Dustin Harrell, resident coordinator of the LSU AgCenter H. Rouse Caffey Rice Research Station, speaks to attendees of the facility’s 112th annual field day in June 2021. Harrell studies the agronomic recommendations of potential varieties released by LSU AgCenter rice breeders. Photo by Derek Albert.

The LSU AgCenter’s efforts to offer best management practices for producing rice start with Dustin Harrell, resident coordinator of the LSU AgCenter H. Rouse Caffey Rice Research Station in Crowley.

Harrell said one of the recurring projects he has undertaken annually is studying the agronomic recommendations of potential varieties released by LSU AgCenter rice breeders. With each release, Harrell and fellow researchers evaluate many aspects of the propagation and growing cycles.

“That answers questions like, at what seeding rate do we need to plant of that particular variety to maximize yields? How much nitrogen do we need to apply to maximize yield without lodging this variety? Under high nitrogen rates are we seeing increased disease pressure?” Harrell said. “There’s a lot of data that we generate as far as knowing more about a variety when it is released from those programs.”

Work continues when it comes to evaluating CLL17, a Clearfield variety that has taken the top spot for rice acreage grown in Louisiana, surpassing CL153. CLL17 was released quickly because of its consistent yield increases and disease resistance over previous varieties. In particular, nitrogen response is being closely examined with CLL17 because that variety seems to need less nitrogen, Harrell said.

“When we test these things, not only do we do it at the rice station, but we do it at multiple locations across the state in farmers’ fields,” Harrell said. “We want to have at least three years of data before we make agronomic recommendations.”

LSU AgCenter rice researchers have reached across state lines for a new program examining agronomic performance in pre-commercial trials. Harrell said facilities in Texas, Arkansas and Louisiana are examining data collected from multiple sites throughout each state.

“We are going to get a lot of good data,” Harrell said. “This is going to help us tremendously because it is going to produce a lot of replicated data each year. We are going to learn a lot more and a lot quicker.”

Furrow-irrigated rice, or row rice, is being explored at several sites in Louisiana. The practice allows for versatility in planting other row crops, such as cotton or soybeans, on fallow rice acreage. Through replicated trials at the H. Rouse Caffey Rice Research Station near Crowley and at the Northeast Research Station in St. Joseph, Harrell and his team are evaluating nitrogen use and response in furrow-irrigated rice versus flooded fields.

“We have several replicated field trials here at the station on a silt loam soil, and we also have the same trials at the St. Joseph station on clay soil,” Harrell said. “That’s going to provide us a tremendous amount of data.”

In those trials, researchers are comparing nitrogen application rates, application timing and methods of nitrogen application that can be directly compared between row rice and the traditional flooded rice fields. Other trials are exploring the use of varied nitrogen sources in the form of enhanced-efficiency fertilizers. Researchers are analyzing the crop’s response to urea, urease inhibitors, nitrification inhibitors and combinations of those in row rice because nitrogen loss in row rice is more significant.

“In flooded rice, we know that we really only need the urease inhibitor, but in furrow-irrigated rice you’re in a completely different environment. It’s not always flooded,” Harrell said. “It’s wet. Then, it’s dry, and it’s wet. So that causes a lot more nitrogen loss.”

Harrell also discussed the LSU AgCenter’s work with ratoon crop management.

“We are always trying to make improvements to the ratoon crop because it is very economically important to the producers of southwest Louisiana,” Harrell said.

The station’s ratoon crop trials do come with their own difficulties to undertake because of increased variabilities. For example, the tumultuous 2020 hurricane season caused grain shattering and harvesting difficulties. Harrell said weather is the major culprit for only being able to retrieve ample ratoon crop data approximately every other year.

A new trial that has been prompted by the Biden administration’s focus on climate change is underway at the Rice Research Station. The agronomy program is working with Manoch Kongchum, LSU AgCenter agronomist, to measure greenhouse gas emissions in rice production. Harrell said soil aeration, which can occur when a field is drained, creates a reduction in greenhouse gases. This research quantifies how much greenhouse gas is reduced using alternate water management practices such as draining events or furrow-irrigated crops.

“We really need some good Louisiana data that quantifies that we can reduce emissions by implementing water management practices,” he said. “There should be some environmental incentive in the future.”

The quantity of arsenic in rice is an issue that has arisen in media reports and has affected consumer opinion. While arsenic is naturally produced in rice because it is grown in flooded conditions, excessive amounts of the element can be harmful when consumed. Harrell said according to Food and Drug Administration data collected this year, the amount of arsenic found in Louisiana-grown rice is below the daily recommended guidelines.

“This is an area where we need to have data to show that rice is a safe and nutritious crop, and the levels of arsenic in the grain are well below current standards,” Harrell said.