Over his 32-year career, Bill Krueger, UC Cooperative Extension advisor, has helped Glenn County farmers triple their tree crop acreage.

“When I started, there were about 22,000 acres, now there are more than 68,000 acres,” said Krueger, who retired July 1 as UCCE advisor in Glenn and Tehama counties and director for UCCE in Glenn County. Part of that expansion can be attributed to Krueger’s research showing how almonds and walnuts can be produced on marginal soils with high density plantings and drip irrigation.

“Bill Krueger is a great asset to our agricultural community,” said Erick Nielsen, who grows prunes and olives in Orland.

“We have enjoyed working with Bill for many years,” Nielsen said. “He has always been the kind of guy to just jump right in and help. We have appreciated his dedication to agricultural research and his knowledgeable guidance.”

Raised on a farm in Prosser, Wash., Krueger was introduced to farming by his parents, who grew Concord grapes and cherries. He earned his bachelor’s and master’s degrees in horticulture at Washington State University, then worked for a year as foreman at Mt. Adams Orchard Company in White Salmon, Wash., tending cherries, apples and pears.

In 1980, Krueger moved to California to become the UC Cooperative Extension advisor for tree crops in Glenn County.

“I’ve spent my entire career in Glenn County,” remarked Krueger, who specializes in production of almonds, walnuts, prunes and olives.

Seeking opportunities for growers to diversify their crops, Krueger and his fellow UC Cooperative Extension advisor John Edstrom planted a test plot of walnut trees at the Nickels Soil Laboratory in Arbuckle in 1986.

They set up a walnut orchard with 202 trees per acre, much closer than the 60 trees per acre of a traditional orchard. The two varieties that Krueger and Edstrom planted produce a large proportion of walnuts on lateral buds, which allows for hedgerow planting and mechanical pruning. Each year, a giant hedger with eight 38-inch saws buzzed down one side of the tree rows, cropping back branches and encouraging production. In alternate years, they pruned the opposite side of the trees. Rather than being flood irrigated as most walnut orchards, the Nickels orchard was watered and fertilized using drip irrigation.

Crop yields from the dense walnut tree plantings compensated for the marginal soils. The successful demonstration plot led to thousands of acres of walnuts being planted on similar soils.

In 1992, he added responsibility for olives in Tehama County, where the number of acres of olive trees has doubled from 4,000 acres to approximately 8,000 acres. Krueger is internationally respected for his research identifying the most effective method of chemically thinning olives to increase the size of the fruit. Chemical thinning of olives has become a common practice among Sacramento Valley table olive growers.

Over the years, he has collaborated on the development of integrated pest management practices for almonds, walnuts and prunes. In 2004, Krueger was a member of the team that California Department of Pesticide Regulation honored with its IPM innovator award for the Integrated Prune Farming Practices Program.

“Over the years he has assisted us with many different pruning trials in both our olive and prune orchards,” said Nielsen. “The last project he helped us work on was a trial for various degrees of hand pruning versus mechanical pruning in prunes. Bill has a great sense of the current market for the different crops and has always been a front-runner on moving forward with research and development projects.”

Krueger developed pruning strategies to enhance early production of prunes while developing tree structure capable of supporting heavy crop loads. He helped refine mechanical thinning to manage prune crop size, a technique developed earlier by UC researchers, and his efforts to extend this research to growers helped it become a common practice when needed.

His work, in collaboration with others, on reduced pruning of almonds has helped growers save money by reducing pruning costs.

In addition to advising growers, Krueger served a total of 13 years as director for UCCE in Glenn County, from 1996 to 2001, then resuming the helm from 2004 until his retirement.  

Krueger has applied for emeritus status with UC so that he can finish up a few projects, but also looks forward to working on his own 10-acre olive orchard south of Orland during his retirement.

On Aug. 17, Krueger will be celebrating his career with friends and colleagues at Mills Orchards in Hamilton City. For details, contact Jody Samons at (530) 865-1155 or jesamons@ucdavis.edu.