Vegetables and milk were the first foods that sparked concerns about the safety of Japanese agriculture after the March 11 tsunami flooded the nuclear plant and its reactors began to overheat and spew radiation. But those worries intensified when highly radioactive water was spotted gushing from the complex into the Pacific and contaminated fish showed up in catches.
Those concerns have abated somewhat after the leak was plugged and bans on produce from some areas were lifted.
But rice has now come under the microscope as the planting season begins in April and May.
"We had to come up with a policy quickly because we are in planting season," said Agriculture Minister Michihiko Kano, who announced the ban Friday.
The ban will apply to any soil found to contain high levels of radioactive cesium, and farmers who cannot grow rice will be compensated. Rice grown in uncontaminated soil will be screened.
Yoshiyuki Ueda, a 47-year-old rice farmer from the town of Futaba, where the damaged nuclear plant is located, said he had already given up on trying to plant this year's crop because of radiation fears.
"The ground is ruined," Ueda said. "I think it will be a long time until things return to normal."
Rice is revered in Japanese culture, and the word for cooked rice, "gohan," also means meal. It's the key ingredient in sake, and citizens proudly buy locally grown varieties.
Plant workers have spent the past month frantically trying to stop radiation from spewing by restoring cooling systems, but they still have a long way to go. Radiation in water pooling around the plant has slowed the efforts to stabilize the reactors, but workers made progress Saturday toward cleaning up that contamination.
In an unusual - and controversial - plan, engineers decided earlier this month to deliberately pump less contaminated water into the ocean from a storage facility they thought might make a good receptacle for the more highly radioactive water.
That dump is expected to finish Sunday, and technicians already are beginning to ensure that the building is watertight, according to nuclear safety agency spokesman Hidehiko Nishiyama.
"We cannot afford a lot of time" in completing this process, Nishiyama said, but he did not say how long it would take.
The Nuclear and Industrial Safety Agency approved those moves as "an unavoidable emergency step," Nishiyama said.
Several areas of the plant are difficult to reach because of radiation. On Saturday, two 190,000-pound (86,000-kilogram) concrete pumps that have been retrofitted to spray water and can be operated by remote control were on their way to the plant from Atlanta and Los Angeles.
The plant operator, Tokyo Electric Power Co., is also hoping to use T-Hawk drone aircraft made by Honeywell to inspect areas of the plant it cannot access. The drone can be operated from six miles (10 kilometers) away and transmit video and still images.
Until reactors are stabilized, radiation will continue to be released. Earlier, high levels of seawater contamination around the plant prompted the nation that gave the world sushi to set limits for the first time on the amount of radiation permitted in fish. Concerns about food have led several countries, most recently China, to ban imports of some items from Japan.
Rice may be particularly vulnerable to absorbing radiation because it has a long growing season.
So far, soil containing cesium that exceeds the new limit has been found in only two places in Iitate, a village about 25 miles (40 kilometers) from the Fukushima Dai-ichi nuclear complex.
Japan produced 8.5 million tons of rice in 2010, almost all for domestic consumption. It exported just 1,900 tons for sale last year, with Hong Kong, Singapore and Taiwan the top recipients. It imported about 664,000 tons last year.
Fukushima, home to the radiation-leaking plant, was the nation's fourth-largest rice producing prefecture (state) last year.
Experts say people would have to eat enormous quantities of produce or dairy products before receiving even the amount of radiation contained in a CT scan, but cesium is a concern because it can build up in the body and high levels are thought to be a risk for various cancers.
Associated Press writers Mari Yamaguchi, Noriko Kitano and Mayumi Saito in Tokyo, and Tomoko A. Hosaka and Jay Alabaster in Sendai contributed to this report.