Examples include cover cropping, water conservation, erosion control, integrated pest management, or organic certification. Although the level of abstraction might be conceptualized as a continuum, this simple categorization is useful for analysis. Another way of thinking about this categorization is that goals are value-driven outcomes of sustainability and strategies represent beliefs about the means to achieving those goals . Hypothesis 2 is that mental models of sustainable agriculture will reflect geographic variation and local context. Differences in farmer knowledge and the practice of agriculture reflect regional biophysical and social differences . In particular, although abstract goals of sustainability are likely to be more universal across geographies, the concrete strategies used to achieve those goals may reflect geographical variation in terms of challenges and opportunities for realizing the goals . For example, achieving the goal of environmental responsibility in the Napa Valley requires water management and cover-crop strategies for reducing soil erosion by surface water runoff on steep hillsides. In Lodi, strategies for wind-born soil erosion control are more relevant across the gentle valley floor topography of the region. Hypothesis 3 is that farmers who subscribe to more central concepts in the mental model are also more likely to engage in a range of sustainability behaviors. In particular, the sophistication of a farmer’s definition of sustainability should be correlated with their participation in extension programs and adoption of sustainability practices. The extension programs in California viticulture explicitly train farmers in the idea of sustainability and also identify specific sustainability practices. Thus, participation, practices,dutch bucket hydroponic and mental models represent a set of coevolving and synergistic processes.We constructed a mental model based on responses to surveys of wine grape growers in all three study regions.
Using content analysis of farmers’ self-reported definitions of sustainability , we classified 56 concepts into 19 abstract goals of sustainability and 37 more concrete strategies. We operationalized the mental model as a network where the concepts are nodes and valued ties represent the number of times two concepts co-occur together in a single definition of sustainable agriculture . We first identified an overall mental model by taking the union of the regional concept networks. A union network is defined as the combination of nodes and ties from two or more networks . The union network provides a comprehensive picture of farmer thinking about sustainable agriculture. The overall mental model from the union network is visualized in Fig. 1. Nodes are scaled by a measure of centrality we call “prominence,” which indicates a concept’s importance in the mental model. Prominent concepts are widely recognized among farmers as legitimate dimensions of sustainability and they are cognitively associated with many other central concepts. Technically, prominence combines the frequency that a concept appears in the network with its centrality . Because prominent concepts are linked to many other concepts, they are effective cognitive entry points for leveraging farmer thinking about sustainability. Ties are unscaled. Nodes are shaded by classification, with yellow-colored nodes representing goals of sustainable agriculture and aqua-colored nodes representing strategies. Table S1 lists all of the concepts, examples of coded text for each concept, classification as goal or strategy , and three measures of centrality: prominence, occurrence probability, and eigenvector centrality. We chose the examples of coded text that best illustrate the core ideas of the concept.Our mental model analysis identified key concepts that are factored into a practitioner’s decision-making process. The goals of economic viability, environmental responsibility, continuation into the future, and crop value are powerful drivers of decision making, with relevance across different social-ecological contexts. The hierarchical structure of the overall mental model suggests that although practitioners focus on achieving a common set of broad goals, the strategies they associate with realizing them are numerous and diverse.
Key strategies include practice adoption, stewardship of resources, reduction or elimination of agrochemicals, and water conservation and quality enhancement. Because of their association with many other goals and strategies, central concepts are potential cognitive entry points for leveraging practitioner thinking about sustainability.Sustainability is notoriously difficult to define for the reason that it is a relative concept , which varies widely across space, time, and scale . Furthermore, diverse stakeholders often have divergent and even conflicting values and goals . Practitioners must grapple with the questions of what is to be sustained, for how long, for whose benefit, at what cost, over what geographical area, and measured by what criteria . We argue that definitions of sustainability that are grounded in practitioners’ viewpoints will have greater relevance to real-world contexts and therefore be more useful for guiding actions . Empirically measuring mental models of sustainability is crucial to know whether the normative ideas about sustainability discussed within academic, policy, and public circles are relevant to on-the-ground decisions. Our study of mental models provided two main insights into practitioners’ definitions of sustainability. First, mental models of sustainability are organized hierarchically along a continuum of abstractness from general goals of sustainability to concrete strategies for achieving those goals. At least among wine grape growers, the overall mental model is sophisticated and reflects many of the concepts discussed in the academic literature and among policymakers . Definitions that focus on central goals are likely to prompt practitioner thinking about their linked strategies, and are more likely to resonate with a greater number and diversity of practitioners. To the extent these goals and strategies are grounded in more general environmental values and norms, the network approach used here emphasizes the interdependent and relational aspects of sustainability thinking. Second, more central abstract concepts are universal across geography, with only anecdotal evidence that strategies are customized to specific social-ecological contexts.
This may be a feature of our study system because sustainability extension programs are advanced within California viticulture and wine grape-growing regions that have more similarities than differences. Mental models from social-ecological systems with more stark differences may show larger differences in how goals are linked to strategies. More research is needed to confirm or disconfirm the hypothesis that concrete strategies are more sensitive to geographic and other contextual variation.Managing knowledge systems to link knowledge and action is a core goal in sustainability science . Knowledge systems include the institutional arrangements, organizations, and social networks that facilitate the transmission of knowledge among decision makers. Our results suggest that knowledge about sustainability, participation in extension programs, and practice adoption are mutually reinforcing processes. In agriculture, local extension programs and partnerships have played a crucial role in managing knowledge systems . In the case of California viticulture specifically, there is a substantial body of literature demonstrating that these programs have had a positive influence on farmer adoption of sustainability practices . The positive association we found between farmer sustainability cognition, participation in extension activities, and practice adoption indicates that knowledge systems do help expand practitioner understanding of social-ecological systems and influence their management behaviors. Extension programs can accelerate the development of knowledge and understanding about sustainability by clarifying the linkages among central sustainability goals and the associated strategies and practices for achieving them. An important component of this learning process may be the explicit use of the concept of sustainability,dutch buckets system as it can serve as a heuristic for guiding practitioner decision making with a framework for balancing economic, ecological, and social costs and benefits. Thinking in terms of sustainability does track with behavior, and knowledge systems have the ability to support this process by providing opportunities for learning.Sustainability and climate-focused initiatives announced by the United States federal government, states, and private sector entities could have meaningful impacts on land use sectors by affecting trends in land use and management as well as shifting commodity markets. Recent policy announcements include potential land-based greenhouse-gas mitigation strategies associated with ambitious new climate targets as part of rejoining the Paris Agreement , as well as a recent presidential executive order protecting 30% of U.S. lands and waters by 2030. The US Department of Agriculture Innovation Initiative has established ambitious targets for the next three decades to increase agricultural productivity by 40%, reduce food waste by 50%, reduce nutrient loss to run of by 30%, reduce carbon emissions, and increase bio–fuel and biomass production.Other policies may not have a primary objective that is environmental or sustainability-focused, but could nonetheless support policies in this domain by shifting resource demands and improving environmental outcomes. Two examples of indirect policy objectives that could interact with sustainability and climate initiatives include enhancing agricultural productivity growth and promoting healthier diets. If widely adopted, U.S. government recommendations for healthier diets could alter protein consumption away from beef and pork and toward plant-based foods, which could indirectly benefit climate and sustainability goals . Furthermore, previous research suggests that agricultural productivity growth can complement climate change mitigation . However, it is unclear how these policy targets could be achieved in isolation, what role market adjustments will play, and how healthier diet transitions and agricultural productivity enhancement might interact.While there have been several recent studies examining combinations of sustainability-related U.S. policy targets , the literature modeling U.S. agriculture and forestry is currently lacking in its representation of demand-side sustainability policies, including transitions to healthier diets.
While shifting to healthier diets is critical to reducing the noncommunicable disease burden , understanding how dietary change could shift resource-intensive commodity production, land use and ecosystem services can help inform complementary sustainability and climate policy actions. U.S. food systems are characterized by high levels of grain and oil seed production to support a highly productive domestic livestock sector and domestic diets that are relatively rich in meat-based proteins and oils , as well as international demands for U.S.-sourced agricultural products. Sustainability priorities such as increasing biodiversity protection or ecosystem service provision could benefit from dietary shifts that reduce pressure on U.S. agriculture’s intensive and extensive margins. Simultaneously, increasing productivity growth in U.S. agriculture could increase incomes and increase comparative advantage for international trade, which may or may not have land sparing effects. The literature on environmental impact of human diets has converged on the multiple sustainability benefits of diets lower in animal-based foods and higher in plant-based foods . These studies have either examined the global impacts of all countries adopting more sustainable or healthier diets or the domestic impacts of changes to a single country’s dietary preferences . Rarely have studies quantified both domestic and global sustainability metrics of a single county’s dietary changes or the country-specific sustainability impacts of the rest of the world adopting healthier diets. In addition, many studies focus on quantifying the impacts of specific personal dietary preferences , rather than a healthier average national diet. Several studies in the U.S. have quantified the sustainability impacts of omnivorous healthy diets recommended by the Dietary Guidelines for Americans . However, there is significant disagreement about whether the DGA diets have lower GHG, land use, or water use than the average American diet today . A handful of these studies have reported slightly lower land use requirements , and three out of four available studies showed similar or greater GHG emissions . The majority of studies quantifying the sustainability of alternative diets and dietary shifts in the U.S. use life-cycle assessments to measure environmental impacts of food production chains . However, LCA studies are limited in being able to quantify land use and land use change and allow for regional variation . Moreover, for projecting the environmental impacts of future dietary changes, it is critical to provide estimates that represent dynamic, rather than steady-state, industry and economic conditions.Alternative approaches such as economic partial-equilibrium models represent the agricultural, forestry, and other land use sectors in detail, and are deliberately designed to estimate land-use-related impacts, a key gap in the existing literature on the sustainability of U.S. diets . The global scale of many of these models allows representation of international trade and thus evaluation of leakage effects of domestic policies. Indirect sustainability levers such as shifting dietary preferences have received substantially less attention in the land use modeling literature relative to carbon pricing , bioenergy, and traditional conservation incentives. However, recent analysis has started to move in this direction . Partial-equilibrium models of the land sectors, such as GLOBIOM, which we employ in this study, are designed to maintain empirically observed market relationships between supply, demand, and prices. These models endogenously determine the demand for certain foods, productivity of specific crops, and the productivity of the livestock sector.