Progress 06/01/22 to 05/31/23
Outputs
Target Audience:During this reporting period we reached a variety of target audiences through a number of different venues. Through our outreach activities we reached: 1) Academic audiences through presentations at the 2022 Tri-Societies meeting, 2022 American Geophysical Union Meeting, and 2023 Global Soil Biodiversity Meeting. 2) Farmers and other practitioners throughfocused conferences and workshops, including: a) 2023 EcoFarm conference, including focus on how barriers and opportunities for adoption of diversification practices differentially impact growers with different farming models and b) 2022 CalCAN Summit, a California grower and policy-maker focused conference. Changes/Problems:With the final no cost extension, we anticipate being able to published at least 2-3 more papers during the last project period, ultimately catching up after the pandemic-induced delays during earlier stages of the project. What opportunities for training and professional development has the project provided?The project has continued to create many informal training and professional development opportunities for postdocs, graduate students, academic staff researchers, and undergraduates. All trainees have gained substantial experience in conducting interdisciplinary science and framing and sharing results with practitioners. The project has supported two postdoctoral scholars during this project period (one soil biogeochemist, one soil microbial ecologist). With guidance from PIs, postdocs have gained mentoring skills through guiding one PhD students and several undergraduates. Since the project PI team is composed of several early career faculty, the postdocs have also observed and participated in discussions around starting a lab, grant writing and outreach. The soil biogeochemistry postdoc, Hannah Waterhouse, began a faculty position at UC Santa Cruz in Agroecology and Watershed Ecology, using work on this project for her job talk and for preparing new grants based on the results from this project. Waterhouse also intensively mentored two undergraduate researchers, both from minoritized backgrounds. The soil microbial ecology postdoc, Khondoker Dastogeer, gained considerable experience in presenting at two international conferences, and in multivariate statistical methods. He has now returned to his teaching position at Bangladesh Agricultural University, where experience on this program will help him develop a new research program in addition to his teaching responsibilities. How have the results been disseminated to communities of interest?Dissemination of results occurred in multiple forms: 1) Academic presentations at the 2022 Tri-Societies meeting, 2022 American Geophysical Union Meeting, and 2023 Global Soil Biodiversity Meeting. 2) Presentations at practitioner focused conferences and workshops, including: a) 2023 EcoFarm conference, including focus on how barriers and opportunities for adoption of diversification practices differentially impact growers with different farming models and b) 2022 CalCAN Summit, a California grower and policy-maker focused conference. What do you plan to do during the next reporting period to accomplish the goals?Our main objective during the next and last reporting period is finishing analysis, writing papers, and publishing.
Impacts
What was accomplished under these goals?
This year we made significant progress completing all laboratory analyses, analyzing data, and preparing publications for Objectives 1 - 3. We published a paper on remote sensing of diversification practices (hedgerows/windbreak and winter cover crops) in California's central coast, including interpreting patterns in their spatial distribution with prior interview data, contributing to Objective 1. For Objective 2, we analyzed the relationship between soil bacterial and fungal community composition and local farm diversification practices and landscape complexity and presented these results at multiple international conferences while preparing publications. Our study unraveled how both local agricultural diversification practices and the surrounding landscape influence soil microbial diversity, community composition, and network structure in production fields of organic farms. Crop diversity positively influenced bacterial richness, while a lower proportion of vegetation in surrounding land negatively affected fungal richness, suggesting that dispersal is important for persistence of some fungi in this intensively managed agricultural landscape. While most studies on soil microbes in agricultural systems have focused on impacts of specific production practices, our results also show that the composition of the landscape surrounding fields exert a similar level of influence. Accounting for soil and climate drivers, local and landscape diversification practices account for 5-8% and 5-7%, respectively, of the variation in bacterial and fungal communities; however, only a small proportion of taxa responded to these drivers. Notably, increases in the relative abundance of nitrifying bacteria with greater proportions of agricultural land surrounding a field have implications for ecosystem nitrogen cycling. Diversification practices also had a substantial impact on microbial network structure, but with divergent responses of cover cropping and soil disturbance vs. crop diversity. Together, our results highlight the importance of both local and landscape diversification practices in shaping multiple aspects of soil microbial communities, with implications for ecosystem functioning in these landscapes. For Objective 3, we analyzed relationships between soil health indicators and nutrient cycling and groundwater protection ecosystem services, as well as between diversification practices and soil carbon cycling.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2022
Citation:
Acevedo, S.E., Waterhouse, H., Barrios-Masias, F., Dierks, J., Renwick, L.L.R., Bowles, T.M., 2022. How does building healthy soils impact sustainable use of water resources in irrigated agriculture? Elementa: Science of the Anthropocene 10, 129. doi:10.1525/elementa.2022.00043
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2023
Citation:
Thompson, J.B., Symonds, J., Carlisle, L., Iles, A., Karp, D.S., Ory, J., Bowles, T.M., 2023. Remote sensing of hedgerows, windbreaks, and winter cover crops in Californias Central Coast reveals low adoption but hotspots of use. Frontiers in Sustainable Food Systems 7. doi:10.3389/fsufs.2023.1052029
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Progress 06/01/21 to 05/31/22
Outputs
Target Audience:During this reporting period we reached a variety of target audiences through a number of different venues. Through our outreach activities we reached: 1) 16 growers in the Central Coast region of California growing high value vegetable crops (including new farmers, Spanish Speaking farmers, and resource-limited farmers); 2) extension personnel (e.g. from University of California Cooperative Extension, and the Natural Resource Conservation Service) involved in vegetable crop and organic crop production; 3) staff from non-profit organizations working at the intersection of agriculture and the environment or direct assistance for small/mid scale and Spanish-speaking farmers (including the California Climate and Agriculture Network, Community Alliance for Family Farmers, and the Agriculture and Land-Based Training Association; 4) Agricultural and soil scientists from the Tri Societies 2021 Annual Meeting; and 5) University of California students. Undergraduates were reached during formal classroom instruction through PI Bowles' courses in Agroecology (80 upper division students) and Introduction to Environmental Science (300 lower division students), each of which includes a relevant unit on agriculture and soil health. Graduate students were reached through formal classroom instruction by both PI Bowles and co-PI Iles through a Food Systems course on a unit about policies to support soil health in California. Changes/Problems:Ongoing supply chain disruptions have continued to impact our ability to conduct lab analyses in a timely way, affecting our purchase of reagents, gloves, and disposable lab plastics, as well as increasing their cost. While we still anticipate completing our objectives, our timeline remains slower than we had hoped. What opportunities for training and professional development has the project provided?The project has continued to create many informal training and professional development opportunities for postdocs, graduate students, academic staff researchers, and undergraduates. All trainees have gained substantial experience in conducting disciplinary and interdisciplinary science. The project has supported two postdoctoral scholars during this project period (one social scientist and one soil biogeochemist). With guidance from PIs, postdocs have in turn gained mentoring skills through guiding one PhD student and several undergraduates. One postdoc gained more experience conducting direct outreach to growers through individual meetings with growers involved in the project. All postdocs have received extensive experience in conducting and writing interdisciplinary research, with two recently published papers containing both current postdocs and a combination of social science and ecological data. The PhD student working on this project has gained considerable experience in social science, building on his background in ecology, and led or co-led the two recently published papers mentioned above. He also gained experience presenting work to an academic audience by sharing a poster at the 2021 Tri-Societies Meeting, where he also now has a leadership role in advancing the Societies' diversity, equity and inclusion. Like the postdoc, he also participated in direct outreach to growers, gaining considerable experience with how to present and frame results from on-farm research. The project also provided research experience for three undergraduate students who have gained experience in various laboratory techniques and will also be included in the downstream analysis and paper preparation. How have the results been disseminated to communities of interest?Dissemination of results occurred in multiple forms: 1) through individual meetings with nearly all the farmers involved in this project (16) in Spring 2022; 2) academic presentations at the 2021 Tri-Societies meeting; 3) blog posts for agriculture-focused NGOs (https://calclimateag.org/is-there-a-sweet-spot-in-the-middle/ & https://sustainableagriculture.net/blog/the-sweet-spot-for-farms-to-enhance-on-farm-biodiversity/); 4) a presentation at the 2022 EcoFarm conference (https://eco-farm.org/conference/2022/session/research-report-back-soil-health-organic-farms-central-coast) What do you plan to do during the next reporting period to accomplish the goals?We will focus on completing analyses for Objectives 2 & 3 and preparing manuscripts to be submitted within the next reporting period. We also plan to complete the cost/return study. We will also continue sharing project results directly with growers, as well as through farmer-focused NGO partners, and with academic audiences.
Impacts
What was accomplished under these goals?
Loss of soil biodiversity, depletion of soil organic matter (SOM) and pollution of groundwater by nitrate leaching are some of the many widespread consequences of intensive, highly-simplified agricultural systems, which undermine the natural resource base on which agriculture depends and threaten the health of rural communities across the United States. Restoration of soil health, an integrative concept describing the dynamic properties of soil, especially soil microbes and soil organic matter, that underpin key soil functions is increasingly recognized as a crucial step toward creating more sustainable agroecosystems by enhancing soil-based ecosystem services. Biologically diversified farming systems use management practices at multiple temporal and spatial scales that promote beneficial organisms in the farm and the surrounding landscape, thereby supplying critical ecosystem services that can result in production improvements with fewer inputs. Yet knowledge of how such practices (for instance, cover crops, organic matter amendments, and crop rotation) affect soil microbes and SOM and the ecosystem services they together underpin remains limited on working farms, especially in high-intensity vegetable systems. Further, such techniques are often not adopted by farmers because of multiple, reinforcing market, knowledge, agronomic, environmental, and policy barriers. In this reporting year we made significant progress on Objectives 1 - 4, along with most of our sub-objectives. For Objective 1, the major activities included publishing two papers on barriers and opportunities for adopting bio-diversification practices. For Objectives 2 and 3, the major activities were to finish laboratory processing of 1000s of soil samples and conduct data analysis, including developing a farm diversification gradient based on a prior management survey so as to capture the relationships between the human and natural systems. For Objective 4, the major activities were conducting four in-depth interviews with growers to gain detailed information on the economics of organic diversified farming systems for small and mid-sized growers to support an ongoing cost/return study. Objectives 1 & 4: We have largely concluded Objective 1 by publishing two papers (see Products). Through 20 interviews with farmers who all grow lettuce and 8 interviews with technical assistance providers, we investigated the persistent barriers that growers in this region face in adopting diversification practices including cover cropping, compost application, crop rotation, insectary strips, and hedgerows. We found that high land rents, the predominance of short-term leases, stringent food safety standards, and other supply chain pressures significantly hamper the adoption of diversification practices. In order to surmount these barriers and increase adoption, solutions must be pursued at three interconnected levels: innovation at the farm level, and pol- icy change at the technical and structural levels. Locally- informed, integrated, and innovative policies across these three levels must be explored to support the creation of a more resilient, sustainable, and equitable food system. We continued work on the farm-level economic component of the project by preparing a cost and return study (CRS). We completed two surveys of farmers (each lasting ~2 hrs and requiring two visits to complete). The surveys cover a wide range of topics, including: a. Labor Costs; (Variable) input costs; (Fixed) input costs; Land costs; Transportation costs; Market participation; Capital assets (infrastructure, other); Diversified farming practices-costs and cost avoidance; Costs related to diversified farming practices; Water requirements and water costs; Administrative costs We also conducted a remote sensing study on the spatial patterns of cover crop and hedgerow adoption, which can also help inform understanding of possible drivers of adoption. We used satellite and aerial imagery coupled with machine learning classification to map the use of hedgerows and winter cover crops. We expected that adoption of both practices would be relatively low and unevenly distributed across the landscape, with higher levels of adoption found in marginal farmland and in less intensively cultivated areas where the pressure to remove non-crop vegetation may be lower. Our remote sensing classification revealed that only ~6% of farmland had winter cover crops while 22% of farm fields had any amount of hedgerows or windbreaks. But hotspot analysis showed significant patterns of adoption in the hillier regions of all counties. Based on interviews with farmers, land values, food safety regulations, production schedules and weather all impede adoption, with topography, social factors, and different farm models all possibly contributing to hotspots. This study shows how remote sensing can be used to map patterns of important diversification practices, with implications for tracking policy interventions and targeting resources to assist farmers motivated to expand adoption. This paper is nearly ready to submit. Objective 2 & 3: In order to assess soil microbial diversity, soil-based ecosystem services, and how soil health management affects both, we had previously conducted a biophysical survey across 28 different lettuce fields (16 different growers) in California's central coast, mainly during spring and summer 2020. The fields fall along a "diversification gradient" (i.e. they vary in the extent to which diversification practices are used), which was based off the initial interviews and initial site visits. We also manually digitized non-crop vegetation in the surrounding landscape (within 1 km) using NAIP and Google Earth aerial imagery which will be used to determine our landscape heterogeneity index. ? We have now completed all laboratory analyses for many soil biogeochemical and soil microbial measurements that act as indicators of four soil-based ecosystem services: soil carbon storage, nutrient cycling, groundwater protection, and water availability, as well as crop (lettuce) yields. See prior progress report for a list of measurements. We are now conducting analyses linking these measurements with inherent soil factors (e.g. texture) and management. For instance, preliminary results demonstrate that farms indeed range significantly in the total organic carbon levels from 0.67 to 3.39% SOC and that cover cropping and tillage practices may be most important in driving %SOC while crop diversity and in-season carbon amendments appear less important. Regarding water, a paper reviewing linkages between soil health and effective use of water resources in irrigated environments is in revision. To scope the potential for how soil health management could impact water resources in irrigated systems, we reviewed how soil health affects soil water flows, plant-soil-microbe interactions, and plant water capture and productive use. We showed how soil health management could: 1) optimize green water availability (e.g., by increasing infiltration and soil water storage), 2) maximize productive water flows (e.g., by reducing evaporation and supporting crop growth), and 3) reduce blue water withdrawals (e.g., by minimizing impacts of water stress on crop productivity). Quantifying the potential of soil health to improve water resource management will require research that focuses on outcomes for green and blue water provisioning and crop production under different irrigation and crop management strategies. Such information could be used to improve and parameterize finer scale crop, soil, and hydrologic models, which in turn must be linked with larger scale hydrologic models to address critical water-resources management questions at watershed or regional scales.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2021
Citation:
Petersen-Rockney, M., Baur, P., Guzman, A., Bender, S.F., Calo, A., Castillo, F., De Master, K., Dumont, A., Esquivel, K., Kremen, C., LaChance, J., Mooshammer, M., Ory, J., Price, M.J., Socolar, Y., Stanley, P., Iles, A., Bowles, T., 2021. Narrow and Brittle or Broad and Nimble? Comparing Adaptive Capacity in Simplifying and Diversifying Farming Systems. Frontiers in Sustainable Food Systems 5, 130. doi:10.3389/fsufs.2021.564900
- Type:
Journal Articles
Status:
Published
Year Published:
2021
Citation:
Esquivel, K.E., Carlisle, L., Ke, A., Olimpi, E.M., Baur, P., Ory, J., Waterhouse, H., Iles, A., Karp, D.S., Kremen, C., Bowles, T.M., 2021. The Sweet Spot in the Middle: Why Do Mid-Scale Farms Adopt Diversification Practices at Higher Rates? Frontiers in Sustainable Food Systems 5, 116. doi:10.3389/fsufs.2021.734088
- Type:
Journal Articles
Status:
Published
Year Published:
2022
Citation:
Carlisle, L., Esquivel, K., Baur, P., Ichikawa, N.F., Olimpi, E.M., Ory, J., Waterhouse, H., Iles, A., Karp, D.S., Kremen, C., Bowles, T.M., 2022. Organic farmers face persistent barriers to adopting diversification practices in Californias Central Coast. Agroecology and Sustainable Food Systems 46, 11451172. doi:10.1080/21683565.2022.2104420
- Type:
Other
Status:
Published
Year Published:
2022
Citation:
Ory, J., Bowles, T., Iles, A., 2022. Connecting Soil Health and Water in California. Center for Diversified Farming Systems Berkeley Food Institute,
University of California, Berkeley. https://food.berkeley.edu/soilhealthwaterbrief
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Progress 06/01/20 to 05/31/21
Outputs
Target Audience:During this reporting period we reached a variety of target audiences through a number of different venues. Through our research activities we reached: 1) 16 growers in the Central Coast region of California growing high value vegetable crops (including new farmers, Spanish Speaking farmers, and resource-limited farmers); 2) extension personnel (e.g. from University of California Cooperative Extension, California Resource Conservation Districts [CARCD], and the Natural Resource Conservation Service) involved in vegetable crop and organic crop production; 3) staff from non-profit organizations working at the intersection of agriculture and the environment; and 4) University of California researchers. Undergraduates were reached during formal classroom instruction through PI Bowles' courses in Agroecology (55 upper division students) and Introduction to Environmental Science (300 lower division students), each of which includes a relevant unit on agriculture and soil health. Graduate students were reached through formal classroom instruction by both PI Bowles and co-PI Iles through a Food Systems course on a unit about policies to support soil health in California, and from PI Bowles in a graduate course entitled "The Science of Healthy Soils". Changes/Problems:We have had to make some adjustments to our research approaches due to the COVID-19 pandemic. UC Berkeley human subjects requirements initially forbid us from going to the field to do interviews, focus groups, or site visits. We pivoted to phone interviews and online surveys and were able to continue collecting data on management and labor, but it delayed the cost / return study portion of the project. While we managed to conduct the extensive field work we had intended prior to the pandemic, it came with considerable effort and cost (e.g. because team members had to drive separate vehicles to field sites). Moreover, campus severely restricted access to research labs and restrictions were not fully lifted until July 2021. That set back our laboratory analyses by ~6 months. We still anticipate being able to finish the objectives of the project but anticipate needing a no-cost extension to accommodate the impacts of the delays. What opportunities for training and professional development has the project provided?The project has continued to create many informal training and professional development opportunities for postdocs, graduate students, academic staff researchers, and undergraduates. All trainees have gained substantial experience in conducting disciplinary and interdisciplinary science. The project has supported two postdoctoral scholars during this project period (one social scientist and one soil biogeochemist). With guidance from PIs, postdocs have in turn gained mentoring skills through guiding one PhD students and several undergraduates. Several specific examples of training opportunities for postdocs include how the soil biogeochemistry postdoc (Waterhouse), led grant-writing to a California state agency building on work conducted for this grant, focused on potential tradeoffs between policies that incentivize building soil health and outcomes for water quality when nitrogen leaches from compost inputs. We have received word that it has been preliminarily funded. All postdocs have received extensive experience in conducting and writing interdisciplinary research, with one recent publication (in review) containing both current postdocs and a combination of social science and ecological data. One PhD student working on this project, Kenzo Esquivel, has gained considerable experience in social science, building on his background in ecology. He has worked extensively with one of the lead social scientist collaborators, Liz Carlisle, to help prepare the two manuscripts currently in review / submitted, as a co-first author. These were Esquivel's first experiences co-lead-authoring large multi-author papers, which provided opportunities for mentorship not only in research and writing but also key aspects of leading research teams that are rarely discussed in formal training, such as determining author order and responding to reviewer feedback. These two papers were developed in series, allowing Esquivel to take on progressively more responsibility and transition from observing a task to completing a task with supervision to executing it on his own. The project also provided research experience for three undergraduate students who have gained experience in various laboratory techniques and will also be included in the downstream analysis and paper preparation. How have the results been disseminated to communities of interest?Dissemination of results has been limited during this reporting period due to cancellation of events from the COVID-19 pandemic and dramatic slow-downs in laboratory processing of samples, which in turn slowed results. Dissemination of results is a central goal of the next reporting period. What do you plan to do during the next reporting period to accomplish the goals?Now that the vast majority of the laboratory analyses have been completed for the soil microbial diversity and ecosystem service, we will rapidly move into data analysis and manuscript preparation for Objectives 2 and 3. We will also conduct tradeoff and synergy analyses to determine whether soil health practices tend to promote multiple soil-based ecosystem services simultaneously or whether tradeoffs result, e.g. with crop yields. We have initiated a new collaboration with a researcher at the Lawrence Berkeley National Lab to use the ecosys model, a process-based ecosystem process model. This model will also allow us to scale our field-level results to the region with several scenarios of diversification practice incentives and regulations, thereby drawing together our biophysical data collection with insights from the social dynamics side of the project. We anticipate submitting the first manuscripts from this portion of the project by the middle of the next reporting period. We would also like to focus on outreach in the next year, especially with the development of reports based on our findings from the grower interviews, supply chain interviews, and grower practices survey. PD Bowles is organizing a field day in the study region with the NGO partner ALBA, focused on sharing project results and facilitating conversations among growers who have varying levels of experience and resources implementing diversification practices. This field day will take place in late winter 2022 when growers are not as busy.
Impacts
What was accomplished under these goals?
Loss of soil biodiversity, depletion of soil organic matter (SOM) and pollution of groundwater by nitrate leaching are some of the many widespread consequences of intensive, highly-simplified agricultural systems, which undermine the natural resource base on which agriculture depends and threaten the health of rural communities across the United States. Restoration of soil health, an integrative concept describing the dynamic properties of soil, especially soil microbes and soil organic matter, that underpin key soil functions is increasingly recognized as a crucial step toward creating more sustainable agroecosystems by enhancing soil-based ecosystem services. Biologically diversified farming systems use management practices at multiple temporal and spatial scales that promote beneficial organisms in the farm and the surrounding landscape, thereby supplying critical ecosystem services that can result in production improvements with fewer inputs. Yet knowledge of how such practices (for instance, cover crops, organic matter amendments, and crop rotation) affect soil microbes and SOM and the ecosystem services they together underpin remains limited on working farms, especially in high-intensity vegetable systems. Further, such techniques are often not adopted by farmers because of multiple, reinforcing market, knowledge, agronomic, environmental, and policy barriers. In this reporting year we made significant progress on Objectives 1 - 4, along with most of our sub-objectives. For Objective 1, the major activities undertaken included qualitative data analysis of ~30 semi-structured interviews, manuscript preparation and submission, administering an in-depth management survey, and conducting additional interviews related to the relationship between diversified farming systems and labor. For Objectives 2 and 3, the major activities were to complete amplicon sequencing of soil microbial communities, including bioinformatics, and laboratory processing of 1000s of field samples. We also translated the management survey into gradients that could capture the relationships between the human and natural systems. For Goal 4, the major activity was to prepare for the cost-return study that is currently ongoing. Objective 1: Analyze how government policies, incentives, and supply chain conditions influence farmer's decisions to adopt, modify, or abandon DPs; and Objective 4: Analyze how farmers become aware of the opportunities and challenges of adopting DPs to promote soil health, including economic tradeoffs. (socio-economic objectives) Led by co-PD Iles and Collaborator Liz Carlisle, we have summarized key results of Objective 1 in two publications, one in review and one submitted. Based on 20 interviews with organic lettuce growers on the Central Coast of California, as well as 8 interviews with technical assistance providers who work with these growers, we constructed a typology to help elucidate the distinct contexts that shape growers' decisions about diversification practices. This typology, which reflects the structural influence of land rent and supply chains, divides growers into three categories: limited resource, mid-scale diversified, or wholesale. In this economic context, limited resource and wholesale growers both experience significant barriers that constrain the adoption of diversification practices, while some mid-scale diversified growers have found a "sweet spot" for managing agroecosystems that can succeed in both economic and ecological terms. The key enabling factors that allow these farmers to choose diversification, however, are not directly related to their farm size, but have more to do with secure land tenure, adequate access to capital and resources, and buyers who share their values and are willing to pay a premium. By focusing on these key enabling factors with targeted policies, we believe it is possible to encourage diversification practices on farms at a variety of scales within California's Central Coast. We also investigated the persistent barriers that growers in this region face in adopting diversification practices including cover cropping, compost application, crop rotation, insectary strips, and hedgerows. We find that high land rents and the predominance of short-term leases, stringent food safety standards, and other supply chain pressures in this region significantly hamper the adoption of diversified farming practices. We suggest that in order to surmount these barriers and increase adoption, solutions must be pursued at three structural levels: innovation at the farm level, and policy change at the technical and structural levels. Locally-informed and innovative policies across these three levels must be explored to better support the creation of a more resilient, sustainable, and equitable food system. Objective 2: Determine how field-scale DPs impact the soil microbiome, and the extent to which these impacts depend on landscape-scale complexity; and Objective 3: Determine how field-scale DPs impact soil-based ecosystem services, and how these services correlate with soil microbial abundance, activity and/or diversity. (ecological objectives) In order to assess soil microbial diversity, soil-based ecosystem services, and how soil health management affects both, we conducted a biophysical survey across 28 different lettuce fields (16 different growers) in California's central coast, mainly during spring and summer 2020. The fields fall along a "diversification gradient" (i.e. they vary in the extent to which diversification practices are used), which was based off the initial interviews and initial site visits. We quantified landscape-level crop diversity by visually mapping and then digitizing all crop types within 500 m of each farm. We also manually digitized non-crop vegetation in the surrounding landscape (within 1 km) using NAIP and Google Earth aerial imagery which will be used to determine our landscape heterogeneity index. At each field, we sampled soil at three key times during the lettuce's growing season: transplant, mid-season, and harvest. At each time point, soil was sampled from five points per field (each point consisting of several soil cores) from 0-15, 15-30, and 30-60cm depths. We completed amplicon sequencing and qPCR for soil bacterial and fungal communities (via 16S and ITS2 regions, respectively) across our 28 sampling sites, and completed bioinformatics to generate complete OTU tables. For soil carbon (C) accrual, we completed soil C analysis of 465 samples and calculated carbon stocks to 60 cm depth across 28 sites based on the equivalent soil mass method. We also completed soil organic matter fractionations to assess the relative stability of soil carbon. For nutrient cycling, we completed analysis and QA/QC of data on the relative activity of microbial extracellular enzymes that control organic matter turnover, including glucanase, β-glucosidase, exochitinase, leucine-amino-peptidase, phosphatase, peroxidase, and phenol-oxidase. For groundwater protection, we completed analysis of over 1200 samples of soil ammonium and nitrate (0-60cm depth). Soil inorganic nitrogen concentrations from lower depths at key points in the growing season will be used to assess potential for nitrogen retention. For water retention, we have completed 90% of the soil water retention and hydraulic conductivity curves, which in turn will allow us to estimate soil properties related to water provisioning. Related to this sub-objective, we have also nearly completed a review paper on how soil health management influences effective use of water resources in irrigated agricultural landscapes. Based on field sampling, we have calculated lettuce yields and prepared lettuce samples for analysis of nutrient uptake. For all these measurements, we are rapidly moving into data analysis.
Publications
- Type:
Book Chapters
Status:
Published
Year Published:
2021
Citation:
Joanna Ory and Alastair Iles. 2021 "Fostering Healthy Soils in California: Farmer Motivations and Barriers". In True Cost Accounting in Food, edited by Barbara Gemmill-Herren, Lauren Baker, and Paula Daniels (Springer).
- Type:
Journal Articles
Status:
Submitted
Year Published:
2021
Citation:
Tipping points in diversified farming systems. Authors: Melissa Chapman, Serge Wiltshire, Patrick Baur, Timothy Bowles, Liz Carlisle, Federico Castillo, Kenzo Eszquivel, Sasha Gennet, Alastair Iles, Daniel S. Karp, Claire Kremen, Jeffrey A. Liebert, Elissa M. Olimpi, Joanna Ory, Matthew Ryan, Amber R. Sciligo, Jennifer B. Thompson, Hannah Waterhouse, Carl Boettiger. Submitted
- Type:
Journal Articles
Status:
Published
Year Published:
2021
Citation:
Petersen-Rockney, M., Baur, P., Guzman, A., Bender, S. F., Calo, A., Castillo, F., et al. (2021). Narrow and Brittle or Broad and Nimble? Comparing Adaptive Capacity in Simplifying and Diversifying Farming Systems. Front. Sustain. Food Syst. 5, 130. doi:10.3389/fsufs.2021.564900.
- Type:
Journal Articles
Status:
Under Review
Year Published:
2021
Citation:
Esquivel*, K.E., Carlisle*, L., Ke, A., Olimpi, E.M., Baur, P., Ory, J., Waterhouse, H., Iles, A., Karp, D.S., Kremen, C., Bowles, T.M. The 'sweet spot' in the middle: why do mid-scale farms adopt diversification practices at higher rates? *co-first authors in review
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Progress 06/01/19 to 05/31/20
Outputs
Target Audience:During this reporting period we reached a variety of target audiences through a number of different venues. Through our stakeholder advisory committee we reached; 1) several farmers in the Central Coast region of California growing high value vegetable crops (including new farmers, Spanish Speaking farmers, and resource-limited farmers); 2) extension personnel (e.g. from University of California Cooperative Extension, California Resource Conservation Districts [CARCD], and the Natural Resource Conservation Service) involved in vegetable crop and organic crop production; 3) staff from non-profit organizations working at the intersection of agriculture and the environment; and 4) University of California researchers. At our stakeholder meeting we presented our target audience with our preliminary findings and received feedback from them on our field sampling campaign and farm management surveys. An audience of technical assistance providers was also reached through presentations at the California Plant-Soil Conference and the CARCD conference. Farmers were reached through a panel presentation at the Eco Farm conference. Undergraduates were also reached during formal classroom instruction through PI Bowles' courses in Agroecology (55 upper division students) and Introduction to Environmental Science (300 lower division students), each of which includes a relevant unit on agriculture and soil health. Graduate students were reached through formal classroom instruction by both PI Bowles and co-PI Iles through a Food Systems course on a unit about policies to support soil health in California. Changes/Problems:We had to make some adjustments to our research approaches due to the COVID-19 pandemic. UC Berkeley human subjects requirements forbid us from going to the field to do interviews, focus groups, or site visits. This means we must currently rely on phone conversations and online surveys to gather our data. This has set back the social science part to some degree but we have a very robust interview dataset from last year that we are building on. Nevertheless, it has also opened a new line of inquiry developed in response to the widespread impacts of the COVID-19 pandemic. The social science team is now examining the ways in which farm diversification influences resilience/vulnerability and adaptive capacity to systemic shocks such as the one created by this crisis. Additionally, lab analysis will be delayed due to the impacts of the COVID pandemic as we have stringent restrictions on how many people can be in a lab space simultaneously. Overall, in spite of large challenges, we were able to obtain exemptions to continue research during the initial lock-down, and our project remains largely on track. What opportunities for training and professional development has the project provided? The project has created numerous informal training and professional development opportunities such as the opportunity for early career researchers to work with an interdisciplinary team, learn about the administration and management of large projects, train in social science research methods, increase professional networks, and outreach through workshops, blogs, and conferences. One participant noted that they would now feel much more comfortable writing such a grant and taking on leadership of a project such as this one. Two postdoc fellows continued their research training as part of the project. Those postdocs received training in publication, data analysis, and soil health and biodiversity issues. One obtained an assistant professor position at the University of Rhode Island in part because of the experiences he gained through the project. The project also provided research experience for several undergraduate students who have gained experience in various laboratory techniques, remote sensing skills, and will also be included in the downstream analysis and paper write up. How have the results been disseminated to communities of interest?Preliminary results have been shared with our stakeholder advisory board (growers, cooperative extension agents, etc..) at an advisory meeting hosted in March, as well as presentations to the California Plant-Soil Society and the California Association of Resource Conservation Districts. Our initial results and tentative survey and field sampling methods were shared with the stakeholders in order for them to provide insight into how we could make the sampling and management survey relevant to our communities of interest. What do you plan to do during the next reporting period to accomplish the goals?Now that the field sampling campaign has been completed our efforts will be concentrated on finishing the lab and statistical analyses and continuing to work on reports and manuscripts. Specifically, in order to measure soil microbial diversity, we will extract DNA from five soil samples from each field and submit the DNA for 16S and ITS2 amplicon sequencing. We will also measure the potential of each farm to provide ecosystem services including soil carbon storage, water regulation, and nitrogen regulation by measuring various indicators on our soil samples including, but not limited to, total soil carbon and nitrogen, soil hydraulic conductivity, and soil nitrate and ammonium. In addition to the ecological work planned for the next year, we plan to finish data collection from the farm management surveys and semi-structured interviews and relate the results to our ecological data. We would also like to focus on outreach in the next year, especially with the development of reports based on our findings from the grower interviews, supply chain interviews, and grower practices survey.
Impacts
What was accomplished under these goals?
Loss of soil biodiversity, depletion of soil organic matter (SOM) and pollution of groundwater by nitrate leaching are some of the many widespread consequences of intensive, highly-simplified agricultural systems, which undermine the natural resource base on which agriculture depends and threaten the health of rural communities across the United States. Restoration of soil health, an integrative concept describing the dynamic properties of soil, especially soil microbes and soil organic matter, that underpin key soil functions is increasingly recognized as a crucial step toward creating more sustainable agroecosystems by enhancing soil-based ecosystem services. Biologically diversified farming systems use management practices at multiple temporal and spatial scales that promote beneficial organisms in the farm and the surrounding landscape, thereby supplying critical ecosystem services that can result in production improvements with fewer inputs. Yet knowledge of how such practices (for instance, cover crops, organic matter amendments, and crop rotation) affect soil microbes and SOM and the ecosystem services they together underpin remains limited on working farms, especially in high-intensity vegetable systems. Further, such techniques are often not adopted by farmers because of multiple, reinforcing market, knowledge, agronomic, environmental, and policy barriers. In this reporting year we made progress on both Objectives 1 and 2, setting us up to realize Objectives 3 and 4. For Goal 1, we completed our soil sampling campaign by sampling soils across 28 farms that lie on a gradient of diversification practice usage and have made ample progress analysing soil chemical, biological, and physical properties. We have begun our community analysis of soil microbial diversity as well as the analyses that estimate soil ecosystem service potential including soil carbon sequestration, nitrogen retention, water conservation, as well as lettuce yields. As for Goal 2, a team of ecologists, soil scientists, social scientists, and agricultural economists came together to design a farm management survey that not only would elucidate which type of farmers use what practices but also determine what were the barriers to adoption of diversification practices. The survey data is still being collected (remotely due to Covid) but will be used to help increase farmer adoption of diversification practices from better policy incentives. Objective 1: Analyze how government policies, incentives, and supply chain conditions influence farmer's decisions to adopt, modify, or abandon DPs; and Objective 4: Analyze how farmers become aware of the opportunities and challenges of adopting DPs to promote soil health, including economic tradeoffs. (socio-economic objectives) Led by co-PD Iles, postdocs and two key collaborators conducted 55 semi-structured interviews with growers, technical assistance providers/extension personnel, and produce processors about decisions to adopt or support diversification practices for soil health. All interviews have been transcribed and preliminary qualitative analyses have been conducted. A farm management survey was sent out to determine how farmers use or do not use several diversification practices (cover cropping, crop rotation, organic amendments, and perennial vegetation) as well as what are the primary obstacles to using them. We identified a loose typology of farms that helps explain why these decisions play out differently for different farmers, including small-scale, medium-scale and large-scale farms. Smaller-scale farms in the region tend to be resource limited and have insecure land tenure, limiting their capacity to use diversification practices for long periods of time, especially when this cuts into production of high value crops in a region with very high land costs. Large scale farms face slim profit margins and must respond to global market demands, also limiting their capacity to incorporate diversification practices. We identified medium scale farmers as a potential "sweet spot" for using diversification practices in this region, based on typically more secure land tenure and regional markets that value stewardship, Based on other grower and technical support interviews we have also found that food safety requirements from buyers are key to how growers make decisions about what practices they use, especially as some buyers forbid the use of compost due to concerns about pathogen transmission. Tight production schedules, including often two or more cash crops per year, and high land values make it very difficult to use cover cropping, even though most growers would like to do more cover cropping to improve soil health. Growers have several innovative approaches for incorporating cover crops when and where they can, such as only cover cropping a proportion of their farms each year, and identifying short time periods over the summer when fast growing cover crops can be produced on the same beds used for vegetable production. Some growers are using over-wintering cash crops like broccoli to serve as nitrogen interceptors while also allowing for some income. Based on these initial findings, we have already begun to draft several articles specifically about farmer decision making and its impact on the natural system. Objective 2: Determine how field-scale DPs impact the soil microbiome, and the extent to which these impacts depend on landscape-scale complexity; and Objective 3: Determine how field-scale DPs impact soil-based ecosystem services, and how these services correlate with soil microbial abundance, activity and/or diversity. (ecological objectives) We conducted a biophysical survey across 28 different lettuce fields (16 different growers) in California's central coast, mainly during Spring 2020. The fields fall along a "diversification gradient" (i.e. they vary in the extent to which diversification practices are used), which was based off the initial interviews and initial site visits. We quantified landscape-level crop diversity by visually mapping and then digitizing all crop types within 500 m of each farm. We also manually digitized non-crop vegetation in the surrounding landscape (within 1 km) using NAIP and Google Earth aerial imagery which will be used to determine our landscape heterogeneity index. At each field, we sampled soil at three key times during the lettuce's growing season: transplant, mid-season, and harvest. At each time point, soil was sampled from five points per field (each point consisting of several soil cores) from 0-15, 15-30, and 30-60cm depths. Soil from the mid-season sampling was frozen and will be used for DNA amplicon-based sequencing to determine the soil bacterial and fungal community (based on 16S and ITS2 regions). We also analyzed soil samples for microbial biomass carbon and nitrogen to determine the abundance of the microbial community. Roots from lettuce plants were taken to estimate rates of arbuscular mycorrhizal colonization. We also collected measurements as indicators of ecosystem services including soil carbon sequestration, nutrient cycling, nitrogen retention, water conservation. To estimate the nutrient cycling ecosystem service, potential activities of the following soil C, N and P cycling enzymes were assessed glucanase, β-glucosidase, exochitinase, leucine-amino-peptidase, phosphatase, peroxidase, and phenol-oxidase. Soil inorganic nitrogen concentrations from lower depths at key points in the growing season will be used to assess potential for nitrogen retention. Intact soil cores were collected (140 in total) to determine complete soil water retention and hydraulic conductivity curves, which in turn will allow us to estimate soil properties related to water conservation. Soil samples for carbon stock calculations were taken using the equivalent soil mass method. Finally, lettuce was harvested to measure yields and plant nitrogen uptake.
Publications
- Type:
Journal Articles
Status:
Submitted
Year Published:
2020
Citation:
Tipping points in diversified farming systems. Authors: Melissa Chapman, Serge Wiltshire, Patrick Baur, Timothy Bowles, Liz Carlisle, Federico Castillo, Kenzo Eszquivel, Sasha Gennet, Alastair Iles, Daniel S. Karp, Claire Kremen, Jeffrey A. Liebert, Elissa M. Olimpi, Joanna Ory, Matthew Ryan, Amber R. Sciligo, Jennifer B. Thompson, Hannah Waterhouse, Carl Boettiger.
- Type:
Book Chapters
Status:
Under Review
Year Published:
2020
Citation:
Joanna Ory and Alastair Iles. (In review.) "Fostering Healthy Soils in California: Farmer Motivations and Barriers". In True Cost Accounting in Food, edited by Barbara Gemmill-Herren, Lauren Baker, and Paula Daniels (Springer).
- Type:
Journal Articles
Status:
Under Review
Year Published:
2020
Citation:
Petersen-Rockney, M., Baur, P., Guzman, A., Bender, S. F., Calo, A., Castillo, F., De Master, K., Dumont, A., Esquivel, K., Kremen, C., LaChance, J., Mooshammer, M., Ory, J., Price, M. J., Socolar, Y., Stanley, P., Iles, A., Bowles,. T. M. Adaptive capacity emerges from diversifying farming systems. Submitted to Frontiers in Sustainable Food Systems.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2020
Citation:
Bowles, T.M., Carlisle, L., Ory, J., Iles, A. Perceptions of cover cropping challenges and opportunities in California's complex socioeconomic and climate environment. California Plant-Soil Conference, Fresno, CA. (presentation)
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Ory, J. Promoting Soil Health Innovations: Barriers, Motivations, and Enabling Conditions. California Resource Conservation District's (CARCD) 74TH Annual Conference. (presentation)
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Bowles, T.M. Soil health for productive and sustainable agriculture: Evidence and Barriers. NRCS Conservation Webinar series. Online.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Claire Kremen, C. Integrating social and ecological data to evaluate benefits and costs of diversified agroecosystems in California" Symposium on Agroecology with Communities: Cross-Disciplinary Collaborations Between Ecology, Agriculture and Social Science. Ecological Society of America, August 2019.
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