When California publishes its crop report in November, there will be a significant change in the ranking order of the state's top agricultural commodities. In 2011, for the first time ever, the value of the California almond crop surpassed the state's iconic grape industry to move into second place, behind dairy.

California almonds are on a roll. In the last 20 years, scientific discovery and grower ingenuity have nearly doubled almond per-acre productivity. A good yield in the 1980s was 1,400 pounds per acre. The average yield for 2011 was 2,670 pounds of shelled almonds per acre.

Forty years ago, California farmers produced less than 100 million pounds of almonds on about 200,000 acres of almond orchards. Mechanization, improved irrigation efficiency, advances in insect and disease management, pruning research and fertilization studies have fueled explosive growth in the industry. Farmers in California's Central Valley now tend 760,000 acres of almond trees, producing about 2 billion pounds of shelled nuts a year.  The crop, which represents 100 percent of U.S. almond production and 75 to 80 percent of world production, was valued in 2011 at $3.87 billion, surpassing table, wine and raisin grapes, which were valued at $3.86 billion.

"Even with this record production, we have more demand than we have supply,” said Bob Curtis of the Almond Board. "The driver behind that is nutrition studies that show almonds are a healthy food and snack.”

A tremendous amount of UC research is behind the California almond success story, said Bruce Lampinen, UC Cooperative Extension specialist in the Department of Plant Sciences at UC Davis, an expert in almond canopy management.

"Higher density plantings of almonds and a trend towards less pruning, and improved water management have led to much higher yields,” Lampinen said.

Many almond growers have replaced flood irrigation with micro-sprinkler or drip irrigation, said Larry Schwankl, UC Cooperative Extension specialist in the Department of Land, Air and Water Resources at UC Davis. These irrigation systems increase the precision of water and fertilizer application. Over the years, UC Cooperative Extension advisors and specialists established demonstrations of micro-sprinkler and drip systems in many parts of the Central Valley and reached out to farmers to show how they could be managed to optimize production.

"Twenty years ago, we simply guessed at the amount of water that the trees needed and we applied it on a calendar basis,” said Joe MacIlvaine, president of Paramount Farming Company in Kern County, one of the state's largest growers of almonds, pistachios and pomegranates.  "Today, we are delivering water and nutrients directly to the root zones when they are needed.”

Two decades ago, a granular form of nitrogen fertilizer was generally applied to almond orchards in the fall to allow winter rain and irrigation to move it into the soil for use by the trees in spring and early summer. Nitrogen use efficiency was believed to be about 40 percent. Now, nitrogen fertilizer is applied through the irrigation system during the growing season, when the tree needs it.