Renewable Agriculture and Food Systems is a multi-disciplinary journal which focuses on the science that underpins economically environmentally and socially sustainable approaches to agriculture and food production. The journal publishes original research and review articles on the economic, ecological and environmental impacts of agriculture; the effective use of renewable resources and biodiversity in agro-ecosystems; and the technological and sociological implications of sustainable food systems. It also contains an open discussion Forum, which presents lively discussions on new and provocative topics. However, the opinions of the Forum and responses are solely those of the authors and do not necessarily reflect the opinions of Renewable Agriculture and Food Systems or Cambridge University Press.

The principal objections to the proposition that organic agriculture can contribute significantly to the global food supply are low yields and insufficient quantities of organically acceptable fertilizers. We evaluated the universality of both claims. For the first claim, we compared yields of organic versus conventional or low-intensive food production for a global dataset of 293 examples and estimated the average yield ratio (organic:non-organic) of different food categories for the developed and the developing world. For most food categories, the average yield ratio was slightly <1.0 for studies in the developed world and >1.0 for studies in the developing world. With the average yield ratios, we modeled the global food supply that could be grown organically on the current agricultural land base. Model estimates indicate that organic methods could produce enough food on a global per capita basis to sustain the current human population, and potentially an even larger population, without increasing the agricultural land base. We also evaluated the amount of nitrogen potentially available from fixation by leguminous cover crops used as fertilizer. Data from temperate and tropical agroecosystems suggest that leguminous cover crops could fix enough nitrogen to replace the amount of synthetic fertilizer currently in use. These results indicate that organic agriculture has the potential to contribute quite substantially to the global food supply, while reducing the detrimental environmental impacts of conventional agriculture. Evaluation and review of this paper have raised important issues about crop rotations under organic versus conventional agriculture and the reliability of grey-literature sources. An ongoing dialogue on these subjects can be found in the Forum editorial of this issue.

The practice of ecological agriculture involves building the strengths of natural ecosystems into agroecosystems, purposely disturbed to produce food and fiber. The overall strategies include using practices that (a) grow healthy plants with good defense capabilities, (b) stressing pests, and (c) enhancing populations of beneficial organisms. These are accomplished by enhanced habitat management both above ground and in the soil. Many of the practices that contribute to the overall strategies are well known—such as intensive use of cover crops or reduced tillage. Reasons for why they have not been more widely used are discussed. The special challenges facing ecological agriculture in the poor countries of the Third World are also discussed. Re-engaging national governments in the active support of their agriculture and addressing the structural inequalities (including access to land) are essential to overcome the many problems facing farmers in the poor countries.

A 1999 United States Department of Agriculture (USDA) policy on organic certification excluded the use of genetically modified (GM) crops. The decision remains controversial because it provokes debate over the fundamental meaning of organic agriculture. Some scholars, farmers and activists claim that organic agriculture represents a value orientation that is opposed to trends in industrial agriculture, of which GM crops are the latest product. Because organic farmers are a significant constituency in this debate, we examined their values and practices related to marketing, environment and GM crops. From a survey of 1181 Washington State farmers, we created a sub-sample of 598 crop farmers (fruits, vegetables and grains), of which 109 described themselves as organic (certified organic, moving towards organic certification and non-certified organic), and we analyzed organic and conventional farmer responses to a number of issues to discern comparative commitment to self-seeking economic interests. Results reveal differences among conventional and organic farmers on GM crops and several marketing and environmental values and practices, suggesting that there is some validity to portraying organic agriculture as an alternative vision to industrial agriculture.

This paper addresses the question as to whether it is profitable to apply a mechanical mulching technology (MT) in the Bragantina region of Brazil and assesses the technology's feasibility as an alternative to the slash-and-burn practices of the Amazon. Using empirical data collected from a prototype assessment and a few secondary sources, the paper employs a cost–benefit analysis of ‘with’ and ‘without’ technology cropping systems (plots that applied the technology are compared with those that did not) to assess the financial and economic feasibility of investing in the MT. The analysis showed that the technology is profitable, both financially and socially, mainly because it is able to produce yields that are high enough to offset the costs, including the hiring of the mulching equipment. However, it may not be a feasible alternative to slash-and-burn farming unless certain conditions are fulfilled by farmers. Most of these conditions relate to farmers' adherence to a set of rules for the successful application of the technology. These rules include the abandonment of a single cropping cycle, typical for the traditional slash-and-burn system, and the adoption of two cycles of crop cultivation. In addition, farmers have to choose profitable crop combinations, such as cassava and beans for both cycles. Since most of the trial farmers did not meet these conditions, the technology received a notably low acceptability (8%). Further analysis indicated that the main reason for this trend was the increase of total labor requirement (by 32%), though the technology reduced labor demand during land preparation to almost zero. Similarly, there was a 22% increase in requirement for inorganic fertilizers. Thus, compared with the slash-and-burn practices of the Amazon, the MT can be regarded as a more intensive method of farming which gives higher crop yields but demands higher quantities of inputs such as labor and inorganic fertilizers. The paper concludes by deriving policy implications for the feasibility of the MT as an alternative to slash-and-burn agriculture in the Amazon. Among these is the importance of creating incentives to extend the cropping period from one to two consecutive cycles. Moreover, the necessity to conduct further studies after the technology has been adopted by the farmers is underscored.

A survey was developed and distributed to the Massachusetts cranberry grower community in 1999 to identify biological, educational, social and political barriers to the adoption of available integrated pest management (IPM) practices. The response rate for the 450 growers who received the survey was 54%. Approximately 80% of respondents claimed to practice IPM frequently and 16% identified themselves as occasional practitioners. Most growers practiced IPM because they agreed with IPM philosophy (80%) and believed it had environmental benefits (73%). Ninety-two percent agreed that more IPM-related research and education programs would encourage them to adopt practices they are not currently using. A significant percentage of respondents used multiple IPM component practices, with practices involving monitoring and detection of pests along with judicious use of pesticides being most common. Factor analysis was used to condense 104 potential responses to 22 factors, which were then used as predictors with six demographic variables (IPM adoption, education level, age, experience, farm size and work status). Demographic factors influenced a grower's tendency to incorporate IPM into routine farm activities. Full-time, highly experienced growers in charge of large operations tended frequently to use more IPM practices than less experienced growers who worked part-time and managed smaller farms. A large proportion of respondents agreed that IPM can reduce pesticide residues in food (92%) and the environment (96%), and can help to preserve beneficial insects (96%). Although many growers held the perception that IPM can pose measurable economic risk (and subsequently act as a barrier to adoption), growers appeared to feel less strongly about the economic benefits than potential environmental ones.

Agriculture faces a multitude of challenges in the 21st century, and new tools are needed to help determine how it should respond. Among these challenges is a need to reconcile how human food consumption patterns should change to both improve human nutrition and reduce agriculture's environmental footprint. A complete-diet framework is needed for better understanding how diet influences demand for a fundamental agricultural resource, land. We tested such a model, measuring the impact of fat and meat consumption on the land requirements of food production in New York State (NYS). Analysis was confined to this geographic area to simplify the modeling procedure and to examine the state's ability to reduce environmental impact by supplying food locally. Per capita land resource requirements were calculated with a spreadsheet model for 42 diets ranging from 0 to 381 g d−1 (0 to 12 oz d−1) of meat and eggs and 20 to 45% total calories from fat. Many of these diets meet national dietary recommendations. The potential human carrying capacity of the NYS land base was then derived, based on recent estimates of available agricultural land. A nearly fivefold difference (0.18–0.86 ha) in per capita land requirements was observed across the diets. Increasing meat in the diet increased per capita land requirements, while increasing total dietary fat increased the land requirements of low meat diets but reduced the land needed for high meat diets. Higher meat diets used a larger share of the available cropland suited only to pasture and perennial crops. Thus, only a threefold difference was observed for the potential number of people fed from the NYS land base (2.0–6.2 million). In addition, some high-fat vegetarian diets supported fewer people than lower fat diets containing 63–127 g d−1 of meat (approximately one- to two-thirds of the national average per capita consumption in the US). These results support the assertion that diet should be considered in its entirety when assessing environmental impact. To more completely understand how diet influences land requirements and potential carrying capacity, this model should be applied across a larger geographic area that encompasses a wider variety of climates and soil resources. To better understand the ability of a local region to supply more of its own food, the model should be moved into a geospatial framework.