State’s Loss of Farmland Accelerates : Agriculture: Between 1984 and 1990, 140,000 acres were taken out of production, mostly because of suburban growth. More reductions are expected.

California lost 31,000 acres of prime farmland in the final two years of the 1980s, an amount four times higher than the figure for the previous two years, a state report released Tuesday said.

In all, between 1984 and 1990, as the state’s population was growing by about 750,000 people a year, California lost 140,000 acres of farmland, mostly to suburban growth. That represents about 2% of the total farming acreage mapped.

More farmland is expected to be converted in the future. The report noted that another 92,000 acres of farm and grazing land are earmarked for housing development and other uses.

The numbers are included in the Farmland Conversion Report, issued every two years by the California Department of Conservation. The mapping project began in 1984 amid concerns that California was losing farmland at a rapid rate.

The project omits key portions of major farm counties in the San Joaquin Valley, including the fast-growing westsides of Merced and Stanislaus counties, as well as San Joaquin County.

But while it may be incomplete, the survey reflects a “continuation of prior heavy activity” in which farms are giving way to housing, said Eric Vink of the American Farmland Trust, a private organization that tries to slow development of farmland.

Vink and some state officials and academics say the loss of farmland could threaten California’s role as the nation’s major producer of fruit and vegetables. However, some critics say the extent and importance of the farmland loss have been overstated.

The figures in Tuesday’s report reflect the net decline in farm acreage because other rural land was being turned into cropland as farmland was being removed from production. But the report said that the rate at which new land was being pressed into farm production decreased--21,000 new acres between 1988 and 1990, compared to 25,500 between 1986 and 1988.

The biggest single loss of the most prime farming land was in Los Angeles County, where 7,000 acres of top-quality land--nearly a fourth of the county’s remaining prime growing acreage--went out of production.

Much of the development occurred in the Antelope Valley. Los Angeles was the state’s leading farm county in the 1940s.

In Fresno, currently the leading farm county, 20,550 acres of farmland in all quality levels were lost between 1984 and 1990, mostly in the last two years of the 1980s.

Orange County lost 2,774 acres of farm and grazing land in 1988-90, including 2,100 acres of prime farmland. In San Diego County, 6,030 acres of farm and grazing land were taken out of production, including 371 acres of prime farmland.

In Ventura County, 2,905 acres of farm and grazing land were taken out of production, including 672 acres of prime farmland.