Annual legumes and mixtures of annual legumes and grasses can perform several functions as understory cover crops in pecan orchards, such as providing nitrogenrich organic matter to improve soil fertility, or by sustaining lady beetles and other arthropods that may aid the biological control of pecan pests. Remaining questions concern selection of appropriate plant materials; whether to use cover crops singly or in mixtures; how to ensure reseeding as well as a substantial N contribution; whether, when, and how to use mowing and tillage; and fertilization options. Different considerations apply when dealing with cool- vs. warm-season cover crops. With minor adjustments, growers could adapt present cultural practices to include cool-season cover crops. These could be used throughout the orchard, by establishing appropriate self-reseeding species and avoiding both excessive mowing and indiscriminate placement of N-rich fertilizers. Within alleys, alternating 2-m strips of cool-season cover crops could be tilled in mid to late April or allowed to mature. The tilled strips would supply N to pecan trees immediately, whereas the adjoining untilled (remnant) strips could be mowed after seed is mature, to ensure dispersal of seed and reestablishment of cover crops over the entire alley. Cool-season annual legumes that die or are killed in late spring will probably furnish N and other nutrients at a suitable time, particularly in orchards with sprinkler irrigation. Warm-season cover crops, if desired, should be restricted to alleys to reduce possible competition with pecan. Alleys provide better illumination than do tree rows during periods when pecan trees are in leaf, and the tillage mentioned above will encourage emergence of warm-season cover crops. If these die or are killed in late summer or early fall, timing of N release may not be optimal, in the absence of adequate irrigation. Many options and tradeoffs need to be explored before choosing a cover-crop system. Attimes, several objectives may appear to conflict, and even delicately-managed mixtures of species may not fulfill all the desired functions.

Winter annual legume cover crops can reduce nitrogen (N) fertilizer requirements and provide a water-conserving mulch to a subsequent crop. A two-year study was designed to test cover crops of rye (Secale cereale L.), hairy vetch (Vicia villosa Roth), and big/lower vetch (Vicia grandiflora Scopoli) for their ability to produce N and to conserve soil water for a succeeding corn (Zea mays L.) crop. We measured the cover crops' biomass, N yield, carbon (C) to N ratio, and influence on a subsequent corn crop grown under two tillage regimes (disk tillage or no-till). Nitrogen content in cover crop biomass at time of corn planting ranged from 37 to 187 kg/ha. Pure stands of hairy vetch and a mixture of hairy vetch plus bigflower vetch had generally higher N yields, and rye was lowest. Rye growing in association with hairy vetch had lower C:N ratios than rye growing alone. Legume C:N ratios remained generally unchanged from earlier (disked) to later (herbicide) kill dates, but total N and biomass typically increased in the last 2 to 3 weeks before corn planting. Soil water retention was affected by tillage in some cases; no-till was superior to disk incorporation in each case where there was a tillage effect. Cover crops with greater biomass resulted in greater soil water retention. Among cover crops, uptake ofNby corn was greater from hairy vetch or hairy vetch plus bigflower vetch mixture. Biological immobilization of N appeared to be reducing N uptake by corn grown in rye residues. Corn in nonlegume plots fertilized with 140 or 210 kg N/ha took up more N than corn following legumes, but there was no corresponding yield increase. Corn biomass yields following the cover crops ranged from 8.6 to 18.0 Mg/ha with no additional fertilizer N. In the second year of the study, average corn yields following hairy vetch (15.3 Mg/ha) or hairy-bigflower vetch mixtures (16.4 Mg/ha) were not statistically different from corn yields produced by a 140 kg N/ha fertilizer rate (17.4 Mg/ha). These results suggest N from a legume cover crop can replace or substantially reduce fertilizer N requirements in corn production systems in the Appalachian region.

Chaff, a by-product of cereal and oilseed production that is largely treated as waste product, may have significant economic value as a ruminant feed, and its collection and removal may reduce herbicide usage and tillage. We surveyed fifty farms located throughout the Brown, Dark Brown, and Black/Grey Wooded soil zones of Saskatchewan to determine the costs and benefits of their chaff collection systems. Benefits measured or estimated included both the feed value of chaff and agronomic benefits in the form of reduced tillage and herbicide requirements. Costs measured were for equipment and machinery ownership, maintenance and operation, including labor. The survey responses showed that, regardless of the type of collection system utilized, feed-related benefits outweighed the costs under the stated assumptions about prices and methods of assigning costs. Agronomic benefits alone also were sufficient to offset chaff collection costs. The net benefits of chaff collection are related to both the quantity of chaff collected and the distance the material is transported.

Excessive nitrogen fertilizer use in corn production has resulted in widespread nitrate pollution of ground water and economic losses for farmers. In addition, reliance on nitrogen fertilizers produced with large amounts of fossil fuels may not be economically or environmentally sustainable in the future. Although leaching of significant amounts of nitrate to the ground water is inherent in growing corn, several techniques are available for more environmentally and agronomically sound management. The following management practices are discussed in this article: sidedress as the main method of N fertilizer application; the pre-sidedress (Magdoff) nitrate soil test; farm-based nitrogen sources (manures, green manures, and rotations with sod crops); cover crops for lowering profile nitrate during the most likely period for leaching; and the end of season stalk nitrate test.

Wildlife and fish have much to gain from the movement toward alternative, sustainable agricultural practices. Interrelated reasons for the habitat improvements to be expected from a change to sustainable systems include reduced use of agricultural chemicals, better care of the soil, and reintroduction of greater landscape diversity. The most well-documented benefits would result from reduced use of agrichemicals, which often are toxic and frequently change the structure and composition of available food and cover. The wildlife benefits of erosion prevention and landscape diversification are less well-documented but may be as significant for habitat improvement. The opportunities to enhance habitat using sustainable farming methods are beginning to receive increased attention from wildlife professionals. As a result, efforts are under way to expand use of sustainable methods on farmlands managed by the U.S. Fish and Wildlife Service.

Labor requirements, production costs, yields, and economic returns were evaluated for conventional and reduced-chemical cropping systems in northeast Iowa from 1978 to 1989. Continuous corn (C-C) and corn-soybean (C-Sb) rotations represented the conventional system; a corn-oat-meadow (C-O-M) rotation represented the reducedchemical system. The C-C and C-Sb rotations used both commercial pesticides and fertilizers. The C-O-M rotation used manure for fertilization and applied pesticides only in emergencies. Operations for all systems were implemented by one farm manager. The C-Sb rotation had the highest corn yield over the 12-year period, and the C-O-M rotation the lowest. The corn within the C-O-M rotation, however, produced the second highest average return to land, labor, and management. With costs of production substantially lower than the conventional systems, the C-O-M corn crop had competitive returns despite lower yield. The C-Sb average return to land, labor, and management was significantly higher than for the other systems. Hourly labor charges of $4, $10, $20, and $50 had little effect on the rankings of economic returns. Because of unusually high alfalfa reseeding costs and low average oat yields, returns to the C-O-M rotation were significantly lower than C-Sb but comparable to C-C. With better alfalfa establishment and higher average oat yields, the reduced-chemical system might have been competitive with the C-Sb conventional system.

Raised field agriculture in southwest Tlaxcala, Mexico, is a sophisticated, intensive traditional system of wetland cultivation that dates back to as early as 300 B. C. It provides an exceptional example of how farming practices can fit into and even take advantage of ecosystem processes. The raised fields appear to be largely self-reliant in energy and nutrients. Tlaxcalan farmers use canals, aquatic plants, polycultures, alder (Alnus firmifolia) and other trees to intensify the nutrient input into their fields and minimize nutrient losses through leaching and runoff Although the raised field system is an impressive, functioning example of a historically sustainable farming system, it is endangered by modern pressures to increase production through higher use of inputs and alteration of agroecosystem design.

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.

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.

A mail survey of Iowa farmers with membership in the Practical Farmers of Iowa, a sustainable agriculture organization, was used to examine perceptions of institutional support for information on reducing chemical inputs, needed research for farming with sustainable practices, and policy needs for encouraging farmers to adopt sustainable practices. We first developed a chemical input index to measure commitment to sustainable practices and to analyze information sources and research and policy needs. Results indicate that sustainable farmers rely primarily on each other and on their personal experience for information about sustainable practices; they use conventional farm practice information sources considerably less. The primary research need identified by the respondents was for better nonchemical weed control. Other important research needs identified were: nonchemical insect control, new seed varieties, cover crops, alternative tillage methods, and the economics of sustainable systems. The primary policy needs identified were more information and educational programs about sustainable agriculture and increased taxes on farm chemical use. We discuss the implications of the relationship between institutional support and the adoption of sustainable agriculture practices.

Combining cover crops and conservation tillage may result in more sustainable agricultural production practices. Objectives of this on-farm study were to quantify effects of cover crops on growth and nitrogen accumulation by soybean [Glycine max (L.) Merr,] and corn (Zea mays L.) on a Nicollet loam (fine-loamy, mixed, mesic Aquic Hapludoll) near Boone, Iowa, Our farmer-cooperator planted soybean in 1988 using ridge tillage into an undisturbed strip with a hairy vetch (Vicia villosa L. Roth) cover crop and into a strip where previous crop residue and a negligible amount of cover crop had been incorporated by autumn and spring disking. In each strip, we established four plots for soil and plant measurements. Our cooperator planted corn on the same strips in 1989 into a cover crop that consisted of both hairy vetch and winter rye (Secale cereale L.). We determined the source of N accumulated by the corn by applying 67 kg N/ha of 15N depleted NH4NO3 fertilizer. In the absence of cover crops, early season soil NO3-N levels in the top 30 cm were higher, and corn growth and N accumulation were more rapid. At harvest, the corn grain, stover, and cob together accounted for 36 and 39 percent of the 15N fertilizer for the ridge tillage and disked treatments, respectively. We suggest that lower net mineralization of organic matter or greater denitrification losses before planting reduced the availability of soil N, This created an early season Nstress in corn grown with cover crops that was not overcome by broadcast fertilizer N applied three weeks after planting. Our on-farm research study has helped focus continuing efforts to determine if non-recovered fertilizer N is being immobilized in microbial biomass, lost by denitrification, or leached below the plant root zone.

Diversification into alternative enterprises appears to be gaining in popularity and economic importance as a way to supplement family income and to provide alternative sources of high-quality food. However, potential rabbit producers lack information about investment requirements and production and marketing costs. The objective of this study was to determine the most profitable operation of small-scale rabbit production by estimating the costs and returns, net present values, and payback periods of two rabbit production systems. Despite a difference in the net income generated, a cash surplus occurred for both systems at the end of the third year. This surplus was the return to land, family labor, and management. Thus, rabbit enterprises may provide economic opportunities for farm families who have limited land and capital.

A rapid reconnaissance survey (sondeo) of twenty-five western Oregon and Washington horticultural producers was conducted using interdisciplinary interviewing teams and flexible on-farm interviews. The group interviewed included both certified organic and conventional farmers who are adopting innovative production methods. Our objectives were to determine the primary factors affecting the choice of farming methods, to identify growers' responses to these factors, to examine the effectiveness of the sondeo technique for gathering such information, to build a team for the longer-term studies, and to locate growers to participate in the longer-term studies. The growers shared characteristics that crossed organic-conventional boundaries. Less experienced growers identified practical crop management issues as their primary problems, while the more experienced ones were concerned with labor and regulatory problems. Most conventional growers were reducing their reliance on agricultural chemicals; organic producers generally used fewer agricultural chemicals, but many relied on organically certified insecticides. A primary regulatory concern among conventional growers was the loss of pesticide registrations for minor crops. Both organic and conventional growers were concerned about government regulation of farm labor, particularly increased paperwork and changing immigration law. Many growers attempted to provide good working conditions to retain a reliable labor force, but a few are mechanizing the harvest to reduce labor requirements. They were aware of the increasing public interest in the health aspects of agricultural methods and were responding with modified chemical use, direct involvement in public education, and membership in commodity groups, cooperative marketing groups, and other grower organizations. The sondeo was a fast and low-cost method for gathering information and provided team members with an interdisciplinary perspective that will be valuable in future research.