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Research Project: The USDA Climate Hubs – Supporting Natural and Working Lands Resilience by Co-Developing and Communicating Research-Informed Agro-Climate Practices

Location: Sustainable Agricultural Water Systems Research

2021 Annual Report

The USDA California Climate Hub program will enable climate-informed decision-making through the successful development of science-based, region-specific syntheses, information products, decision support tools and technologies for agricultural, forestry and natural resource managers, and where possible provide assistance to enhance adoption and implementation of the same. The aforementioned will be accomplished through investments via three primary pathways: (i) data and information syntheses; (ii) tool and technology development, curation and implementation support; and (iii) convening to support technical assistance, training and information exchange. The work will be conducted as the California USDA Climate Change Hub (CACH) and will be coordinated with ARS, NRCS, USFS broadly and locally, and other USDA and non-USDA organizations in accordance with guidance found in the USDA Climate Change Hubs Charter, and Terms of Reference. The focus of these activities will be the regions natural and working lands, inclusive of all farms, ranches, forests and other production and natural systems however with special attention to agro-climate applications in specialty crop and forestry contexts.

The CACH program will co-develop and produce science-based syntheses to elucidate expected climate impacts, stressors and/or disturbances using largely readily available climate and weather data. These outputs will lead to products to report and communication climate-linked impacts to natural and working land interests and assets that are place- and/or resource-based including climate scenarios (forecasts) and vulnerability assessments. Efforts will also include the translation of climate and weather data to communicate current conditions, extreme events and lookout forecasts. The program will also support and/or co-develop products resulting from novel frameworks, stakeholder need (or barrier) assessments, technologies or techniques leading to the advancement of practices founded in climate adaptation and mitigation science. Products may include but are not limited to peer reviewed, government, trade or technical assistance papers, reports, bulletins or articles. Investments and products that result from synthesized information sets or tools leading to an improved interpretation of and/or new understanding of changing natural and working land management systems in context of climate change in the form of decision support tools, toolkits, dashboards, factsheets, agriculture or forestry alerts will remain a core program focus. Generally speaking, this can include outputs akin to agro-climate or other climate informed agriculture or forestry decision support systems or web-based applications. These products will provide a better understanding of climate change information (literacy), facilitating improved management practices to both adapt and mitigate the effects associated with climate change. Designing, developing and organizing opportunities for information exchange, content appropriate/specific conferences, workshops, symposia, dialogs, field days, site demonstrations, trainings through convening of focused groups of managers, practitioners, scientists, technical assistance provider’s etc. Additionally, we will regularly produce, develop and disseminate information products in the form of newsletters, blogs, etc. using a variety of media including social, trade and popular outlets. CACH staff will contribute and serve on advisory and steering committees, give lectures, webinars, presentations to audiences that support the broader mission and function of the USDA Climate Hub program and needs and requests of stakeholders. We will also continually evaluate (assess) and communicate the needs of producers and managers to the science community as well as sharing science-based knowledge and applications to those that can act on that information.

Progress Report
This is a new project that was established in April 2021 in accordance with a Fiscal Year 2021 Program Increase. In support of Objective 1, research was conducted to assess the potential reductions in frost exposure for high-value California orchard crops due to future climate change. Derived contemporary temperature data from the gridded surface meteorological dataset (GridMET) were compared to downscaled future data using Multivariate Adaptive Constructed Analogs (MACA) to a 4-km gridded surface to analyze future frost risk for the early- and mid- 21st century focusing on future experiments under the Representative Concentration Pathway 8.5 (RCP 8,5). The impact of climate change on frost incidence for the coldest winters (98th percentile) was analyzed for almonds, avocados and oranges. Relatedly complementary research was conducted to explore the role of ocean-atmosphere climate indices on chill accumulation for specialty crops in California. The Oceanic Nino Index (ONI), Pacific-North American (PNA) teleconnection pattern and the Pacific Decadal Oscillation (PDO) were the three indices analyzed for their relationship with chill accumulation. Results demonstrated that the ONI is most weakly correlated with chill accumulation, whereas PDO had the strongest positive correlation with chill portion accumulation. A review of the literature was conducted to evaluate the role of climate change on forest and rangeland ecosystems at the wildland-urban-interface (WUI) in the southwest United States. The findings revealed that the direct and indirect effects of climate change will strain or force change across the WUI through the individual and/or combined effects of wildfire, water scarcity, development pressure, and shifting economic markets. Ongoing research is exploring the potential role of soil management practices, chiefly soil amendments, in their role toward accelerating carbon capture in both cropping and rangeland agricultural contexts. Also, in support of Objective 1, progress was made toward the development of a synthesis of potential climate adaptation strategies, approaches and practices for potential application for specialty crop production systems in California. A guidebook was developed to assist private forest landowners in creating a management strategy for forest parcels in the Sierra Nevada / Cascade region. Advancements have been made toward the web-based compendium of climate-based decision support tools for agricultural production called CalAgroClimate. A prototype tool is in beta testing phase for predicting pests and disease by crop type x location and growing degree days by crop type x location. In further support of Objective 1, we conducted five regional roundtable dialog (listening/exchange) sessions focused on assessing opportunities and barriers leading to the advancement of region-appropriate nature-based solutions on natural and working lands. The information gained from those events will eventually be synthesized and related in a summary report. We developed and conducted two workshops for the United States Forest Service (USFS) to assess reforestation priorities and opportunities on the Creek fire landscape. The information gathered is being used by the interdisciplinary team of specialists preparing the project documentation (environmental impact report) for eventual implementation. We co-led two climate adaptation planning workshops for two individual USFS districts in Region 5. The data collected from those workshops will be used by specialists in the units in their preparation of project documents (environment assessments) for eventual implementation.

1. Climate change reduces frost exposure for high-value California orchard crops. For agriculture, frost impact can cause hundreds of millions of dollars in crop damages to high-value perennials in California alone. Irrigation is the most common means of mitigating damage, but draws on limited water resources, is costly, and energy intensive. To understand how a changing climate might reduce future frost exposure for select high value orchard crops (almonds, avocados and oranges), ARS researchers at Davis, California, used downscaled climate models to predict the future shift of frost impact. Across the agricultural regions evaluated, the researchers found that frost exposure is expected to decline by 63% by the mid-21st century. The results further suggest that the majority of almond and orange acreage will see approximately 50–75% reduction in frost exposure by mid-century, with avocado acreage expected to experience over 75% fewer frost hours. This then, yielded attendant reductions in water use and energy costs, and growers in the highest acreage counties may save more than 50,000 acre feet of water and $4.2 million in electricity costs for water pumping per year, collectively – a significant benefit to the industry.

2. Impacts of large-scale teleconnection indices on chill accumulation for specialty crops in California. For California's agriculture sector, one consequence of climate change and the overall warming of minimum temperatures is the reduction of chill accumulation in winter. Sufficient chill accumulation is essential for the optimal growth and development of many perennial specialty crops in California. Research by ARS scientists in Davis, California, was conducted to explore the role of ocean-atmosphere climate indices on chill accumulation for specialty crops in California. Global-scale meteorological or climatic anomalies showed significant correlations with chill accumulations in California. The correlations between chill accumulation and climatic anomalies are generally weaker during the summer than other seasons, and a significant correlation can be observed 2–10 months before the start of the chill accumulation period. A better understanding of the role of global-scale climatic anomalies can help inform approaches for agriculture to adapt to climate change.

3. Promotion of soil carbon in working lands as a gateway for negative emission technologies. The impacts of climate change are already being felt on a global scale, which is expected to amplify in the years and decades to come. Net zero emission technologies (NETs) will be an important means for achieving greenhouse gas sequestration targets. Soil amendments in the forms of organic compost, biochar and crushed rock are promising soil management practices that may facilitate the update of atmospheric carbon into cropland and rangeland production systems. Scientist at Davis, California, used published values of soil carbon sequestration (SCS) rates in response to different working land management practices to parameterize a carbon sequestration model and demonstrate the potential near-term carbon benefits of SCS strategies in working lands. Results found that combined working land NETs, if deployed to their fullest extent, could remove 14.7 billion tonnes of CO2/year by 2050. These results demonstrate the potential promise of soil amendments for achieving sequestration goals while also providing associated climate resilience benefits to farmers and ranchers.

4. Forest management handbook for small-parcel landowners in the Sierra Nevada and Southern Cascade Range. Contemporary forests in the Sierra Nevada and southern Cascades are stressed by a number of factors that put them at risk. High severity wildfire, drought stress, insect outbreaks, disease, and a backdrop of changing climate, all pose a threat to the persistence of these forests. A significant portion of these forests is owned and managed by non-industrial private landowners who typically own small parcels (for example, 10 to 50 acres). ARS scientists in Davis, California, prepared a guidebook structured in a step-by-step manor that walks the small parcel forest landowner through the process of objective setting for their property, site inventory, performing a basic risk assessment, exploring potential management options and outlining available resources. The intent of the handbook is to enable decision making that is both informed by scientific information and yet easy for forest landowners to understand.

Review Publications
Parker, L., Pathak, T., Ostoja, S.M. 2020. Climate change reduces frost exposure for high-value California orchard crops. Science of the Total Environment. 762. Article 143971.
Zhang, N., Pathak, T., Parker, L., Ostoja, S.M. 2021. Impacts of large-scale teleconnection indices on chill accumulations for specialty crops in California. Science of the Total Environment. 791. Article 148025.