Before the Salinas Valley wrapped up production for the winter, approximately 80 farmers and others gathered to learn about habitat, natural enemies, food safety and healthy soils. We met at Braga Fresh, a progressive, large vegetable operation that is bringing biodiversity back to the farm, one step at a time. This is a welcome and exciting change for a farming region that was previously required to forsake ecosystem health and sustainable pest management for strict buyer food safety requirements–no matter that the science has proven otherwise. Today, buyers also want regenerative agriculture and Braga is leading the way to achieve both.
Co-managing Fresh Produce Farms to Support Natural Enemy Insects, Birds, Crop Production and Food Safety – Dr. Danny Karp (UC Davis) discussed how removing habitat does not improve food safety on fresh produce farms and may even increase pathogen prevalence. In lettuce studies, he determined that surrounding ungrazed habitat carried lower food-safety risks from birds as compared to higher risks in grazed habitats. Ungrazed habitats also promote birds of higher conservation concern. Additionally, pest control increases on farms with more non-crop habitat. In his strawberry studies, birds were less likely to carry Campylobacter on farms with more surrounding habitat. In both lettuce and strawberry research, he found that big flocks of birds (which cause the most damage) are less likely to occur on farms with more surrounding ungrazed habitats.
Vegetated vs. Un-vegetated Ditches and Their Effect on Rodent Presence–Pam Krone (CA Marine Sanctuary Foundation (CMSF)) discussed how bare ground ditches amplify rodent activity and specifically increase the abundance of deer mice, as compared to vegetated ditches. While the vegetated ditches also had rodents, there was a diversity of rodent species, and they were present in much lower numbers. These preliminary findings, which are part of a study that CA State Univ. Monterey Bay is conducting, aligned with other studies showing that increased rodent diversity occurs with increased habitat diversity. These latter studies also found diversity of rodent species decreased pathogen prevalence because they don’t interact with each other as much as individuals of the same species. Therefore, the bare ditches do not seem to improve food safety risk and may increase it. Vegetative ditches can reduce pesticide residue in waterways, as well as other runoff like nitrogen and phosphorus; and they can support beneficial insects.
Plant Species that Optimize Arthropod Pest Biocontrol – Stephen Pryor (WFA) discussed plant species that help with biocontrol in leafy greens and brassicas. Green lacewings, voracious predators of aphids, need protein-rich pollen that promotes egg development, and Phacelia (P. tanacetifolia) and cilantro (Coriandrum sativum) can provide that. The Minute Pirate bug, a major thrips predator, needs something more than pest insects and flowers to survive, such as peppers which have thin skins and few hairs, making an ideal place for the beneficial to oviposit its eggs. Collard greens (Barbarea vulgaris) are a dead-end trap crop for diamondback moth (DBM). This plant produces saponins which attract the DBM and then kill it. Perennial native plant hedgerows support all kinds of beneficial arthropods, and are especially important in the winter when little other habitat may be around.
Braga Fresh Demonstration Site for CDFA’s Healthy Soils Program–Katie Chiapuzio (Braga Fresh) and Pam Krone (CMSF) shared cover crop trials on Braga’s cilantro fields, where they are striving to reduce tillage that will minimize disturbance, provide continuous living roots, and maximize soil cover. A tall grass was intercropped with the cilantro, and it helped to increase water infiltration, reduce erosion, and provide a warmer microclimate that promoted cilantro growth. Katie reported that the benefits of the grass were substantial but she would be changing the species to a shorter/ slower growing variety in future demonstrations so it does not become overgrown as the cilantro continues to develop.
Beneficial Flower Strip Demonstration – Gina Colfer (Wilbur Ellis) and Katie Chiapuzio (Braga Fresh) showed off the beautiful and functional floral strips adjacent to Braga’s vegetable crops. These strips provide overwintering habitat so beneficial insect populations can establish early in the spring, and they also offer nectar and pollen that support pest control benefits throughout the year. Another way the farm optimizes floral resources, while also turning a problem into an opportunity, is by planting sweet alyssum (Lobularia maritima) plugs in places where crop transplants were missed, drawing the beneficials out into the field.
Successes and Learning Opportunities, Grower Panel –Three growers discussed key challenges and insights of growing regeneratively. Eric Morgan (Braga Fresh), John McKeon (Taylor Farms) and Mark Pisoni (Pisoni Vineyards) emphasized the importance of “failing forward.” As panelists described their successes, failures and challenges of increasing soil carbon, soil fertility, pollinators and beneficial insects, they continued to emphasize the importance of collaboration among growers, knowledge sharing, and having an open door policy. The wine grape industry has seen for decades that consumers and buyers are driving the pace of regenerative implementation, and this may be taking hold in vegetable crops now that Walmart and others are setting high IPM standards for their growers. Lastly, there was a discussion of sap analysis used on Braga’s crops, and its ability to quantify their crops nutrient deficiencies. Sap analysis has enabled them to implement regenerative practices more effectively, increasing plant photosynthesis, and healthy soils that support healthy plants which pest insects don’t prefer.
California Department of Pesticide Regulation’s Sustainable Pest Management (SPM) Roadmap – Dr. Andy Viet Nguyen (CDPR) provided an overview of their Research and Alliance Grants Program which funds many projects, including WFA’s current field days. He also discussed their SPM Roadmap that is transitioning the agency to a system-wide adoption of safer, more sustainable pest management practices.
Paying for Your Habitat – Shelly Connor (WFA) and Ariel Delara (NRCS) described how farmers can apply for funding and technical assistance to install on-farm habitat such as hedgerows, riparian buffers and cover crops (among other climate smart agricultural practices) through NRCS programs, CDFA’s Healthy Soils Program (HSP), Pollinator Habitat Program (PHP) and other state and federal sources. WFA and NRCS also can provide assistance to California growers for free, helping to develop conservation plans that can address conservation and habitat goals.