A study of transition to organic production on a large California farm showed that flexible management techniques and careful planning are keys to a smooth, successful transition, according to a University of California, Davis researcher.

“This project tells me that organic transition is possible in the midst of a conventional growing environment,” said Louise Jackson, UC Davis professor and Cooperative Extension specialist and project leader of a three-year study that followed the conversion to organic of more than 150 acres of Salinas Valley farmland.

Project members' biggest worry — that the organic fields, set in the middle of conventionally grown lettuce, broccoli, spinach and celery, were going to become oases for large populations of nearby pests — never materialized.

“We were concerned because organic farms are generally on the periphery where they are isolated by grasslands or other ecosystems,” Jackson said, but Tanimura and Antle Inc.'s one- to five-acre organic parcels of specialty greens, leaf lettuce and herbs showed excellent performance.

Biodiversity changes

The project, which was funded by the U.S. Department of Agriculture's Sustainable Agriculture Research and Education program (SARE), included an outreach component that focused on how UC researchers, the farmers, and farm advisors teamed up to develop the experimental design and identify potential problems. Because they expected weeds, pests and soil fertility to be problems, researchers monitored changes in the field and provided continuous feedback to growers. The growers adapted their strategies to compensate, in one instance switching from legume cover crops to rye and mustard because weeds became a problem with the legumes, Jackson said.

“The growers made changes based on understanding how biodiversity could help them,” said Jackson. “They planned species mixes and cropping patterns and managed fertility well, which is the basis of a good organic strategy.”

Frequent hand-hoeing kept weeds in check, while less susceptible crop species and some types of organic pest control reduced impacts of insect pests like aphids and leaf miners, according to Jackson.

“The growers shifted planting dates to avoid pest problems,” she said. “They developed a reusable irrigation drip line to deliver soluble organic fertilizers, which not only conserved water and cut costs, but also kept the surrounding soil much drier, reducing weeds and diseases.”

Ron Yokota, farm manager at Tanimura and Antle, said making the transition to organic vegetable production was a challenging but ultimately rewarding experience.

“We were very pleased with the results, and are happy to be able to deliver a wide range of organically produced vegetables to a growing market,” he said.

Jackson was involved in project outreach, telling Central California growers at workshops, meetings, field days and short courses about using whole-farm research as a way to analyze organic systems.

“This project has provided information of vital importance to growers interested in making the transition to organic, a growing segment of agriculture today,” said David Chaney, education coordinator for UC's Sustainable Agriculture Research and Education Program and the Western Region SARE representative. “The information is not limited to organic systems, however. Other vegetable growers will also benefit from these findings.”

More information about Jackson's organic transition project is at http://www.sare.org/highlights/2005/organic_transition.htm.