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.

In many respects the long standing and vigorous debates over alternative agriculture and organic farming are becoming less strident and less polarized. However, despite the mounting evidence that key elements of both the conventional and alternative agricultural communities are beginning to “build bridges” to each other, and to establish formal institutional programs and arrangements for improved communication and program development, important differences continue to separate the proponents and opponents of alternative agriculture. In part, these lingering differences result from the lack of adequate and reliable data, misinformation, and faulty data analyses. In order to clarify those issues which continue to divide the critics and advocates of alternative agriculture, this reappraisal of the debate begins with a methodological critique of comparison studies of conventional and organic farms. Also included is an assessment of fertilizer and pesticide use in American agriculture, the environmental impacts of conventional and reduced-input systems, the relationship between alternative agriculture and efforts to save the family farmer, and the prospects for increased public sector research on reduced-input farming systems.

Increased food production and greater income for farm families are primary goals of agricultural development in the Third World. Most strategies to achieve these goals are unrealistic in assuming that limited resource farmers can move out of basic food production in multiple cropping systems to high-technology monocropping for export. These strategies are based on petroleum-based inputs that demand scarce foreign exchange. They may include excessive use of chemical fertilizers and pesticides, which adds unnecessary production costs, endangers the farm family, and degrades the rural environment. Dependence on export crops and world markets is economically tenuous, especially for the small farmer. Future agricultural production systems can be designed to take better advantage of production resources found on the farm. Enhanced nitrogen fixation, greater total organic matter production, integrated pest management, genetic tolerance to pests and to stress conditions, and higher levels of biological activity all contribute to resource use efficiency. Appropriate information and management skills substituted for expensive inputs can further improve resource use efficiency. On the whole farm level, appropriate cropping on each field can be integrated with animal enterprises, leading to a highly structured and efficient system. Such systems can serve the needs of national agricultural sector planners, who in many countries are concerned with increased self-reliance in farming inputs and in production of basic food commodities. This includes a realistic focus on training of local development specialists, increased research on food crops under limited resource conditions, and providing information, incentives, and appropriate technologies for operators of both large and small farms. Well-conceived national plans include varied food production strategies and options for farmers with different resource levels.

A 294-acre Pennsylvania crop and livestock farm was modeled under alternative management practices using linear programming. The management practices included conventional, organic, and no-till production, with and without the use of overseeding and cover crops. For each of the management practices, soil erosion was estimated using the Universal Soil Loss Equation. Profitability was compared across the options with and without constraints on soil erosion. Prior to constraining soil erosion, no-till was found to be the most profitable option. The conventional option was next most profitable, followed closely by the organic option. The use of cover crops or overseeding was found to be unprofitable when high levels of soil erosion were allowed. When soil erosion was constrained, the relative profitability of the options changed. It was found that practices that can control erosion with the least reduction in the intensity of rotation, such as planting cover crops, overseeding and no-till, are the most profitable options when soil is constrained to below 5 tons per acre. No-till remained the most profitable option at low levels of soil erosion. The economic advantage of conventional over organic production diminished as soil erosion was constrained. Below 5 tons per acre of soil erosion, the organic system became more profitable than the conventional system. It was found that use of overseeding or cover crops makes a more profitable rotation possible at low levels of soil erosion.

In areas where farmland is under heavy development pressure but where farms are too small to compete in major marketing channels with larger farms in other regions, producers must use channels that capitalize on their proximity to consumers. This advantage is greatest for fresh fruits and vegetables, provided farmers understand their urban customers' purchasing preferences. This study interviewed more than 600 customers at farmers' markets and supermarkets in six urban and suburban communities in eastern Massachusetts and at agricultural fairs. Respondents were asked about their reasons for purchasing fruits and vegetables at various sites, about their preferences, if any, for produce grown locally, and about changes that might cause them to purchase more local produce. The results suggest that for local origin to be taken into account by consumers, the produce should be sold in a locally oriented environment, e.g., a farmers' market. Although the particular supermarkets in this study featured locally grown produce in their advertising, this seems to have had little effect on consumers' buying. Conversely, consumers' highly favorable opinion of farmers' markets involved several factors besides the localness of the produce in a purely geographic sense. These included the pleasant environment, the (presumed) short time since the produce was picked, and the opportunity to purchase directly from the producer in a face-to-face transaction.

Basic microbiological information is presented which is relevant to an understanding of the decomposition of crop residues in conservation and conventional tillage practices. Little has been known about the role in crop residue decomposition of microbial populations that grow on dead leaves and stems of crop plants standing in the field after maturation. Even the identity of such organisms has not been thoroughly defined. Dead leaves and stems were collected from corn and from other field crop, garden, and native plants standing during weathering after maturation in fields at Beltsville, Md., and at seven other U.S. locations in the fall of 1984 and the spring of 1985. Certain “field fungi” from the genera Alternaria, Cladosporium, Fusarium, and Helminthosporium (Bipolaris) occurred as a common population growing on samples from most locations in spite of major differences in temperature and precipitation during the weathering. All fungi observed are known from the literature to be able to decompose native cellulose in pure culture. Some can grow on plant waxes. They grow poorly, if at all, in the absence of oxygen. All grow best in the presence of free water; none are true xerophytes, although some can resist wetting-drying cycles. They are mesophiles and exhibit most rapid growth at about 25–28 C. Some can survive over winter in plant tissues in cold climates. Probable relevance of these characteristics to residue decomposition in field situations is discussed.