As rice-planting season in California enters its home stretch, drought-related water restrictions will curb the state's acreage to its lowest point in nearly 40 years, according to estimates.

The USDA foresees 348,000 acres of rice plantings in the Golden State in 2022, representing a steep decline from 407,000 acres planted last year and 517,000 acres in 2020.

With the decline, California's rice acreage will be the lowest it's been since the 1983-84 growing season, the California Farm Bureau notes. Rice farmers fallowing ground tell the CFB that crop insurance will help, but they worry about long-term impacts for farming.

Related: Northern Calif. not spared from irrigation cuts

Critically low water supplies in Shasta Lake are prompting significant restrictions in federal Central Valley Project water, which are expected to idle nearly 400,000 acres of farmland across the Sacramento Valley.

For farmers in the Glenn Colusa Irrigation District (GCID), the largest water district in the Sacramento Valley, irrigation deliveries may be less than 20% of what growers have historically received from Shasta Lake via the Sacramento River. For a district that saw 100,000 acres planted to rice in 2019, early estimates suggest as little as 875 acres of rice will be planted across the district this season.

A water-saving plan unveiled in March by California and federal officials was expected to result in about 35,000 acres of Central Valley rice ground being left idle. The plan is part of a larger agreement signed March 29 that send an extra 824,000 acre-feet of fresh water through the Sacramento-San Joaquin River Delta to protect water quality, according to The Associated Press. An acre-foot is enough water to serve an average household for a year.