Franz Niederholzer, manager of Nickels Soil Laboratory, inspects an almond tree for shot hole, a fungal disease that can infect almonds and other stone-fruit trees, resulting in yield losses. (Photo: Ching Lee)

By Ching Lee, Assistant Editor, Ag Alert 

Reprinted with permission by the California Farm Bureau Federation 

Use of micro-irrigation may be commonplace in California orchard systems today, but the practice of applying precise water to individual plants rather than broadcasting with sprinklers may not have taken off if not for the research trials conducted decades ago at the Nickels Soil Laboratory in Colusa County. 

The privately owned research farm in Arbuckle is often credited with helping to propel the state’s tree nut industry to the powerhouse it is today. Through its demonstration research projects, Nickels showed growers management techniques that allowed them to produce higher yields on marginal soils. This led to dramatic expansion in acreage and changed the agricultural landscape of the Central Valley. 

Just as growers have faced tough times in recent years as the price of almonds and walnuts has plummeted, research funding for Nickels has depleted because of shrinking crop revenue. That’s because the so-called “soil lab” operates as a 200-acre working farm, sustaining its research largely through sales of almonds, walnuts and table olives. 

“When the price dropped and costs rose, we find our business model no longer works,” said Franz Niederholzer, manager of the research farm and a University of California Cooperative Extension farm advisor for Colusa, Sutter and Yuba counties. 

The research farm now must transition to a new way of funding itself. The Almond Board of California and various agricultural businesses have provided some financial support, but with its budget ballooning to $400,000 to $500,000 a year, Niederholzer said more help is needed. 

Last spring, the farm asked the state for a one-time fund of $500,000 to cover expenses through 2024. But with the state budget deficit, the money was put on hold. Niederholzer said he was told last week the funds “have been released,” but he has yet to get a check. Private donations so far have reached about $86,000. That means “people are carrying us on their books,” he said. 

Sebastian Saa, associate director of agricultural research for the almond board, described Nickels as a “hub for innovation,” conducting research that solves practical problems that growers face. The board has had “a very strategic partnership” with Nickels, he said, and has funded its projects for years, including research on pest management, irrigation, nutrients, orchard configuration, rootstocks, almond varieties, growing habits of almond trees and organic almond production. 

As a working farm, Nickels can produce crops at a commercial scale, which allows growers to see how certain practices work in real life, he said. Various researchers, himself included, have used the farm for experiments, he noted. Nickels shares research results at annual field days, set for May 7 this year, Niederholzer said. 

“I don’t find another place in California that can connect all the different dots—from basic research to very applied research to education and outreach,” Saa said. “Losing something like that would be very detrimental for the industry.” 

The property, originally an almond orchard, once belonged to Leslie Nickels, who died in 1959. His will specified that the land should be used for research that benefits growers who farm on marginal soils, as opposed to prime farmland along river bottoms that was already the subject of other research, said John Edstrom, UCCE farm advisor emeritus who managed Nickels Soil Lab from 1984 to 2011. It was Edstrom’s predecessor, UC farm advisor Tom Aldrich, who learned of the will and initiated research on the property in the 1970s. 

Under an agreement reached in 1982 with the Leslie J. Nickels Trust, which owns the land, the university manages and coordinates research activities and farming practices. Aside from farm advisors’ salaries, no UC money flows to Nickels Soil Lab, Niederholzer said. The trust employs a half-time farm manager and two full-time workers. An advisory committee reviews research proposals and makes recommendations to Nickels trustees. The Colusa County Board of Supervisors and the Colusa Irrigation District provide added support. 

Of the 200 acres, about half of it is currently in production: 81 acres of almonds, 9 acres of walnuts and 2 acres of table olives. The rest is open ground and roads, with a shop that houses farming equipment. Despite its name, there is no actual lab with test tubes and beakers at the site. 

The farm sells its almonds to Blue Diamond Growers in Sacramento, walnuts to Mariani Nut Co. in Winters and olives to Musco Family Olive Co. in Tracy. 

Early projects introduced growers to drip irrigation, which Edstrom described as perhaps the most important technological advancement that allowed growers to increase acreage and production. He noted that when he managed Nickels, California had 300,000 to 400,000 acres of almonds. There were 1.56 million acres in 2023, according to the almond board. 

Edstrom noted much of the acreage growth has occurred in areas that previously did not support commercial tree nut production, proving that Leslie Nickels “was prophetic in realizing that if the industry was going to advance, it needed to expand its productivity onto marginal soils.” He said successful plantings of almonds and walnuts at Nickels Soil Lab gave growers the confidence to plant orchards where they otherwise probably wouldn’t have planted. 

Other key research at Nickels included the evaluation of new rootstocks and almond varieties, higher-density plantings, fertilizer application and minimum pruning. 

“We made a lot of advances there,” Edstrom said. “There’s been numerous revolutionary discoveries there that have been implemented within walnuts and almonds over the years.” 

Edstrom said he thinks the type of work Nickels does is “more crucial today than ever” because universities have trended more toward fundamental science while doing less research on production agriculture. 

“There’s a lot of freedom involved in a private property than there is a state-owned property or university property,” Edstrom said. “There’s many advantages without restrictions and bureaucracies that slow things down. 

“That’s part of the reason for its success, is it had the freedom to do things differently, to be managed differently,” he added. 

Colusa County almond grower Gerry Rominger farms about 3 miles from Nickels Soil Lab and has been a regular attendee of its field days. As someone who does not farm on first-class soil, he said he appreciates the work done at the site, some of which can outright kill the crop but provides useful information for growers. Using concepts developed at Nickels, he said, “you can raise as good of a crop as anywhere in the state.” 

“They do a lot of things on the fringe that are extremely important to us as growers and help us in our day-to-day decisions,” Rominger said. 

For example, in one study, the farm purposely attracted a type of beetle to its walnut orchard to see how damaging the pest really is, Niederholzer said. In another trial, researchers tested how well almond trees survive without irrigation. 

Current projects include an experiment involving whole orchard recycling to see the effects of grinding entire trees into chips and incorporating the wood into the soil before planting. An ongoing study compares the self-pollinating Independence almond variety with the traditional Nonpareil variety. Niederholzer said there are also plans to plant high-density olive trees for oil. Other research priorities include regenerative agriculture and climate-savvy practices that allow growers to reduce greenhouse gases, he added. 

Rominger said Nickels research is often “ahead of the curve,” tackling problems before they take hold. Such foresight, he said, is especially important in farming. 

“They can see issues that may be coming at us,” he said, “and they figure out a way to address them and hopefully find some solutions.” 

To donate to Nickels Soil Lab, go to

Previous articleWhat Does It Mean to Be a Disciple of Christ? 
Next articleFarm Bureau Continues to Help Fight Hunger Through Harvest for All Program