To examine the long-term productivity, profitability, and ecological interactions associated with whole farming systems, we established an interdisciplinary replicated comparison of a conventional and an experimental alternative crop-livestock farming system in southwest Virginia in 1988. The conventional system uses the best management practices commonly used in the mid-Atlantic region. The alternative system puts more emphasis on crop rotation, grazing and forage management, conservation tillage, cover crops, and integrated pest management. Each is managed as a year-round system, with management decisions based on the system's overall goals.

The comparison is planned to run for 10 years, so that only preliminary conclusions can be drawn so far. These include the following: 1) similar total productivity can be achieved with either reduced or full use of herbicides and insecticides; 2) the need for N fertilization can be decreased using grazing management and short-rotation alfalfa; and 3) recycling of manure from cattle fed corn silage provides most nutrients needed for the following corn crop. The comparative profitability of the two systems has fluctuated among years, and it is too early to know which system is more profitable. The process of interdisciplinary systems research has increased our knowledge of total system interactions, challenged prior assumptions, and clarified the methodological problems of integrated systems research.

On-farm field demonstrations provide a useful method of technology transfer for researchers and extension specialists, and the proponents of alternative agriculture have adopted on-farm experimentation as an important means to establish the value of sustainable methods. For on-farm research long narrow strips harvested by machine are often employed in place of small hand-harvested plots commonly used at research facilities. The use of this approach, however, could bring the methodology into question if field variation should make determination of statistical differences difficult. Analysis of harvest data from ten irrigated and four dryland site-years for small hand-harvested corn plots and for machine-harvested long narrow strips was conducted to determine the impact of sampling method upon experimental variation. Analyses of variance indicated that six of the ten machine-harvested irrigated sites had significant yield response to applied nitrogen while only one of the ten hand-harvested sites exhibited significant nitrogen effects (P ≤ 0.10). The difference in statistical precision was not a result of increased range in yields, but rather of more consistent yields for each treatment. An economic analysis was performed, and the results indicated that optimum nitrogen rates depended on corn and nitrogen price ratios. When 1989 corn and nitrogen prices were used, the calculated marginal profit levels between the reduced nitrogen and recommended nitrogen rate ranged from $8.92 to -$8.14 per ha. For the irrigated sites, when experimental variation (F-test of total sum of squares) was compared by harvest method, hand harvest had significantly greater variation than machine harvest in five experiments. Machine harvest was significantly more variable in one comparison. Coefficients of variation for machine harvest were less than for hand harvest in nine of ten irrigated experiments. For the dryland sites, differences between harvest methods were significant in one of four experiments. These data suggest that under certain conditions machine-harvested long narrow strips provide more accurate estimates of treatment differences than do small hand-harvested plots despite potential differences in soil texture, soil fertility, or available soil water.

Evidence indicates a strong positive relationship between increases in nitrogen fertilizer use on cropland and nitrate concentrations in shallow ground water. This raises concern about the fate and efficiency of nitrogen fertilizer with current farming practices. Approximately 50 percent of the nitrogen fertilizer applied may be recovered by agronomic crops and 35 percent or less removed in the harvested grain of a crop such as corn. The residual nitrogen is subject to loss by several processes, one being leaching from the crop root zone. Alternative production systems that provide ground water protection must give attention to improved management of nitrogen fertilizer and to practices that minimize the need for nitrogen fertilizer and reduce soil nitrate concentrations. Most important in nitrogen fertilizer management is to more closely match nitrogen availability in the soil with crop needs and to avoid over-fertilization. Nitrogen fertilizer use can be reduced by alternate cropping of low and high nitrogen-demanding crops, use of legumes in the crop rotation to fix nitrogen, and proper use of manures, crop residues, and other organic wastes. Residual nitrates in soil can be reduced by use of cover crops, nitrogen-scavenging crops in the rotation, and alternating shallow and deep-rooted crops. Conservation tillage alone as used with many conventional cropping systems will probably not change the current status of nitrate leaching. Practices used by organic farmers should be carefully studied as possible approaches for ground water protection and adaptation into conservation tillage systems for conserving soil and water resources.

Most of Austria's organic farms are located in mountainous areas and produce mainly milk and beef, whereas a low percentage of cash-crop farms are organic. As a result, the demand for organically grown crops cannot be fully met by domestic production. This paper investigates the barriers to adoption of organic agriculture by cash-crop farmers in Austria. In a written survey, 383 conventional farmers provided information on their perception of organic farming and rated the importance of potential barriers to adoption. Technical challenges in cropping and additional labor requirements were rated as the most important barriers, followed by fear of decreased income and marketing problems. Structural and social issues, such as farm size and lack of support from family members, were less important.

U.S. crops have the potential routinely to produce 15–25% more, and in some cases 100% more, with no more water or fertilizer, but are prevented from doing so by diseases, nematodes, arthropod pests, and weeds. It is not compatible with the goals of a sustainable agriculture to fertilize, cultivate, and water for maximum production, but then allow diseases and pests to limit actual yields to some fraction of what was paid for with the capital investments and agronomic inputs. In eastern Washington and adjacent northern Idaho (The Palouse), wheat generally yields 4,800–6,200 kg/ha in years of normal precipitation (45–55 cm), but yields 6,900–9,000 kg/ha with the same water and fertilizer if the soil is fumigated to eliminate root disease organisms and weeds, and the plants are protected from rusts, pseudocercosporella foot rot, and aphids. Some practical alternatives to soil fumigation (depending on the value of the crop) include crop rotation, tillage, flooding the soil, heating the soil (using clear plastic tarp or by burning residue on the soil surface), and organic amendments that intensify the biological stresses on pathogen propagules in soil. Other disease controls include using pathogen-free planting material, maintaining a diversity of genetic resistance, and adjusting planting date and method of seeding to escape pathogens. Some of the emerging technologies include improved serological and molecular methods for diagnosing pathogens, microorganisms that kill pathogen propagules in soil or protect the plant, simulation models of epidemics to forecast disease outbreaks, and integrated pest management systems. Better experimental a pproaches are needed to identify and determine the priorities of the combinations of biotic and abiotic factors that limit yields, and more attention should be given to holistic plant health care.

Many of the characteristics of common purslane that describe this species as a “weed” are also desirable traits for a living mulch. Common purslane was investigated as a living mulch in spring broccoli production in Connecticut and was compared with mechanical and chemical weed control, as well as black plastic mulch. Common purslane seed was broadcast prior to transplanting broccoli in late May 1993 and in early June 1994. Broccoli yields with the purslane living mulch were comparable to yields with conventional methods of weed management and with no reduction in crop quality. Common purslane living mulch was able to effectively compete with weeds in broccoli when between-row areas were kept relatively weed-free by hoeing or hand pulling during the first 2 weeks after broccoli transplanting. High levels of weed control and ground cover occurred when purslane became established between crop rows. Broccoli plants were tolerant of purslane living mulch and weeds up to a critical threshold level without a significant reduction in yield. Purslane living mulch established through periodic mechanical weed management was determined to be the most economical treatment in the study. While including purslane living mulch in a spring broccoli crop production system may be a novel approach to controlling weeds, the strategies involved in this system still rely on basic weed management principles.

The March 1989 food safety episodes involving Alar on apples and the cyanide tainted grapes found in a Chilean shipment were seminal events in the history of U.S. organic agriculture. Demand for organic produce soared as a consequence of these events, and mainstream supermarkets began adding more organic produce to their traditional product lines. But when organic supplies proved scarce, and as prices increased, consumer purchases decreased and many marketing managers began to question the rationality of allocating scarce shelf space to organic products. In fact, many supermarket chains either drastically reduced their organic offerings or dropped them altogether. Some analysts proclaimed that organics had failed the market test. However, two surveys we carried out in 1989 and 1991 among major California supermarket chains show that forecasts of the demise of organic produce in mainstream markets may have been premature. Of 16 chains responding to our survey, 12 continue to carry organic produce. All had carried organics for more than six months, two-thirds of them for more than a year. Of the 12 that carry organics, six rate organics as worse overall than conventional produce. But, interestingly, six rate organics as “about the same” as conventional produce. This is a significant achievement for organics. Organics rated better on environmental impact and residues, worse on appearance and shelf life, and “about the same” on flavor and nutritive value. Despite the constraints and difficulties encountered in marketing organic foods, 8 of the 12 chains that carry organics would carry more organic fruits and vegetables if supplies were available. The prospects for certified “pesticide free” produce are less definite.

An areawide program for biological control of the alfalfa weevil showed expected economic benefits of $2.2 billion, expressed in present value terms. Alfalfa producers and consumers of livestock products are the main beneficiaries. The control program was highly successful, with a benefit/cost ratio of about 91. Not all areawide biological pest control programs will be as successful; a benefit-cost analysis like the one described here should be performed before areawide control is initiated to identify programs expected to provide economic benefits.

One of the major gaps in the empirical literature comparing conventional and organic farmers is the degree to which conventional farmers would prefer or can be motivated to use reduced-input practices comparable to those of alternative agriculturalists. This paper presents the results of a 1987 survey of a random sample of New York farm operators and a two-thirds sample of the membership list of the New York State chapter of the Natural Organic Farmers Association (NOFA-NY). The results show that while conventional farmers tend to have a lower preference for reduced-input practices than do alternative agriculturalists (NOFA-NY members), conventional farmers tend to prefer pest- and disease-resistant crop varieties, nonpurchased, on-farmproduced sources of fertility, and nonchemical means of disease control over high-input, chemically-based production practices. The largest differences between conventional and alternative agriculturalists are with respect to preferences for weed control practices. For six of the eight practices assessed, operators of small farms (annual gross sales less than $40,000) were intermediate in their preferences between commercial-scale farmers (gross sales $40,000 or more) and alternative agriculturalists. There was, however, virtually no difference between conventional and organic farmers in their tillage practice preferences; similar percentages of the NOFA members and commercial-scale farmers preferred minimum tillage practices, while the percentage of small farmers preferring to use as few tillage operations as possible was lower than that of both commercialscale and organic farmers. Differences between conventional and organic farmers in their production practice preferences are far smaller than differences in their environmental orientations.

A traditional flooding practice showed promise for reducing pesticide use in Massachusetts cranberry beds. The 4-week long spring flood, termed “late water,” checked pressure of two of the most prevalent and severe management problems, cranberry fruitworm (CFW) and fungal finit rots (CFR). Fruit rot generally was equal or lower and infestation of fruitworm was consistently lower at the late water beds compared with unflooded beds, even though no fungicides were used for CFR control (standard practice is two or three applications per season) and insecticide applications for CFW were cut by almost 70%. Although there were no significant reductions in yield in two of the years studied, a significant decline (about 25%) occurred on late water beds in one year for unknown reasons.

Over 61% of farmers who sell agricultural products through farmers' markets are satisfied with the returns they generate. Producers who are 50 years of age or older and those who retail at least 70% of the dollar value of the products are more likely to be highly satisfied with their profit margin from farmers' markets. A strong positive relationship is documented between profit margin satisfaction and growers who offer organic produce for sale. Furthermore, the results suggest that producers with farmers' market businesses in the growing stage are more likely to be highly satisfied with profit margins.

A survey of organic farmers in New York State identified problems in need of university research. Weed management was the most frequently mentioned problem by far, identified as significant by two-thirds of the organic farmers. Only a few other problems were listed as significant, including insufficient time for farm work, lack of markets, low prices, and lack of appropriate tools. These were cited by more than a third of the farmers. Drought, insect management, and a lack of a dependable supply of labor were cited by about one-third of the respondents. The survey also examined organic farmers' information sources. They do not use conventional sources of agricultural information, such as the extension service and conventional agricultural media, as much as books, magazines, and newsletters on organic f arming, other organic f armers, and on-farm experiments. Many respondents noted that local extension agents did not know very much about non-chemical solutions to organic production problems. They considered University Extension to be accessible, but not very useful in solving problems specific to organic farming, and had many suggestions to improve Land Grant research in organic agriculture.

Crops grown on sand and gravel spoil areas are subject to temperature, moisture, and nutrient stresses due to the infertile, acidic, and coarse-textured properties of the spoil material. Additions of organic materials such as feedlot manure and sewage sludge compost applied at rates of 40, 80, and 160 Mg/ha were found to improve these spoil areas by providing (1) a more favorable pH for seedling germination and root development, (2) essential crop nutrients, and (3) a greatly increased water content of the spoils in the treated plots compared to fertilized controls. The manure-treated spoil plots had a higher water content than either the compost-treated spoils or the limed and fertilized control plots. In a drought year when the wastes were reapplied, both grain and stalk yields of sweet corn were highest for the manure-treated plots. The low heavy metal content makes these organic materials safe for use as soil conditioners. In addition, uptake and accumulation of toxic metals by sweet corn is generally less than other crops. The interaction between the kind and rate of organic amendment applied, the amount of rainfall in any given growing period, and the water content of the treated spoils determined the final nutrient composition of the stalks, leaves, and grain, as well as the grain and stalk yield.

Living mulches are vegetative covers that can be grown in association with row crops to reduce soil erosion, improve trafficability and suppress weeds. Interference by the living mulch can reduce yields of an associated crop. The interference between a white clover (Trifolium repens L. ‘New Zealand’) living mulch and sweet corn (Zea mays L. ‘Golden Jubilee’) was studied using an established clover sward that was mowed and then sprayed with 1 to 1.5 kg ai/ha of atrazine. Corn was planted at different densities and planting arrangements into a narrow band tilled in the clover. Interference by clover reduced corn yields by 12 to 39%. However, when corn row width was reduced from 0.76 to 0.38 m, competition among corn plants declined; they became more vigorous and clover- suppress ive and reached even higher yields than conventional (no mulch) corn in 0.76 m rows. Similarly, sweet corn planted at a range of densities into a clover mulch killed by atrazine yielded more in equidistant planting than in wide (0.76 m) rows. A near equidistant corn planting arrangement can be a low-input alternative to achieve season-long clover suppression and thus minimize clover's competition with the intercropped corn.

Wood residues are applied to soils to improve their organic matter content and related biological, physical, and chemical properties. We monitored the changes in soil total C and N content, the bacterial, fungal and actinomycetal populations, and microbial biomass and activity during 20 weeks in the first season following the application of chipped wood from twigs (CWT), and as residual effects during the second growing season on a loamy soil (coarse loamy, mixed, frigid, Humic Fragiorthod) in Sainte-Brigitte-des-Saults (Québec) Canada. Wet-aggregate stability and the content of nutrients of the soil also were determined. Adding CWT stimulated the bacterial and actinomycetal populations very rapidly (within 8 weeks); in the second season the effect was less pronounced and gradually disappeared. The most significant and long-lasting effect was on the fungal population in two consecutive years of observation, with increases of up to 24-fold. This stimulation of fungi possibly was responsible for the large and significant increase in wet-aggregate stability observed in the second year. The effect of CWT on alkaline phosphatase activity and total C and N was observed only in the second season. Some immobilization was seen only in the season immediately following residue application. The addition of the CWT also supplied micronutrients, in particular Zn, which would make it a useful source of some elements in deficient soils. Application of CWT to this soil greatly improved its quality, as revealed by its biological, chemical, and physical attributes.

Practical Farmers of Iowa was founded in 1985 to help farmers generate and share information on environmentally sound farming methods. Its on-farm research trials allow farmers to do statistically valid comparisons of competing techniques, such as different weed control methods. However, sustainable agriculture means more than providing farmers with adequate information about appropriate techniques. It also requires policies that reward farmers for adopting sustainable methods and that support rural community well-being.

Permanent pastures produce far below their potential, as they are usually managed in the northcentral and northeastern United States. Dairy farmers in these regions generally feed their cattle year-round from stored forage and purchased concentrates, and use permanent pastures as mere holding or exercise areas, grazing them continuously. This practice involves high operating costs that, combined with lower milk prices, have resulted in greatly reduced profit margins. Farming practices that return more net income are needed. The Voisin system of rotational grazing management, which applies intensive management to forage crops on pastureland, is widely used on dairy and sheep farms in New Zealand. Farmers using the Voisin system there have low operating costs and obtain high yields of excellent quality forage over long grazing periods; increased net income results Between 1 May and 1 October 1984, 497 forage samples were taken and analyzed from permanent pastures grazed according to the Voisin management system on six Vermont dairy farms. This was done to provide farmers with current estimates of forage feeding value so that they could balance their cows' rations accordingly throughout the season, and determine if they could improve the profitability of their farms by using Voisin grazing management. Average grazingseason analyses (dry weight) were: 22.5% dry matter, 22.4% crude protein, 20.8% available protein, 28.4% acid detergent fiber, 1.18% calcium, .48% phosphorus, 1.60% potassium, .22% magnesium, and 1.58 Mcal/kg net energy lactation. Average dry forage yield was 8.9 metric tons/ha. Dry matter intake was adequate for milk production up to 36 kg/cow/day. Forage protein and energy contents were sufficient for at least 25 and 18 kg milk/day, respectively. On three farms where economic factors were calculated, net profits per cow averaged $67 more during the 5-month period from using Voisin grazing management, compared to continuous grazing of the same pastureland in the year before Voisin management was used. This profit resulted mainly from feed savings and a more favorable milk:concentrate ratio of 4.1:1 obtained with Voisin management, compared to 2.7:1 with continuous grazing and more feeding of stored or machine-harvested forage. Voisin-managed pastures can produce high yields of excellent-quality forage that can be incorporated into dairy feeding programs, thereby reducing feed costs and increasing profitability of the farming operations.

Research aimed at advancing conservation farming practices is typically performed using traditional scientific approaches, which have been highly successful in increasing agricultural output and efficiency. With the current emphasis on environmental and economic sustainability of agriculture, there is a need for a more integrated approach to applied agricultural research. Participatory research helps to bring scientific methods and the integrated production needs of farmers together to develop practical, effective, and carefully tested farming methods. The strength of participatory research is in the synergism of scientists and farmers working together to design, implement, and evaluate research. The development of new technologies for farming systems large or small, conventional or organic, can be greatly enhanced through more extensive use of participatory research.

Interest in reducing purchased chemical inputs to reduce production costs and avoid possible environmental damage prompted this 7-year study. Two management systems, current management practices (CMP) and reduced chemical inputs (RCI), were evaluated for four crop sequences from 1985 through 1992: continuous grain sorghum; continuous corn; a 2-year rotation of corn and double-cropped winter wheat and soybean; and a 4-year rotation of corn, winter wheat/soybean, corn, and red clover hay (changed in 1989 to a 3-year rotation of corn, red clover hay, and wheat/soybean). No-till planting and recommended rates of fertilizer and pesticides were used in the CMP system. In the RCI system, N was supplied by a crimson clover green manure crop or the red clover in the rotation. Weed control was by chisel plowing, disking, and cultivation.

Crimson clover top growth accumulated from 70 to 180 kgN/ha, red clover from 77 to 130 kg N/ha. Rotating crops increased corn yield with CMP but not with RCI. lndry years, corn yields were low (less than 3000 kg/ha), corn did not respond to fertilizer N, and yields generally were higher with CMP than with RCI. With adequate rain, yield of all RCI treatments were the same as yield in CMP continuous corn receiving no fertilizer N. Johnsongrass competition was the main reason for low yields in the RCI treatments. Soybean yields were higher with CMP in 4 years and higher with RCI one year. Wheat and grain sorghum yields were higher with CMP than with RCI. A dramatic decline in johnsongrass in sorghum was noted in 1989, and several plots remained relatively free of johnsongrass through 1992.

Management decisions made during the experiment included the degree of input reduction in RCI; whether to either end or modify unproductive treatments; whether to use newly available varieties and pesticides; whether to suspend the experiment to eliminate johnsongrass; and how to add new treatments while retaining the original treatments.

The transformation of agriculture according to an industrial model has had clear benefits in improving efficiency and lowering production costs, but also has had adverse consequences on rural culture and the environment. Sustainable agriculture offers alternative practices and values intended to promote environmental stewardship, conserve resources, preserve farm traditions, and support rural communities. Strong arguments can be made that it will have these consequences, based on the interactions among agricultural structure, rural community viability, and environmental quality. However, counterarguments can also be made, and the claimed benefits of sustainable agriculture for rural communities must be regarded as not yet demonstrated.