Progress report for OW24-011
Project Information
Academic researchers have demonstrated many benefits to cover cropping in almond orchards including better soil retention, soil structure, soil health, water utilization, pollinator activity, and yield. The Almond Board of California has invested in educating growers about the benefits of cover cropping and provided an incentive to try cover cropping through their Seeds for Bees program. Yet today 90-95% of almond orchard floors are managed as bare soil.
Growers perceive that winter annual cover crops are more complex and costly than a clean, bare orchard floor. Growers also worry that cover crops will interfere with harvest and sanitation operations, and reduce yields by competing for water and nutrients.
The recent debut of Oakville bluegrass enables a no-till cover cropping system for almond orchard floor management that has lower operating costs than the standard practice. Oakville bluegrass is a perennial, reverse season, drought tolerant grass. Because it is dormant while the cash crop is growing, it doesn’t compete for water or nutrients. It stays low so it does not impede operations. It can reseed, so the effective lifespan may be as long as the lifespan of the orchard.
The optimal cover cropping system would cover the entire floor with a combination of Oakville bluegrass and bee forage. Presently there is no information available about the business case for adopting this system. Our project aims to fill that void by conducting a cost-benefit study of the system relative to the standard practice and disseminating the information to growers.
We will quantify the impact of a novel no-till cover cropping system for orchard floor management versus the standard practice of bare, clean soil in terms of management costs, impacts on harvest operations, and environmental benefits including soil retention, soil health, water utilization, pollinator activity and yield.
Season 1 (2024)
- Refine the project plan in consultation with the 3 producers. Select the locations and acreages for the treatment and control cells. (all objectives)
- Create version 1 of the Growers Guide (Education Objective 3)
- Create version 1 of the Operating costs model (Education Objective 2)
- Create an operations planning worksheet for data collection (Research Objective 1)
- Publish a web page about the study and invite viewers to be notified when results become available (Education Objective 1,2)
- Gather baseline data on soil, water, nutrients at each site. (Research Objective 3)
- Plant the acreages in the treatment cells with Oakville bluegrass and bee forage. (Research Objectives 1-3)
- Conduct interviews with growers after planting (Research objective 1,2)
- Deliver the first annual report summarizing learning to date (all objectives)
Season 2 (2025)
- Track progress of the cover crop installation and adjust maintenance plan as needed in consultation with producers (Research Objectives 1-3)
- Gather data on soil, water, nutrients at each site to assess the change after a year of the cover crop in place. (Research Objective 3)
- Plant bee forage for second season (Oakville bluegrass perennial is self-seeding) (Research Objectives 1-3)
- Conduct interviews with growers after harvest operations (Research objective 1,2)
- Create Version 2 of Operating Costs model based on learning (Research Objective 1)
- Create a Case Study and Fact Sheet describing grower assessment of the system costs, benefits and harvest operations impacts (Education Objectives 2,3)
- Deliver second annual report summarizing learning to date (all objectives)
Season 3 (2026)
- Hold 2 educational events for growers to publicize results of the study (Education Objectives 2,3)
- Conduct multi-modal advertising campaign to raise awareness of the system (Education Objective 1)
- Deliver third annual report summarizing learning to date (all objectives)
Cooperators
- - Producer
- - Producer
- - Producer
Research
The purpose of this project is to equip growers with the information they need to make informed business decisions about adopting a more profitable and sustainable orchard floor management model. To achieve this goal, our research will address the following research objectives:
- Quantify the operating costs of a new floor management protocol (no-till perennial cover crop with bee forage) versus the operating costs of the standard floor management protocol (bare, clean soil).
- Assess the harvest operations impacts of the no-till perennial cover cropping system.
- Validate the benefits of the cover cropping system for soil health, soil structure, water utilization, and pollination. Many of these benefits are well-established in academic research. It is not our objective to quantify the impacts with precision - that would require more sites, a larger budget, and more time. Our objective is to confirm that the desired benefits are, in fact, observed in practice by producers.
We will pursue these research objectives by conducting a multi-orchard, multi-year analysis of the costs and benefits of the new practice versus the standard practice. To pursue the objectives, each producer selected a management unit ranging from 30 to 58 acres to include in our study. The management units were divided into two portions: one treated with the no-till perennial cover cropping system and the other with bare floor management. Seeding of the management blocks occurred in late fall to early winter 2024.
The no-till cover cropping system consists of high coverage of the orchard floor with a combination of 79-85% Oakville bluegrass reverse-season perennial cover crop and 15-21% bee forage. The bee forage mix was selected by the producers and is managed as an annual crop, which requires a different management protocol than the Oakville bluegrass. The block perimeter was not available for the bee forage, so the growers planted it within the no-till treatment section of each study site, with the majority of the orchard block planted with Oakville bluegrass.
A management plan was established to plan and track all operations planned and implemented throughout the season. A management schedule was shared with the producers, instructing them to track floor management activities for each portion of the management unit. There is a differentiation between installation activities for the perennial cover crop vs ongoing maintenance activities. The bee forage is a winter annual cover crop; in this case, the annual maintenance activities will include planting and termination.
A set of cost metrics was established for producers to track and report on for each management unit, with benefit metrics defined to measure progress throughout the study. The operating cost metrics include equipment overhead (using the cost recovery method used in UC Davis cost studies), labor hours, fuel, and materials. The research team will consult with experts to develop a set of cost-effective metrics to evaluate the impacts of each floor management protocol. The categories of benefit metrics will include:
- water infiltration
- water holding capacity
- soil organic carbon
- bulk density
- total organic carbon
- pollinator activity
- yield
A monitoring team was contracted to conduct the soil monitoring visit, collecting baseline soil data for each study site and treatment type to ensure consistent data collection procedures. The data collected included water infiltration, bulk density, and soil samples, which were analyzed by a soil analytical laboratory for total organic carbon. The results of this monitoring event are still pending; however, it marks the first step toward achieving the third research objective, which is to validate the benefits of the cover cropping system for improving soil health, soil structure, water utilization, and pollination.
The Project Manager developed a floor management and operating cost tracking sheet for producers to begin documenting the costs of their floor management activities. The PI will develop a model of the operating costs of each treatment. After harvest, the PI will interview each producer's operations team to validate the quantities used in the model to calculate operating costs. The model will be refined each season based on actual cost data for the season.
Each producer was asked to keep a log of observations about the state of each portion of the management unit throughout the season. The producer staff will be trained to make observations related to each of the benefit metrics listed above.
The PI will interview each producer post-harvest to determine whether and how harvest operations were affected by the presence of the cover crop on the orchard floor. The PI and producer will identify adjustments to be made to the management protocol for the next season to minimize any adverse impacts.
The Project Manager developed a first draft of a survey form for growers to report operational costs, observed benefits, and provide an overall assessment of the study area. An interview guide is in development to elicit the producer's overall assessment of the relative merits of each floor management protocol. An interview will be conducted after each season with each producer, with the first round of interviews still pending.
At the end of each season, the PI will produce a report of
- Operating costs for each protocol, total and per acre.
- Harvest operations impacts of each protocol, and any adjustments that will be made to streamline operations in the future.
- The benefit metrics and qualitative assessments of the benefits from the POV of each producer.
The research results for the study are ongoing and proceeding as planned, with partial data available for only one season to date. The research results and findings of the study, according to each objective, are as follows.
The first research objective is to quantify the operating costs of a new floor management protocol (no-till perennial cover crop with bee forage) versus the operating costs of the standard floor management protocol (bare, clean soil). The effort to collect cost data necessary for conducting a cost analysis of the floor management protocols is proceeding as planned. At this stage, only a partial analysis of operating costs for adopting a new floor management protocol compared to the standard floor management protocol could be conducted. The preliminary results only compare the implementation cost of planting a no-till perennial cover crop. Following the first installation season, initial findings indicate that the average implementation cost for the three producers was $5,723. Considering the difference in acreage among the producers, the average implementation cost per acre for all producers is $296 based on the installation cost summary results (Table 1). No floor management cost data have been collected since planting the cover crop. Additional floor management costs must be collected and analyzed to complete the operating costs analysis before sharing the final results from the first season.
The second research objective is to assess the impacts of the no-till perennial cover cropping system on harvest operations. Progress on this research objective is expected to occur once the first harvest season has concluded; however, no results or findings are available to report at this time.
The final research objective is to validate the benefits of the cover cropping system for soil health, soil structure, water utilization, and pollination. The research objective is to confirm that the desired benefits are observed in practice by producers, rather than to quantify the impacts with precision. To make progress toward validating the benefits of cover cropping, baseline soil data were collected for each project location and treatment type. A consulting group successfully collected baseline soil data, which will be used to track changes in soil conditions throughout the study. Unfortunately, no results or findings can be shared, as the lab analysis is not available for review or analysis. Once the results are available and observational data from the producers are received, an initial analysis will be conducted to validate the benefits from the first growing season.
Research Outcomes
Education and Outreach
Participation Summary:
The education and outreach methods and analysis conducted include initial efforts to address the three education and outreach objectives.
The study's first education and outreach objective is to increase awareness of the new Oakville bluegrass cover crop among almond growers in the Central Valley. The project has been published on the website, offering interested parties the opportunity to express their interest in receiving results as they become available. Any interested party visiting the cooperative's website can learn about the research initiative and submit a request to receive updates on the results. Once ready, sharing the results with interested parties will further educate growers about the return on investment of incorporating Oakville bluegrass and bee forage to cover the orchard floor. Additionally, the team contacted multiple growers and invited them to participate in the project. The team conducted phone calls and scheduled meetings to share the learning opportunity in the study and the benefits of adopting Oakville Bluegrass as a cover crop.
The second education and outreach objective is to inform growers about the Return on Investment associated with covering the orchard floor with a combination of Oakville bluegrass and bee forage. The team reviewed cost management studies and consulted with grower partners to establish a data collection process for obtaining management costs from the growers. Not all data have been collected, and not all benefits have been attributed correctly in the model design to compare the benefits or costs of adopting Oakville bluegrass in almond orchards. The initial version of the operating cost model is not complete.
The final education and outreach objective is to educate growers about the best management practices for establishing the cover crop on their orchard floor and recommend ways to prepare the floor for harvest. To achieve this, the team started developing a robust growers' guide. The team reviews past learning before the new planting season to ensure that educational materials and resources are accurate and comprehensive, including any significant learnings from the previous season. Before seeding the cover crop, the cooperative's grower guide was reviewed and revised to ensure that lessons learned from the prior season were incorporated before circulation.
The education and outreach results for the study are ongoing and proceeding as planned, with partial data available for only one season to date. The study's education and outreach results and findings, organized by objective, are as follows.
The first objective is to increase awareness of the new Oakville bluegrass cover crop among almond growers in the Central Valley. The majority of activities planned to increase awareness of the new Oakville bluegrass cover crop among almond growers in the Central Valley will take place after the first growing season. The activities completed to date are essential for staging the study; however, they have not yet provided any results or findings. To confirm producer participation, six almond growers were initially educated about Oakville bluegrass through outreach efforts, which invited them to participate in the study. We also increased awareness among 45 additional almond growers through activities conducted by the cooperative that were not part of the study. Of the 45 almond growers, 15 attended webinars held by the cooperative, and 30 growers shared their information through in-person events. All of these efforts are important marketing tools for increasing cover crop adoption. Overall, these efforts have collectively increased exposure, a key outcome for the study. Still, further outreach and education will occur once the first cost-benefit model is established and feedback from the participating producers is received. Updates about the study's progress will be posted on the website and shared with the list of interested producers.
The second objective is to educate growers about the Return on Investment associated with using a combination of Oakville bluegrass and bee forage to cover the orchard floor. At this time, there are no results since the first year is not yet complete. The benefit data required to complete the return on investment analysis is ongoing, as the entire management year for the almond orchards will not conclude until the 2025 harvest season.
The final objective is to educate growers on the best management practices for establishing a no-till perennial cover crop on their orchard floor, as well as recommendations for preparing the floor for harvest. To make progress on this objective, we need to receive feedback from the participating producers on the reality of adopting a perennial no-till cover crop in an almond orchard and learning about the producers' perspective on how the orchard floor appears and any management activities that might be necessary to support a successful harvest season. By incorporating these new learnings about best management practices and installation prep into the grower's guide, the result can be improved adoption and establishment of Oakville bluegrass in almond orchards. Due to changes in federal funding announced in January, the research team was unable to continue working, resulting in delays in collecting initial feedback from growers on installation prep and cover crop management activities. No updates or revisions of the grower guide have been made yet.
Education and Outreach Outcomes
The project's education and outreach activities are ongoing; therefore, we have not yet determined recommendations for education and outreach.