The long-term health of a community's food system is an important indicator of its vitality and sustainability. A logical and appropriate way to revitalize a community is by the development of a local food economy. People throughout the United States are designing and implementing sustainable, local food systems that are rooted in particular places, aim to be economically viable for farmers and consumers, use ecologically sound production and distribution practices, and enhance social equity and democracy for all members of the community. This paper reviews the existing literature on local food systems, examines a variety of strategies and initiatives that are currently underway, and identifies steps that community kaders and citizens can use to develop their own local food systems. Finally, I suggest what research is needed to support these community efforts.

Maximum crop yields require sufficient phosphorus fertilization. Only phosphate in a soluble ionic form (Pi) is effective as a mineral nutrient. Current fertilizer technology supplies the soil solution with Pi via the application of large amounts of phosphate salts. Problems with this technology include energy-intensive production processes, the need for large scale mechanical application with associated environmental consequences, and reprecipitation of the phosphate into insoluble mineral complexes. It has been estimated that in some soils up to 75% of applied phosphate fertilizer may be lost to the plant because of mineral phase reprecipitation. Many approaches, ranging from cultural practices to biological inoculants such as mycorrhizal fungi, are being employed to enhance P-use efficiency. One area that is currently under-investigated is the ability of certain types of bacteria to solubilize mineral and organic phosphates. A review of the literature in the area of bacterial phosphate solubilization confirms that this trait is displayed by a wide range of bacteria. The phosphate starvation inducible (PSI) organic phosphate-solubilizing capability of E. coli is a component of a coordinately regulated gene system: the pho regulon. It has long been known that bacteria are also capable of solubilizing mineral phosphates such as hydroxyapatite. To date there has been no systematic study of the genetics of this phenomenon. Data from my laboratory indicate that the bacterial mineral phosphate-solubilizing (MPS) trait is regulated by the external level of Pi This conclusion is supported by results obtained from several types of molecular genetic studies. It is proposed that bacteria have mineral phosphate solubilizing (mps) genes. The potential agronomic applications of bacterial mineral and organic P solubilizing systems are discussed.

The impact of soil degradation on human welfare and the global environment presents a major challenge. A significant decline in soil quality has occurred worldwide through adverse changes in its physical, chemical and biological attributes and contamination by inorganic and organic chemicals. There is a need to develop criteria to evaluate soil quality so that the progress of any corrective action required by the international community can be monitored.

There currently are no generally accepted criteria to evaluate changes in soil quality. This lack impedes the design and evaluation of meaningful soil management programs. This paper examines the principal physical and chemical attributes that can serve as indicators of a change in soil quality under particular agroclimatic conditions. Proposed indicators include soil depth to a root restricting layer, available water-holding capacity, bulk density/penetration resistance, hydraulic conductivity, aggregate stability, organic matter, nutrient availability/retention capacity, pH, and where appropriate, electrical conductivity and exchangeable sodium. We also discuss the justification for selecting these key attributes, their measurement, critical limits for monitoring changes in soil productivity, and future research needs in soil quality.

Different chemical, physical, and biological properties of a soil interact in complex ways that determine its potential fitness or capacity to produce healthy and nutritious crops. The integration of these properties andine resulting level of productivity often is referred to as “soil quality.” Soil quality can be defined as an inherent attribute of a soil that is inferred from its specific characteristics and observations (e.g., compactability, erodibility, and fertility). The term also refers to the soil's structural integrity, which imparts resistance to erosion, and to the loss of plant nutrients and organic matter. Soil quality often is related to soil degradation, which can be defined as the time rate of change in soil quality.

Soil quality should not be limited to soil productivity, but should encompass environmental quality, human and animal health, and food safety and quality. There is inadequate reliable information on how changes in soil quality directly affect food quality, or indirectly affect human and animal health. In characterizing soil quality, biological properties have received less emphasis than chemical and physical properties, because their effects are difficult to measure, predict, or quantify. Improved soil quality often is indicated by increased infiltration, aeration, macropores, aggregate size, aggregate stability, and soil organic matter, and by decreased bulk density, soil resistance, erosion, and nutrient runoff. These are useful, but future research should seek to identify and quantify reliable and meaningful biological/ecological indicators of soil quality, such as total species diversity or genetic diversity of beneficial soil microorganisms, insects, and animals.

Because these biological/ecological indexes of soil quality are dynamic, they will require effective monitoring and assessment programs to develop appropriate databases for research and technology transfer. We need to know how such indexes are affected by management inputs, whether they can serve as early warning indicators of soil degradation, and how they relate to the sustainability of agricultural systems.

A mail survey was used to gather information from the main food buyer in random households in southeast Missouri to analyze consumer preferences for locally grown food. A majority of shoppers in the region were not aware of the state's AgriMissouri promotion program. Consumers defined locally grown not as a statewide concept but as a narrower regional concept that could cross state boundaries. Most important when purchasing produce were quality and freshness, and most consumers perceived local produce at farmers' markets to be of higher quality and lower price. Farm households were not significantly different from other households in the region and did not show a preference or willingness to pay a price premium for local food products. Food buyers who were members of an environmental group had higher education and income and were more likely to purchase organic food and more willing to pay a higher price for local produce. Households in which someone was raised on a farm, or had parents who were raised on a farm, had a preference for locally grown food and were willing to pay a price premium for it. Marketing local products should stress quality, freshness, and price competitiveness, and appeal to environmentalists and those with a favorable attitude towards family farms.

The 1999 severe crop season drought in the northeastern US was followed by hurricane-driven torrential rains in September, offering a unique opportunity to observe how managed and natural systems respond to climate-related stress. The Rodale Institute Farming Systems Trial has been operating since 1981 and consists of three replicated cropping systems, one organic manure based (MNR), one organic legume based (LEG) and a conventional system (CNV). The MNR system consists of a 5-year maize–soybean–wheat–clover/hay rotation, the LEG of a 3-year maize–soybean–wheat–green manure, and the CNV of a 5-year maize-soybean rotation. Subsoil lysimeters allowed quantification of percolated water in each system. Average maize and soybean yields were similar in all three systems over the post-transition years (1985–1998). Five drought years occurred between 1984 and 1998 and in four of them the organic maize outyielded the CNV by significant margins. In 1999 all crop systems suffered severe yield depressions; however, there were substantial yield differences between systems. Organic maize yielded 38% and 137% relative to CNV in the LEG and MNR treatments, respectively, and 196% and 152% relative to CNV in the soybean plots. The primary mechanism of the higher yield of the MNR and LEG is proposed to be the higher water-holding capacity of the soils in those treatments, while the lower yield of the LEG maize was due to weed competition in that particular year and treatment. Soils in the organic plots captured more water and retained more of it in the crop root zone than in the CNV treatment. Water capture in the organic plots was approximately 100% higher than in CNV plots during September's torrential rains.

Diverse soil microbiological studies have attempted to assess deterioration or improvement in soil quality. These studies have been done on three levels: population level studies of the dynamics of species that are presumed to be important or sensitive; community level studies of microbial community structure, such as species diversity and frequency of occurence of species; and ecosystem level studies of a range of soil processes. We suggest that ecosystem level approaches offer the best possibilities for rapidly assessing changes in soil quality. Data from such studies will allow researchers to decide whether to proceed with population or community level studies.

Invertebrates are an integral part of soils and are important in determining the suitability of soils for the sustainable production of healthy crops or trees. We discuss the importance of the soil invertebrate fauna in relation to terrestrial habitats and global biodiversity as we understand it. We describe the role of the main invertebrate groups in soils, including earthworms, termites, springtails, and nematodes, and how they determine soil quality. Practical problems in dealing with the invertebrate fauna include sampling, taxonomy and availability of biological information on species. Various measures are available that use invertebrates to assess soil quality, each with its advantages and disadvantages. They include abundance, biomass, density, species richness, trophic/guild structure, food web structure, keystone species and ecosystem engineers. We propose the three most useful and practical of these as suitable to be combined with other biological (microbial) and non-biological (hydrological, physical, chemical) criteria into a single index of soil quality that might be used on a regional, if not international basis.

Weed seed consumption experiments involving comparison of rates of seed loss by seed feeders were conducted over a five-week period in low-input (no insecticide, low herbicide usage) conventional- and no-tillage soybean agroecosystems. Seeds of four broadleaf weed species (ragweed [Ambrosia artemisiifolia L.], pigweed [Amaranthus retroflexus L.], sicklepod [Cassia obtusifolia L.], and jimsonweed [Datura stramonium L.]) and one grain crop species (wheat [Triticum aestivum L.]) were provided in a free choice design at densities of 10, 25, and 50 seeds/24 cm3. Approximately 2.3 times more seeds overall, and 1.4 times more large seeds as a group were consumed in notillage systems than in conventional-tillage systems. In our experimental low-input, notillage treatments, large ground beetles (Carabidae: Coleoptera) (15–25 mm) and mice preferentially fed on the larger seed species, while small carabids (< 15 mm), ants and crickets, fed almost exclusively on the smaller seed species. Carabid beetles were responsible for more than half of all seeds consumed. Laboratory and field studies indicated that ground beetles selectively consumed specific seed species. In conventional-tillage, ants were one of the dominant consumers of seeds, suggesting different patterns of resource partitioning in each tillage system. We suggest that selective feeding by arthropod seed feeders, in combination with their high number, could affect the species composition and possibly the abundance of weeds in low-input, no-tillage agroecosystems.

To promote agricultural sustainability, there is a growing interest in developing soil quality indicators that can be used as early indicators of changes in management practices by growers, agricultural professionals, and researchers. A study was conducted on four commercial growers' fields and two research stations in western Oregon with treatments that had been started from 1 to 7 years prior to initiating the investigation. The primary comparison at each site was a winter cover crop and winter fallow in rotation with summer vegetable crops. The effects of these treatments on microbial biomass carbon (MBC), mineralizable N, soil enzyme activity (arylsulfatase and β-glucosidase), and cotton strip decomposition were analyzed to monitor changes in soil quality over a 2-year period. The cotton strip method was tested because of its simplicity (buried in soil for short periods and then assessed for tensile strength or weight loss) and potential as a soil biological indicator. Results showed that cover cropping significantly affected MBC and soil enzyme activity. Mineralizable N and CO2 respiration (laboratory incubation) did not respond to winter cover crop treatment. Cotton strip decomposition was relatively insensitive to field treatments. Because MBC and β-glucosidase activity responded quickly to field management treatment and were less variable than the other measurements, they showed the most potential as soil quality indicators. Total C (organic matter index) and extractable nutrients were not significantly affected by cover cropping (even after 7 years), indicating selected biological properties are superior to these chemical properties for detecting effects of soil management.

In the past several years, researchers, educators, policymakers, and activists have initiated sustainable agriculture programs and efforts the world over. This development has sometimes been accompanied by a sense that it is time to stop discussing sustainability at a conceptual level and get on with the work of making agriculture sustainable. Our perspective is that it is critical to pursue a comprehensive definition of sustainability in order to set sustainable agriculture priorities and ensure that sustainable agriculture takes a path that does not reproduce problems of conventional agriculture. In this paper we briefly review some popular definitions of sustainable agriculture and find that their focus is primarily on farm-level resource conservation and profitability as the main components of sustainability. Others have challenged this approach for either not examining the social aspects of sustainability or for containing an implicit assumption that working on the environmental, production, and microeconomic aspects of sustainability will automatically take care of its social aspects. We propose an expanded conceptualization of sustainability—one that focuses on the entire food and agriculture system at a global level and includes not only environmental soundness and economic viability, but social equity as well. In this perspective, issues such as poverty and hunger are as central to achieving agricultural sustainability as those of soil erosion and adequate farm returns.

This paper summarizes data from previous and current studies on two adjacent farms, one organically managed and the other conventionally managed, in the Palouse region of eastern Washington. The 320-hectare organic farm has been managed without the use of commercial fertilizers and only limited use of pesticides since the farm was first plowed in 1909. The 525-hectare conventional farm, first cultivated in 1908, began receiving recommended rates of commercial fertilizers and pesticides in 1948 and the early 1950's, respectively. The organically-farmed Naff silt loam soil had significantly higher organic matter, cation exchange capacity, total nitrogen, extractable potassium, water content, pH, polysaccharide content, enzyme levels, and microbial biomass than did the conventionally-farmed Naff soil. Also, the organically-farmed soil had significantly lower modulus of rupture, more granular structure, less hard and more friable consistence, and 16 centimeters more topsoil. This topsail difference between farms was attributed to significantly greater erosion on the conventionally-farmed soil between 1948 and 1985. The difference in erosion rates between farms was most probably due to their different crop rotation systems; Le., only the organic farm included a green manure crop in its rotation, and it had different tillage practices. These studies indicate that, in the long-term, the organic farming system was more effective than the conventional farming system in maintaining the tilth and productivity of the Naff soil and in reducing its loss to erosion.

Many farmers and consumers are reevaluating chemical weed control because of the environmental risks of herbicides and their influence on farm size and diversity. This paper reviews research of the last 35 years on mechanical and cultural weed control in corn (Zea mays L.) and soybeans (Glycine max L.). Soybeans can better use the weed control advantages of late planting and narrow row spacing and are less affected by early stand losses from mechanical weed control. In Minnesota, delaying planting to early June allows early germinating weeds to be controlled by preplant tillage but reduces the maximum yield potential of corn by approximately 25 percent and soybeans by approximately 10 percent. Narrow rows allow the crop canopy to close earlier, preventing emerging weeds from developing. However, in a nonchemical weed control system, the row spacing should allow for inter-row cultivation to control weeds that emerge with the crop. Up to a 10 percent reduction in crop stand may be expected in fields that have been rotary hoed. In Minnesota, a 10 percent stand loss results in a 2 percent loss of corn yield potential and no loss of soybean yield potential. Successful mechanical weed control is directly related to the timeliness of the operation. Rotary hoeing is effective on weeds that have germinated but not yet emerged but not on weeds that germinate from deeper than 5 cm, on no-till fields, or on fields with more than 20 to 30 percent crop residue. Inter-row cultivation is most effective on weeds up to 10 to 15 cm tall. Successful nonchemical weed control requires highly refined management skills and is as much an art as a science.

“Sustainable agriculture” means many things to different people in agriculture. At least three different definitions of sustainability are available: sustainability as food sufficiency; sustainability as stewardship; and sustainability as community. Since increased human populations will cause demands for food to continue to grow in the foreseeable future, agricultural sustainability needs to be assessed in ways that will incorporate competing definitions. We suggest that analyzing agriculture as a hierarchical system is the appropriate way to incorporate different concepts of sustainability. Using this concept, we propose a hierarchical definition of sustainability. Agronomic sustainability refers to the ability of a tract of land to maintain productivity over a long period of time. Microeconomic sustainability is dependent on the ability of the farm, as the basic economic unit, to stay in business. Ecological sustainability depends on the maintenance of life-support systems provided by non-agricultural and non-industrial segments of a region. Macroeconomic sustainability is controlled by factors such as fiscal policies and interest rates which determine the viability of national agriculture systems. In our view, there are critical constraints to sustainability at different scales of the agricultural hierarchy. We propose that agronomic constraints are most important at the field scale; microeconomic constraints are dominant at the farm scale; ecological constraints override at the watershed or landscape scale; and macroeconomic constraints are foremost at the regional and national scale. In this paper, we describe the actions of these critical constraints, discuss interactions among various hierarchical levels, and propose ways that agricultural researchers and policy makers can integrate the various views of sustainability.

Several factors can directly or indirectly affect the nutritional quality of crops. Among these are soil factors, such as pH, available nutrients, texture, organic matter content and soil-water relationships; weather and climatic factors, including temperature, rainfall and light intensity; the crop and cultivar; postharvest handling and storage; and fertilizer applications and cultural practices. This paper deals primarily with fertilizer and cultural management practices, and on certain environmental factors that affect the nutritional quality of field crops and of fruits and vegetables. Earlier research that has investigated the nutritional status of crops grown with either chemical fertilizers or organic fertilizers is discussed. These studies often have given contradictory results on crop yields and on crops' mineral and vitamin contents. Other factors, such as maturity at harvest, postharvest handling and storage, anti-nutritive components, and residues of chemical fertilizers and pesticides are reviewed with respect to food safety and quality, and their implications for human and animal health. Future research needs are identified so that comparable results and valid comparisons can be obtained to identify the best management practices to ensure that food is safe and nutritious for the consumer.

Our knowledge of soil is based primarily on quantitative analysis of isolated physical, chemical, and biological properties. However, the interaction of these quantitative aspects determines soil quality. Integrative tools are needed by researchers, farmers, regulators, and others to evaluate changes in soil quality from human activity at a local and global level. An index needs to be adaptable to local or regional conditions. For example, the parameters needed to determine changes in soil quality may differ between a semi-arid wheat field and a rice paddy. Suitable reference points and optimum ranges are needed for soil quality attributes. The present challenge is to integrate a suite of soiltests into a meaningful index that correlates with productivity, environmental, and health goals.

Genetic improvements in crop tolerance to diseases, insects, and other stresses have reduced or eliminated applications of pesticides and other inputs for many crops. However, little work has been done to examine the potential for increasing levels of tolerance to weeds, even though herbicides account for 69% of the pesticides used in the United States eachyear. This paper documents thatfor all 21 crops examined, varieties differ in their tolerance of non-parasitic weeds. Characteristics influencing varietal tolerance to weeds are summarized.

Microbial activities important to effects on crop productivity and nutrient cycling can be altered by agricultural management practices. This study was conducted to determine whether soil microbial populations and their N cycling activities differ between conventional and alternative management practices. Physical, chemical, and microbial soil properties were measured at soil depth intervals of 0 to 7.5, 7.5 to 15, and 15 to 30 cm at a site in southeastern Pennsylvania during the second and fifth years after conversion from a conventional, chemically intensive system to alternative systems utilizing legumes and animal manure as N sources. In the second year after conversion, populations of fungi and bacteria, dehydrogenase activity, and soil respiration in the surface soil layer were greatest with alternative systems planted to red clover (Trifolium pratense L.). Differences in soil biological factors between management systems were related primarily to crop characteristics and, to a lesser extent, to soil physical properties. Levels of microbial populations and activities with conventional management were the same as with alternative management systems when similar crops such as corn (Zea mays L.) or soybean [Glycine max (L.) Merrill] were grown. Soil NO3-N contents, at most sampling depths, were markedly increased by application of fertilizer N or recent plow-down of red clover or hairy vetch (Vicia villosa Roth). The growth of red clover in the second year or hairy vetch in the fifth year was accompanied by significantly increased microbial biomass and potentially mineralizable N (PMN) reserves in the top 30-cm soil layer-these changes being most pronounced in the surface 0- to 7.5-cm layer. Nitrogen deficiency symptoms and lower corn grain yields in a legume/cash grain rotation as compared with conventional management in the second year were associated with lower soil NO3, levels and a greater proportion of N present as weed biomass and belowground microbial biomass. In 1985, management systems comparisons were limited to corn as the main crop; soil NO3 levels during the growing season were inversely related to soil microbial biomass and PMN levels where hairy vetch was overseeded and incorporated as green manure by plowing before corn planting. Under the conditions of this study, the use of chemicals had little effect on microbial populations, their activity, or the cycling of nitrogen. Cropping systems-in particular, the growth of red clover or hairy vetch—profoundly influenced soil microbial biomass levels and soil pools of organic and available NO3-N during the growing season. Competitiveness of alternative management systems employing legumes as? sources for grain crops may depend largely on the grower's ability to synchronize supplies of available soil N with periods of maximum uptake by grain crops.

Underestimation of the pivotal role played by managed and native insect pollinators is a key constraint to the sustainability of contemporary agricultural practices. The economic value of such insects to pollination, seed set, and fruit formation greatly outweighs that suggested by more conventional indices, such as the value of honey and wax produced by honeybees. Although the European honeybee has been widely regarded as the single most important pollinating species, the increasing spread of trachael and Varroa mites and Africanized bees threatens the distribution and magnitude of traditional honeybeekeeping enterprises in North America. A number of other bee and insect pollinators, such as orchard bees, bumblebees, and squash bees, which are not affected by either the mites or the Africanized bees, are considered as likely candidates for management and use in commercial agriculture. An additional role can be played by native or wild pollinators, provided that attention is given to curtailing of population losses caused by both inadvertent insecticide poisoning and habitat destruction. To ensure a reliable source of pollinators, both managed and native, a more comprehensive strategy for management of crop pollination is needed. Elements of this strategy include an increased understanding of the biology and ecology of pollinating insects, as well as providing appropriate nesting habitat, and ensuring the availability of alternative sources of “forage” to sustain populations when the target crops are not in bloom. Examples are discussed to illustrate how private initiatives and changes to public policy can enhance pollinator habitat, and ultimately, agricultural productivity.

Soil is the world's most vital component for food and fiber production: preservation of this critical natural resource is paramount for protecting the environment, and ensuring that current and future populations are healthy and well-fed. In many countries of the world, including the United States, soils are being degraded at an alarming rate by wind and water erosion, desertification, and salinization resulting from misuse and improper farming practices. Often the topsoil is lost at a rate that far exceeds the capacity of natural processes to regenerate it. With soil degradation, there is a concomitant decline in soil quality, i.e., the soil's capacity to produce healthy and nutritious crops, resist erosion, and reduce the impact of environmental stresses on plants. Many decades of research have consistently shown that the best means of improving and restoring soil quality and productivity is by proper and regular additions of organic materials mainly through the use of crop rotations, cover crops, crop residues, animal manures, composts, and reduced tillage.