Exploring Regenerative Vegetable Systems on the Central Coast of California

Author

• Una S. O'ConnellFollow

Available at: https://digitalcommons.calpoly.edu/theses/3271

Date of Award

6-2026

Degree Name

MS in Agriculture - Crop Science

Department/Program

Horticulture and Crop Science

College

College of Agriculture, Food, and Environmental Sciences

Advisor

Charlotte Decock

Advisor Department

Natural Resources Management

Advisor College

College of Agriculture, Food, and Environmental Sciences

Abstract

As climate change and current agricultural practices place pressure on the long term sustainability and resilience of food production systems, there is growing interest in whether existing agricultural systems can adapt to maintain productivity while improving environmental outcomes.

This study evaluated the effects of regenerative versus standard organic vegetable production systems on yield, insect communities, and weed suppression across three field trials conducted on California's Central Coast. In addition, I collected baseline soil health data for all trials. Trials 1 and 2 were carried out at the Cal Poly San Luis Obispo Organic Farm using cabbage and broccoli as cash crops, respectively, while Trial 3 was conducted at Braga Fresh in San Ardo using baby broccoli in a commercial-scale setting. All regenerative treatments integrated grass cover crops with reduced tillage. In Trial 3, the only trial conducted on a commercial grower’s land, regenerative systems produced statistically significantly lower yields than standard organic. . Insect communities in regenerative systems showed higher densities of both beneficial and pest insects, particularly in the well-established commercial trial, suggesting that cover crop habitat supports multiple trophic levels without reliably improving pest suppression. No measurable weed suppression benefits were detected in any trial. Across all trials, depth was the primary driver of soil health patterns.

These findings highlight a fundamental tension in regenerative agriculture: while these systems offer ecological benefits and align with long-term sustainability goals, yield losses and increased variability present real barriers to grower adoption. Further research across longer time horizons and diverse cropping systems is needed before broad recommendations can be made.