UC Davis has played a key role in the California almond industry’s leap into second place in the latest annual valuation of the state’s agricultural commodities, beating out grapes for the first time.

The state crop report for 2011 is not due out until next month, but UC’s Agriculture and Natural Resources division is already reporting on the success of the almond crop — based on data from the federal government.

The state's almond crop has nearly doubled over the last 20 years, and ANR is crediting grower ingenuity and scientific work by the likes of Professor Patrick Brown and Cooperative Extension Specialists Bruce Lampinen and Larry Schwankl, UC Davis affiliates who work in the areas of canopy management, irrigation and nitrogen fertilizer.

In the 1980s, a good yield averaged 1,400 pounds of shelled almonds per acre. In 2011, the industry recorded an average yield of 2,670 pounds per acre — for a harvest of about 2 billion pounds, a record, and still not enough to meet demand.

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

The California crop — representing 100 percent of almond production in the United States, and 75 percent to 80 percent of global production — brought in $3.87 billion in 2011, compared with $3.86 billion for table, wine and raisin grapes. Both commodities trailed dairy.

Forty years ago, California farmers produced less than 100 million pounds of almonds from orchards covering a total of about 200,000 acres.

Today, the crop covers about 760,000 acres in the Central Valley, as farmers benefit from mechanization, improved irrigation efficiency, and advances in insect and disease management, plus research on pruning and fertilization.

Cutting back on pruning

As almond acreage expanded, farmers new to the industry tended to do too much pruning — based on prior experience tending fruit trees. In a pruned orchard of fruit trees, more sunlight reaches the fruit — giving it better color.

In almonds, however, more canopy generally means more yield, Lampinen said. “Today, most almond growers only prune when branches are growing in the way of tractors or other equipment,” he said.

UC research also determined that almond trees could be planted closer together, at an average density of 110 per acre, instead of the old standard of 60 to 70, and still get enough sun.

But there is a point of diminishing return, too, according to research that looked at the orchard floor — where the almonds land after being shaken from the trees, in the traditional method of harvesting.

“If the orchard floor becomes too shaded by trees planted too densely, the orchard floor temperature and humidity become optimal for growth of pathogens that could become a food safety problem,” Lampinen said.

“You want enough sunlight to hit the orchard floor to reduce potential pathogens, like salmonella,” he said. Otherwise, such pathogens could migrate to the almonds when they are sitting on the ground, prior to being swept up.

More efficient irrigation systems

Schwankl, of the Department of Land, Air and Water Resources, said many almond farmers are also watering their trees in more efficient ways, as opposed to flood irrigation.

These microsprinkler and drip systems are more efficient because they apply water and fertilizer more precisely, as shown by Cooperative Extension advisers and specialists in demonstration plots around the valley.

Joe MacIlvaine, president of Kern County’s Paramount Farming Co., one of the state’s largest growers of almonds, pistachios and pomegranates, said: “Twenty years ago, we simply guessed at the amount of water that the trees needed, and we applied it on a calendar basis.

“Today, we are delivering water and nutrients directly to the root zones when they are needed.”

Another change in almond farming deals with the application of nitrogen fertilizer.

Two decades ago, farmers generally applied it in granular form in the fall, after which irrigation water and winter rain would take the fertilizer into the soil. But the fertilizer would not go to work until spring and summer.

The end result? An efficiency factor believed to be about 40 percent.

Today, standard practice has the fertilizer going through the irrigation system during the growing season — for efficiency as high as 85 percent, according to Blake Sanden, a Cooperative Extension adviser in Kern County, who joined Brown in running nitrogen trials at Paramount Farming. Brown is a professor of plant nutrition in the Department of Plant Sciences and a pomologist with UC's Agricultural Experiment Station.

MacIlvaine acknowledged Cooperative Extension’s role in helping the almond industry move up in the crop rankings.

“The University of California has been a wonderful partner in improving our farming practices,” he said. "The whole system is not only more efficient, but more sustainable at the same time.”

UC Agriculture and Natural Resources contributed to this report.