Groundwater levels have been declining in parts of northeast Arkansas for years. Unfortunately, the areas of decline often coincide with those with the greatest amount of rice acres in the Wonder State.
So it only makes sense that a large part of the new, 600-acre Northeast Rice Research and Extension Center being developed by the University of Arkansas System Division of Agriculture would be devoted to improving irrigation efficiency.
Dr. Tim Burcham, director of the Northeast Rice Research and Extension Center or NERREC, which is located near Harrisburg, Ark., in Poinsett County, described some of the planning that has gone into its irrigation capabilities during the University of Arkansas’ Rice Agricultural Sustainability Virtual Field Trip.
“I’m standing in front of this beautiful 32-acre, 10 feet deep man-made reservoir that was already on the farm,” said Burcham, formerly dean of the College of Agriculture and Technology at Arkansas State University. “Our Division of Agriculture folks did a great job in selecting this farm because it is the epitome of what you would look for in sustainable rice production.”
The western side of the farm is bordered by the L’Anguille River, which provides drainage for the city of Jonesboro, north of the center. The NERREC has two relift pumps on the L’Anguille River so that it has ample opportunity to use surface water in its irrigation studies.
The reservoir is connected to 3.3 miles of underground irrigation network. “A portion of that was already here when we purchased the farm, and we’ve added sections to that,” said Burcham. “Now every field on this farm has a riser available to it. We’ve also designed in a valve network that allows us to use river water directly to the irrigation system, this reservoir directly to the irrigation system as well as well water to the system.
“So in any field on this farm if we wanted to do an experiment looking at cold water influence, for example, we could use well water and move that to any field on the farm.”
The irrigation system, which was designed by Burcham and Dr. Chris Henry, Extension irrigation specialist for the University of Arkansas Division of Agriculture, will provide ample water capacity and flexibility for research.
“In addition, we have moved three-phase power into the reservoir side here,” Burcham noted. “So all of those pumps that are running our irrigation system will be electric three-phase and the two primary ones will have variable frequency drives on them so that we can dial in the precise amount of water that's necessary, whether we're flooding the field up on zero grade or using it for row rice production.”
The NERREC also has fields leveled to 0.1 per 100 feet. It also has a field that is at 0.05 feet per 100 feet and another field at 0.03 per 100 feet.
“So for the research components that are going on here we have a number of different slope topographies that we can work off of with regard to sustainable rice production,” he said in a video from the Virtual Field Trip. “The field you’re seeing is part of 110 acres of zero grade fields that are broken up into blocks or six different fields that are 20 acres a piece.
“This gives us a great opportunity in the future to do larger block studies and plot studies on zero grade rice production. As you know, zero grade rice production is one of the best methodologies from a water use standpoint. Typically, between 14 and 19 inches of water are used for zero grade rice production fields.”
Burcham said researchers have planted furrow-irrigated or row rice on one of the fields along Arkansas Highway 1 that was leveled to 0.1 of a foot per 100 feet. “That’s so we can look at conservation methods and nutrient management methods that will enhance row rice production for our Arkansas farmers. We’re excited about this particular concept for sustainable rice production.”