Nitrate contamination of surface water resulting from inputs of agricultural drainage water is a widespread problem. To learn whether alternative agricultural practices might ameliorate this problem, we measured NO-3 in water draining from three neighboring fields from 1970 to 1992. Drainage water from two fields fertilized with N exclusively as composted and liquid manure had NO-3 concentrations less than 2 ppm (20% of the Public Health Service recommended limit for drinking water). When these fields were converted to a corn/soybean rotation fertilized with anhydrous ammonia, NO-3 concentration increased about 7- to 10-fold. On a third field, corn was always fertilized with anhydrous ammonia. Changing this field from a rotation of corn, oats and hay to corn/soybean and increasing the rate of N fertilization by about 18% almost doubled the NO-3 concentration in the drainage water. The corn/soybean rotation most prevalent in the Corn Belt today resulted in high NO-3 concentrations in the drainage water, while the alternative system prevented NO-3 problems.

The long-term productivity, sustainability, and environmental impact of cropping systems cannot be assessed adequately using conventional agronomic experiments. This pap erdiscusses the use of computer-based technologies as support tools for this type of assessment, including crop growth simulation models, weather generators, geographical information systems, and risk assessment and economic models. Comprehensive systems that integrate these technologies are just emerging, offering great potential for the analysis of agricultural systems in the future.

Soil erosion is occurring at an alarming rate and threatens soil productivity and crop growth. A regional research committee was formed in the North Central region of the US in 1983 to develop a better understanding of soil erosion and productivity relationships on a broad geographic scale. This paper presents the history, project development and implementation and results of the committee, and a perspective on soil erosion-productivity research approaches. The original project included multistate field experiments on soils selected f or their local extent or agricultural importance. Erosion was classified as slight, moderate, or severe. Cropping practices were continuous corn or small grains, with cultural practices appropriate f or the area. The crop yields on moderately and severely eroded soils were consistently lower than on comparable slightly eroded soils. Precipitation and soil available water holding capacity were the factors most often identified as affecting yields. Other specific limitations were soil- or location-dependent. The most frequent soil limitations were depth of the mollic epipedon/topsoil, organic matter and clay content. Evolving objectives of the committee and state-based research emphases have provided additional information germane to soil erosion-productivity research. More than 40 papers have been published on soil properties, crop growth, management, and modeling as a result of this effort. The regional approach has fostered research on complex interactions among management and environmental factors and led to an increased understanding of functional relationships between soil erosion and productivity.

Sustainable crop production in the Pacific Northwest dry-farmed areas relies heavily on tillage and residue management systems to conserve water. Stable, sustainable yields cannot be achieved without adequate water conservation techniques. Frozen soil can reduce infiltration markedly, which decreases overwinter profile water storage and can cause severe soil erosion. Uncurbed evaporation losses throughout the year can greatly limit yields, particularly with summer fallow.

In both summer-fallowed and annually cropped regions where soil freezes frequently, fall tillage is used to increase surface macroporosity and to provide open channels to below the frost depth. This enhances infiltration throughout the winter and insures better water intake during rapid snowmelt and rainfall when the soil is frozen. Fall tillage enhances overwinter water recharge under these conditions, whereas in areas where soil freezes infrequently, it does not improve water storage efficiency.

In the dry-farmed regions receiving less than 330 mm annual precipitation, a winter wheat-fallow system is used to reduce the risk of uneconomical yields. Successful establishment of winter wheat following summer fallow is feasible only when proper management has suppressed evaporative loss. During the dry summer fallow, tillage is used to develop and maintain a soil mulch that restricts the flow of water, as both liquid and vapor. The tillage mulch effectively conserves stored soil water and maintains adequate seedzone moisture for fall establishment of winter wheat. However, the soil mulch can lead to high wind and water erosion.

In the Pacific Northwest dry-farmed region, tillage by itself is not considered a substitute for proper residue management. Crop residues following harvest are important for conserving water and controlling erosion. Under conservation programs implemented since 1985, shallow subsurface tillage systems that maintain residues on the surface have substantially reduced wind and water erosion in the region. Surface residues are effective in decreasing evaporative water loss and trapping snow during the winter, and therefore increase overwinter recharge. While surface residues are much less effective in suppressing evaporative losses in dry-farmed areas during extended dry periods, residues provide substantial control of wind and water erosion during the fallow.

Before conservation tillage systems came into use in the Pacific Northwest, water conservation frequently was achieved only through tillage. This helped to stabilize yields, but at a high cost to the soil resource. Poor use of surface residues and intensive tillage contributed to extensive wind and water erosion. Continued use of these practices would have caused yields to decline over time and required greater agrichemical inputs. To meet soil and water conservation needs, site-specific tillage and residue management systems were developed to account for the diversity and variability of soils and climate across the Pacific Northwest. Common to all these production systems is that both water conservation and effective residue management to protect the soil are required for long-term sustainable production.

Emergent research shows how some farmer groups in the United States are gaining visibility as a critical knowledge community, making important contributions to the ecological health and overall sustainability of the natural resource base. This study focuses on funded farmer research projects in the north central region, to analyze the process and outcome of local inquiry embodied in the discursive contents of reports to a funding agency, the U.S. Department of Agriculture's Sustainable Agriculture Research and Education program. The analyses suggest that farmers' locality-specific agricultural practices may constitute a reflective and learning community, generating local knowledge keenly attuned to an underlying value system that supports actions towards sustainability.

Organic farming systems differ fundamentally from conventional ones in their primary focus on management practices that promote and enhance ecological harmony. Organic farmers also tend to have a different socioeconomic profile. In this study, we summarize average socioeconomic characteristics and production practices of a national sample of about 300 certified organic vegetable growers from 14 states and compare them to a large sample of about 6,900 conventional vegetable growers. We also examine the specific materials used by organic growers for pest and nutrient management.

Organic vegetable growers tend to be younger, more educated, less experienced in farming, and less likely to have grown up on a farm than conventional vegetable growers, and tend to operate smaller farms. Over three-quarters of the organic vegetable growers surveyed have small operations (less than 10 acres of vegetables), and they are much younger and work fewer days in off-farm jobs than conventional small growers. In contrast to conventional marketing practices, nearly half the surveyed organic growers, and the majority of small ones, market their vegetables directly to consumers through farmers' markets and other direct marketing channels.

The organic growers rely primarily on traditional organic processes such as green manuring (legumes), animal manuring, composting, and crop rotation to supply crop nutrients, and on cultural and biological tools, including pest-resistant plant varieties, water management techniques, adjustment of planting and harvesting dates, and beneficial organisms, for pest management. Animal meal, fish products, and lime are their most frequently reported supplemental nutrient sources (14, 20 and 28%, respectively, reported using these materials), and Pyrellin EC and petroleum-based soaps were the most frequently reported supplemental pest management materials (used by 6 and 8%, respectively). The pest and nutrient materials used by the organic growers are generally consistent with current guidelines of major certification organizations that provide services to organic growers, and there is high consistency among those guidelines and national recommendations for most of these materials.

The demand for more ecologically and economically sustainable agriculture arises because we currently integrate products economically in a fashion that distorts ecologica I relationships. Earfy farms were ecologically integrated through feeding of forage crops and crop residues to livestock, with livestock contributing draft power and manure for crops. Today we have almost entirely uncoupled plant and animal production, eliminating the contribution that each can make to the productivity of the other. Barriers to integrating farming systems include the large volume of information needed for sophisticated production systems and the lack of infrastructure. Also, many chemicals used on crops have not been evaluated for their safety in food animals. Winter feeding and calving may conflict with crop production cycles; balancing year-round forage supplies is another obstacle. Opportunities include using the Conservation Reserve Program to shift land to livestock production. Domestic demand for meat is changing, and range livestock production is seen by some people as more humane than confinement. Animals fed less grain may be more acceptable in some markets. As agriculture responds to changes in society, ecologica I integration may become more compatible with economic integration.

Eight dairy farms located in western Ontario were surveyed as part of an ongoing comparative economic study. The sampled farms had been using organic methods for an average of 5.5 y ears and, therefore, were beyond the “transition” stage. Diversified cropping systems were characteristic of these farms, with most crop products (grain and straw) being used directly by the farms' livestock enterprises. Crop rotations were complex, and generally involved sequences of forages and small grains into which cover crops such as oilseed radish and red clover were integrated. Weed control, year-round soil cover, and production of feed and bedding all contributed to the design of cropping systems. Both solid and liquid manures were composted before application. No feed additives or growth hormones were used, but homeopathic remedies, probiotics, and antibiotics were commonly used. The high cost of synthetic fertilizer and concern for the environment were the main reasons given by the f armers f or adopting organic methods.

Swine production is a major component of Corn Belt agriculture; thus development of a sustainable Corn Belt agriculture depends on sustainable swine production systems. Swine are versatile enough to adapt to sustainable concepts, and swine production raises several opportunities to enhance sustainability. These include: 1) feeding with increased use of forages and by-product feeds; 2) nutrient cycling through improved handling of manure; 3) low-capital housing systems that offer an improved environment for the operator and reduced financial risk; 4) management systems suited to the swine's behavior; and 5) preventive approaches to swine health and a broader genetic base. The challenge beyond identifying the opportunities is research and technology transfer and incorporation of sustainable concepts into ecologically based swine production systems.

A 6-yr interdisciplinary field project using large plots was initiated in 1985 to assist Pacific Northwest growers in developing an integrated pest management system to control weeds, reduce erosion and grow crops profitably. Run by a network of 10 to 14 scientists from eight disciplines supported by five agencies, the project showed that wellmanaged conservation tillage systems had a higher average profit and lower economic risk than traditional conventionally tilled systems. Information was disseminated successfully to user groups by field days, plot tours and an educational video. Organizational strategies included an interdisciplinary design with three levels of objectives. Cooperating scientists were invited to participate in writing the proposal and followed strict field protocols and attended mandatory organizational meetings. This long-term study used large machinery, went beyond the transitional stage and allowed treatments to mature. Limitations included the restricted number of experimental variables, the location of the plots, the large labor force required, and publication decisions.

Conversions from conventional to sustainable farming systems could affect local rural economies either positively or negatively, by several means: changes in income of agricultural households; backward linkages to input supply firms; forward linkages to transportation, processing, and marketing firms; and changes in consumer expenditures by agricultural and other households. We estimated these effects for five local rural economies in South Dakota, representing different agroclimatic and population settlement patterns. Whole-farm economic models of case study conventional and sustainable farms in each area were used to estimate differences in input purchase and marketing patterns. We found declines in on-farm personal income (returns to farm labor and management) in four of the five case comparisons under a conversion to sustainable farming systems if organic price premiums are ignored; we found increases in three of five cases if applicable organic premiums are included. In all five study areas, total off-farm personal income drops in the portions of local economies connected to farming through backward linkages. It also drops in four of the five study areas in the portions of local economies connected through forward linkages if organic premiums are ignored (all five if organic premiums are included). However, net forward linkage effects are usually much smaller than net backward linkage effects, and on-farm personal income effects are substantially greater than either backward or forward off-farm linkage effects in most cases. The total (on-and off-farm) personal income effect of converting to sustainable systems is positive in only one area without organic premiums, and in one additional area with premiums. The ratio of total to on-farm personal income effects within local economies, considering only first round effects on backward- and forward-linked firms, averages 1.2 without organic premiums, or 0.6 with them. Taking account of more complete multiplier effects, which also consider changes in consumer expenditures and changes in expenditures for supplies by backward- and forward-linked firms, the average is 1.8 without organic premiums, or 0.8 with them. With more time for changes in sustainable production techniques and in the structure of farms and the rural economy, the overall economic effects of conversions to sustainable farming are likely to be more positive than our estimates.

As concern about the long-term viability of our food and fiber system has grown, many agricultural research administrators, prominent scientists and policymakers have focused increasing attention on the important research and educational needs in sustainable agriculture. Colleges of agriculture should be important in meeting the challenges of sustainable agriculture; a central question is whether they are adequate for the task. This paper highlights several individual and institutional constraints that limit the ability of these colleges to address the needs: 1) assumptions and biases regarding the relationship between humans and nature, and the concept of progress; 2) the demographic characteristics, education, and experience of research scientists; 3) the specialized departmental organization of research institutions; 4) imbalances among analyses on the molecular, cell, organism and ecosystem levels; 5) emphasis on farm level analysis and technology development; 6) new agricultural biotechnologies that may overemphasize short-term, narrow technical considerations and proprietary products; 7) compartmentalization of education by discipline, and the limited informal and field experiences for students; 8) the background and education of current Extension Service agents; 9) the emphasis on economic effects in research impact assessments, to the neglect of environmental effects and social consequences for farmers, rural communities and society at large; 10) limited capability for comprehensive public policy analysis.

Despite these limitations, new research agendas and college programs are effectively addressing many needs of sustainable agriculture systems. To be more successful, these efforts must be broad-based and sensitive to a wide range of issues, and must include all participants in the system.

A review of orchard soil management effects on tree growth and soil parameters is presented. It shows the gap between present common practices and results achievable in other systems. An alternative soil management system for newly planted peach trees, termed “killed-sod”, is described. This system has improved soil structure and rainfall infiltration and greatly increased early tree growth and yield. A fertilization study has demonstrated that the addition of a complete fertilizer in four different soil management systems could not account for the increased growth resulting from the improved soil environment in the killed-sod system.

Involvement of farmers in sustainable agricultural research can have important benefits, since farmers originated many sustainable agriculture innovations and can contribute a valuable perspective different from that of researchers. However, this does not mean, as is sometimes said, that all kinds of sustainable agricultural research necessarily should give farmers a major role—perhaps the dominant role—in choosing topics and overseeing the work. This belief overlooks the fact that farmers are just one of many groups that publicly supported research is supposed to serve and that their interests do not by themselves embody the full range of goals that sustainable agriculture tries to achieve. Moreover, although farmers can bring valuable insights to research, these alone will not be enough to insure that a sustainable agriculture research program has an appropriate mix of applied versus basic, short-term versus long-term, and component-level versus system-level studies.

We surveyed a total of 549 Cooperative Extension clientele (consumers), farmstand owners, and food industry representatives in New England to assess the potential for certification and labelling of produce grown using integrated pest management (IPM). The survey elicited self-reported knowledge of IPM, perceptions of current pesticide use and IPM, and attitudes toward certification and labelling of produce as “IPMGrown.” The respondents expressed widespread support for certification and labelling of produce grown using IPM. Potential barriers to the marketing of IPM-labelled produce were also revealed. The survey showed the need for education to inform the public about pest management in agriculture and to build confidence in the safety of our food supply.

A shortage of effective, non-chemical pest control measures is a major constraint to more widespread adoption of sustainable agricultural practices. Overcoming this constraint with biological pest control tactics appears to be an attainable goal but will require substantial public sector support. Biological agents that are self-perpetuating do not offer profit incentive to private industry. On the other hand, microbial pesticides, which do require annual application, often are so highly specific for particular pests that the private sector is unable to risk venture capital for their development. Collaboration between public- and private-sector scientists is essential for biological pesticide development. In the U.S., a model working relationship for technology transfer between the private and public sector has been achieved with two commercial mycoherbicides, Collego™ and DeVine™. The model illustrates the strengths of the public sector for creating and storing fundamental knowledge of biological interactions at the organismal and ecosystem levels, also the capability of the private sector for large-scale production of fungi, for drying labile, living products, for effective patent protection, for satisfying EPA registration requirements, and for the commercial distribution, marketing and servicing of agricultural products. From three perspectives-biological, technical, and commercial—the success of Collego™ and DeVine™ has provided a definite step in the quest for low-cost weed control methods that are not hazardous to the environment nor in ground water. These successes also provide a model for an approach to reducing the dependence of agriculture upon chemical herbicides, the most extensively used chemical pesticides in agricultural production, likewise a useful insight toward technology that can lead to more widespread adoption of low-input, environmentally compatible and sustainable agricultural production.

Agricultural and health policies are not integrated in the U.S. despite their obvious similarities and linkages. Sustainable agriculture can undoubtedly play an important role in joining the two sectors; however, before this can occur research is needed to answer questions in many areas. Some consumer concerns regarding the safety of the food supply can be abated through the use of sustainable practices in food production and processing which can lessen exposure to toxic contaminants and conserve resources. Among the farming issues considered here are pesticide toxicities and their synergistic interactions, yields, storability, nutrient quality, nitrates, mycotoxins, and antibiotics used in meat production. The manipulation of commodities during processing is also addressed, including the intense refining of grains, fortification and vitamin supplementation, imitation food, and food additives. Analogies between production and processing operations are drawn and specific research needs identified.

Construction of small water-harvesting structures (WHS) across seasonal streams, in the vicinity of cultivated areas, has proved to be a viable technique of water harvesting in the Shiwalik foothills of northern India. This paper reports on the performance and impact of one such structure in this area. Sufficient rainwater was available for harvesting because 86 ± 5.4% of monsoon rainstorms were runoff producing, resulting in collection of 29 ± 5% of the total monsoon rainfall. Out of this harvested water around 62% was available for irrigation at the start of the Rabi season (i.e., the dry season starting around 1 November). With time the water losses from the WHS declined from 66% in the first year of construction (1985) to 18% in 1996, because of sealing of soil pores from siltation of the reservoir bed. The life of the WHS was estimated to be 65 years at the observed average siltation rate of 47 Mg/ha/year. After construction of the WHS, the area under cultivation increased from 17 ha to 20 ha and the cropping intensity by 170 to 200%. The Rabi crop yields were approximately doubled. Assured availability of water and fodder increased milk production by 103%. Additional annual income of Rs. 7,015 per year was generated through fish culture. A rise in the groundwater level and higher growth of vegetation around the WHS were also observed. On the basis of increased crop production alone, the WHS proved to be an economically viable venture resulting in a benefit:cost ratio of greater than one. Socioeconomic considerations in the management of the WHS were also studied and showed that community involvement was essential to the success of this project.