Walking across a rice field usually is occasion to don rubber boots, but as Brian Ottis surveyed his research plots at the University of Missouri Delta Research Center, the rice agronomist didn't bother — and not because he likes to feel the mud squish between his toes.
It was because these particular rice plots weren't flooded. No standing water, no mud, no fuss, but perhaps a new way to grow the grain in Missouri.
“We're evaluating a drip-irrigation system similar to that used in other crops such as cotton in west Texas and melons in southeast Missouri,” said Ottis, who is stationed at the center in Portageville, Mo. “If it proves successful, it could bring rice production to non-conventional, upland areas of Missouri.”
The floodless system uses lengths of drip tape — a high-tech soaker hose buried 5 inches deep and spaced 30 inches apart — that run parallel to the crop rows. Each length of tape is connected to a common water source with flexible polyethylene pipe at the field edge. An 8-foot-tall water tank exerts all the force necessary to power the low-pressure, low-volume system.
Drip irrigation does offer advantages over conventional rice production, Ottis said. “The water savings are significant, with up to a two-thirds reduction in water use,” he said. “You only replace the water that is lost to evapotranspiration.”
Fertilizer applications can be made directly through the system, allowing the crop to be “spoon fed” over time and fully utilize available nutrients.
“Planting and herbicide applications also can be done from the ground,” Ottis said. “Instead of aerial water seeding, producers can use conventional seed drills. And because there are no levees or water to deal with, ground rigs can be used to spray herbicides.”
The system does has some disadvantages, namely cost. “It does cost quite a bit to install, but once you get it set up, management is minimal,” he said. “An additional herbicide application may be necessary in the absence of weed suppression provided by the flooded conditions.”
Ottis said that because the system is buried only 5 inches, producers would be restricted to a no-till production system. “The system should last two to three years,” he said. “After three years, the emitters in the drip tape get gummed up.”
While comparing the overall drip irrigation system to conventional flooding, Ottis also is evaluating three rice varieties to determine which is best suited for drip irrigation. Another component of the project is assessing nitrogen rates.
“Right now, this system probably has a niche in high-value crops such as pharmaceutical and organic crops,” he said.
Jason L. Jenkins is Senior Information Specialist, Extension & Ag Information, University of Missouri(573-882-2980 or JenkinsJL@missouri.edu).