Hemp Growing

Groups of thought and practice as disparate as the California organic movement, the Italian slow food movement, the eat-local phenomenon, low-carbon diets, geographically protected traditional denominations of origin like Champagne and Parma ham reflecting ideals of quality, and proponents of the French concept of terroir have all attempted in different ways to bring food back from nowhere, to celebrate that which makes it locally specific, non-industrial, non-standard, and anti-capitalist . Julie Guthman has observed that while eco-labels and place-based certifications putatively re-embed lost social values in the market economy and protect them from being further eroded by neoliberal market development, such forms of resistance also reinforce the power of market dynamics through their reaction to them, and allow further penetration of capitalism into new markets . Moreover, although these efforts continue to make important gains, they remain in their truest form at the periphery of the dominant global food system. The psychological and physical divide between mainstream food production and the food consumption still continues to grow. Food luminaries ranging from journalist and professor Michael Pollan to celebrity chef Jamie Oliver have noted that we as a society no longer seem to understand what “food” truly is. The less we know about the how our food comes to arrive on our tables—how it is farmed, harvested, processed and transported, by whom, under what conditions—the more disconnected we become from the politics associated with our food. A consumer may have opinions about how farm laborers should be treated, what amount of carbon emissions should be generated by a meal, or how fresh a salad should be, ebb and flow tables but if the farm landscape and its people and technologies are out of sight and out of mind, that consumer is unable to make a link between those values and the agricultural system.

The farther away food production feels, the less empowered consumers and even regulators are to engage with food production and its challenges. Lack of attention at many levels threatens the ability of the food system to deliver to us the food we need and the deeper values that make up our society.‘Food from nowhere’ affords the consumer an unprecedented degree of choice, freed from many constraints. Modern grocery store shelves offer consumers high degrees of cosmetic quality, standardization, multi-seasonal availability, and low price . But these benefits come with a wide array of costs, the result of producing food within a corporate capitalist structure of distribution. The stable supply, large volume, and dependable quality that must be present to create food from nowhere, in turn require longer supply chains and more industrialized production to deliver them. To reduce competition, to accomplish effective transportation of fresh products across long distances and to insulate themselves from financial shocks, food companies have grown larger and more diversified. Corporate food giants like Pepsico, General Mills, Cargill, Coca-Cola, Unilever, ConAgra and Nestle grew to their present size primarily through mergers and acquisitions of smaller brands. A handful of major corporate food firms now represent hundreds of smaller brands that are still sold under their original brand names, hiding the consolidation of the market . Some of these firms have also widened their influence into adjacent market spaces such as genetic engineering, energy, seed and pesticide manufacture, and agricultural securities, while corporations such as Monsanto and Syngenta originally based in those sectors have also begun to add food to their portfolios. During the 20th century, food producing corporations also began to actively influence both regulations and public opinion through their lobbying and advertising campaigns, focused on increasing sales and not necessarily on increasing human wellbeing . 5 The result is a cluster of agri-food conglomerates that wield immense financial and political control in the global marketplace . Soon after the American colonial period closed, market forces operating in the American free market for agricultural goods incentivized the consolidation of agri-food producers into corporate conglomerates, and spurred a pattern of vertical and horizontal integration of supply chains and financialization of the agriculture industry .

The result today is that the American food system is dominated by a highly vertically integrated, highly consolidated set of agricultural markets in which corporate food companies now control the entire life cycle of production of a plant or animal in the food system . Farmers in this type of production are increasingly corporate employees rather than free operators, constrained by production contracts, and both legally and financially controlled by the vertically integrated corporations for whom they grow food products. Fresh salad greens demonstrate this rise of corporate consolidation, vertical integration, and the shift to contract farming. As with many foods, lettuce production systems exist along a spectrum from small-scale farms to immense industrialized corporate farms. Salad mixes were initially developed in California as a luxury commodity for restaurants that made their name by offering small-scale organically-grown food and emphasizing a close connection between farm and table . This packaging innovation was then copied as part of the portfolio of large corporate farms serving audiences with less concern over organic methods or farm-to-table cuisine, and the production systems behind this new commodity began to industrialize. Scholars have described the resulting bifurcated market, in which some small alternative producers still deliver fresh salads directly from farm to table, but the bulk of the market is dominated by large corporate farms run under contract, and that now operate under increasingly industrial and conventional supply chain models . Rural sociologist Thomas Lyson describes the impact of these changes thus: “The development of supply chains means that on-farm decisions will no longer be made to benefit the long-term sustainability of the farm, the good of the community, or the health of the natural resources that sustain the farm” . In such a system, the profits of agriculture are owned by the corporate conglomerate, not the farmer, and farm management decisions are also made by the corporate conglomerate, not the farmer. Distancing of human consumers from our food is thus taken to a mind-boggling extreme: Even the dwindling percentage of the population who wake up each morning on farms or whose livelihood comes directly from growing food, are not those who are in control of the way farming takes place. At the same time, the psychological and geographical distancing of consumers results in a packaged food purchasing landscape where consumers cannot tell which products come from which of the large firms, or how those products and firms may reflect their values. In both fresh and packaged foods, corporate consolidation and control of all levels of food and agriculture presents growing regulatory challenges for ensuring that food delivers on desired outcomes such as healthy environments, fair labor practices, and safe food.The 20th century’s population explosion, increasing urbanism, and new technologies for agriculture, food manufacture and food marketing gave rise to corporate food culture in the Global North. Grocery retailers and food brands consolidated, vying for control of emerging consumer markets. Capitalist industrial development over the following half century then allowed mega-corporations like Cargill, Nestle, and Unilever to amass unprecedented financial and political resources.

Vertical integration makes these corporations some of the largest agricultural producers worldwide, managing multinational supply chains and posting yearly profits larger than many smaller countries’ GDPs. These goliath corporate entities also wield considerable political power, through their size and financial importance, as well as through lobbying and direct political involvement. As the power held by these large corporations grew toward the end of the 20th century, scholars from many disciplines began pointing to a decrease in the power and influence held by nation-states . In this globally linked world where movements of capital, goods and information now happen faster and at a scale never before seen, transnational corporate interests have gained economic and political clout in a way that crossed and almost erases borders, allowing them to escape or influence regulation of their activities. Scholars have also noted that “globalization is developing in the context of a new international division of labor” as a result of the dynamics of agrarian change and the rise of capitalist farming that have occurred in the industrialized world. Different areas of the world have come to specialize in—or be trapped within—different types of goods or services within the new global market, with differential degrees of political and societal bargaining power, industrial drying racks much of which is now exerted within supply chains by means of private standards . It has even been suggested that the rise of transnational corporations may make the concept of the nation-state economically irrelevant . Using their concept of food regimes, Friedmann and McMichael posit that transnational corporations are the owners of geopolitical power now in the emerging present-day Corporate Food Regime in the same way that national governments held this geopolitical power in food regimes prior to 1970 . These trends have resulted in a weakening of public regulatory power in favor of an increasingly diffuse array of non-state actors exerting power over food and agriculture. When foods are produced and consumed in locations so far apart that they fall under different cultures, languages, political divisions, and social norms, little can be relied upon without being codified into standards that follow supply chains rather than borders . A corporation that sources a food crop from a country that has fewer or less effective environmental and labor regulations may operate there in a way that their home country would not allow . Both governments and consumers of goods in the many countries where this product eventually ends up for sale are then left unable to influence or fully regulate the activities of the transnational corporation in its broader supply chain. There are no formal public governmental entities in this interstitial space, necessitating alternative forms of non-state governance to achieve a degree of regulatory oversight where traditional state regulation cannot penetrate . In addition to—and sometimes in place of—traditional state-led public regulation, what has begun to take shape in the modern marketplace is a devolution of regulatory power from the state to an array of non-state actors. This development is not inherently problematic, and may in many cases reflects attempts to make regulation more flexible, more responsive, and less costly to pursue. However, when regulation by state regulatory authorities is replaced by quasi-governmental regulation designed and promulgated by authorities that are not publicly accountable, and for whom there are no established codes of conduct, important questions surround the resulting regulation. Private corporations, activist NGOs, and independent certification bodies have spearheaded the emergence of an array of privately-held production and quality standards, designed to provide assurances where public regulation does not suffice or does not exist . Thus, the new landscape is marked by a network of standards and certifications maintained by private entities, some separate from industry, some industry-led or industry-influenced. Examples include certifications managed by non-profit groups like the Forest Stewardship Council, industry-led governance bodies like the Roundtable on Sustainable Palm Oil, and advocacy-based campaigns to inform the consumer public through “naming and shaming” corporations like popular campaigns to hold Nike or Apple accountable to consumers for their environmentally and socially questionable overseas activities . The global rise of transnational corporations and the rise of private standards and certifications in the global marketplace coincided with a shift in how states exerted power over food and agriculture. Prior to this shift, states had sole power to control food and agriculture production within their borders. But since the late 1980s and 1990s, this power has become constrained, and shared with private industry. Transnational trade has made it harder to regulate the activities of food and agriculture because products cross borders and regulatory systems between production and sale, and neoliberal reforms in many global markets have led to public regulatory rollbacks. Against this backdrop, markets have developed and firms have sought to differentiate their products in ways that do not rely exclusively on state regulation, perhaps reflecting a new emerging economic order . Capitalist market development under this framework can focus on product differentiation through “a turn to quality”, in which products are marketed based on qualities such as environmentally friendly production practices, high food safety assurances, or other attributes verified by non-state certifiers . The result of these changes has been described as a shift from government to governance , in which states retain a degree of basic rulemaking authority and supervisory control, but private systems of certification hold much of the responsibility for defining controls and ensuring compliance.

In the current study, the majority of Enterococcus spp. isolates that were susceptible to macrolides were found in hospital cows, similar to previous work demonstrating that Enterococcus resistance to macrolides was found in isolates from clinical animals. Moreover, all MDR Enterococcus isolates were from hospital and fresh cows, indicating that macrolide resistance genes might originate from hospital cows that are being treated for a variety of medical conditions and then spread to fresh cows. Among Enterococcus isolates, a negative association was noted between the occurrence of tetracycline and macrolide genes, indicating that the presence of the tetracycline resistance genes was associated with a reduced risk of simultaneously finding the macrolide resistance gene in these fecal bacteria. This finding is interesting given the previous observation that resistance to tetracycline and macrolide–lincosamide–streptogramin group was observed through transposable elements. In dairy production, lincosamide is used to treat mastitis in conventional farms; however, lincosamide resistance genes were found in hutch calves based on the CARD database. This may indicate the transfer of resistance genes along the production line and calves can acquire resistance genes at this early age. Similarly, it was reported that calves at 1–2 weeks of age acquired tetracycline-resistant genes, likely due to colonization with resistant bacteria from their mothers and/or the dairy farm environment, greenhouse rolling benches given the ubiquity of manure. According to genes identified from the CARD database, resistance to ≥3 antimicrobial classes genes was commonly observed among E. coli and Enterococcus spp.

No significant links between resistance to tetracycline and fluoroquinolone were observed in this study, which may be due to the mechanism of resistance to fluoroquinolone being frequently related to chromosomal mutations, while the mechanism of resistance to tetracycline can occur due to genetic mobility.For this study, we identified genes by evaluating two publicly available databases in E. coli—namely, sulphonamide, trimethoprim, and beta-lactamase resistance genes from ResFinder, and tetracycline and aminoglycoside resistance genes from both ResFinder and CARD. These resistance genotypes were in concordance with resistance phenotypes we characterized previously. For Enterococcus spp., high levels of agreement between resistance genotypes and phenotypes were only found for tetracycline resistance genes from the ResFinder . Similarly, a previous study observed a lower concordance between phenotypes and genotypes of streptomycin in Salmonella isolates. In contrast, high correlations between the presence of resistance genotypes and observed phenotypes have been reported in nontyphoidal Salmonella from retail meat specimens and human cases. Another study reported 67.9–100% concordance between resistance phenotypes and genotypes and 98.0–99.6% concordance between susceptible phenotypes and genotypes in Campylobacter from retail poultry. Although relatively few studies have been performed on Gram-positive organisms using WGS to study AMR, a high correlation between resistance genotypes and phenotypes in Enterococcus isolates was reported. The lower correlations between resistance genotypes and phenotypes of Enterococcus in the current study could be due to the small numbers of bacterial isolates tested, availability of drugs for antimicrobial susceptibility test in the commercial kits, and a different method used to analyze correlations between genotypes and phenotypes. In addition, the lower correlations also could be due to discrepancies between genotype and phenotype resistance that vary with bacterial species and antimicrobials.

Therefore, a combination of genotypes for resistance prediction with phenotypes determined by antimicrobial susceptibility would provide a more accurate assessment of resistance of different bacterial species from different samples and against different antimicrobials. Results of genotypes in the current work and phenotypes in our previous work on the same bacterial strains allowed us to better understand the resistance of E. coli and Enterococcus spp. on dairy farms.Based on phylogenetic analysis of resistance genes in E. coli detected from the ResFinder database, a quarter of the isolates that were in cluster 2A were from hutch calves. Phylogenetic analysis of resistance genes of Enterococcus detected from ResFinder also indicated a unique cluster of MDR genes mainly from hutch calves . Similarly, phylogenetic analysis of genes detected from the CARD database found distinct clusters of genes in E. coli and Enterococcus from hutch calves. Therefore, these results indicate that bacteria from hutch calves had AMR characteristics that were distinct from isolates from cattle at other stages of dairy production. Most E. coli isolates from hutch calves were MDR to aminoglycoside, phenicol, sulphonamide, and tetracycline, which is consistent with other studies in that E. coli from calves were frequently resistant to multiple antimicrobials. For example, MDR bacteria were very common from integrated veal calves. A review article indicated that young dairy calves often carry high levels of AMR in their fecal E. coli and Salmonella enterica, which could provide a potential reservoir of AMR genes for the greater dairy farm environment depending on how calf manure is managed or mixed into the general manure stream on the dairy. Our results, in addition to these prior studies and reviews, suggest that monitoring of MDR bacteria in hutch calves may be important for reducing the spread of AMR bacterial genes to other production stages in dairy farm settings. On the other hand, heat maps and phylogenetic analyses indicated a wide distribution of multiple resistance genes among multiple adult cattle production stages for fecal E. coli based on the CARD database . Given that one adult dairy cow can produce in excess of 20 to 30 kg of feces a day, conventional dairy herd sizes in California often exceed 1000 adult cows, and the concentration of fecal E. coli in dairy manure typically exceeds 106 cfu/g , one can expect that MDR fecal bacteria are widely distributed throughout the greater dairy farm environment and likely in relatively high concentrations. A previous study reported that AMR gene profiles varied between farms and different types of samples but a greater proportion of genes were common to all types of samples, suggesting horizontal transfer of common resistance genes among production stages. Samples in this study were collected within one farm at one point in time, and the sample size from each production stage was small due to the cost of WGS and available funding; these constraints may limit the representativeness of our results. However, our study warrants further investigation of the relationship between AMR clusters in different cattle groups and different types of farm sample matrices to support the effort to better control the spread of AMR within modern conventional dairy farms.In our previous work, we characterized the antimicrobial resistance phenotypes of E. coli and Enterococcus spp. from cattle at different production stages on a commercial dairy farm in Central California, USA. Briefly, using convenient sampling, fecal samples were collected from the rectum of dairy cattle at twelve different production stages on a commercial farm in the San Joaquin Valley, the major dairy production region of California.The antimicrobial susceptibility of E. coli and Enterococcus strains was determined by minimum inhibition concentrations of tested antimicrobials using a microbroth dilution method. Antimicrobials tested for E. coli were cefoxitin, azithromycin, chloramphenicol, tetracycline, ceftriaxone, amoxicillin/clavulanic acid, ciprofloxacin, gentamycin, nalidixic acid, ceftiofur, sulfisoxazole, trimethoprim–sulfamethoxazole, ampicillin, and streptomycin. Antimicrobials tested for Enterococcus were tigecycline, tetracycline, chloramphenicol, daptomycin, streptomycin, tylosin tartrate, quinupristin/dalfopristin, linezolid, nitrofurantoin, penicillin, kanamycin, erythromycin, ciprofloxacin, vancomycin, lincomycin, and gentamycin. Resistance phenotypes of E. coli and Enterococcus from the previous work were used for the analysis of associations with genotypes in the current work. In the current study, greenhouse bench top based on the availability of strains from cattle at different production stages that determined resistance phenotypes in our previous work, 40 strains of E. coli and 49 strains of Enterococcus from our culture collections were selected for genotype characterization using whole-genome sequencing .

Descriptive statistics were used to examine the distribution of AMR and MDR genes in E. coli and Enterococcus detected from the CARD and ResFinder databases. Logistic regression analysis was used to identify the relationship between the presence of various resistance genes. The production stages and bacterial species were also included as independent variables for the regression models. Univariate regression analysis for all independent variables was screened for potential significance, and a p-value threshold of 0.05 was used as an inclusion criterion in the model. Kappa coefficient analysis was used to assess the level of agreement between a bacterial isolate having a specific resistance genotype and also having the corresponding resistant phenotype for the isolates. The resistance genotypes used in the Kappa analysis were the genes detected from the CARD and ResFinder databases, while the resistance phenotypes were determined from our work on the same set of samples published previously . For the Kappa analysis, each bacterial isolates’ phenotypic resistance was compared to its corresponding pattern of resistance genes by classes of antimicrobial drugs. The percentage generated by the Kappa analysis indicated the degree of agreement between a pair of resistance phenotype and genotype class. A Kappa value of 100% indicated perfect agreement, while a Kappa 0% means no agreement between the presence of an AMR genotype class and its associated phenotype and. All statistical analyses were performed using Stata version 14 . A p-value < 0.05 was considered as statistical significance.Absorption and scattering of shortwave solar irradiance in the Earth’s atmosphere is balanced by absorption, emission, and scattering of long wave radiation. This balance between the shortwave radiation and the long wave radiation determines the temperature structure of the atmosphere and local temperature values on Earth’s surface. The SW and LW balance is essential for understanding climate change, but also for the thermal design of radiant cooling systems, cooling towers, solar power plants, and of the built environment in general. Current interest in the optical designs of passive cooling devices that take advantage of atmospheric windows to reject heat to outer space requires detailed balance between the incoming thermal radiation from the atmosphere and the outer space and the outgoing emissive power from the coolers in order to calculate the equilibrium temperatures and cooling efficiencies. These figures of merit depend on the local atmospheric conditions, which include the convective environment around the device and the downwelling radiative flux from the atmosphere. The convective contribution can be minimized by design, but the thermal radiation from the atmosphere is geometrically constrained by the ability of passive cooling devices to radiate directly to outer space. Absorption bands of water vapor dominate the absorption and emission of infrared radiation in the atmosphere when conditions are wet . When the relative humidity is low,other contributors such as CO2 and aerosols contribute in a non-negligible way through specific bands of the spectrum to the overall thermal balance of the passive cooling devices. Therefore, a detailed spectral model for the long wave radiative transfer in the atmosphere is in need to calculate the thermal balances of such optically selective devices. Two distinct solar power technologies have emerged as most competitive in the renewable energy market of utility scale solar plants: direct photovoltaic conversion and concentrated solar power using heliostat fields to direct solar radiation to a central boiler. In addition to greenhouse gas emission offset, large scale solar farms also interact with the atmosphere through surface albedo replacement. While both PV and CSP technologies affect the local environment, the extent in which they do so has not been studied in detail. Thus a spectrally resolved shortwave radiative model is needed to quantitatively evaluate the effects of albedo replacement on the local shortwave radiative exchange between the ground and the atmosphere. Therefore, to better understand the thermal balances of the Earth-atmosphere system, passive cooling devices and solar power farms, the objective of this research is to develop detailed radiative model to simulate the shortwave solar and long wave atmospheric radiative transfer in the atmosphere, with and without the presence of clouds. The model is validated against ground measurements and other radiative models for varies meteorological conditions. By comparing the modeling results with ground telemetry, representative cloud characteristics for given surface conditions are proposed. Thus a complete spectral model is presented that allows for determination of long wave and shortwave irradiance and can be used for a wide range of meteorological conditions. With the developed radiative model, the albedo replacement effects of large scale PV and CSP farms can be qualified for varies conditions. In addition, the model also serves as a valuable tool to analysis the contribution of each atmospheric constituent to the thermal balance of the Earth-atmosphere system, for seven critical bands of the infrared spectrum. Furthermore, the determination of thermal equilibrium temperatures for radiative cooling devices, also requires knowledge of the spectral atmospheric solar and long wave radiation.

Key practices such as no-till farming, optimal use of biomass , groundwater recharge, and substitution of chemical inputs for natural processes require further place-based research in order to develop and disseminate “best practices” for large scale operations through farmer-to-farmer and extension networks.Inspired by Dr. Timothy Wise’s book Eating Tomorrow: Agribusiness, Family Farmers, and the Battle for the Future of Food and Dr. Molly Anderson’s recent paper “The importance of vision in food system transformation,” I aim to contribute to building and implementing a shared vision for tomorrow’s food system, one that is climate mitigating, ecologically restorative, land based, and empowering of small farmers and historically marginalized groups in food system politics. A vision “is a beginning for transformation, but it requires policy that enables it to be enacted, ideally through democratic processes. The vision, buttressed by policy and democratic governance, is what determines where people are able to buy food, how much they pay, whether farmers earn decent incomes, and whether the food is healthy” . Lopez Island food system actors have made incremental progress articulating a vision since 1989, starting with the mission statement of the Lopez Community Land Trust. The East Bay region of the San Francisco Bay Area is building a vision for increasing food security via urban agriculture through the work of Food Policy Councils in Berkeley, Richmond, and Oakland. Small farms in both Washington and California are starting to put forth a vision for how regenerative agriculture and farm-based education can aid in the battle against climate change. Bringing these visions together under the polycentric governance model, hydroponic shelf system policy recommendations must be targeted at the appropriate level: county governance for zoning code updates and land use designations, state governance for climate and environmental education standards and funding, and national level policy to revamp the Farm Bill into an incentive package for smaller-scale, regenerative, relocalized agricultural operations.

Building off of the body of research presented in this dissertation, one of my future goals is to establish a Climate Farm School, where young people can come to a demonstration farm and deepen their understanding of the climate crisis while engaging in climate solutions through producing food. The purpose would be threefold: 1) establish a demonstration farm that models climate friendly agricultural practices while producing and distributing food, 2) educate young people and aspiring farmers how to implement and improve climate friendly practices, and 3) engage with local universities in research projects to explore and scale agricultural climate change mitigation/adaptation. My vision is that this farm school could arise through partnership with an existing farm, or through the right opportunity of land acquisition and fundraising.While I seek to engage first with the youth education sector, I can imagine a parallel “Climate Farm School” for policymakers to better understand and connect with climate-friendly farming operations in their areas of jurisdiction to inform and direct their policy proposals. Bringing young people and policymakers into the sustainable food system transition process is a critical step for food system researchers to take in order to realize positive change. Dendritic wetland designs, which consist of a sinuous network of water-filled channels and small, vegetated uplands, can help reduce water turbulence associated with high winds .Vegetative cover has been shown to decrease sediment re-suspension. For example, Braskerud found that an increase in vegetative cover from less than 20 percent up to 50 percent reduced the rate of sediment re-suspension from 40 percent down to near zero. Wetland depth may also have an indirect effect on sediment retention.

The water should be deep enough to mitigate the effect of wind velocity on the underlying soil surface, but if the water is too deep, vegetation will not be able to establish and a significant increase in re-suspension of sediment will result. Water depths between 10 and 20 inches optimize conditions for plant establishment, decreased water velocity, well-anchored soil, and a short distance for particles to fall before they can settle . An excess of vegetation can significantly reduce a wetland’s capacity to retain E. coli. Maximum removal of E. coli occurs under high solar radiation and high temperature conditions , and vegetation provides shading that can greatly reduce both UV radiation and water temperatures. While vegetation can provide favorable attachment sites for E. coli, a dense foliage canopy can hinder the free exchange of oxygen between the wetland and the atmosphere. This vegetation induced barrier to free exchange of oxygen limits dissolved oxygen levels, and that in turn reduces predaceous zooplankton, further decreasing removal of microbial pathogens from the wetland environment . Vegetation plays an important role in filtering contaminants in wetlands. The plants’ uptake of pollutants, including metals and nutrients, is an important mechanism, but is not really considered a removal mechanism unless the vegetation is harvested and physically removed from the wetland. Wetland vegetation also increases the surface area of the substrate for microbial attachment and the biofilm communities that are responsible for many contaminant transformation processes. Shading from vegetation also helps reduce algae growth. However, certain types of vegetation can attract wildlife such as migrating waterfowl, which may then become a source of additional pathogens. Vegetation that serves as a food source or as roosting or nesting habitat for waterfowl may need to be reduced in some settings. Among other important considerations for vegetation coverage in wetlands, one must include total biomass and depth features.

Vegetation should provide enough biomass for nutrient uptake and adsorptive surface area purposes, but must also be managed to allow sufficient light penetration to enable natural photo degradative processes and prevent accumulation of excessive plant residues, which would prevent the export of dissolved organic carbon. One way to promote this balance is to create areas of deeper water intermixed with the shallower areas. Plants will establish more readily in the shallow areas and less so where the water is deeper. In an agricultural setting, it may be hard to establish plantings of native species within wetlands due to the large seed bank of exotic species that may be present in input waters . You can also manage the type and amount of vegetation by manipulating the timing and duration of periods of standing water in the system. In extreme instances, you can actually harvest excess biomass.In addition to managing vegetation and water depth to maximize sedimentation and pathogen photo degradation, cannabis drying racks commercial growers can also manipulate hydrology to maximize the removal of microbial pollutants in wetlands. The importance of hydrologic residence time is apparent when you recognize that a longer HRT increases the exposure of bacteria to any removal processes such as sedimentation, adsorption, predation, impact of toxins from microorganisms or plants, and degradation by UV radiation . E. coli concentrations have been shown to increase in runoff from irrigated pastureland when the volume of runoff is increased . High runoff rates increase the mobility of contaminants from fields and decrease the HRT within the wetland, thus reducing the opportunity for filtering pathogens. Despite variations in several characteristics among the four flow-through wetlands in the case study described earlier, HRT wasa consistently good predictor of E. coli removal efficiency. Mean removal efficiency was 69, 79, 82, and 95 percent for wetlands having mean HRTs of 0.9, 1.6, 2.5, and 11.6 days, respectively . Remarkably, an HRT of less than a day can allow for considerable E. coli retention , which means that a relatively small wetland area can treat runoff from a relatively large agricultural area. The relationship between removal and HRT was not so clear for enterococci . In this case, W-1, with an HRT of 2.5 days, demonstrated a lower removal rate than W-2 or W-3, which had HRTs of 0.9 and 1.6 days, respectively . As discussed above, there are many parameters that can influence the environmental fate of pathogens in wetlands, including vegetation density, design, age, size, contributing area, and depth. A number of these wetland characteristics can doubtless be altered to increase bacteria removal efficiency. The efficiency with which contaminants can be reduced in agricultural water as it passes through a wetland is largely dependent on the extent to which water is evenly distributed across the wetland area. A wetland’s retention capacity is diminished if its design results in stagnant zones that either reduce the effective treatment area or short-circuit longer flow paths, decreasing the HRT. Efficient wetlands come in a variety of shapes and sizes.

A wetland should be wide enough to allow sufficient trapping of sediment and other particulate materials and long enough to permit sufficient residence time for nutrient removal. Most researchers agree that the surface area of a wetland should be as large as possible in order to maximize its HRT and storage capacity. The even dispersion of water across the wetland, termed hydraulic efficiency, is largely defined by the wetland’s dimensions and the relative locations of input and output channels. High hydraulic efficiency maximizes the removal of contaminants. Designs with good hydraulic efficiency have a shape that facilitates complete mixing throughout the wetland without the persistence of stagnant zones, or may incorporate barriers that achieve the same effects . All designs with good hydraulic efficiency have their input and output channels positioned on opposite ends of the wetland.The sediment trap is an important design feature in settings where the input water has a high level of suspended solids . Sediment traps are essentially small swales or ponds positioned between the source of the agricultural water and the main wetland to promote the settling of coarse particles before the water is distributed across the wetland. Sediment traps should be located in easily accessible areas where sediment can conveniently be removed on a regular basis. Incorporation of sediment traps in your design will decrease the amount of sedimentation within the wetland, lengthening the time you can go between dredgings. They also prevent the burial of germinating seedlings in the wetland and help limit channelization and short circuiting of flow paths.The amount of microbial pollutants in wetland soils is significantly higher than in the standing water. Bacteria survive longer in soil than in water . Fecal coliforms can persist in sediments for as long as 6 weeks , so the degree to which sediments are deposited in a wetland has a significant effect on the degree to which bacteria are exported in effluent waters, post-wetland. The survival time for pathogens varies widely in agricultural settings, probably as a result of local differences in environmental conditions . If conditions are conducive to pathogen survival, any of a number of wetland conditions that cause the re-suspension and entrainment of sediment—e.g., high water flow pulses into wetlands, wave action, or channelization—may lead to the release of waters that contain microbial pollutants. If you manage wetlands to allow for alternating episodes of flooding and drying, you may be able to decrease the survival of microbes in the wetland soil. In addition to desiccation associated with episodes of dry wetland soil, fluctuations in wetted surface area and depth can facilitate a diversity of biological and bio-geochemical conditions that optimize wetland function and minimize the duration of pathogen survival .There are two general options to reduce non-point source pollution from agriculture: on-site farm management practices that control the pollution source or limit the application of excess materials and their subsequent loss from farmlands, and off-site practices that intercept non-point source pollutants before they reach downstream waters. Wetlands can be used within a farm scape as either an on-site farm practice or an off-site tool, where downstream flood plains are converted to wetlands to mitigate pollution at the watershed scale. In settings where the attraction of wildlife is of concern, you may want to consider placing the wetland off-site, but at a place where it will intercept the runoff before it enters a natural water body. This may also require re-routing of the agricultural runoff into an off-site wetland.Johne’s disease is a chronic, infectious gastrointestinal disease of domestic and wild ruminants , caused by Mycobacterium avium subsp. paratuberculosis . Johne’s disease is a global disease, which was first observed in dairy cows in 1895. Environmental viability studies found that MAP can survive for 8 months in feces at ambient conditions and for 19 months in water at 38 degrees of centigrade. MAP remains viable in a desiccated state for up to 47 months.

At the same time, in exploring the radical democratic politics of groups like Food-Not-Bombs, Heynen describes the kind of anarchist philosophy of mutual aid and cooperativism through food sharing that we see in the East Bay agroecosystem. Farms are not just distributing food to the hungry in hidden basements or exploiting free labor, but engaging in highly visible work, inviting those who visit or consume farm outputs to work, cook, learn, teach, share and get political. The reality is that growing food in cities has particular challenges, increasing the costs of farming on top of issues already outlined regarding the cost of land and labor . We find that the importance of donated money and time to further the anti-hunger and advocacy efforts of farms is not counter to the transformational goals of AE broadly or UAE in particular. In this way, we seek to nuance the premise that volunteer labor is universally problematic and counter-productive to radical food system reform efforts, aligning instead with some urban agroecological scholarship that argues for improved work-life balance through living wage jobs that afford more people opportunities to pursue hobbies and interests and volunteer their time supporting community efforts that align with their values . Pimbert outlines three dimensions of urban agroecological transformation that are needed, including economic, indoor vertical garden system with new forms of organization and relocalized wealth production as well as “creation of free time for citizens to shape and re-govern urban spaces” . Volunteerism has a place in a transformed, equitable, environmentally sustainable local food system, although reliance on it as the primary source of labor is undesirable.

Our findings around labor in particular stand in contrast to the often-referenced benefit of urban agriculture as a job creation tool . At least in the current political economic landscape of the East Bay, urban farms do not generate enough economic revenue or city investment in order to hire many full time positions; this remains a goal of many operations and opportunity for policy intervention, especially with respect to enhancing the resilience of urban agroecosystems to economic disturbance.Farms in our case study display a strong focus on reducing hunger and promoting food equity, namely through culturally appropriate diets, and the emphasis on human and social values. Due to the plethora of produce going home with volunteers, circulating at neighborhood crop swaps, and gleaned or harvested by community members that is not weighed and tracked before it is consumed, it is understandably difficult to quantify the “food security” impacts of urban agriculture . While food security may be difficult to quantify, it is nevertheless being addressed by urban farms in unique ways . In school gardens, for example, produce that is not used for classroom cooking demonstrations sometimes goes home with students or families excited to find culturally relevant crops growing in their neighborhood. Supporting healthy, diversified and culturally appropriate diets are an important element of agroecology. The diversity and quality of produce grown, especially when it is an item that might not otherwise be available to a family in a “food desert,” contribute greatly to the value produced on urban farms. One farmer interviewed described how one school garden site serves students from Hispanic, African American, Middle Eastern, Asian, and Eastern European families. The garden teacher spoke about the diversity of crops relevant to various cultural food traditions; for example, the chayote plants were of particular interest to Latinx students excited to bring them home to their mothers, while African American students eagerly collected bunches of collards, and Middle Eastern mothers came to the garden in person to collect fava beans and figs. In this way, urban agroecology contributes to food security and nutrition as well as biodiversity.

It also serves to reaffirm cultural identity and a sense of place for immigrant and refugee families. Agroecology places a strong emphasis on human and social values, such as dignity, equity, inclusion and justice contributing to improved livelihoods of [urban] communities . Our study demonstrated that the majority of farm respondents placed food security, education, and environmental sustainability above profit, sales and yield. Forty percent of respondents self-identified as “Educational” farms, and most others offer educational workshops and demonstrations as part of their focus on horizontal knowledge-sharing. The majority of our study respondents were also women. As a grassroots movement, urban agroecology can empower women to become their own agents of change.Our results suggest the opportunity to reconceptualize and refocus the urban food policy discussion in U.S. cities around urban agriculture in a way that includes and values their social, educational, and cultural services. Urban farms are recreational and cultural heritage sites bearing comparison to public parks and museums, while also producing invaluable healthy food in areas that most need it. They provide important respite, social connection, and stress reduction to urban residents, often particularly in need of peaceful spaces. In the words of one farmer, “Urban farms can be havens of peace, health, and community, but it requires heavy involvement and advocacy from those communities for the long term in order to be successful” . Agroecology calls for responsible and effective governance to support the transition to just, equitable and sustainable food and farming systems. In an urban environment, this requires the creation of enabling policies that ensure equitable land access and producer control over access to land, especially among the more vulnerable and historically marginalized populations.

Land access is expressed most frequently as an obstacle to scaling urban food production by survey respondents, and it is certainly more of a challenge for lower-income and minority groups interested in cultivating their own “commons” . There are examples among our East Bay survey respondents of collective governance at the farm and community level, such as one farm site which is owned cooperatively by three non-profit organizations that collectively serve minority and formerly incarcerated populations, aspiring beginning farmers, and the local community through a cooperative goat dairy, fruit tree nursery, and annual vegetable production plots. City and county governance bodies have an opportunity to strengthen the resilience of urban agriculture operations and opportunities for farmer collaboration by providing subsidies and incentives for social and ecosystem services. City-level efforts to compensate or recognize farmers for ecosystem services such as soil remediation and carbon sequestration, for example, are not yet realized. Further examples of responsible governance from our data include recommendations for public procurement programs to source food from aggregated urban produce . Our respondents are engaged in circular and solidarity economies, key features of agroecology, including bartering, sharing, and exchanging resources and produce with those in their social networks. They are also interested in collaborating in a localized effort to strengthen the link between producers and consumers by aggregating produce and sharing distribution . As cities work to fulfill their role in providing basic services to citizens, farmers are pointing out an important opportunity to provide refrigerated transportation, storage, and organizational infrastructure to transfer all possible produce grown on urban farms to the best distribution sites. Communication platforms, transport systems, and streamlined procurement in this arena following from other regional “food hub” models could improve the landscape for urban food distribution dramatically . All urban farm respondents are also engaged in closed-loop waste cycles: through composting all farm waste onsite and collecting food scraps from local businesses, farms are involved in a process of regeneration, clone rack from food debris to soil. The activities of urban farms fall naturally under definitions and descriptions of agroecology. Through extending the UAE framework from farms to urban policy and planning conversations, more efficient pathways for addressing food insecurity in part through strategic centers of urban production and distribution can emerge in cities of the East Bay and elsewhere in the United States. Finally, agroecology relies on the co-creation and sharing of knowledge. Top-down models of food system transformation have had little success. Urban planners have an opportunity to address food insecurity and other urban food system challenges including production, consumption, waste management and recycling by co-creating solutions with urban farmers through participatory processes and investing in community-led solutions. In our systematic review of the literature on whether urban agriculture improves urban food security, we found three key factors mediating the effect of UA on food security: the economic realities of achieving an economically viable urban farm, the role of city policy and planning, and the importance of civic engagement in the urban food system . A radical transformation toward a more equitable, sustainable and just urban food system will require more responsible governance and investment in UA as a public good, that is driven by active community engagement and advocacy.

We believe that urban agroecology principles provide an effective framework to capture the multiple ecological, social, economic and political dimensions of urban farming, beyond yield and profits, enabling those seeking transformative food systems change in the U.S. in the U.S. a common language and opportunity to measure and communicate more clearly the multiple benefits worthy of public investment. Framing this work as urban agroecology values the knowledge creation, community building, and human well-being that are also products of urban food initiatives. Our data illustrates how urban food sites are spaces of vibrant civic engagement and food literacy development yet remain undervalued by city planners and under constant threat of conversion as well as pressures of gentrification. With the majority of operations in our study functioning as non-profits, it is questionable whether many urban farms would actually be considered a true “agricultural” operation per the USDA definition as a majority of farms earn less than $1,000 in sales annually. As such, they are largely ineligible to apply for funding or loans from many of the federal and state agencies or granting programs such as the Farm Service Agency or NRCS. The idea that the UAE framework can illuminate multiple and often hidden sociopolitical dimensions of urban food production sites is powerful. For example, over 75% of urban farming sites in our study came into being for a multitude of reasons: including re-establishing justice and dignity into historically neglected and marginalized urban communities, fighting poverty, resisting the environmentally extractive, exploitative, racist, and obesity-inducing industrial farming system, reclaiming the ability to be self-sufficient and work with your hands, and re-educating society about the physical and emotional value of cultivating the Earth. Urban farmers aspire to many things: affirming a human right to healthy food, a food literate civil society, land tenure arrangements that favor socially beneficial rather than profit-maximizing land uses, and alternative forms of exchange and value creation outside the capitalist political economy. The term “agroecology” locates these values in a historical network of similar efforts to transform the global food system along socially just and ecologically resilient lines.Reframing UA through the lens of UAE can ultimately help U.S. policy makers and city planners better understand and support urban agroecological endeavors, and provide researchers, urban citizens and urban food producers a more inclusive mode of inquiry that can lead to transformative food system change, taking care not to dismantle, invalidate, or eliminate the revolutionary, anti-oppression elements through overly prescriptive “policy solutions.” When it comes to researching, documenting, and advancing transitions to sustainable food systems through agroecology, the urban context is an important one to consider, given the growing percentage of the global population living in cities. We acknowledge Gliessman’s call for applications of his “5 levels of food systems change,” showing in our data how East Bay urban farmers are endeavoring to scale up to Level 5: “build a new global food system, based on equity, participation, democracy, and justice, that is not only sustainable but helps restore and protect earth’s life support systems upon which we all depend” . We encourage future engaged scholarship in the U.S. that employs a UAE framework to ask and answer important remaining questions about the transition to sustainable food systems, in partnership with urban farmers, around valuation, preservation, and connectivity of diversified food production sites in the modern city.As a whole, the Lowell middle school demonstrated much higher levels of knowledge and engagement around climate change than the average American teenager or adult. Based on a 2010 nationally representative survey of American teenagers, knowledge of climate science basicfacts was found to be very low . 59% of American adults fall into the “Alarmed” or “Concerned” categories of the YPCCC Six Americas spectrum as of December 2018 compared to 82% of Lowell middle school students.

Supermarket access studies demonstrate mixed results on whether providing a supermarket alone is sufficient to resolve problems of “food deserts”; in fact, supermarkets can contribute to displacement through “supermarket greenlining” . Critical scholarship in the food desert literature finds that revealing food access inequities “often leads to a public response that focuses on only food stores themselves [or creation of new sites for market transactions], rather than a broader focus upon the inequities in economic investment, political and economic power, and health that the food desert issue highlights” .Farmers markets as distribution sites receive critical assessments in the literature for their ability to serve as distribution channels to low-income consumers. Alison Hope Alkon writes about the closing of a farmers’ market in West Oakland, a historically African American neighborhood, juxtaposed with the white spaces of farmers markets that are thriving in neighboring Berkeley in her book Black, White and Green: Farmers Markets, Race and the Green Economy . She theorizes the promise and limitations of the “green economy” and chronicles the food movement’s anti-capitalist roots yet ultimate manifestation as reproducing capitalist inequalities. Lucan et al.’s study of farmers markets in the Bronx took issue with limited hours of operation, seasonality, affordable common produce, and availability of predominantly healthy foods among farmers markets compared to nearby stores . Accepting Electronic Benefit Transfer payments is a basic prerequisite for farmers markets to be considered accessible to low-income consumers, a concept pioneered by the GrowNYC’s Greenmarket program . While farmers markets in all 50 states now accept food stamps , indoor farming systems the price of offerings such as a bunch of kale still exceeds the price of nearby fast food options that may offer a more filling but less nutritious meal option.

Some states are moving in the direction of matching EBT funds through various “market match” policies, a step towards improving food distribution and access at farmers markets .The concept of a foodshed in the distribution literature, “like its analogue the watershed, can serve as a conceptual and methodological unit of analysis that provides a frame for action” . Foodshed analysis “provides a way to assess the capacity of regions to feed themselves” through proximate location of food production, distribution and consumption . Applying this concept, Peters et al. found that 34% of New York State’s total food needs could be met within an average distance of 49 miles, . The foodshed, embedded in the local food systems and short food supply chain concepts, is a useful organizing principle for city planners to consider when designing effective food distribution networks, such as the example highlighted in integrating a farm into a housing development project in the South under the title of a “civic agriculture community,” facilitating proximate, affordable distribution channels. This exemplifies planning with a foodshed lens by specifying areas at the neighborhood scale for semi-commercial agriculture, neighborhood CSA, residential kitchen gardens, and residential development in order to build food access and ease of distribution into the neighborhood fabric. If urban farmers aren’t able to easily distribute their produce to consumers, either through sales or other forms of distribution, questions of improving food access are jeopardized as well, revealing the interconnectedness of the food systems framework from production to distribution to consumption. Planning for improved urban food distribution includes ideas such as food hubs, agri-hood developments, public storage and transportation options, food aggregating facilities or organizations, mobile food distribution, or state investment in public markets . Mobile food distribution options are modeled and shown to increase access in Buffalo, NY, in Widener et al.’s theoretical analysis . Agri-hoods have gained increasing mention in local news outlets as a real estate trend in “Development Supported Agriculture , and as many as 200 currently exist or are under construction across the country” .

They facilitate distribution by colocating food producers and consumers on strategically planned sites, providing shared infrastructure resources, and making land access affordable for farmers by cross-subsidizing with real estate development. Cooper’s report on food hubs in the south, a form of aggregating supply to enable expanded market access, highlights grassroots solutions developed by and for farmers of color, yet “major challenges [remain] associated with developing and maintaining food hubs within a racial equity framework” . Here again, the Google Alerts provide useful insights from gray literature and local news outlets into recent and effective strategies for city planners, be it food hubs, mobile food distribution options, online platforms for gleaning, second harvest, crop swaps, or distributing excess produce from backyard gardens. These are also areas that stand to benefit from additional scholarly research in terms of quantifying impact on consumption, food insecurity, and nutrition, expanding evaluations of urban food systems to include nonmonetary and informal distribution mechanisms. Integrating the access and distribution literature from above, we identified three themes that speak to the efficacy of urban agriculture in meeting food access goals: economic viability, policy and planning models, and civic engagement.In this section, we consider the economics of urban agriculture and the “economic marginalization” that prevents many operations from meeting all the social and environmental benefits of urban agriculture within a for-profit or capitalist-oriented production scheme. The urban food justice and food sovereignty movements in the U.S. are limited inpractice in achieving their more radical or transformative goals due to the fact that they are operating within “a broader framework of [capitalist] market neoliberalism” . The challenge has not been growing enough food per se, but rather “producing and distributing food in ways accessible and affordable for the growing urban poor” while sustaining UA operations in a capitalist, production- and profit-oriented society. Daftary-Steel, Herrera and Porter declare that an urban farm cannot simultaneously provide jobs to vulnerable individuals, provide healthy food to low-income households and generate sustainable income and/or profits from sales. Therefore, what forms of urban agriculture are economically viable in today’s political economy? Operations that provide jobs, job training and professional development but sell mostly to high-end consumers , operations that are volunteer-driven or publicly funded and operations that cross-subsidize healthy food donations with revenues generated from other services besides food production or from crowd-sourced funding . When it comes to economic viability, many urban farming operations openly acknowledge that they are dependent on grants and donations to sustain their operations, which is a double edged sword. On the one hand, as long as an organization can prove itself worthy in receiving grants and donations, it may represent economic viability and longterm sustainability.

On the other, if the organization is wrapped up in a charismatic individual leader or fails to receive ongoing grant injections beyond one or two initial successes, it will not achieve long-term economic viability. Examples include redistributive business models, barter and exchange networks, food aggregators, food recovery organizations, cooperatives, food hubs, and “agrihoods” . Food hubs are reframed as both tools for provision of market access and self-determination for black farm cooperatives in the South in Cooper’s report with potential to subvert historic racism and economic marginalization of black farmers. Key to this and other food policy reports in the gray literature is elevating voices and fostering dialogue led by communities of color.While food, vertical farming equipment suppliers and urban agriculture, used to be “strangers to the planning field” or “puzzling omissions” from American Planning Association resources prior to the early 2000s , there has been an increase in academic work in the past 10 years dealing with urban food systems planning. In this section we consider the policy landscape of various city and state efforts to incentivize and create space for urban agriculture. Policy is needed to lower costs for low income consumers and urban farmers seeking land, provide strategic location of distribution sites, and encourage year-round produce supply, often enabled by greenhouse systems in urban farms. Are current policy incentives enough to create expanded food access and community food security from urban farms? Horst et al. would argue no; rather, an explicit commitment to food justice and an “equity lens” is needed for policymakers and planners to create UA spaces that benefit low income and minority communities equally if not more than already advantaged groups. Due to the current landscape of “disparities in representation, leadership and funding,and insecure land tenure,” unless these problems are explicitly addressed, “even the most well intentioned initiatives will perpetuate or even reinforce the injustices that practitioners and supporters aim to address” . This sentiment is echoed in Morales’ chapter in Cultivating Food Justice, which calls for “applied research to discover and advance policy objectives related to the antiracist and economic objectives espoused by the Growing Food and Justice Initiative” . This suggests that only by foregrounding issues of race and economic inequality can cities create UA spaces that address food insecurity. In asking the question “Can cities become self-reliant in food?” Grewal and Grewal find that, in a best-case scenario, the City of Cleveland can achieve almost 100% self-reliance in fresh produce needs, poultry and eggs, and honey, but only with huge amounts of planning support . Blum-evitts puts forth a foodshed assessment tool to allow planners to assess local farm capacity in relation to local food needs . Theoretical work such as this is important to advance ideas of what is possible and motivate efforts to make change, although it must constantly stay in dialogue with what is happening in practice and expand beyond a productivist focus on local food systems. Urban farms are, after all, producing a lot more than food, and “increasing food production in cities does not guarantee that people experiencing food insecurity will access that food” . UA is re-valued along a broader spectrum of “products” or outputs in Figure 12 below.Creating urban agriculture incentive zones is one possible approach to policy and planning, likely to benefit the propertied class via tax breaks . Policies such as California’s AB 551, the Urban Agriculture Incentive Zone act, have come under criticism for not going far enough to build a just food system, relying on private rather than public spaces to support UA. It is unclear whether incentive zones will be widely adopted by cities and counties in California, and whether they will meaningfully address food access or food sovereignty, especially when the length of time required to devote a piece of land to urban agriculture is only 5 years. In cases where tax incentives are used to promote urban agriculture, primary beneficiaries of the policy are often the privileged class of property owners rather than low-income households or non-property-owning urban farmers. Cities with some sort of food policy regulating, allowing for or promoting urban agriculture include the City of Baltimore , City of Somerville, Detroit, Portland, Madison, Seattle, San Francisco, San Jose, Los Angeles, San Diego, Austin, Minneapolis, New Orleans,Milwaukee, Boston, and Chicago12. Many policies allow for commercial sales of urban-produced food within the city as “approved sources” ; allow for value-added processing and sale of urban produced foods in people’s home kitchens ; create tax incentives for property owners to convert land into urban farms ; amend zoning regulations ; or set up urban beekeeping pilot projects . The Baltimore example is especially noteworthy for its long-term planning approach to structuring urban agriculture into the landscape of the city, with considerations for equity in place. However, legalizing the ability to grow food in cities is not enough to promote equity and justice, nor resolve all the legal conundrums related to compliance with the terms of legislation . Creating incentive zones for certain types of UA practices is not the same as creating supportive policies to allow and encourage the existence of the diverse array of practices and practitioners that constitute UA. Especially in cities with growing population and housing pressures , particular attention must be paid in policy making to avoid advancing gentrification and displacement. This is less of a concern in cities without such housing pressures , but development is always a threat that must be considered when siting urban farms on private land. A promising policy direction pioneered by the City of Seattle is to dedicate public lands in low income neighborhoods to UA, which Seattle does through its P-Patch program. Other policy recommendations gleaned from the literature include: creation of a citywide UA task force with citizen representatives; efforts to tie in local “good food” policies with city Climate Action Plans to promote UA and alternative food waste management alongside climate benefits; devote public lands to urban farms and gardens in perpetuity; “retrofit” affordable housing developments with community gardens ; provide public storage, transport, and aggregation options for urban farmers; and convert corner stores into neighborhood groceries offering fresh produce from local farms.

Doug Benoliel and Tamara Buchanan are among the most knowledgeable and skilled people to be producing and distributing diverse vegetables to the Lopez Island food bank . After 25 years of running a successful plant nursery in Kirkland, WA, the couple “retired” to Lopez Island to start their own farm. Doug has a degree in botany from UW and wrote a book titled Northwest Foraging, and Tamara has exemplary culinary skills that she developed through self-guided experience. With a 5-year crop plan in hand, they began diversified vegetable production at Sweetbriar in 2011, cultivating an array of seed varieties for each crop . They hired LCLT interns for several summers and recruited an additional crew of volunteers to help out with farm harvests and multi-person chores weekly, on Fridays throughout the growing season. Produce was sold through a farm stand at the end of the driveway, a CSA subscription, and at the island Farmer’s Market for a few seasons. However, due to personal health conditions and a series of operations, Doug and Tamara had to scale back from production-sales operations. They currently run a scaled-down farm and do not sell any vegetables; all of the harvest is used for self-consumption and processing or delivered to Lopez Fresh and specific families in need . Volunteers still come by several times a month to bring in the harvest and package it for delivery to the food bank and take home vegetables for their families. This donation-based model of farming is supported by the farm owners’ personal wealth from previous careers and life pursuits . It rests on the recognition that many of the island-grown vegetables and specialty products are unaffordable to large sectors of the island population, who work in the tourism industry and do not own land.

Food insecurity in San Juan County is estimated to affect 39% of residents, according to a United Way of the Pacific Northwest ALICE report in 2018. The island food system as a whole is precarious, hydroponic rack system and not equitable, when such large percentages of the population cannot afford to access nutritious, locally produced food. It is unclear how long Doug and Tamara will continue their mission of supplying Lopez Fresh with produce from their farm, as they are in the active process of scaling back and downsizing. Doug has offered up space for gardening on his land to other individuals, but so far no one has taken him up on the offer, for a variety of personal circumstances. Whether other farms will follow suit in donating produce as they exit market-oriented production is an open question, which might require policy incentives and nudges to facilitate a more robust food donation system. The volunteer-based gleaning operation run by the Lopez Island Family Resource Center and the LIFE program8 are two other examples that donate fresh food to low income families. Addressing food security problems with donations of food serves an important interim purpose, but larger policy and economic changes, in the form of increased living wage jobs and affordable housing, are needed to address the root cause .Two of the three farms highlighted in the section above acquired farmland in the first place due to wealth transfers from previous careers or family members. The value proposition of purchasing farmland and paying off debts through limited farm incomes is otherwise extremely difficult and disadvantages low income and minority groups who have been excluded from generational land and wealth accumulation.

There is not yet a “social safety net” in place to enable farming as an equal-opportunity, financially viable or desirable career pathway, in terms of guaranteed income, health care, and time off to support personal wellbeing. This is preventing the easy transition of farmland from current to new farmers and causing hesitancy among young people seeking to make an early career as a farmer in the San Juan Islands, ultimately challenging the sustainability of agriculture on the islands as a “way of life.” In order to avoid a situation where only the wealthy can afford to farm sustainably, policy mechanisms must be put in place to democratize land access. Promoting and facilitating cooperative ownership and buy-in to farmland is something the county has yet to address effectively; it is challenging, and yet a promising action step for enabling successful farmland transition for a more diverse array of new farmers . Opportunities exist on the production side of the Lopez food system in the form of local knowledge accumulated over decades of implementing sustainable and regenerative, agroecological practices, that is ripe for sharing and transferring to new and beginning farmers through mentorship programs or the establishment of a more formalized “farmer training program” on the islands. Additionally, on the land acquisition front, the LCLT long-term affordable lease model piloted with the Stonecrest Farm purchase could lead to other transfers of farmland at low cost to new farmers .On a small island such as Lopez, there are opportunities to share and collaborate on distribution activities especially for complementary products. However, the limited number and size of markets could prohibit entry into a channel that is already dominated by one farmer or food business; therefore, diversifying and coordinating with other farmers is an opportunity to streamline distribution activities.

Opportunities exist for farms growing fruit to partner with and distribute alongside farms growing vegetables, meat or dairy products, which would be expedited by access to enabling infrastructure such as a shared refrigerated truck, aggregated cold storage, and designated food delivery person to transport products from farms to customers and retail locations. Ideally a shared transport system could be optimized to reduce vehicle miles traveled for food distribution, and a transport vehicle could be a hybrid or electric model to meet local goals of carbon emissions reductions in all facets of the food system. Efforts to streamline distribution exist in the form of the proposed San Juan Island Food Hub, which would provide institutional support for aggregating and distributing farm products between islands, improving transparency between producers and food purveyors. According to a 2015 Food Hub Feasibility Study led by the Ag Guild and ARC, there is a strong desire and opportunity for a San Juan County Food Hub to provide an online platform for ordering, aggregated cold storage, and aggregated purchase opportunities that would help meet the unmet demand for local food products in restaurants, grocery stores, and other food businesses9. Most farmers currently do not have the time and capital to transport their produce to other islands but stand to benefit from accessing these additional markets. While food security is a stated goal of the project, it is unclear how increased access and affordability to low income consumers would be accomplished, other than through assumed improvements to local economic development and job creation. A specific plan for meeting the needs of low-income residents in the activities of the food hub would be a valuable improvement to the current planning process. The Lopez Farmer’s Market is an opportunity for farmers willing to participate weekly throughout the summer, as farmer participation has dwindled in recent years and there is interest in attracting more farmers to sell at the market. Finally, rolling tables grow the close-knit Lopez community breeds the trust and interpersonal relationships that facilitate many non-monetary forms of exchange, whereby farmers can trade food products directly for other goods and services they may need from island residents, in mutually beneficial trades that create solidarity and sovereignty from financial institutions. It is challenging to establish a successful CSA distribution on Lopez, requiring farmers to think creatively about how to structure weekly shares in a way that provides products that many residents do not grow for themselves, and accounts for the shorter-term seasonal demand of summer visitors.There are limited retail establishments on Lopez, many of which have outstanding relationships with specific farmers to supply certain goods. This can create a barrier to entry for new producers, who must either provide something that is not already present in the retail environment or establish affordable marketing opportunities off island . The school cafeteria is seeking to procure more locally sourced meat and dairy, providing a retail opportunity for producers of those products. As new restaurants, food trucks, and food businesses come to Lopez , new retail opportunities inevitably present themselves to farmers given the culture of prioritizing local food procurement.

The processing opportunities have been an active area of progress for the past several years, leading to the establishment of two commercial kitchens on the island. One is privately owned and accessible to island growers who sell their products commercially, and another is available for public use. There is a strong community desire to consume local foods year-round, supporting the expansion of the processing and preparation sector, and abundant local knowledge of creative processing techniques that could be taught or shared in community workshops. Additional cold storage is required to allow for local fruits in particular to be consumed six months out of the year, rather than just two. Food safety certification and training is required for all users of commercial kitchens and for the kitchen itself, which is time-consuming and expensive.Waste management is already fairly streamlined on Lopez due to the expense of transporting waste products off the island, and the organization of the award-winning solid waste facility . Current opportunities for improvement include the local biochar production and co-composting effort, as well as maximizing food waste recovery from all island retail stores and restaurants to be returned to local farms for composting. Food recovery from the fields and orchards occurs through a volunteer-run gleaning program, which could be scaled up with further support or participation incentives. A significant challenge for farmers is to reduce all plastic use and substitute with alternative materials, as plastic is no longer accepted at the Dump for recycling and must be paid for at time of disposal.In order to build a climate-themed farmer training program on Lopez, fundraising and/or grant-writing is needed to bring together land and human resources to execute such a program. Hiring a skilled farm-based education and other staff to support educational efforts is a challenge that must be worked out before this opportunity can be realized. Improving upon the K-12 food and climate education efforts at the school is a more easily accomplished opportunity through partnership and participation of more farms and educated adults on the island. Additionally, recognizing that several young people on Lopez are already actively farming and interested in doing so in the future presents an opportunity to strengthen countywide Young Farmer leadership programs in order to expose these aspiring young farmers to new practices and skills needed to create successful farm operations.Using data gathered from interviews and observations of current farmland operations on Lopez and referring back to Ostrom’s ten variables, it becomes clear that farmer self organization to sustain the local food system is very likely . Nevertheless, the propensity for farmers to self-organize does not guarantee that the more complex and overarching political and economic challenges will be resolved through grassroots self-organizing; farmers must integrate and collaborate with other circles of the polycentric governance structure in which they are nested to adopt necessary reforms. The ARC, for example, is a Citizen Advisory Committee tasked with advising the County Council on issues affecting the Agricultural environment comprised of 15 voting seats, at least 50% of which must be farmers. It is currently seeking to advance the goals expressed by farmers for favorable county land use policies through promoting the adoption of an “Agriculture” specific section of the Land Use Element of the Comprehensive Plan, currently under revision. A revaluation and realignment of county policy and political economy are needed to accurately account for and support the endeavors of the Lopez agricultural community. Currently, revenues from sales of local food products comprise roughly 2% of total county revenue . However, farms are contributing so much more to the island economy than sales of food products: they are attracting tourists, educating community members at farm tours, quantifying efforts to sequester carbon on working lands, creating resilience to off island food supply chain disruptions, building community health, and weaving a fabric of community land ethics that infuses the Lopez “sense of place.” Tourists, local residents, and restaurants alike attribute their desire to come to the San Juan Islands in large part to the local food scene and pastoral island character.

Significant to the presentation of results and discussion is the supremacy of private property in the United States legal system. When comparing the Lopez agricultural case study to “idealized” visions of agroecological food systems, many steps towards the “ideal” are thwarted by private property “enclosures” of the agricultural commons, which is more pronounced in the United States than in other geographic contexts. Thus, progress towards visioning and establishing agroecological local food systems must reconcile with unique challenges in the U.S. land tenure system, and ultimately promulgate strategies for loosening the supremacy of private property if real power is to be restored to those growing our food. Through a compilation of fieldwork, ethnographic notes, participant-observation, and immersion into the community, this chapter presents data on the Lopez Island sustainable foodsystem case study, and constructs analysis of food system transformation framed by the paradigm of agroecology . I draw on social science research methods including semi-structured interviews and ethnographic techniques to bring forward ideas and solutions from leaders in the agricultural community of the San Juan Islands. Research partners include the San Juan Island Agricultural Resource Committee , the San Juan Islands Agricultural Guild , the Lopez Community Land Trust , the Lopez Island Farm Education program, Washington State University San Juan County Extension, San Juan Islands Conservation District , Midnight’s Farm, Stonecrest Farm, Sweetbriar Farm, and Lopez Harvest. I find that the Lopez food system transformation towards resilience, sustainability, plant grow trays and equity is a work in progress, requiring political and economic shifts in order for regenerative food production practices to spark regeneration and equity in other branches of the food system.

Significantly, farmland transition barriers and land access challenges3 combined with new and beginning farmer training are areas requiring further investment, investigation, and institutional capacity in order to secure the progress made to date into subsequence generations of sustainable farmers.It is already well established in the agroecology and sustainable food systems literature that the chemical-industrial farming system causes adverse human health, labor, social justice, environmental and climate outcomes . Thus, alternatives to the chemical-industrial farming system are imperative to develop and advance for environmental and social justice reasons. The current dominant food system is driven towards yield-maximizing outputs enabled by increasingly consolidated, mechanized monocultures, which are in turn reliant on a potent mix of chemical fertilizers, pesticides, and fossil fuels. This system functions at the expense of human health, fair labor conditions, equitable food distribution, and environmental preservation. Furthermore, the current food system contributes significantly to the problem of climate change, emitting approximately 25% of the global greenhouse gas emissions portfolio . Conversely, regenerative agroecological food systems have the potential to store more carbon annually in the soil than what is emitted through processes like respiration and plant decay, which at scale could amount to significant global carbon offsets , buying time for theplanet to adopt other necessary technological and social changes to reduce carbon emissions . Agroecological, sustainable, and organic farmers are leading the way towards demonstrating new ways to both produce sufficient quantities of food and mitigate climate change through soil C sequestration.

Regenerative agriculture 4’s climate mitigation potential is highlighted in a recently released report from the Rocky Mountain Institute, stating that “negative emissions technologies—natural and engineered strategies for actively removing CO2 from the atmosphere such as agroforestry and silvopasture, biomass gasification and biochar—deployed at scale in the United States could sequester between 0.6 and 1.4 gigatons of C annually by 2050” . A report by Terra Genesis International further breaks down the mitigation potential of regenerative agriculture practices per hectare as depicted in Figure 4. According to Silver, “plants, and the soils they live in, are tremendous resources in the battle against climate change… soils have the potential to be deep, long-term repositories of some of the carbon captured by plants, keeping it from returning to the atmosphere for years to decades or longer” . Silver and her team of researchers quantify the impact of existing “agricultural mitigation practices” as potentially lowering global temperatures by 0.26°C by 2100, under RCP 2.6 . Other researchers helped develop the “Soil C 4 per Mille” initiative, launched at the COP21 talks in Paris in 2015, calling for all nations to increase soil carbon storage on agricultural lands by 0.004%, which would create a significant global carbon drawdown effect of 2-3 Gt C annually, offsetting 20-35% of anthropogenic emissions . What are these “agricultural mitigation practices” and how exactly can they be scaled across global agricultural acreage? Undoubtedly, local geography and context matter, along with available social, intellectual, and financial resources. This chapter will explore the first half of the question and explore the application of mitigation practice in the San Juan Island geographical context. A selected list of practices most relevant to Lopez Island farms are listed in Table 1 below. It is worth noting that many of these practices, in particular no-till and cover cropping, are broadly relevant to agricultural producers in both the conventional and organic industry, offering opportunities to build a “big tent” in the agriculture sector’s response to climate change.

In the face of climate change and its accelerating impacts, solutions and strategies for adapting and mitigating climate change through island farming are clear. What is needed is governance structures and skillfully crafted policy change to fund and scale these practices democratically. So, this chapter examines Lopez governance structures, from farms to island to county and state scales, and asks: What are the strengths and barriers to realizing a truly sustainable local food system on Lopez? How do perceptions of strengths and barriers differ or align among different governance scales? What are opportunities for immediate action or next steps to move towards the county vision for a sustainable local food system? As Figure 5 illustrates, farms and farmers on Lopez are nested within island, county, and state governance scales. Farms can and do relate to each other horizontally, coming up with mutually beneficial and differentiated roles, responsibilities, and practices, where for example one farm may supply compost to others, while others provide woody debris back to that farm, and all farmers share strategies for eradicating common pests/weeds, taking care of animals in the absence of an island large animal vet, and securing inputs/supplies from both on island and off island sources . Farmers who raise meat share access to a USDA-inspected, certified organic Mobile Processing Unit for slaughtering animals on the island, the first of its kind in the nation and an example of polycentric governance involving island, county, and federal coordination. Each of these levelsof governance are relevant to the conversation, research, and process of working towards a sustainable, equitable and resilient local food system on Lopez. Ultimately, state- and county level political reforms are needed to unlock goals and changes sought by island organizations and farmers at the grassroots level, who are already attempting to self-organize to ensure sustainability of their SES. Governing and “understanding a complex whole requires knowledge about specific variables and how their component parts are related. Thus, we must learn how to dissect and harness complexity, custom grow rooms rather than eliminate it from such systems” .In addition to policy and governance structures, education is a key component surrounding food systems that can unlock transformative change. In this case study, a range of environmental and food systems education research are relevant, most significantly: 1) farmer to farmer education on regenerative agricultural practices and 2) climate change education for youth, farmers, and the general public.

Farmer to farmer education is a cornerstone of the agroecological paradigm, which recognizes the vast knowledge stores held by experienced farmers as well as trust and value created when farmers share information with each other in horizontal knowledge transfers . Farmer to farmer, or Campesino a Campesino networks are seen as essential to scaling up and out agroecological practices that “enhance the resiliency of agroecosystems” . This educational form shares much with critical pedagogy, popularized by Paolo Freire in Brazil in the 1970s, which similarly emphasizes horizontal relationships between teacher and student, where both teachers and students are encouraged to ask and answer questions in an anti-oppression, anti-hierarchical “classroom” that aspires to higher goals of transformational social change and justice . Farmers hold unique and practical forms of knowledge that have developed historically in the United States context through both firsthand experience and institutions such as land-grant universities, Cooperative Extension, and the Farmer’s Bureau. Farmer knowledge in the United States has become centralized in the hands of institutions and corporations who exercise power over large aspects of the food system, from production to consumption. This consolidation of knowledge is related to corporate consolidation and corporate funding of agricultural sciences in research institutions including land-grant universities and Cooperative Extension offices . Corporate and institutional influence over farmer knowledge and practices intersects with the National Farm Bill policies and system of subsidies and crop insurance, policies over which corporations also exercise influence, thereby dictating a pattern of mechanized, chemical intensive farming that is practiced on a large scale in the United States, a pattern that is self reinforcing. Unsurprisingly, as part of this top-down knowledge transfer funded by fossil fuel interests, farmers as a population demographic in the United States have been skeptical about human-caused climate change and expressed reluctance to take mitigative action . However, there has been a notable shift recently due to extreme weather impacts on the Midwest and California that are making climate change a harder reality to ignore, and leading some farmers to declare that “farmers and rural Americans, that’s who’s going to solve this; We have the land for renewable energy, and we have the farming systems to sequester carbon” . A farmer in Missouri informed The Guardian that “as climate change bites, farmers are increasingly accepting of the science as they are forced to spend more money on equipment and seeds to maintain current crop yields” . Importantly,research indicates that “farmers who were concerned about the impacts of climate change on agriculture were more supportive of adaptive and mitigative action and those who attributed climate change to human activities were more likely to support government action on mitigation” . Experiential education in climate resilient agriculture for farmers will be important to translating research into action, enabling sustainable local food systems transformation. Improving farmer and future farmer climate literacy is a crucial component of scaling and handing off climate friendly practices such as those identified in the literature , yet remains an area that has been under explored in food systems research. There is little mention of training or educating farmers about climate change, and minimal mention in the K-12 educational arena of incorporating climate change into school food programs like Farm to School. Farm to School programs refer broadly to environmental literacy in their education program element, but there is much room to grow for both FTS and adult beginning farmer training programs to incorporate coherent standards and curricula around climate literacy. Like all forms of environmental literacy, it comprises knowledge, attitude, and engagement/action dimensions . Concepts like environmental and climate literacy are notoriously difficult to measure and quantify but are nevertheless important educational objectives to build into both K-12 and farmer education spaces coherently through content and activities aligned with the best available science. While the Lopez farmer population is already largely climate-engaged and active, the development of climate and environmental literacy among young people and aspiring farmers is important and in need of development, outlined further below and in Chapter 4, which focuses on education. The following sections apply literature on agroecology, agriculture and climate change, SES, and climate education to the past, present, and potential futures for the Lopez Island farming community.Historically, Lopez was an island of woodlands and native prairie, populated with Coast Salish communities who used regular burning practices to clear land for subsistence cultivation, hunting, and fire risk management. European settlers arrived in the mid-1800s, some fleeing the Irish potato famine to resume a life of farming and fishing on Lopez. Following the European theft of native land and the settlement of a boundary dispute between the United States and Great Britain in 1872, the islands were surveyed into 160-acre parcels and opened up to homesteading under the Homestead Act .

Initially, we reviewed the title of the first 60 documents resulting from each search. If the document was a manuscript, we then examined its abstract and conclusion. If the content of either the abstract or conclusion was relevant to the subjects of interest , the manuscript was selected for further review of the entire manuscript. For the cases in which the document was not a manuscript , we skimmed through the document to assess its content. Content relevance to the topics of interest was evaluated manually and individually by two researchers to establish inter-rater reliability.30 When both researchers agreed on a certain content, the document was further reviewed. The third step of the review process was performed by searching for specific keywords within each document selected in step 2. For example, for each source found in the search for the required physical and mental capabilities of youth, keywords such as force, anthropometry, body size, weight, and strength were searched to identify the relevant material. In the last step , experts in youth and ATV safety reviewed and categorized the relevant information in each document in a table. Based on our search terms, we retrieved 182 documents from Google Scholar and 1,189 from Google. As expected, some documents were repeated due to the five separate queries in two search engines. After filtering the titles, we identified 649 unique documents. Among those, 115 documents were selected for further review based on the inclusion/exclusion criteria. Our findings are outlined in the next section of this manuscript.A summary of the literature review process is illustrated in Figure 1. In addition to the initial literature review , hemp drying racks we also evaluated documents that were directly cited by the original 115 selected documents that emerged from our search. For those documents, we repeated steps two , three , and four .

After filtering the titles, we identified four additional documents.ATVs can weigh up to nearly 1,200 pounds31 and reach speeds up to 80 mph.32 The engine size ranges from 50 cc to approximately 1,000 cc for youth and adult-size ATVs. Controlling heavy, fast, and powerful vehicles require physical and mental capabilities that youth operators may not possess. For this matter, several consensus-derived guidelines, rules, and recommendations have been developed regarding the minimum age for operating ATVs on farms. These guidelines include age limitations for youth to ride utility ATVs and youth models. Nevertheless, these recommendations are inconsistent and may be affected by laws that vary among states. The American National Standard Institute/ Specialty Vehicle Institute of America propose age limitation based on the abilities of children from different age groups and the ATV’s maximum speed. Furthermore, based on the medical associations and safety experts’ concerns about child safety and health, some have concluded that permitting children younger than 16 years-of-age to operate or ride ATVs could be construed as a form of child neglect or endangerment. According to ANSI/SVIA, youth under the age of 6 should not be allowed to operate ATVs, and youth aged 6–10 should be limited to motorized vehicles that can go no faster than 24 km/h and require constant adult supervision. Youth between the ages of 11 and 12 can ride ATVs with a maximum speed of 48 km/h . In the U.S., ATV manufacturing and sales are regulated by the U.S. Consumer Product Safety Commission and not by the U.S. Department of Transportation . The DOT regulates motor vehicles designed to be used on public roads, and ATVs are not intended for public roadway use. In 2002, nine consumer groups petitioned the CPSC to ban the sales of adult-size ATVs for use by children under the age of 16. 

However, the petition was denied. The CPSC, theindustry, and many consumer advocates recommend selling only youth-model ATVs for children. Nevertheless, there are no ATVs designed/manufactured for children younger than 6. Vehicles for children 6 years-of-age and older have traditionally had engine sizes less than 70 cc, and those for children 12 years-of-age and older have been 90 cc or less. The CPSC recommends that these vehicles be used by children with adult supervision. Previous recommendations based on engine size by operator’s age are given in Table 2.  In the case of ATVs, the CPSC currently has adopted the 2017 voluntary standard developed by the Specialty Vehicle Institute of America and the American National Standards Institute , which is the most up-to-date standard regarding ATV-youth fit. The American National Standard for Four Wheel All-Terrain Vehicles42 is a “voluntary” standard that provides definitions for youth category ATVs . Based on this standard, the criterion determining age-designated youth labels is the maximum speed of the vehicle. For example, Y-10+ ATV models should only be used by children aged 10 and older. The maximum speed associated with each ATV category is presented in Table 3. The European standard titled “ATV Safety requirements and test methods” determined several requirements that ATVs should meet to be commercialized in Europe. This standard categorized youth-ATVs into four groups, including, Y-6+, Y-10+, Y-12+, Y-14+ based on the speed limits, similar to the standard from ANSI/SVIA . In addition, the European standard suggests that only operators older than 16 should ride adult-sized ATVs for utility or recreational purposes. Despite the recommendations based on age categories, several national and international organizations prohibit youth under 16 from riding ATVs of any size . Moreover, several medical associations inthe U.S., including the AAP40 and the ACS,41 warn that all ATVs are unsafe for youth, and no one under 16 years should ride ATVs at all. 

Some also indicate that youth under 12 have neither the required physical capabilities nor the motor skills to safely handle an ATV. They also indicate that youth under 16 do not possess the cognitive capabilities required to control highpower motorized vehicles. Lastly, Franklin et al. advocated that the sales of youth-size ATVs should be stopped in Australia for safety reasons. There are different regulations and laws at the state and federal levels. However, most rules/laws do not pertain to operations on private land. In addition, most laws are exempted if the vehicle is used for agricultural purposes. For instance, operators can ride without a helmet if they are farming in North Carolina or Wisconsin. In addition, ATVs in Pennsylvania used exclusively for agricultural purposes are classified in the Pennsylvania Vehicle Code as multipurpose agricultural vehicles and are exempt from the Pennsylvania ATV law. None of the states’ regulations address the physical or mental capabilities required to ride the ATVs. Numerous studies related to youth’s age and ATV use have been conducted; two key studies regarding the age of youth’s involvement in agricultural activities and age-based patterns in youth ATV riding behaviors are summarized in .The ATV operator should be strong enough to activate the ATV controls, including the throttlelever, hand gearshift lever, foot gearshift pedal, ignition switch, headlight switch, handlebar, hand brake lever, and foot brake pedal. An operator’s inability to consistently activate these critical ATV components could increase the injury risk to operators and bystanders. Several reviewed documents discussed the required strength to activate different ATV controls. However, most of these documents relied on qualitative criteria for evaluating the required youth strength. For instance, the National Children’s Center for Rural and Agricultural Health and Safety ATV guidelines state that “youth should be strong enough to operate the controls without straining and be able to push the ATV off if pinned underneath.” Furthermore, the ATV Safety Institute ’s “readiness checklist” recommends that “youth should have enough strength to activate the hand controls, shift lever, parking brake, choke and fuel valve, and the brake lever with sufficient pressure.” In contrast, industrial rolling racks the British Standard Institution , provides quantitative data for actuation forces of some ATV controls. For example, BSI recommends hand lever brake activation forces between 22 N and 245 N for all adult-sized ATVs. In an ongoing study, Araujo and Khorsandi measured the forces required to activate the main ATV controls. The activation forces were then compared to the corresponding strength of youth of various strength percentiles , genders , and ages . The authors found a significant mismatch between the forces required to operate the ATV controls and the corresponding strength of most youth. Furthermore, several study articles and guidelines reviewed in this manuscript recommended that youth should be capable of performing active riding, which refers to the operator moving their pelvis on or off the seat to counterbalance forces while holding the handlebars and keeping both feet on the footrests. 

Some researchers reported that active riding increased the stability of the ATV and decreased the chance of a rollover. However, the capability of performing effective active riding requires that the youth weight be significant compared to the ATV weight. Based on the CPSC, the appropriate child to ATV weight ratio should be 1:3.44 Figure 2 shows the weight of the lightest and heaviest youth in each age group compared to the mean weight of an age appropriate ATV. Based on the youthATV weight ratio recommended by the CPSC, 95th percentile kids as young as 7 years old are too heavy for the ATV recommended for their age , and by age 14, most kids are too heavy for ATVs designed for 12–15-year-olds. Based on the CPSC youth-ATV ratio recommendations , adolescent youth aged 12 to 15 years old might be too tall or heavy for the youth-model ATVs currently on the market and approved by the CPSC. If a youth is too tall or overweight, their knees may interfere with the handlebars, and they will be unable to control the ATV properly. Moreover, overly tall or heavy youth may significantly raise the center of gravity when on youth-size ATVs, affecting their stability and riding. A higher center of gravity likely increases the probability of the vehicle rolling over, posing a risk of injury or fatality. Different standards and organizations have developed recommendations to evaluate youth’s ability to effectively reach the ATV’s main controls: handlebar, hand brake, foot brake, hand gearshift, foot gearshift, and throttle lever. A summary of youth-fit criteria for ATVs proposed by various organizations and a research manuscript are shown in Table 5. In addition to reaching different controls, the European standard and the N4-HC55 suggest evaluating hand reach to hazardous zones on the ATV . This recommendation is based on another standard , which determines safety distances required to prevent hazard zones that could burn operators from being touched by upper and lower limbs. A previous study evaluated the fit of one adultsized ATV and one youth-model ATV for male youth aged 6–15 years old based on 5 of the safety recommendations mentioned in Table 5. The study found that most youth aged 6–15 years did not anthropometrically fit the ATVs based on the fit criteria used. Furthermore, the study suggests that rider age and ATV engine size are poor indicators of youth-ATV fit, and quantitative metrics would improve the assessment of which rider can anthropometrically fit which ATV. Furthermore, Araujo et al. evaluated youths’ ability to reach the main controls of various ATVs following some of the safety recommendations presented in Table 5. The authors developed virtual 3D mockups of ATVs and youth and simulated their interaction using an ergonometric software. The study’s major finding was that most youth failed to pass at least one of the ATV-youth fit recommendations.The field of vision of an ATV operator is the visible area they can scan from their seated position on the vehicle. Many believe that youth operators have a reduced field of vision compared to adults. Youth’s limited stature and eye height while seated on an ATV may affect their field of vision. Previous studies have shown that a restriction in an operator’s field of vision significantly increases the likelihood of a crash and/or loss of control which can lead to rider and bystander injuries. The ATV operator should have a wide field of vision to better access ATV controls, keep the ATV on the path, and detect shapes, sizes, and distances of obstacles. This ensures that the operator can react to unexpected riding situations and make decisions about riding strategies. The ASI youth “readiness checklist” includes a section to help parents assess their children’s visual perception. This part of the checklist evaluates youth’s capability to see, perceive depth, have adequate peripheral vision, judge the speed of moving objects, estimate the distances of objects , and follow the movement of objects.

For growth and broodstock, fish prevalence stabilizes around 100% from late 2013 until the end of the simulation .When the effect of local spread was removed from the simulation , a model that includes spread between farms is only possible via fish movement . In this scenario, the spread of PMCV slows down, but the overall pattern remains of an increasing trend reaching a between-farm prevalence of 100%. This level of prevalence was reached for the first time in late 2015, compared to the full model where 100% prevalence was reached 1 year earlier in 2014. For the model where transmission was only possible via local spread , between-farm prevalence never reached a 20% level until mid 2017, and oscillated most of the time around 10%. Under this scenario, the only time that between-farm prevalence is higher than in the scenario with spread only via fish movement is at the beginning of the epidemic , indicating that local spread was the main driver of the transmission between farms at this early time .Of the evaluated centrality based interventions, the most effective were the ones based on out degree and outcloseness, for both the reactive and proactive approaches . For the former, after all spread via fish movement from the targeted nodes is stopped in July 2012, the increasing trend in between-farm prevalence immediately stops, stabilizing around 60% until the end of the simulation for both out degree and outcloseness based interventions. The between-farm prevalence obtained with these interventions was slightly higher than the prevalence obtained when pathogen spread via fish movements from all fish farms was stopped, the difference being clearer from 2016 until the end of the simulation . In terms of the time required to reach set prevalence benchmarks, vertical farming system both out degree and outcloseness based targeted interventions are virtually indistinguishable, with the former being slightly better .

Regarding the targeted interventions based on the other centrality measures, the one based on incloseness was the one that performed worst, with virtually the same result as when no intervention is applied, followed by the ones based on indegree and betweenness, with the latter being similar to the ones based on out degree and outcloseness until early 2014, after which it produces a higher between-farm prevalence. Similarly, when targeted interventions are applied from early on in the proactive approach , the most effective targeting strategies are those based on out degree and outcloseness, which are virtually indistinguishable from the one based in removing spread via fish movement from all nodes. The strategies based on these centrality measures produced between-farm prevalences around 10% from their implementation through the end of the simulation. Similar to the reactive approach, the worst performing strategy here is the one based on incloseness, which produces virtually the same result as if no intervention was applied, although with a slight delay in the increase of between-farm prevalence from 2010 through mid 2014. The strategy based on indegree was second to last, reaching a between-farm prevalence of around 90% in early 2016 and stabilizing around that value until the end of the simulation. A betweenness-based strategy did not show a clear difference with the best performing strategies based on out degree and outcloseness until late 2012, where between-farm prevalence increased slightly above the value for the other two strategies, andthis difference remained until the end of the simulation .In this paper, we describe the use of data-driven network modeling as a framework to evaluate the transmission of PMCV in the Irish farmed Atlantic salmon population, and the impact of targeted intervention strategies.

To do this, we have simulated the introduction and spread of PMCV in the Irish Atlantic salmon farming industry using real data of live fish movements, compulsorily reported to local authorities during 1 January 2009 to 23 October 2017, and data from a prevalence study conducted from 30 May 2016 to 19 December 2017. Additionally, using the fish movement data set, we have imputed population dynamics events at the farms by using a set of rules based on domain knowledge of the fish production cycle. We were able to reproduce population dynamics and the observed PMCV prevalence in the observational study that was used to estimate model parameters, evaluate the importance of infection spread via fish movement and local spread, and evaluate the effects of different farm centrality based control strategies. Parameter estimation showed that the best fitting model was the one with increasing transmission rates as fish aged and with a rate of decay of the environmental infectious pressure that varied each quarter . In common with other viral infections of farmed Atlantic salmon, studies have shown that fish have increased PMCV prevalence and higher concentration of the virus in fish tissues as they age during the production cycle. Further, the probability of developing CMS increases with the length of time at sea . In the freshwater phase, viral particles are detected in low quantities, and CMS outbreaks and CMS-related pathological lesions have not been described . In a study to evaluate vertical transmission of the agent, PMCV was found in 128 of 132 broodfish, and later detected in all stages of progeny, but only at prevalences of < 25% and with concentrations close to the detection limit of the method .In the observational study used for estimating the parameters in our model, PMCV was found at higher concentrations in broodstock fish and lower concentrations in younger age groups . Although pathogen concentration was not part of our model, a possible extension would be to allow α, the rate of viral shedding, to vary by age group. In our modeling, simulation was initialized at two broodstock farms.

Within these farms, transmission was horizontal . As highlighted in the model, horizontal transmission between farms is important, but only via fish transfer and not via local spread. Our results indicate that the introduction of the agent in two specific farms during the second half of 2009, coupled with the structure of the network of live fish movements in the country, is enough to account for the widespread occurrence of PMCV currently observed in the country. These findings are in agreement with the recent work of Tighe et al. , who found that PMCV strains in Ireland are largely homogenous, without evidence of geographically linked clustering, consistent with a hypothesis of agent spread through fish movement . If local spread were the main driver, several locally distinct viral strains would be more likely. In addition, Tighe et al. suggests that the Irish strains from cluster I could have arrived in Ireland between 2010 and 2012, while the strains from cluster IV could have arrived between 2007 and 2009. This is very close to our simulated introduction during 2009 based on the results of archived samples. This study also suggests that these dates are supported by the testing of archived heart samples from Irish Atlantic salmon broodstock which showed that all samples collected prior to 2009 were PMCV negative, whereas those tested from 2009 onwards were positive. It is these data, from Morrissey et al. that form the basis for the current simulation study. PMCV is observed at low levels during the freshwater phase. Further, it is unclear whether persistent virus in these fish is a substantial contributor to mortality at sea compared to the infection pressure that is exerted from neighboring farms and other factors, external to the farm, that are associated with infection and disease . In recent work, Jensen et al. have highlighted a possible pathway of transmission from broodstock to smolt, a pathway that is not explicitly modeled in the current study. We consider that our modeling approach would be well-suited to evaluate the plausibility of alternative transmission routes. Although current parameter estimates appear to reproduce age-varying fish susceptibility, it was not possible to reproduce the observed drop in prevalence during the May-July period. There are reports of slight seasonal variations of clinical CMS in seawater farms, with an increase in cases in autumn and spring , but no reports on seasonal patterns in the detection of PMCV via RT-PCR or other diagnostic tests, let alone seasonality of detection in freshwater. The fact that all model parameterizations used were not able to reproduce the observed drop during the month of June leads us to think that further observational data is required, possibly with a study with sampling conducted evenly throughout the year, so it can include the months where no samples were taken and a more homogeneous number of farms and fish sampled at each time. Nonetheless, we believe that our model is valuable, and that important lessons could be learned from it, like the major importance of spread via fish movement and the best intervention strategies in order to prevent extensive infection spread. These lessons would apply not only to PMCV, vertical farming racks but also to infectious diseases whose spread is predominantly via fish movement . The decision to use a susceptible-infected over a susceptible-infected-susceptible model for within-farm spread was based on the fact that different experimental studies have found the viral genome present in tissues of challenged fish throughout the whole duration of the study, indicating that the salmon immune response may be unable to eliminate the virus .

This, together with studies where PMCV has been consistently found in cohorts of fish sampled through long periods of time, indicating that PMCV can be present in fish for some months , provides further support for the modeling approach used here. Nevertheless, more research is required to further validate or refute this modeling choice, as it is possible that fish clear the infection beyond the time frames used in both experimental and observational studies. The model was sensitive to changes in the values of the indirect transmission rate, rate of decay in environmental infectious pressure, and the rate of viral shedding from infected individuals, but not to changes in the level of spatial coupling . Model outputs were also not substantially influenced by different parameter assumptions regarding either distance or seasonality , noting that information about distance thresholds was derived from other viral infections such as infectious salmon anemia , where estimates have varied from 5 to 20 km or more . Collectively, these results suggest that local spread may play a secondary role in the spread of PMCV across the Atlantic salmon farms in the country. When local spread was removed completely from the model , it was even clearer that this transmission pathway under current model assumptions was not the most important. On the basis of these results, we hypothesize that the widespread presence of PMCV in Ireland is most likely a product of the shipments of infected but subclinical fish through the network of live fish movements that occur in Ireland. This is consistent with fish being infected but subclinical for months prior to manifesting signs of disease , and by the structure of the network of live fish movements in the country . There is limited knowledge of agent survival of PMCV in the aquatic environment. Infection risk is higher on farms with a history of CMS outbreaks , which could suggest survival of the causal agent in the local environment. Further, infection pressure from farms within 100 km of seaway distance was found to be one of the most important risk factors for clinical CMS diagnosis , although this study did not evaluate spread via fish movement. It is noted that the distance over which infection can be transmitted via water is determined by an interaction between hydrodynamics, viral shedding and decay rates . Further research on PMCV survival in the environment is needed to guide parameterization of future models. The most effective intervention strategies are based on out degree and outcloseness , with the highest impact being observed when using these intervention strategies with a proactive approach . Note that all outgoing shipments from selected farms are assumed to include only susceptible fish , which can be equated with high levels of bio-security. The out degree and outcloseness based strategies are comparable, most likely because both strategies refer to outgoing shipments from a farm , the former with the number of farms receiving fish from a given source, and the latter inversely related to the number of intermediaries between the source and the rest of the farms in the network. Both centrality measures were moderately correlated with each other, with a Pearson correlation of 0.53 for the proactive approach when including all farms for each time window used.

Many papers have tried to address this issue in their own unique ways. A common method seen is a polygonal representation of the boundary. With these polygons, Guirguis et al. uses the nearest edge to define an equivalent circular constraint. Risco et al. uses the nearest edge of the polygon to define the signed distance function. Note that both of these method’s use of the nearest edge in their formulation, which means that the constraint function is non-differentiable when there are two edges of equal distance away from the wind turbine. Additionally, there is a trade-off between computational cost and accuracy in the constraint function with respect to the number of edges in the polygon. The unique approach by Reddy poses an interpolation problem using a support vector domain description to describe the boundaries in an optimal way. This approach is continuous and differentiable, but the report does not provide any accuracy and scaling studies, so it is unknown how it may perform with increasingly complex boundaries.To the author’s knowledge, no other wind farm boundary constraint has taken the unique implicit surface reconstruction perspective as was described in Section 2.1. Implicit surface reconstruction constructs a level set function that represents the wind farm boundary by its zero level set. The inputs to most surface reconstruction methods is a point cloud, which is easily obtainable from the polygonal representations of previous studies. Note that Reddy’s SVDD method is very similar to the interpolation formulations in surface reconstruction. In this way, SVDD may suffer from the aforementioned limitations, including blobby reconstructions and significant computational expense for large scale SVDDs . The SDF is useful when the feasible zones are disconnected.

In gradient-based optimization, it is not possible for wind turbines to move across disconnected domains in a continuous way, however, drain trays for plants a relaxation approach to the boundary constraints can allow for wind turbines to move freely across regions until the true constraint is represented. The relaxation approach is shown to work well in avoiding turbines getting stuck within disconnected domains. With the SDF approximation described in Chapter 3, the relaxation approach is easily repeatable using the surface reconstruction method. We identify three of these frameworks relevant to the work within this thesis: PyWake, TOPFARM, and FLORIS. PyWake is an open-source Python library that contains many engineering wake models to calculate the annual energy production of wind farms. TOPFARM is an Open MDAO-based Python library that performs gradient-based optimization on wind farms using PyWake as its backend for modeling turbine wakes and calculating annual energy production. FLORIS is an open-source Python library that is controls-focused framework that models the wakes of yawed turbines and supports gradient free and gradient-based optimization. Gradient-based optimization within FLORIS is at alimited capacity, as it only supports automatic differentiation on some models. Otherwise, the finite difference method is used for derivative calculation. The finite difference method is less accurate and requires many more model evaluations. This section, in part, is currently being prepared for submission for publication of the material. The authors of this work are Anugrah Jo Joshy, Ryan C. Dunn, and John T. Hwang. The thesis author was a contributor to this material.We now apply our formulation to a number of geometric shapes involved in novel aircraft design. Aircraft design optimization is a long standing problem and has been the subject of recent interest in problems involving geometric non-interference constraints, e.g., the layout optimization of air cargo and aerodynamic shape optimization.

To enable gradient-based design optimization involving these constraints, a new generic method is required to represent numerous components within an aircraft’s design. We recognize the potential for our formulation and demonstrate its capabilities by conducting an experiment. In this experiment, we apply our formulation and quantify the resultant errors of five geometric shapes commonly associated with aircraft design. The geometries we model include a fuselage and a wing from a novel electric vertical take-off and landing concept vehicle, a human avatar, a luggage case, and a rectangular prism representing a battery pack within the wing. A visualization of these components in a feasible design configuration is illustrated in Fig. 4.7. Table 4.3 tabulates the on-surface error of the energy minimized LSF for each geometry. We observe that the smallest relative on-surface error is of the smooth fuselage shape, while the largest relative error is of the human avatar. We note from this example that geometries with features reasonably proportioned to their minimum bounding box diagonal are easier to represent using our method, hence our formulation poorly represents small scale features of the human avatar while it can represent the smooth fuselage very well. We observe that the bounding boxes of the fuselage, wing, and battery pack are poorly proportioned, yet they do not result in an increase of relative error compared to other geometries. However, their longer minimum bounding box diagonals will result in larger absolute errors.We now apply our method for enforcing geometric non-interference constraints to a medical robot design problem involving concentric tube robots . CTRs are composed of two or more long and slender pre-curved tubes made of super elastic materials. They can be designed to reach points in a large region of interest by rotating and translating the tubes relative to each other at their bases.

These characteristics make them ideal for minimally invasive surgeries where a surgeon can operate on a small region of interest with high dexterity through actuation at the base. In the foundational works of Sears and Dupont and Webster et al., expressions for the shape and tip position of the CTR are derived with respect to the robot’s geometric and control variables. Bergeles et al.use these expressions to perform gradient-free optimization of the CTR’s geometric and control variables with anatomical constraints. These anatomical constraints, i.e., geometric non-interference constraints, enforce that the CTR does not interfere with the anatomy during operation. Recent work by Lin et al. shows that gradient based optimization enables an efficient and scalable solution to simultaneously optimize the large set of the tube’s geometric and control variables while enforcing anatomical constraints. The experiment we now present follows the workflow of Lin et al., however, using our new formulation for representing the anatomical constraint function. The presented workflow involves the solution of multiple optimization problems, including an initial path planning problem, and the geometric design and control of the CTR . The path planning problem solves for a parametric 3D curve that represents an optimal collision-free path to the surgical site within the anatomy. Then, points along this path serve as inputs to the geometric design and control optimization of the CTR, which involve a kinematic model of the robot. In both subproblems, the non-interference constraints are enforced by evaluating a discrete set of points along the path or physical CTR to ensure that no points lie outside of the anatomy. We begin our experiment with an investigation in the heart anatomy which represents the non-interference constraint of the problem. The initial oriented point cloud of the heart is obtained from segmentation and 3D reconstruction by magnetic resonance imaging scans. Due to the limited machine accuracy, error introduced by aligning multiple scans, and normal approximation, the oriented point cloud is noisy, nonuniform, and contains poorly oriented normals. We perform a simple and necessary smoothing step on this point cloud as illustrated in Fig. 4.8. Although less precise at capturing small scale features, 4 x 8 grow tray the smoothing step assists our method in reconstructing a smooth zero contour for constraint representation.The smooth representation has relative errors 3.1×10−3 and 1.9×10−2 compared to the original noisy representation. The error in our energy minimized function obtained from the smoothed heart model is tabulated in Table 4.4. We observe that the on-surface RMS and max error of our representation is an order of magnitude less than the error introduced by the smoothing step. This implies that our representation of the smooth model is no worse than the smoothing step itself. We see that our method generates a function with a reliable zero level set of the smooth heart geometry, with an on-surface RMS error of 2.1×10−4 .

This error is lower compared to all the other examples in Table 4.2, and we attribute this to the smoothness of the heart geometry. We also note that the max on- and off-surface absolute errors of our representation are of the same order as the diameter of the CTR itself, typically 0.5-2.0 mm.Models of the wind turbine are necessary for characterizing the flow field in its wakes and for the power production of an individual turbine. For the analytical wake models and the calculation of annual energy production, we solely need a wind turbine to provide coefficient of thrust and power production . For simplicity and computational efficiency, the wind turbine model is simplified to a surrogate model where CT and P are simply functions of the wind speed experienced at the rotor. We note that any increase to the fidelity of the model will improve the power and CT accuracy, however the analytical wake models used in this study do not consider varying thrust/power at different radial sections of the blades. We do recommend a more accurate turbine model in the future work that will account for structural loading and fatigue on the blade structures. The two wind turbines considered in this study are the National Renewable Energy Laboratory 5MW open-source turbine model, and the International Energy Agency Wind Task 37 15MW turbine model. These wind turbines were selected for their size and viability in off-shore wind farms on small and large scale. The power and coefficient of thrust curves for the NREL 5MW and IEA37 15MW reference wind turbines are shown in Fig. 5.1 and Fig. B.1, respectively. The parameters of each wind turbine are also tabulated in Table 5.1. Note the significant diameter size.While this thesis does not provide validation with ground-truth, verification is provided to the existing models within PyWake and FLORIS. The major assumptions with this model depends on the accuracy of models individually. Validation studies are important and would be a valuable future work to this thesis. A study on flexible and stiff blades found that low fidelity models have significant discrepancies at low wind speeds and small inter-turbine spacing. Additionally, we rely heavily on the assumption an accurate thrust coefficient curve for the given wind turbine. An example to verify the Bastankhah wake model in a simple 3 turbine row is done in Fig. B.3. The error in the AEP calculated from our model on the order of machine precision, confirming the model’s accuracy. Derivative calculation is automatically done in CSDL, but for additional validation it is verified with finite differencing during optimization, and is confirmed to be on the order of the step length of the finite difference O. A verification of the Gaussian wake model in a simple 3 turbine row is done in Fig. B.4. The net AEP calculated from our model has a normalized error on the order of machine precision, confirming the model’s accuracy. Derivative calculation is automatically done in CSDL, but for additional validation it is confirmed to be on the order of the step length of the finite difference O. This chapter, in part, is currently being prepared for submission for publication of the material. The authors of this work are Anugrah Jo Joshy, Ryan C. Dunn, and John T. Hwang. The thesis author was a contributor to this material.In this optimization study, we perform a yaw misalignment optimization with the Lillgrund site. We utilize FLORIS’s built in boolean optimization tool called Serial Refine in order to initialize our optimization. Serial Refine reduces the design space by considering wind turbines in order of upwind to downwind, and recursively discretizes the design space and checks the model evaluations for the maximum value. In this way, it is a gradient-free optimizer, and it has shown to be very fast at finding a near-optimal solution and not susceptible to local minima. Because SR is fast and robust to local minima, we may apply it to get a good initial guess for our optimization. Our new model can take this suboptimal initial guess and improve it further using gradient-based optimization by considering yaw as a fully continuous variable. The yaw optimization problem is shown in problem 5.27, and the Gaussian wake model was used with the Crespo and Hern´andez turbulence intensity model. Using the Lillgrund site, the optimization problem has a total of 3,456 design variables.