FRESNO, Calif. -- Dozens of farmers in the Sacramento-San Joaquin River Delta submitted plans Monday to the state saying they intend to plant less thirsty crops and leave some fields unplanted to meet voluntary water conservation targets amid the relentless California drought, officials said.

The farmers -- with the strongest water rights in the state -- devised the plans as part of a deal struck last month that would spare them deeper mandatory cuts by the state in the future.

Under the agreement, they must submit plans for using 25 per cent less water, fallowing 25 per cent of their land, or other strategies to achieve the necessary water savings. Officials hope the deal can become a model for other farmers around the state.

California cities and businesses have also been ordered to reduce water use by 25 per cent. State Water Resources Control Board on Tuesday is expected to release its report for how communities met the goal in April.

At least 120 farmers in the delta east of San Francisco had filed plans and more were expected to submit proposals before the midnight deadline, said Michael George, delta watermaster for the State Water Resources Control Board.

Further details involving particular crop changes were not immediately disclosed.

"These are serious well-conceived plans that will result in some significant conservation," said George, who is tasked with calculating how much water the changes will save.

California grows nearly half of the fruits, nuts and vegetables consumed in the U.S. However, agriculture experts say the California drought hasn't had a significant impact on food prices because other regions are making up the difference.

Delta farmers who proposed the voluntary cutbacks have never had their water use restricted.

John Herrick, an attorney and manager of the South Delta Water Agency, said he was busy Monday answering last-minute questions from farmers trying to meet the deadline. He had no hard figures but believed as many as 90 per cent of the farmers eligible for the program would apply.

The delta accounts for less than 10 per cent of the 6.9 million acres of irrigated farmland in California, but it is the hub of the state's water system. About 25 per cent of California river water runs through the delta, supplying communities and farms throughout the state.

John Kisst, who farms 900 acres in the delta, said he will irrigate some of his alfalfa once a month rather than twice and will leave some fields unplanted. Some farmers may turn to growing safflower, which needs to be watered just once, or to some types of corn and beans that grow in three months rather than four, reducing the need for irrigation.

"This is not a science," Kisst said. "But we're expected to make our best effort."

State officials this year have already ordered water curtailments for thousands of farmers and other water users with lesser rights, but the state has not yet forced cuts on farmers with rights predating 1914 or who have land along rivers or streams.