Progress 07/01/24 to 06/30/25

Outputs
Target Audience: This project is relevant to water managers and regulators, farmers, and communities who have lost access to clean drinking water. To date we have conducted multiple outreach events for farmers and community members. During this past year, we conducted outreach to farmers in California's Central Coast region to solicit participation in our team's cover crop research trial. We also held a Farmer Resource Fair on March 5, 2025 at the Monterey County Cooperative Extension office in Salinas, CA, where we shared information about cover crops and other conservation agriculture practices. There were 86 attendees (excluding presenters), representing 48 farm businesses, 12 aspiring farmers, and 7 partner organizations. We have reached 30 farmers who are willing to participate in our baby trials starting this October, 2025 and who will allow us to conduct soil sampling three times over the cover cropping season with the goal of addressing challenges and successes in their experiences to be able to increase cover crop adoption in the region. Further, Dr. Waterhouse gave a presentation at an event held at the Center for Agroecology on UCSC's campus where ~45 community members were in attendance where she discussed nitrate from fertilizer in drinking water and how cover crops can be one part of the solution for retaining nitrogen in the root zone and preventing it from entering our water resources. In this presentation, she mainly focused on California and the challenge of growing food while protecting our water resources. Changes/Problems:The only change made was in our experimental design. We added a treatment to have a complete treatment set for October and November. Treatments now include Rye planted in October, Rye/Vetch planted in October, Rye planted in November, Rye/Vetch planted in November, and a Fallow treatment.?While a few problems arose last year in our first year of the "parent trial" we were able to overcome them or pinpoint the issue and improve on our approach next year. Fourteen of our sensors had gone offline due to the cables being cut or chewed through. We were able to buy repair kits but they took a month to arrive, after which we successfully repaired them. We now have extra kits and can remediate the broken sensor cables more immediately in case this happens again this upcoming year. Further, our Li-COR 7500, which measures carbon dioxide and water fluxes, was not measuring accurately when we began measuring. We sent it out for repair, however it took months for the company to send it back to us and we were unable to get these plot level ET measurements this first year. However, we now are prepared for this second year and have done trial runs on very tall growing rye and built multiple chambers to accommodate the growing plants. Finally, last year we outfitted plot level runoff collectors in all the plots (5 treatments and 4 replicates each for a total of 20 plots) which took a lot of time to install. However, no runoff was observed at all. This is likely due to the high infiltration rates occurring at this parent site and the low intensity storms we had last winter. What opportunities for training and professional development has the project provided?One graduate student, a Jr. Specialist, and seven undergraduate students have gained significant training and experience in soil sampling, field management, sensor management, experimental design, laboratory analysis, and data analysis within this first year mentored by two faculty members. Students learned how to properly establish a randomized controlled field experiment and the importance of multiple replicates and compositing samples. Students also learned how to safely and rigorously measure soil moisture and inorganic nitrogen levels, the latter requiring the understanding of the theory underlying colorimetric analysis for nutrients and how to properly use a spectrophotometer. Students also gained experience in how to organize and manage data to later be statistically analyzed. The Jr. Specialist and the graduate student have gained experience in data analysis and data visualization using Python and R codes. The graduate student also received training in how to prepare samples for and run an isotopic mass-spectrophotometer at Lawrence Livermore National Lab. These data will be used to untangle evaporation from transpiration to understand the mechanisms underlying higher or lower water use in the treatments vs the fallow plots. Finally, an early career staff member at the Monterey County Resource Conservation district has received training and real-world experience in project management and farmer outreach, helping to conduct the outreach and education necessary to successfully recruit farmers to the research and educate them about cover cropping. How have the results been disseminated to communities of interest?Since we have only had one year of data collection and the data are preliminary, we haven't yet disseminated the findings to communities of interest, however, we have had two media pieces published describing the project. A description and narrative of the project was published in the Berkeley Food Institute Blog, as well as UCSC's News. This has led to interest from a reporter at GRIST magazine who will potentially be featuring our work within the next year and is planning on interviewing the research team and participating farmers. Further, our research approach is designed to include farmers in on-farm trials and support them in learning about and experimenting with cover crops throughout our 4-year project. Initial outreach to farmers has included information about experimental design and the potential benefits and challenges of cover cropping, with an emphasis on collaborating with family farmers who are not usually involved in university-led research initiatives. This approach is already generating interest and conversation within the farming community about soil health, nitrogen cycling, and on-farm water use. What do you plan to do during the next reporting period to accomplish the goals?For the next reporting period we will continue with our second year of the "parent trial" and begin the first year of our "baby trials." In this second year we will: Continue the parent trials and collaborate with the engineering department on the drone data Conduct a survey of the farmer's management practices in the "baby trials" Purchase cover crop seed Work with the farmers to implement a fallow treatment and one of the cover crop treatments on their farm and help them manage the cover crop Sample three times throughout the season, prior to planting, mid-season, and termination of the cover crop, for soil moisture, soil inorganic nitrogen, soil water isotopes, and at the end we will take plant biomass samples and measure nitrogen content in the plants Continue the 2nd year of the "parent trial" and improve upon last year Host two workshops with participating farmers to discuss their ongoing experiences with the trial and to share aggregated data from the first year of the trial This past year we had an incident with our soil sensors where someone (or some animal) cut a few of the sensor cables and we were unable to collect data from those sensors for a month. However, we were lucky in that the loss of data didn't compromise any of the treatments due to replicate plots. We also bought repair kits and were able to successfully repair them. We now have extra repair kits in case this happens in the second year. Additionally, during the first year, we began taking ET measurements using the Li-COR 7500 and immediately noticed the results looked strange and had to send the equipment to the company to be repaired and thus missed a bulk of plot level ET measurements this year. However, it is in working order for this second year of the trial. We will also better managed the plot borders so that moving in and out and between plots is easier and we will be able to more seamlessly implement the harvested vs. incorporated subplot treatments.

Impacts
What was accomplished under these goals? The goal of this project is to create a community of practice amongst farmers, researchers, and technical assistance providers to increase the adoption of cover cropping in the Central Coast Region. Perceptions of increased water use and depleted soil moisture from both farmers and water regulators alike have resulted in low adoption of cover crops in the region, despite the multiple ecosystems services they provide - especially water quality protection. With this project we are scoping the effect cover crops have on the entirety of the soil water balance and to assess if their are tradeoffs with water quality protection. To date we have established the "parent trial" (objective 1.1) and conducted the first year of soil, water, and plant measurements. We have very preliminary results on soil moisture differences between treatments taken from soil moisture sensors installed at 15, 30, and 90cm. So far we have found that the fallow treatment plots and the October planted rye plots had lower soil moisture at the end of the season compared to the other cover cropped treatments (October planted Rye/Vetch, November planted Rye, November planted Rye/Vetch) (objective 1.2). We also found that the fallow plot had more nitrate accumulation at 90cm compared to all cover crop treatments (objective 1.3 and 2.1). The preliminary results are promising showing that potentially cover cropping does not reduce soil moisture for the growing season while reducing nitrate loss. We also learned a lot about how to improve management of the parent trial and measurements for this upcoming 2nd year of the trial. We will create managed alley ways between each treatment replicate to be able to more easily access the plots and data loggers once the cover crop begins to get taller than the data logger mounts. We also have recruited participating farmers to our community of practice and will begin the "baby trials" this October (objective 3.1). In engaging in this outreach we have also provided farmers with education needed to promote cover crop adoption. We have also created a survey of questions for them to fill out about their specific management practices to try and be able to see what might be driving differences in initial conditions before we implement the treatments.

Publications