While winter in the Midwest's breadbasket often means snow, cold rains and blustering winds, over in California’s "salad bowl" region it's sunny, and this year it's particularly dry.

I recently traveled to California's Central Valley to do some reporting on how climate change may affect agriculture there. Having traipsed about farms in the Midwest for nearly two years now, it was striking to see just how different agriculture is in sunny California. For one, seeing blossoms in February, alive with bees and soaking up the balmy, 70-degree weather, confused my four-seasons brain. 

But the difference that was most immediately obvious was the vast diversity of crops grown in the state. California farmers grow over 200 different crops and several farmers I talked with grow at least eight varieties at any given time. Not only that, but farmers are much more accustomed to, and adept at, switching between crops relatively rapidly.

That's been true for years, says Louise Jackson, a professor in plant and environmental sciences at University of California Davis.

"(Crops) in California have moved around like crazy," Jackson said. "Around the turn of the century, the Los Angeles basin was an incredible production area for vegetables." Now, much of the vegetable production has moved north, to the Salinas Valley.

As for farmers across the U.S., most of these changes in crop production are driven by economics. For example, Yolo County Farm Bureau president Chuck Dudley told me his area used to be chock full of sugar beet farmers. From the 1930s up through the 1970s, sugar beets were among the three top-grossing commodities in the region. But with changes in demand and the closure of some processing plants, the crop doesn't even make the top ten today.

Other crops like melons and asparagus have shifted in popularity, too. Both have featured prominently in the region's commodities, but in recent years have dropped off the list.

Because most California crops are irrigated, farmers have a lot more flexibility in changing the crops they grow – in some cases, right up until a farmer actually does the planting. 

Bruce Rominger farms about 5,000 acres with his brother, Rick, in Yolo County near Davis. They grow processing tomatoes, rice, wheat, alfalfa, corn, sunflowers, safflower, wine grapes, seed onions and they're even starting to raise sheep. 

"We like to not have our eggs in one basket and have a lot of different crops," Rominger said. "Depending on the volatility of the markets, we're usually OK if something is very low one year."

Rominger said he keeps his options open to make farming changes based on weather or commodity markets. For example, if the weather is particularly dry one year, he might switch a field he planned to plant with alfalfa, which is quite water-demanding, to a gentler crop. He might not make up his mind until a few days before he plants. He just has to give the seed company a call, he said.

Contrast that with the Midwest, where agriculture in the last decade has been dominated by corn and soybeans, with some wheat, rye and alfalfa thrown in. Farmers have very specialized equipment and often make their planting decisions well in advance.

The bottom line, of course, is that all farmers are business people. They make decisions about what to plant based on what they think will keep their farm afloat financially. 

Most farmers I've talked to say they've chosen their livelihood because they love farming. To stay in the business of working the land, they make themselves businessmen – watching markets and trends and trying to time things right. But in the end, they're all subject to the fickle hand of Mother Nature and unpredictable global markets. Diversifying crops is just one way farmers can work to hedge against uncertainty.