Avocado Lab Offers Hope for Growers : Agriculture: Researcher seeks the best way to irrigate and feed trees--and save water.

For inspiration as he conducts his agricultural experiments, Ben Faber need only step into his dusty outdoor lab in Camarillo and look up--or down.

Skyward, he sees arid foothills sprouting cacti. Under his feet, he sees parched earth, cracked and shriveled.

The desert all around Faber reinforces the urgency he feels about his experiments. His mission: to uncover the best way to irrigate and fertilize avocado trees, while saving precious water and preserving underground aquifers from contamination.

As the second-largest avocado producer in the state, Ventura County has a definite stake in Faber’s research, one of 24 experiments around Southern California designed to pinpoint the most efficient, environmentally sound methods of farming.

Improving yields could be vital to the regional economy, since avocado groves make up 25% of the total agricultural acreage in Ventura County.

When the dollar value of the county’s lemon, orange and strawberry crops plummeted last year, avocados slipped only slightly, demonstrating the importance of maintaining a diversified crop base, Deputy Agricultural Commissioner Kerry Bustamante said.

In fact, the avocado crop actually gained ground in its relative importance to the local agricultural industry, accounting for 4.1% of the county’s total crop value in 1992, up from 3.7% in 1991.

And avocado growers think they can do better yet--with the help of research such as Faber’s.

A farm adviser at the University of California Cooperative Extension in Ventura, Faber has spent countless hours during the past two years on a remote Camarillo ranch, in a 10-acre laboratory thick with the glossy leaves of avocado trees.

His $124,000 experiment, funded by the California Avocado Society, still has three years to go. But already, farmers are eagerly anticipating the results.

“With the pressure you guys are putting on us, we have to do this kind of research--how else are we going to survive?” said avocado rancher Don Reeder, referring to the pressures from environmental groups to save water and cut back on fertilizers.

Well aware of how important irrigation and fertilization issues have become, Faber and his two assistants put on their hats and sunscreen each day and trek out to Thornhill Ranch. There, in their blazing hot lab, they conduct cutting-edge research with the help of a few rubber tubes, measuring tapes and a stagnant pool festering with algae and dead bees.

The basin is called an evaporation pan, a low-tech way to measure how much water the sun sucks into the air each day. Using the pan and a sleeker, more modern instrument called an atmometer, Faber can calculate how much moisture each tree has lost.

He then uses those numbers to figure out how much to irrigate.

In the experiment, some trees receive 70% of the water they’ve lost to evaporation each week, some get 100%, and some are showered with 130%. Over five years, Faber will determine which trees produce the best fruit and which are the healthiest.

Most of Ventura County’s avocado growers follow the 130% rule, Faber said. His research will indicate whether the most generous sprinkling system is justified--or whether farmers could cut back, saving thousands of gallons and hundreds of dollars per acre each month.

As Faber points out, most farmers these days are not squandering huge amounts of water. “In agriculture, if you don’t do something at least half-right, you go out of business pretty quickly,” he said.

But Faber said he believes he may be able to scientifically prove that growers are overwatering.

Whatever the results, the prospect of definitive guidelines for proper irrigation thrills some ranchers.

“Believe me, we’d love to be able to save $500 an acre on water,” said Len Francis, who coordinates research programs for the avocado industry. “Or, if we could get a substantial increase in production by using more water, we need to know that, too.”

If water is a hot-button issue among growers, so is Faber’s other topic of research--fertilization.

And while his irrigation research is still preliminary, Faber has already drawn some startling conclusions from his fertilizer experiment.

According to his study, growers can dramatically reduce the amount of pollutants that trickle through the soil and contaminate underground water supplies. To do so, they need apply fertilizer weekly, rather than monthly or in a single bulky deposit each spring.

When several pounds of nitrogen fertilizer are poured onto the ground at once, the chemical seeps below the tree’s roots and percolates into the ground water, Faber said.

In contrast, when small amounts of fertilizer are sprayed on tree roots through the irrigation system each week, the nitrogen remains close to the surface--where hungry trees can lap it up before it contaminates aquifers.

The majority of farmers have long since switched from the traditional once-a-year application of fertilizer to monthly sprayings. The more frequent application allows the grower to reduce the total amount of fertilizer used, saving both money and the environment.

“I’m not a scientist, so I kind of do things by the seat of my pants, but we are working hard to cut back on fertilizers,” said Reeder of ProAg Inc., which manages 1,000 acres of avocados in Moorpark and Santa Paula.

But Faber’s preliminary results indicate that waiting a month between fertilization is almost as bad for ground water as waiting six months.

Instead, he recommends weekly fertilization--something few growers do.

“Some say it’s impossible, they can’t do it,” Faber said. “Then you ask why, and they say, ‘Well, my way works.’ But how do they know it works? What do they have to compare it to?”

Faber’s research will yield scientific comparisons among trees fertilized weekly, monthly and semiannually. He will be able to tally both the amount of ground-water contamination and the avocado production for trees in each category, so growers can do their own cost-benefit analysis.

“This type of research is very important to us, because we are in charge of the land, and we need to take good care of it,” said Bob Tobias, director of field operations for Mission Produce in Oxnard, which packs avocados for 1,000 growers from across the state.

Even if they agree with Faber, however, farmers say they may not be able to follow his suggestions to the letter. They don’t always irrigate every week, for example, so they may not be able to fertilize on the recommended schedule. And some don’t own a nitrogen fertilizer storage tank, so they may have to wait several weeks to rent one.

Besides, some avocado growers, like Farm Bureau President Chris Taylor, want to get away from on-the-ground fertilizer altogether. Taylor thinks the best hope lies in a new technique: spraying liquid fertilizer directly onto the leaves from a low-flying helicopter.

“We’re as environmentally sensitive as anybody,” Taylor said. “We can’t pollute our water, because we’re out there on the farm drinking it and using it to irrigate our crops.”