FIREBAUGH — In wetter times, these feathery beds of asparagus would produce generations of tender green spears, reaching for the vast San Joaquin Valley sky.

On Monday they were disked into the dry dirt, their long lives cut short by unreliable and expensive water.

“It’s a really sad day,” said Fresno County’s Joe Del Bosque, who has destroyed 100 acres of organic asparagus so he can divert precious water to more valuable melons. “The water is so uncertain this year. We didn’t think we’d have enough to carry it through.”

With no guarantee of irrigation water this summer, Del Bosque and other California farmers are making tough choices, sacrificing one crop to save another. The strategy is part of a larger and longer agricultural shift here in the heart of California’s $50 billion agriculture industry: Low-value, high-water crops are disappearing from the Golden State.

Cotton, the San Joaquin Valley’s main cash crop for much of the 20th century, is nearly abandoned. Alfalfa, whose purple blossoms once filled fields with a tangy fragrance, is also shrinking. Crops that are labor intensive and face fierce foreign competition, such as asparagus, have lost their luster.

Instead growers are moving to less thirsty or more lucrative fruits, vegetables, grapes and nut trees, according to USDA data. Some are making seasonal shifts to avoid summer’s punishing drought, relying more on winter-planted crops like garlic, carrots and onions.

“There’s a concentration of value,” said Josue Medellin-Azuara, associate director of the University of California’s Center for Watershed Science, who studies agricultural trends. “We still have crop categories that use substantial water. But we’re shying away from some crops that do not offer as much in revenues and jobs.”

Scarce winter rains mean that fields and pastures are already dry in a springtime season that is normally lush and generous. The reservoirs are suffering as well. Storage levels at Lake Shasta and Lake Oroville are only 53% and 47% of average.

Farmers on the west side of the San Joaquin Valley started the season with a government-issued allocation of only 5% of water from federal sources. As more recent settlers in the state, they are “junior” water rights holders; their allotments are an offer, not a guarantee. Now even that tiny allocation has been suspended.

And there’s a newer and more startling problem, as well: Water “transfers,” which allow thirsty irrigation districts to buy water from other districts, are delayed.

What happened? This spring, Mother Nature threw a surprise punch that made our ongoing drought even worse. We expected about 500,000 acre feet of water to drain from the snowy Sierra into our reservoirs. Instead, due to a warm March and April, it was absorbed or evaporated. That missing water would have supported 385,000 acres of melons, 125,000 acres of almonds or a million households.

With less incoming water, the state is saving it to protect salmon, rather than releasing it to agriculture. It is also assessing how much water to save for next year.

Normally, farmers would get one-quarter of their transfers, already purchased, from other districts in July, with another one-quarter in August and one-half in September. That’s all in limbo.

And unlike previous droughts, they can’t just turn to groundwater. Under the state’s new Groundwater Management Act, agriculture is required to adhere to strict “sustainability plan” guidelines for pumping in dry years, said Medellin-Azuara.

“We’re looking at an absolutely catastrophic year,” said Ryan Jacobsen of the Fresno County Farm Bureau. “But farmers have options. So they’re figuring out what their water portfolio looks like. Then they’re looking at potential (financial) returns.”

Dairy farmers and beef ranchers are feeling the pain, too. With so little grass, they must pay extra for feed to supplement livestock feeding. Some are reducing herd size, said Karen Sweet, director of the California Rangeland Conservation Coalition. This could flood the market with beef, reducing ranchers’ earnings even as their costs rise.

In the Altamont hills east of Livermore, a large semi-truck drops off almond hulls to supplement the diets of the 70 Black Angus cattle on Sweet’s 900-acre ranch, which dates back to the 1860s. Normally, the Sweets let calves stay with their mothers until June; this year, they weaned in March, to ease the nutritional demands on their pregnant cows.

Normally, ranchers move herds to parts of the state with more grass. “But because the drought is covering most areas to which cattle may have been moved, there is no place to ship them for most ranchers,” said Sweet. “There are not too many places to go.”

For consumers, all this might mean higher food prices and greater reliability on foreign imports, said Jacobsen. California supplies two-thirds of the nation’s fruits and one-third of its vegetables. It contributes 5% of the nation’s beef cattle but leads the U.S. in both milk cow inventory and sales.

Faced with uncertainty, some growers are directing their water to sustain permanent crops, such as almonds and pistachios, which are long-term investments. A few are enlisting what’s called “deficit irrigation,” temporarily reducing flows to a plant in hopes that it can catch up later.

But other crops aren’t worth saving. Acreage of alfalfa, one of the thirstiest crops grown in the state, has fallen by half. Cotton was once one of the state’s biggest crops, with 1.3 million acres planted at its peak in 1995; now, only 250,000 acres are in production. With water and prices plummeting, farmers have shifted to Pima cotton, a different variety that fetches much higher prices. But even that’s risky.

“Cotton has gone way down. And I don’t think it is ever going to come back,” said sixth-generation farmer Cannon Michael, who runs an 11,000-acre farm in Los Banos.

Asparagus is also declining.  Plants live and produce for nine years, and require, on average, nearly 260 gallons of water per pound. It’s also labor-intensive to cut multiple spears every day. Due to 1990s-era trade agreements, there’s price competition from Latin American imports. It’s far more popular in the Imperial Valley, where growers have senior rights to Colorado River water.

By contrast, melons and other annual crops, such as tomatoes, offer greater profits and much more flexibility. When there’s no water, fields can be easily fallowed.

“I’m giving up 100 acres of asparagus to try to grow 150 acres of melons,” said Del Bosque. “With the same water.”