Arbuscular mycorrhizal fungi (AMF) are plant root symbionts that provide many benefits to crop production and agro-ecosystem function; therefore, management of AMF is increasingly seen as important to ecological farming. Agronomic weeds that form a symbiotic relationship with AMF can increase diversity and abundance of agronomically beneficial AMF taxa. Also, AMF can strongly affect plant community composition, and may thus provide some degree of biological control for weeds. Therefore, relationships between weeds and AMF have a dual significance in ecological farming, but are relatively unexamined. In glasshouse experiments, seedlings of 14 agronomic weed species were grown in the presence or absence of AMF inocula sampled from each of three types of cropping systems: organic, transitional-organic or high-input/conventional. For each weed species, AMF root colonization rates and growth responses to AMF were assessed. On the basis of observed colonization levels, the species were classified as strong hosts (five species), weak hosts (three) and non-host species (six). Among species, biomass responses to AMF were highly variable. Strong hosts showed more positive responses to AMF than weak hosts, although the range of responses was great. Non-hosts did not suffer consistent negative biomass responses to AMF, although strong biomass reductions were noted for certain species–inoculum combinations. Biomass responses to inocula from different cropping systems varied significantly among weed species in one of two experiments. Results suggest that weed–AMF interactions can affect weed community dynamics. We recommend investigation of these interactions in agro-ecosystems that use management methods likely to intensify weed–AMF interactions, such as conservation tillage and cover cropping.

Organic and low-input farmers often plant seed varieties that have been selected under conventional practices, traditionally including high inputs of artificial fertilizers, crop protection chemicals and/or water. In addition, these crops are often selected in environments that may or may not represent the local environment of the farmer. An evolutionary participatory breeding (EPB) method emphasizes the utilization of natural selection in combination with site-specific farmer selection in early segregating generations of a heterogeneous crop population. EPB is a combination of two specific breeding methods, evolutionary breeding and participatory plant breeding. Evolutionary breeding has been shown to increase yield, disease resistance, genetic diversity and adaptability of a crop population over time. It is based on a mass selection technique used by farmers for over 10,000 years of crop improvement. Participatory plant breeding programs originated in developing countries to meet the needs of low-input, small-scale farmers in marginal environments who were often overlooked by conventional crop breeders. The EPB method is an efficient breeding system uniquely suited to improving crop varieties for the low-input and organic farmer. The EPB method utilizes the skills and knowledge of both breeders and farmers to develop heterogeneous landrace populations, and is an effective breeding method for both traditional and modern farmers throughout the world.

Crop producers are challenged to operate profitably, use resources efficiently, meet high standards of quality and protect the environment, while sustaining rural economies and societies. Cropping systems are generally fine-tuned and improved through changes that have small effects which can often be verified only through research. The processes and successes of two farmer research projects were studied. Results of these studies, information from other sources and the authors' reflections on their own experiences were integrated to develop guidelines for the implementation of farmer research projects for alternative agriculture and multi-functional agro-ecosystems with diverse stakeholders. Surveys were mailed to 118 farmers currently or previously participating in a farmer research project, and to 15 advisors. Responses show that involvement in a farmer research project was profitable, stimulating, enjoyable and worthwhile, despite a substantial time requirement. Tillage and soil fertility research had greater impact on annual farm profit than research on other topics. Farmers and advisors emphasized the importance of the farmers' roles in identification of research topics, research planning and implementation, and interpretation of the results. Replicated trials conducted over 2 or 3 years were recognized as necessary to adequately verify practices for the corn–soybean rotation of eastern Nebraska, USA. Such trials may need to be complemented with alternative research approaches for improving alternative agriculture and multi-functional agro-ecosystems where knowledge about some system components is relatively scarce and there is a need to evaluate long-term effects. In conclusion, organized farmer research is an efficient means to cropping system improvement. Guidelines are given for initiation and implementation of farmer research projects.

In anticipation of the Philippines being a major producer of organic bananas, this study was conducted to provide a quantitative basis for certain practices in organic farming. The nutrient supplying capacity of banana residues in combination with leguminous materials and chicken manure was investigated in composting studies. Changes in the chemical composition of ten formulations of banana residue-based compost involving leguminous plants (Sesbania rostrata, Flemingia macrophylla, Arachis hypogea) and chicken manure were analyzed periodically during a composting period of 16 weeks. Results showed that combinations of banana residues (BnR) and chicken manure or leguminous plants were highly decomposed compared to untreated BnR. The use of leguminous plants and/or chicken manure enhanced the composting process significantly compared to the effect of Bioquick. The compost piles were characterized by increases in pH, total N and total P, and decreases in total K, total carbon and C/N ratio with time. Notably, BnR+chicken manure attained a C/N ratio of 15 at 4 weeks, while the BnR+leguminous materials reached such a low C/N ratio at 8–16 weeks. An incubation study was conducted under greenhouse conditions for 24 weeks. It was designed to follow the dynamics of nitrogen (N), phosphorus (P) and potassium (K) availability in two clay soils (Antipolo and Lipa) amended with five compost formulations (BnR alone, BnR+Sesbania prunings, BnR+Flemingia prunings, BnR+peanut stover and BnR+chicken manure) and with uncomposted banana residue at an application rate of 20 Mg ha−1. Results showed that net N mineralization occurred in soils amended with BnR+chicken manure and BnR+leguminous materials, which had C/N ratios ranging from 12 to 16. Net N immobilization during the earlier period of incubation was observed in uncomposted and composted banana residues with a C/N ratio of 68 and 24, respectively. Significantly higher net P mineralization was obtained only in soils amended with BnR+chicken manure. An abrupt increase in exchangeable K was observed in all treatments 2 weeks after the incorporation of organic residues. Higher available K in pure BnR treatments (uncomposted or composted) exhibits the inherently high K content of banana residues.

This study was carried out under field conditions with the aim of evaluating the period of time necessary for soil cover, dry matter production and accumulation of nutrients by perennial herbaceous legumes with different phosphorus sources at different levels. Four legumes were evaluated: calopo (Calopogonium mucunoides Desv.), forage groundnut (Arachis pintoi Krap. & Greg.), siratro (Macroptilium atropurpureum (OC.) Urb.) and tropical kudzu (Pueraria phaseoloides (Roxb.) Benth.). Each of these species received different phosphorus (P) sources and levels: no phosphate fertilization; 44 and 88 kg of P ha−1 applied as rock phosphate; and 44 kg of P ha−1 as triple superphosphate. Calopo, siratro and tropical kudzu completely covered the soil surface 129 days before forage groundnut. Phosphate fertilization did not increase the dry matter production of any species. The legumes forage groundnut, siratro and tropical kudzu showed desirable characteristics that promote their use as cover crops, such as high dry matter production and shoot accumulation of nitrogen (N) and potassium (K). Forage groundnut had the highest proportion of N derived from the atmosphere at the end of the rainy season, while there were no significant differences between the legumes at the end of the dry season. There was an elevation of soil pH and calcium+magnesium (Ca+Mg) contents, associated with a reduction of aluminum (Al) content, in the surface soil layer (0–5 cm) for siratro in relation to groundnut and tropical kudzu. Tropical kudzu promoted higher soil organic C contents when compared to groundnut.

Local food system potentials were studied in Washington County, Nebraska. As a departure from most studies of locally based systems, farmers were surveyed in addition to consumers for potential participation. Data about the current food system and opinions and preferences for local production, marketing, and purchasing of food were collected using self-administered mail questionnaires. The response rate was 35% for the farmer survey and 37% for the consumer survey. Results indicated that, on the farming side of the food system, conventional corn and soybean production and marketing predominated in Washington County, and farmer interest in producing for local markets was low. Consumers reported a high level of interest in purchasing food from farmers' markets, local grocery stores, local restaurants and directly from farms, and indicated a willingness to pay a price premium for local foods. They also reported that quality and taste were the most important factors in food purchase decisions, but environmentally friendly production and support for local farmers were also important. We conclude that there is tremendous potential for local marketing of farm products, but that there is a large gap between consumer demand and willingness of farmers to meet this demand. Further study of motivations and opinions of farmers is needed, in addition to determining production thresholds for the number of farms and farmers needed to meet local food demands.

Management intensive rotational grazing (MIRG) has garnered a great deal of interest in recent years as a method for returning profitability to Northeastern dairy farms. This work uses a random sample of Connecticut dairy farmers to estimate a binary choice adoption model and then cost, productivity, and profit functions that control for the adoption choice. MIRG adopters are shown to be more educated and have less rented agricultural land (a proxy for lack of access to land within a short distance of the barn). MIRG adoption had no significant effects on costs and productivity, nor did it lower profits, per cow. Evidence was found, however, to suggest that full adopters of the technology had more profitable farms than partial adopters. These results also show the importance of controlling for the different characteristics of adopters when evaluating the returns to animal grazing.