SACRAMENTO -- Farmworkers in the nation's largest agricultural state will be entitled to the same overtime pay as most other hourly workers under a law Gov. Jerry Brown said Monday that he had signed.

The new law, which will be phased in beginning in 2019, is the first of its kind in the nation to end the 80-year-old practice of applying separate labor rules to agricultural laborers.

California employers currently must pay time-and-a-half to farmworkers after 10 hours in a day or 60 hours in a week. That's longer than the overtime pay for other workers, who get it after eight hours a day or 40 hours a week.

AB1066 will gradually lower the number of hours that irrigators, ranchhands and people who sow and harvest fields must work before accruing additional compensation.

It will take full effect in 2022 for most businesses and in 2025 for farms with 25 or fewer employees.

Brown signed the bill following a push by the United Farm Workers union and its allies, who say exempting farmworkers from labor laws is racist and unfair. The governor had declined to comment on the bill throughout the legislative process and again on Monday through spokeswoman Deborah Hoffman.

Opponents argued the seasonal nature of farm work does not lend itself to overtime. They said the legislation would raise costs for farmers and make it more difficult for them to compete with rivals in other states and countries, and that added costs would force employers to cut workers' hours, ultimately hurting hundreds of thousands of farmworkers in California.

Farmworkers have been exempt from overtime pay requirements since Congress approved the Fair Labor Standards Act in 1938 to outline workplace protections.

Farmworkers were again exempted in 1999 when California guaranteed overtime pay after eight hours in a day, not just 40 in a week.

California has for decades been a battleground over farmworker rights. Cesar Chavez brought together farmworkers and founded the UFW in the Central Valley in the 1960s, organizing thousands of workers who demanded better wages and working conditions.

California was the first state to give farmworkers collective bargaining rights, workers' compensation and unemployment service. The state also requires that employers provide rest breaks and access to water and shade.