September 13, 2020
Conserving groundwater is an important conservation practice to help conserve the limited supply of groundwater in the Alluvial Aquifer.
Guilherme Prezotti, the Delta project manager for The Nature Conservancy (TNC), provided an example of conservation efforts during the online 2020 Sustainable Agronomy Conference held by the American Society of Agronomy. He described a project in Arkansas that uses irrigation timers on rice farms to conserve water.
"The Arkansas Delta is one of the major rice-producing regions in the U.S.," Prezotti said. "The economy is dominated by agriculture, and besides rice, the region is a major producer of cotton and soybeans as well. With so much agriculture going on in the Delta, there's a lot of water used for irrigation. Our goal with our project was to use sustainable practices to protect and preserve water resources while also helping farmers."
With 162 irrigation timers used on 30 rice farms in Arkansas covering 15,000 acres, participant farmers self-reported savings of up to 650,000 gallons of water per acre, per year.
"We have timers spread across the Delta saving water in critical groundwater areas and helping farmers save time and money," he said. "It is important for us that as many timers as possible are installed in areas that have a critical groundwater status. This helps give the aquifer a bit more time to refill and not be overused, which is a huge benefit for the overall environment."
Some areas of the Alluvial Aquifer in the Delta are classified as a critical groundwater area. In a region where the economy depends heavily on agriculture, these critical groundwater areas also mean higher costs for farmers to irrigate. According to the Arkansas Natural Resources Commission, measures must be taken to protect the state's precious underground water supply.
The project was launched in 2019 to help farmers improve their irrigation efficiency practice and reduce water waste by over-irrigation. Major partners in this project, who believe in this win-win scenario, include Kellogg's, Syngenta, Delta Plastics and Riceland.
"The current use of groundwater in the Arkansas Delta is an average 7.7 billion gallons per day," Prezotti said. "However, only 44% is being used sustainably. Also, portions of the critical groundwater areas are 70% to 90% depleted of water."
Shown here is one of the timer-switches. "The timer-switches help farmers in a few ways," Guilherme Prezotti said. "It reduces energy and labor costs, reduces groundwater consumption, reduces fertilizer runoff, and reduces runoff erosion from overfilled irrigation fields."
Using irrigation timers
The Nature Conservancy used fliers and direct outreach throughout Arkansas to meet farmers who were interested in participating in the project.
"Our focus was on helping farmers who are a paramount part of this process," he said. "We designed the program to require minimum time from the farmer. We wanted to make the process simple so as not to add any extra burden. Another important aspect is that this is no cost to the grower. We install the timer-switches on the well pumps at the farmers' convenience. The timer we use does not connect to a smartphone or any electronic device, but it's activated when the well is turned on and set to automatically shut off within 24 hours."
The timer works like a kitchen timer, which automatically turns off from one hour to 24 hours. This way, no one needs to go back to the well to turn off the irrigation, but, instead, they can make one trip to turn it on.
"The timer-switches help farmers in a few ways," Prezotti said. "They reduce energy and labor costs, reduce groundwater consumption, reduce fertilizer runoff, and reduce runoff erosion from overfilled irrigation fields. We received a lot of positive feedback from the farmers. One farmer said, 'The timer made things easier. Now, I don't have to go or send anyone to shut the pump off at 6 in the morning.'"
The timer-switches help farmers save time, which is a huge benefit during the busy growing season.
"This gives farmers a little more time to do other tasks around the farm, and because of the program's design, the farmers have the flexibility to choose where they want the timers to be," he said. "For example, a lot of farmers chose the timers to be installed on their furthest and hardest to reach wells. In some cases, that means that they do not have to go 30 minutes out of the way to shut off the irrigation.
"Some farmers also mentioned how it helped them by not having to drive as much around the farm. Fewer hours driving and fewer hours of the engine of the wells running saves time and money. Plus, the timer shutting off automatically means one less thing to worry about."
Oftentimes, if something happens on the farm that requires a farmer's attention, the wells and irrigation needing to be turned off become the last thing on their minds. In turn, the irrigation could run for several more hours unnecessarily. This means more cost and water runoff that carries away soil and nutrients.
"If the water savings stay consistent with the preliminary data seen so far, we could potentially save up to 9 billion gallons of underground water per year," Prezotti said.
"This is an ongoing project and will save much more over time, which is a huge win for conservation and farmers."
Prezotti may be contacted at (501) 626-8959 or at [email protected].
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