Low Rice Yields Resulting From Unusual Weather This Year

Steven Linscombe, Eskew, Charles E., Saichuk, John K., Schultz, Bruce, Dunand, Richard T., Groth, Donald E.  |  4/19/2005 10:29:08 PM

A combine harvests a field of rice farmed by the Loewer brothers of Acadia Parish. Like many other farmers, the Loewers say their harvest is down from last year.

News Release Distributed 07/29/04 

Too much rain and not enough sunshine – both at the worst times – are being blamed as the culprits that stole a bountiful rice harvest.

"The rain was in the right place at the wrong time," said LSU AgCenter plant physiologist Dr. Richard Dunand.

The problems started in mid-May, when most rice plants were at green ring stage where the panicles from which the rice grains will form start to develop. Dunand said several days of rain and heavy cloud cover resulted in an inadequate amount of sunlight vital for photosynthesis.

"The plants were under stress," Dunand said.

When that happens, he explained, a plant’s natural reaction is to limit the amount of energy it can direct toward reproduction, and it will produce fewer florets, the small flower-like reproductive structures in the panicles. At stressful times, plants will produce fewer grains that may also be smaller, he said. In addition, he said the plants generated fewer tillers, resulting in fewer panicles.

After that setback came the heavy rainfall of mid-June – with several days of consecutive rainfall exceeding more than 20 inches in some areas. Most of the rice was in the process of pollination, and the heavy rain may have interfered with that crucial step, Dunand said.

Rice is a self-pollinating plant, Dunand explained, so it doesn’t use insects or wind for reproduction. The florets open, and the pollen cases dry and open, releasing pollen that falls onto the stigma for fertilization with the ovary, he said.

Dunand said pollination occurs within a small time-frame, with the florets opening between 10 a.m. and mid-afternoon. Rain falling on the florets can interrupt the process, he said.

Generally, not all florets on a panicle open simultaneously, he said. As a rule, florets on the top third will open the first day of pollination, followed by the middle florets and the bottom third on the last day. Roughly, rice plants in a field have a 10-day window for pollination, he said.

High winds during thunderstorms also could be a factor that interferes with pollination, said Dr. Steve Linscombe, LSU AgCenter rice breeder.

Heavy rainfall also set the stage for diseases, such as sheath blight, that thrive under moist conditions, said Dr. Don Groth, LSU AgCenter plant pathologist.

"The plant canopy never dried out," Groth said.

Frequent rain kept the plant canopy wet and may have washed away fungicides before they had a chance to be effective, Groth explained, adding that the wet plants provided an ideal environment for disease to thrive.

Linscombe said heavy rains interfered with schedules for applications of fertilizers and pesticides, since pilots couldn’t fly during inclement weather and the fields may have been too wet to use ground spraying rigs.

A common method of fighting rice water weevils, whose larvae eat the tender roots of developing rice plants, is to drain rice fields to dry the soil. But Linscombe said saturated ground made that impossible for many farmers.

It’s a common misconception that rice thrives in tropical weather, Linscombe said. While the plant can withstand heavy amounts of rain, he said, "It doesn’t like as much as we got this year."

Early numbers from the field indicate a harvest far below last year’s record yield.

"We’re not going to hear a lot of bragging on this year’s yields," said LSU AgCenter rice specialist Dr. Johnny Saichuk.

Saichuk said a farmer in Vermilion Parish, Ted Girouard, cut 36 barrels an acre Tuesday – where he had predicted a 41-barrel yield.

"It was real disappointing," he said. "We’re probably running three barrels (per acre) under last year’s yields, or about 500 pounds an acre."

The Loewer brothers in Acadia Parish have started their harvest, and they’re also not excited with what they’ve seen so far.

James Loewer said a field cut Wednesday produced slightly more than 40 barrels an acre.

"It should have made 45," he said.

Another field yielded only a little more than 35 barrels, he said.

Eddie Eskew, an LSU AgCenter county agent for rice in Jefferson Davis, Allen, Cameron and Calcasieu parishes, said maturity is inconsistent. Even in the same field, the rice isn’t maturing at the same time, Eskew said.

Many farmers planted fields at different times, so harvest could be spread out over several days, Eskew said, but that planning may have been in vain.

"It appears all the rice is going to be ready at the same time," Eskew said.

By late July, he said, harvest should be 50 percent to 60 percent complete under normal circumstances, but only a fifth of the crop had been cut as of the last week of July this year.

Some of the crop will remain in the field beyond the LSU AgCenter’s recommended deadline of Aug. 10 for a second crop, he said.

Eskew said the mood of the agricultural community now is opposite of what it was earlier this year before planting.

"There was so much optimism in February with high prices," he said. "If you go out in the farming community now, there is a lot of disappointment out there."


Richard Dunand at (337) 788-7531 or rdunand@agcenter.lsu.edu 
Don Groth (337) 788-7531 or dgroth@agcenter.lsu.edu
Steve Linscombe (337) 788-7531 or slinscombe@agcenter.lsu.edu
Johnny Saichuk (337) 788-7547 or jsaichuk@agcenter.lsu.edu  
Eddie Eskew (337) 824-1773 or eeskew@agcenter.lsu.edu
Bruce Schultz at (337) 788-8821 or bschultz@agcenter.lsu.edu

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