Many consumers are trying to reduce their food's environmental impact by purchasing more locally sourced food. One choice for local food is Community Supported Agriculture (CSA), in which farmers provide a share of produce on a regular basis to pre-paying farm members. The number of CSAs in the USA has grown from two in the mid-1980s to perhaps as many as 12,617 according to the latest US census of agriculture (2014). We use a case study approach to investigate the greenhouse gas (GHG) emissions associated with five CSA operations in the Sacramento Valley of California. By understanding the GHG emissions of CSAs and the practices that might be improved, we hope to support innovative strategies to reduce GHG emissions in these agricultural production systems. Input, production and distribution data were collected from each farm and reported in CO2e emissions for 1 kg CSA produce at the pickup location. Results show large variation in total emissions, ranging from 1.72 to 6.69 kg CO2e kg−1 of produce with an average of 3.94 kg CO2e kg−1 produce. The largest source of emissions was electricity, contributing over 70% of total CO2e emissions on average. Based on our findings, despite the seemingly similarities between these operations in terms of production site, acreage, customers and production practices, there is still a large amount of variability with regard to total GHG. Thus we argue coming up with a standardized production function for diversified production and deriving GHGs or calculating average total emissions overlooks the heterogeneity of the system. Food systems can never be reduced to a simple binary of local is better and conventional is worse, or its inverse local is worse and conventional is better, because of the complexities of the production and distribution systems and their relationship to GHG emissions. Yet, we can say that localized production systems that are low in electricity use (or use renewable energy sources) and use efficiently-produced compost use have lower GHG emissions than those that do not.

Alongside associated forms of socially and politically conscious food production, community food growing is routinely connected to a wide range of social and environmental benefits. However, robust evidence in support of these associations remains scant, and while the conversation has shifted in recent years to take account of the sometimes unintended or negative aspects of these activities, no consensus has been reached about how such forms of food growing should adapt to new conditions, or be scaled up to maximize their positive impacts. A July 2016 conference was organized to address this strategic shortfall. This themed issue presents the papers resulting from the conference.

Traditional African vegetables have recently received considerable attention for their contribution to food and nutrition security and opportunities for enhancing smallholder livelihoods. Promoting the production and consumption of traditional vegetables is expected to enhance household nutrition among urban and rural households. The Good Seed Initiative (GSI) program promoted production and consumption of nutrient-dense traditional African vegetables in Arusha region in Tanzania to reduce malnutrition through diet diversification. We estimated the impact of promotion activities on households, women, and children's dietary diversity. The study used cross-sectional data from 258 and 242 households in intervention and control regions, respectively, and applied matching techniques and inverse probability weighting to control for unobserved heterogeneity and selection bias, which could otherwise bias the outcome estimates. We found that households benefiting from traditional vegetable promotion and demand creation activities had significantly higher dietary diversity of children under 5 yr and women in reproductive age. We found no significant impact of promotion activities on households’ dietary diversity. The policy implication is that scaling up promotional and demand creation activities to encourage consumers to grow and eat traditional African vegetables would be an important element in initiatives to increase dietary diversity, particularly for children under 5 and women in Tanzania.

Tillage is decreasing globally due to recognized benefits of fuel savings and improved soil health in the absence of disturbance. However, a perceived inability to control weeds effectively and economically hinders no-till adoption in organic production systems in the Upper Midwest, USA. A strip-tillage (ST) strategy was explored as an intermediate approach to reducing fuel use and soil disturbance, and still controlling weeds. An 8-year comparison was made between two tillage approaches, one primarily using ST the other using a combination of conventional plow, disk and chisel tillage [conventional tillage (CT)]. Additionally, two rotation schemes were explored within each tillage system: a 2-year rotation (2y) of corn (Zea mays L.), and soybean (Glycine max [L.] Merr.) with a winter rye (Secale cereale L.) cover crop; and a 4-year rotation (4y) of corn, soybean, spring wheat (Triticum aestivum L.) underseeded with alfalfa (Medicago sativa L.), and a second year of alfalfa. These treatments resulted in comparison of four main management systems CT-2y, CT-4y, ST-2y and ST-4y, which also were managed under fertilized and non-fertilized conditions. Yields, whole system productivity (evaluated with potential gross returns), and weed seed densities (first 4 years) were measured. Across years, yields of corn, soybean and wheat were greater by 34% or more under CT than ST but alfalfa yields were the same. Within tillage strategies, corn yields were the same in 2y and 4y rotations, but soybean yields, only under ST, were 29% lower in the fertilized 4y than 2 yr rotation. In the ST-4y system yields of corn and soybean were the same in fertilized and non-fertilized treatments. Over the entire rotation, system productivity was highest in the fertilized CT-2y system, but the same among fertilized ST-4y, and non-fertilized ST-2y, ST-4y, and CT-4y systems. Over the first 4 years, total weed seed density increased comparatively more under ST than CT, and was negatively correlated to corn yields in fertilized CT systems and soybean yields in the fertilized ST-2y system. These results indicated ST compromised productivity, in part due to insufficient weed control, but also due to reduced nutrient availability. ST and diverse rotations may yet be viable options given that overall productivity of fertilized ST-2y and CT-4y systems was within 70% of that in the fertilized CT-2y system. Closing the yield gap between ST and CT would benefit from future research focused on organic weed and nutrient management, particularly for corn.

Globalization of food trade in agricultural commodities is in some senses the antithesis of key concepts of sustainable agriculture. Global trade in food products distances the depletion of resources and environmental impacts of food production from the economic and social processes that drive consumption and increases the global risks from introduction of species that become pests. However, both supply and market value chains have emerged as major sub-systems in the larger global agro-food trade system that exert enormous importance over the potential for change in agricultural production at the farm level. This special issue presents studies of seven value chains that exhibit the breadth of research about value chains and their potential contributions to sustainable agriculture. They address value chains at different scales and dealing in various products. These studies contribute to the body of knowledge with a focus on lesser researched regions and products. Most important, they demonstrate the potential for value chains to enhance agricultural sustainability for rural populations and reduce food insecurity and inequities.

Benefits of reduced tillage and diverse crop rotations include reversing soil C loss, and improving soil quality and function. However, adoption of these strategies is lagging, particularly in the Upper Midwest, due to a perception that reduced tillage lowers crop yields. Therefore, an 8-year comparison of these conservation systems with a conventional, tilled, 2-year rotation system was conducted to evaluate effects on yields, system productivity (measured with potential gross returns) and weed seed densities. This study compared conventional moldboard plow + chisel till (CT) to reduced strip-tillage + no-tillage (ST), each with a 2-year (2y) or 4-year (4y) crop rotation, abbreviated as CT-2y, CT-4y, ST-2y and ST-4y. The 2y rotation was corn (Zea mays L.) and soybean (Glycine max [L.] Merr.); the 4y rotation was corn, soybean, spring wheat (Triticum aestivum L.) underseeded with alfalfa (Medicago sativa L.) and alfalfa. Only corn grain was significantly influenced by tillage strategy; CT systems yielded more than ST systems, regardless of rotation. Soybean grain yields were similar among CT-2y, CT-4y, ST-4y and lowest in the ST-2y. Yields of wheat and alfalfa were the same under both tillage strategies. Weed seed densities were higher in wheat and alfalfa, followed by corn then soybean, but were not influenced by tillage or rotation, nor universally negatively correlated to yield. Due to greater corn yields, overall system productivity was highest in CT-2y, the same between CT-4y and ST-2y, and lowest in ST-4y. Within years, productivity of CT-2y was different from only one other system at a time in 3 of 8 years and had the same productivity as all systems in another 3 of 8 years. Additionally, the similarity of productivity among three of four systems in 6 of 8 years indicated reduced tillage and diverse rotations have potential for adoption. Results support the need for research on a rotational tillage strategy, i.e., moldboard plowing before corn, to improve overall productivity if using ST before soybean, wheat and alfalfa.

Cover crops are known to promote many aspects of soil and water quality, yet estimates find that in 2012 only 2.3% of the total agricultural lands in the Midwestern USA were using cover crops. Focus groups were conducted across the Corn Belt state of Iowa to better understand how farmers confront barriers to cover crop adoption in highly intensive agricultural production systems. Although much prior research has focused on analyzing factors that help predict cover crop use on farms, there is limited research on how farmers navigate and overcome field-level (e.g. proper planting of a cover crop) and structural barriers (e.g. market forces) associated with the use of cover crops. The results from the analysis of these conversations suggest that there is a complex dialectical relationship between farmers' individual management decisions and the broader agricultural context in the region that constrains their decisions. Farmers in these focus groups shared how they navigate complex management decisions within a generally homogenized agricultural and economic landscape that makes cover crop integration challenging. Many who joined the focus groups have found ways to overcome barriers and successfully integrate cover crops into their cropping systems. This is illustrated through farmers' descriptions of their ‘whole system’ approach to cover crops management, where they described how they prioritize the success of their cover crops by focusing on multiple aspects of management, including changes they have made to nutrient application and modifications to equipment. These producers also engage with farmer networks to gain strategies for overcoming management challenges associated with cover crops. Although many participants had successfully planted cover crops, they tended to believe that greater economic incentives and/or more diverse crop and livestock markets would be needed to spur more widespread adoption of the practice. Our results further illustrate how structural and field-level barriers constrain individual actions, as it is not simply the basic agronomic considerations (such as seeding and terminating cover crops) that pose a challenge to their use, but also the broader economic and market drivers that exist in agriculturally intensive systems. Our study provides evidence that reducing structural barriers to adoption may be necessary to increase the use of this conservation practice to reduce environmental impacts associated with intensive agricultural production.

Innovation is essential for agricultural and economic development, especially in today's rapidly changing global environment. While farmers have been recognized as innovation generators, many innovation studies continue to consider them as recipients or adopters of externally promoted innovations only. Based on household data from Ghana, this study, in contrast, investigates the innovation-generating behavior among rural farmers. Inspired by two innovation theories—induced innovation and innovation systems—we specifically focus on how to build the capacity of farmers to generate innovations. Controlling for selection bias, we show that participation in farmer field fora (FFF), a participatory extension approach, can play a positive role in strengthening farmers' innovation-generating capacity. Specifically, we show that FFF participants have about 27% higher probability of generating innovations than non-participants, and FFF participation appears to increase the number of innovation-generating practices implemented by a farm household by about 49%. However, we do not find significant spillover effects of FFF on the innovation-generating capacity of non-participants, which has implications for the cost-effectiveness of the FFF program. The results also indicate that education and risk preference are important drivers of farmers' innovations. We conclude that policies for the generation of innovations among farmers should focus on building innovation capacity through institutional arrangements that permit interactions and learning between stakeholders.

The paper reports on a study of community gardening in Stockholm. We contribute to the body of knowledge about the sustainability of community gardens and this new form of citizen-led initiatives in Stockholm, with the ambition of creating a debate about the best way to sustain and develop these initiatives in Sweden. We argue that although community gardening may provide leverage for means of developing a sustainable city, it is a marginal phenomenon and contributes little to sustainable development its present form. Through interviews we have investigated how the citizens and municipality officers of Stockholm try to adapt to the renewed interest in community gardening by looking at the policy makers’, municipality officers’ and grassroots movements’ incentives to start community gardens. We specifically focus on how the community gardeners articulate their reasons for participating in collaborative initiatives in the city and how these expectations evolve when they are faced with the reality of gardening and the problems relating to producing food in the city. We have found that there are a growing number of citizens and local authorities advocating community gardening, but the sustainability and endurance of gardens are hampered by vague responsibilities, lack of leadership and unclear expectations of the outcome. Community gardening cases in Stockholm contribute to the debate by exemplifying how formal (e.g. policy making) and informal advocacy (e.g. civic engagement in community gardening) groups are collaborating, but also showing that they often have different agendas and initial motivations for setting up new gardens. We argue that uncritical enthusiasm results in an overly instrumental approach to governance of community gardening and that the sustainability and endurance of the community gardening is not an issue that the governing bodies plan for, and hence it is forgotten. We suggest some routes forward, involving employing facilitators from various stakeholders such as the municipality, housing companies and various NGOs.

Climate change impacts on agriculture have been intensifying in the Northeastern United States. In order to encourage the adoption of climate change adaptation and mitigation practices by farmers, it is critical to understand their perspectives on the risks they face and actions they are taking. However, very few empirical studies have considered how farmers are interpreting and responding to climate impacts, risks and opportunities in the Northeast. This study investigates farmer views and decisions related to climate change using data from six farmer focus groups conducted across New York and Pennsylvania. The study examined how farmers perceived climate impacts on their farms, the practices they are willing to adopt, and how perceived risks and vulnerability affect farmers’ decision-making related to adaptation and mitigation strategies. Although farmers articulated concern regarding climate impacts, they also made clear that other business pressures, such as profitability, market conditions, labor availability or government regulations were often more critical issues that affected their decision-making. Decisions about adopting climate change adaptation and mitigation practices vary widely, and personal experience with extreme weather and changing seasons affected decision-making. The findings from this study provide improved understanding of farmers’ needs and priorities, which can help guide land-grant researchers, extension and policymakers in their efforts to develop and coordinate a comprehensive strategy to address climate change impacts on agriculture in the Northeast.

Governments and NGOs have enthusiastically promoted value chains for lesser-known indigenous fruits in the pursuit of poverty reduction and other development goals. This paper examines experiences in Peru in building the value chain for camu-camu—a fruit native to the Amazon that is in the process of being domesticated. We look at interventions to build the chain, the environment in which the chain operates, the implications of chain development on livelihoods, and prospects for future chain development. Information was collected from gray literature as well as from primary data from household and key informant interviews. The results of this study suggest that the emergence of the camu-camu chain has led to higher farm income without generating large trade-offs in livelihood activities or the environment. However, the results also demonstrate an unrealized potential to achieve greater impact at scale due to gaps in services and inputs, limited coordination among farmers and chain actors, and a risky business environment. Building value chains for lesser-known fruits will require more than a techo-managerial focus on smallholder production. Greater attention is required to build stronger public–private collaboration to expand and diversify markets, with particular attention on strengthening institutions and growing local markets for high-value products.

Many states including California allow fruit and vegetable checks (FVCs) issued by the Women, Infants and Children (WIC) Program to be redeemed at farmers’ markets. Despite the potential of the FVC program to increase the revenue of participating farmers and to provide fresh, locally grown fruits and vegetables to WIC participants, analysis of data for California shows that redemptions of FVCs at farmers’ markets have to date been miniscule. We study the barriers to use of FVCs at farmers’ markets and consider strategies for expanding both farmer and WIC client participation in the farmers’ market program. Our methodology involved design, implementation and analysis of surveys of both farmers’ market managers and farmer vendors who participate in the program and analysis of the behavior of WIC participants through California WIC program redemption data. One major factor limiting redemptions in California is that relatively few farmers’ markets currently accept FVCs and both market managers and farmers report that the authorization process is onerous. WIC participants who shopped at authorized markets more fully utilized the fixed-dollar value of their voucher, compared with participants who shopped at other authorized WIC vendors. Nevertheless, participants who visited a farmers’ market are unlikely to return. The study concludes with suggested pathways to increase WIC participant utilization of farmers’ markets.

Agricultural diversification has been identified as one of the mechanisms for managing household food security and poverty in developing economies, because it can spread the risk among multiple production enterprises and provide a range of food items for the households. By examining the integrated farming systems of 608 smallholders in Ghana, this paper presents empirical evidence to support the development of effective strategies that enhance diversified farming systems. The estimated mean diversification indices were 0.45, 0.32 and 0.59 for crop, livestock and crop–livestock diversification systems, respectively. Using the Cragg two-step regression model, this paper shows that the decision to diversify and the extent of diversification are distinct decisions affected by different sets of factors. Likewise, the effect of these factors also varied across the three categories of diversification examined. Careful consideration needs to be given to the selection of factors and the methods for examining the diversification process to avoid confounding recommendations. The findings underscore the importance of households’ access to tillage equipment, fertilizers, credit and market information in encouraging farmers to diversify.

Although crop diversity has been identified as essential to enhance global food security and adapt to climate change, high loss of genetic resources is occurring due to agricultural industrialization and market requirements. Value chain development is an emerging market strategy that seeks to simultaneously achieve agrobiodiversity conservation and economic goals, though little empirical evidence exists regarding the extent to which value chains encourage biodiversity maintenance. This study considers the conservation of native potatoes among households in the highlands of Peru where value chain development is being pursued to create market niches for certain native potato varieties. Utilizing a mixed-methods case study approach, the findings of this study indicate that the conservers of native varieties are the households with more endowed resource bases as well as those that sell native varieties in value chains. However, the findings suggest that value chains themselves likely have only a marginal effect on conservation. Native potato conservation and potato production for value chains exist as two separate livelihood activities, and households with more resources are best positioned to engage in both. While value chains allow households to capitalize on the economic value of certain native varieties, the production of other native varieties allows households to fulfill cultural values. Based on these findings, this study concludes that value chain opportunities for native varieties should continue to be identified but they alone are not an adequate strategy to conserve agrobiodiversity. Therefore, in addition to value chain development, a full suite of conservation schemes should be implemented simultaneously.

Agriculture is one of the most vulnerable sectors to climate change, and in many agricultural communities climate change adaptations by farmers are underway. Farmers’ beliefs about climate change and their experiences with climate change, along with a range of other factors, could influence climate change adaptation. Utilizing a framework which draws from research examining how farmers’ climate change beliefs and experiences affect their adaptation strategies, and research on farm succession and adaptation at the rural–urban interface (RUI), we ask ‘How do climate change beliefs and different farm attributes (particularly the presence of an heir and location at the RUI) affect adaptation strategies?’ Preliminary findings indicate that adaptation varies based on multiple factors, including belief in climate change, the presence of an heir, geographical location and a variety of other farm characteristics and farmer attributes.

Hulless oats are of interest as an alternative to corn and wheat in organic poultry diets because they offer potential to enhance agrobiodiversity and produce locally grown feeds both within and outside of corn-growing regions. Hulless oats are easily certified GM-free and have demonstrated nutritional value for poultry. A feeding study was carried out to examine: (i) the effects of substituting corn, wheat or a fraction of each with hulless oats in organic layer diets, and (ii) the importance of oat variety in feed performance. Productivity and economic implications in the context of current organic markets were explored. Experimental diets included an oat-free control, Oat + corn, Oat + wheat and Oat + corn + wheat, each of which was formulated with three hulless oat varieties, AC Gwen, Paul and Streaker. All but the control diet included oats at 200 g kg−1. Three hundred Hy-Line Brown hens were individually caged and allocated to diets in groups of 10 in a completely randomized design with three replicates per diet. Experimental diets were fed between 24 and 32 weeks of age during which time hen health, egg production and egg quality indicators were monitored. Results indicated that hulless oats had no negative effects on hen health and productivity. On the basis of current organic feed ingredient prices and an estimated cost of USD 533 mt−1 for production of oats in the study region, oat containing diets were more expensive than the oat-free control. In an evaluation of revenue based on current market prices for organic eggs, the additional cost was completely offset by larger egg sizes of hens on oat containing diets. There were no major differences associated with oat variety.

Greater London has a vibrant food scene comprising of many different types of urban and peri-urban ‘short food supply chains’ (SFSCs). This paper reports on exploratory research, which used examples of SFSCs from London to build a more detailed understanding of different types of urban SFSC and their relative performance compared to each other. To do this, we undertook a participatory sustainability impact assessment (SIA) in which local food system stakeholders were asked to rank the perceived impacts of five different urban and peri-urban SFSCs compared with the current ‘mainstream’ food supply system (defined as supermarkets retailing mass-produced, standardized food products). The SFSCs ranked were: (1) urban gardening (self-supply), (2) urban gardening (commercial), (3) community supported agriculture (CSA), (4) direct sale (on-farm) and (5) direct sale (off-farm). Results from the SIA showed that CSAs were regarded as delivering the highest overall social, economic and environmental benefits, followed by urban gardening (commercial), urban gardening (self-supply) and direct sales (off-farm). The lowest overall rating was for the supply chain direct sales (on-farm). All five SFSCs were ranked highest on the social aspects of sustainability. Following the participatory SIA of perceived sustainability, we next developed a questionnaire in order to test the feasibility of measuring the specific (rather than ‘perceived’) impacts of an urban SFSC. We applied the test at a community-led local food market in South London, where we conducted face-to-face interviews with all market stallholders (18 respondents) and a random sample of consumers (51 respondents). Results from the community-led market were similar to those acquired at the SIA workshop, with greater agreement about the social benefits of the market, compared with economic and environmental impacts. The results also suggest that producers underestimated consumers’ willingness to share the risks that the producers face and we identify this as an important aspect for future research. The paper concludes with reflections on the strengths and weaknesses of the SIA methodology.

Global value chains (GVCs) have grown to represent the major source of modern food and grocery items. Yet there is an increasing preference among consumers toward locally sourced and supplied foods among perceptions of health, economic and community benefits. Typically purchased in farmers’ markets and specialty outlets, local foods are becoming more widely available in supermarkets, who are now interested in how they might introduce or increase that product range. We collect actual purchase data from a regional supermarket chain and analyze the drivers of higher local food proportional outcomes across a sample of consumers. Attempts to link theoretically important drivers of local food purchasing in traditional (e.g., farmers’ market) outlets to supermarket settings proved difficult. Results do, however, suggest some means by which parties interested in developing local value chains between regional suppliers and supermarket outlets could be achieved. As such, the study is a useful first-step in the development of new value chains to address future potential issues of socio-economic stratification and inequality as a consequence of GVC prevalence.

Agricultural service providers often work closely with producers, and are well positioned to include weather and climate change information in the services they provide. By doing so, they can help producers reduce risks due to climate variability and change. A national survey of United States Department of Agriculture Farm Service Agency (FSA) field staff (n = 4621) was conducted in 2016. The survey was designed to assess FSA employees’ use of climate and weather-related data and explore their perspectives on climate change, attitudes toward adaptation and concerns regarding climate- and weather-driven risks. Two structural equation models were developed to explore relationships between these factors, and to predict respondents’ willingness to integrate climate and weather data into their professional services in the future. The two models were compared with assess the relative influence of respondents’ current use of weather and climate information. Findings suggest that respondents’ perceptions of weather-related risk in combination with their personal observations of weather variability help predict whether an individual intends to use weather and climate information in the future. Importantly, climate change belief is not a significant predictor of this intention; however, the belief that producers will have to adapt to climate change in order to remain viable is. Surprisingly, whether or not an individual currently uses weather and climate information is not a good predictor of whether they intend to in the future. This suggests that there are opportunities to increase employee exposure and proficiency with weather and climate information to meet the needs of American farmers by helping them to reduce risk.