Finding the ‘goldilocks’ zone or conditions in rice irrigation

Alternate wetting and drying, a rice irrigation practice dating back to the 1980s, is part of a broader Texas A&M AgriLife study investigating its potential to reduce water and fertilizer use.

The practice is a water management system where rice fields are allowed to dry intermittently during growth stages instead of remaining continuously flooded.

The research has sparked broader interest, specifically from Texas rice producers who are participating in field trial studies and those following the main work with controlled plots at the Texas A&M AgriLife Research and Extension Center at Beaumont and Eagle Lake research station.

Funding for the four-year research project is through the U.S. Department of Agriculture-National Institute of Food and Agriculture.

‘Finding the goldilocks zone’

The advantages of alternate wetting and drying could include cost savings for Texas rice farmers through efficient water irrigation practices as researchers continue to seek the most fruitful methods. Another benefit is the potential to reduce methane emissions from flooded rice fields.

“The idea is to not continually pump water into the fields,” said Jake Mowrer, Ph.D., Texas A&M AgriLife Extension Service state fertility specialist in the Texas A&M College of Agriculture and Life Sciences Department of Soil and Crop Sciences, Bryan-College Station. “There are efficiencies with regards to water savings, greenhouse gas emissions and fertilizer use, but we need to find this ‘goldilocks zone’ before farmers get out there and adopt.”

Modeling, data gathering

“This is not a new concept,” said Fugen Dou, Ph.D., Texas A&M AgriLife Research scientist, crop nutrient management, Beaumont, and professor in the Department of Soil and Crop Sciences.

The practice originated in Asia in the 1980s and has since been utilized by rice farmers in Arkansas, Louisiana and California. It’s a relatively new practice for Texas due to emerging challenges from nitrogen loss, weed control and yield penalty.

Dou said the project outcomes could be beneficial for Texas rice farmers.

“Water availability plays a big role with Texas rice, particularly west of Houston,” he said. “They primarily rely on a ratoon crop to make money. (The study results) could be a larger benefit to our farmers to keep farming. We are seeing a lot of urban expansion around Katy and west of Houston. We want to try to do our best to support the growers.”

The project trials will be carried out both at Texas A&M AgriLife’s research stations at Beaumont and Eagle Lake using controlled plots, Mowrer said.

“We will start measuring things in small scale and build upon that,” he said. “At the stations, we will be dealing with multiple varieties of work between our research efforts and then also the trials with rice producers. The results will tell us to either do this or don’t do it. It will really help Texas rice producers.”

Reducing carbon emissions

Nithya Rajan, Ph.D., AgriLife Research agronomist and professor in the Department of Soil and Crop Sciences , said one of the goals of the project is to evaluate the impact of various management strategies on greenhouse gas emissions, especially, methane.

“The water management strategies being tested in the project have the potential to reduce methane emissions,” Rajan said. “Given that rice is traditionally cultivated under flooded conditions, the anaerobic soil conditions create an environment conducive to the release of methane by microorganisms. Implementing alternate wetting and drying cycles can significantly influence the overall greenhouse gas emission footprint of the entire rice cropping system. Although the exact extent of emission reduction remains uncertain, we will employ state-of-the-art instrumentation technologies to monitor emissions in collaboration with regional rice producers.”

The data will really be significant in helping rice producers get more information, providing insights into the carbon footprint and potentially opening avenues to participate in carbon markets.

Researchers will conduct data collection from both experimental plots and large fields and might include drones in producing new data points on weeds and pest challenges.

With traditional irrigation practices, weed control is a big concern.

“Especially with red rice, we don’t want weed control to get out of hand,” Mowrer said. “Overall, it’s a complicated system, but we are determined to find the right solutions to benefit Texas rice farmers.”