Comparison of Organic Farming Systems Using Off-Farm Nitrogen with - without Animals
The objectives of this project are to evaluate the sustainability of organic farming systems that rely on biologically-fixed nitrogen versus those using off-farm nitrogen to maintain cropland, and to compare the production, soil quality, and environmental impacts of crops-only organic farming systems with systems integrating crops and livestock. The project continues one begun in 1999 when the West Virginia University Horticulture Farm underwent the transition to organic practices. Replicated field trials in vegetable (market garden) and field crops using a randomized factorial design are being continued through 2005. Plots receiving compost are amended with compost to supply 150 pounds nitrogen per acre each year to enhance soil fertility. A four-year crop rotation is being maintained in both market garden and field crop farming systems. In addition, in the field crop system, livestock production (sheep and poultry) and pasture are being integrated into half of the field crop systems. Pest management practices are being evaluated in replicated field plots and in on-farm trials with five grower-cooperators. Results are being communicated to growers, extension staff, and the public through field days, internet web pages, and other media outlets.
The overall objective of the project is to compare organic farming systems using biologically-derived nitrogen (legumes) with systems using supplemental nitrogen from off-farm composted manure. Soil quality, pest impacts, yields and economic performance are being measured and results are being communicated to growers.
Specific performance targets include:
1. Ten growers identified from our grower advisory committee, attendees at Farm Field Days, or commodity organizations, will base, at least in part, their compost use rates on soil quality and economic performance criteria developed from this phase of the project.
2. The proportion of growers that are transitioning from conventional to organic production that have incorporated research and cost-benefit results in their decision-making in designing a transition system for their operation will increase to 50 %.
3. Nine undergraduate students will be trained in organic farming practices through internships. Farm-related experience will be provided to additional undergraduate and graduate students through work experience, research opportunities, field days, and classroom and non-classroom activities.
4. Five growers per year, identified at field days and through direct contacts, will participate in on-farm evaluations/demonstrations of selected practices in the following year. These selected practices will include: use of barriers (row cover, particle film sprays, etc.) for pest management; rotation practices, diversification through integration of livestock into the farming system, and weed management using mulches.
5. Twelve producers will incorporate practices for management of internal parasites in sheep using either rotational grazing and/or alternating sheep and poultry on pastures.
Small plot trials continued evaluation of acetic acid as a weed management practice, and compost application rates were evaluated for optimum bean and millet yield response. Companion planting trials showed differences in crop productivity between intercropped plants versus monocultures, but few significant differences in pest prevalence.
In the farming systems trials, compost application rates were modified as high rates begin to saturate nutrient holding capacity of soils. Compost application is being restricted to crops that show maximum yield response. Yields were usually slightly but not significantly higher with compost than without.
Four undergraduate student interns were enrolled for the 2003 field season and worked in soil monitoring, horticultural production and crop/livestock systems integration. The 2003 Field Day was held August 7 and featured demonstrations, research tours, and hands-on workshops. Approximately 200 people attended.
Five growers were solicited, from a pool of applicants collected at the last Field Day, to participate in on-farm evaluations of organic management practices. Growers evaluated use of floating row covers, paper mulches, kaolin clay particle film sprays for pest suppression, and acetic acid sprays for weed suppression. Some growers found floating row covers to give excellent yield response in cucurbits, peppers, and crucifer crops, however one grower reported delays in fruiting and shorter, bushier pepper plants under row cover. Kaolin was not effective on crucifers, due to poor sticking ability on the waxy leaves. Acetic acid provided a quick “knockdown” of weeds, but best results occurred when acetic acid was applied to newly-emerging weeds as established weeds quickly re-grew.
Rotational grazing of sheep continues to maintain sheep with low intestinal parasite burdens. Poultry production was integrated with the existing sheep/crops production system in summer 2003. In the first year, pastured poultry without supplemental methionine in the ration achieved growth comparable to poultry with supplemental methionine in the ration.
Impacts and Contributions/Outcomes
Five growers have conducted on-farm evaluations of organic practices under study at the WVU Organic Research Farm. Grower participation at field days and in on-farm application of management practices has increased and student participation in the project is resulting in an increasing pool of trained practitioners. Scientific papers reporting results from the project were presented at meetings of the Weed Science Society of America, the American Phytopathological Society, and the Agronomy Society of America (Northeast Branch). Fact sheets have been prepared (see attached), with assistance and support from the West Virginia University Cooperative Extension program.