is buried 14-inches deep under the plant bed, about 28-inches apart.

A computer software program allows Dees to operate the system in the field from his desk in the office. The system uses wires and cables, radio frequency and ultra-violet rays to transmit the information. A control box is installed at each pumping station in the field, where information is received to turn-on, turn-off or change the drip system's valves automatically. The valves control 26-acre blocks in the fields, which are identified on a map on the computer.

Buried wires transmit the information from the valves to the control box. The control box must be kept under 110-degrees Fahrenheit or the heat will cause the system to shutdown. To prevent this, a small cooler in the control box is used to keep the temperature from getting too high.

From the pumping plant in the field, the information is transmitted to the office via a radio frequency, which Dees says works much like a modem on a computer. As a result, Dees never has to leave his desk to change the irrigation water in the field, and could, in fact, change his irrigation from other locations, provided he has a lap-top computer, cell phone and modem.

The FCC assigns the radio frequency.  The system's power source is electricity, with a battery back-up system. In addition, liquid fertilizer can be applied with the irrigation water. The fertilizer is mixed with the water in a tank, which also runs through a sand filter to keep solid materials from clogging the emitters on the drip tape. The filters can be flushed automatically.

The flexible system allows Dees to provide a measured amount of water when the plant needs it. "Most of our irrigation runs are from 6 p.m. to noon the following day. We have an 18-hour window to irrigate in, but if it turns real hot, we can run the water for 24 hours and get across the field quickly," said Dees.

By using drip tape they have seen yield increases of about 40 percent in bell peppers, and are expecting a 20-30 percent increase in cotton, said Dees. Because of better distribution of the irrigation water, there has also been better plant growth uniformity and reduced cultural practices. Weed growth is minimized, fertilizer is applied during irrigation, which saves on trips through the field and equipment can get into the field quickly, if needed, even while irrigation is occurring. Drip tape also helps farmers with saline groundwater problems by not adding more water to already high perched water tables.

"I don't know many negatives with drip, except maybe the initial costs," said Dees. "But there's a ton of positives to take away from the few negatives. The cost for a drip system can ranges from $600 to $1,500 per acre."

But the increase in efficiency means most people are able to pay for their systems after the first year, he said.

"The costs and availability of water have forced us to look at new technology to produce more crops per acre using less water," said Stefanopoulos, who grows and ships about nine million cartons a year of melons, bell peppers, sweet corn and broccoli, as well as cotton.

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