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.
As in previous years multiple crops were evaluated for their yield response to varying application rates of compost. Both pumpkins and sunflowers showed a significant effect of compost rate on yield. Pumpkin yields, however, were maximal at intermediate compost rates (10 and 20 tons per acre) and not at the maximum compost application rate of 40 tons per acre as has been observed in other crops in previous years. Based on these results and our experience with both agronomic and horticultural crops in low (no compost) versus high (compost) input organic farming systems, a decision tree was developed to provide compost rate recommendations to growers. The decision tree has seen limited implementation by growers up to this point.
A weed control study, as part of our yearly weed management trials, was initiated to measure the potential weed suppression effects of members of the mustard family on weeds in a large-seeded crop (corn). The experiment was abandoned after the mustards failed to yield enough biomass in late spring (June) to continue the study.
Three undergraduate student interns worked on the organic farm project in 2005 in the compost rate trial, market garden, and farming systems trials. In addition 3 M.S. graduate students concluded their research on the farm. Their thesis topics ranged from lamb production to vegetable production in organic farming systems. The results of their research will be used to prepare manuscripts for submission to peer-reviewed journals.
Growers and farmers participated in multiple on farm evaluations of organic management practices developed by the WVU organic farm project. We now have 10 lamb producers enrolled in on farm rotational grazing trials. Rotational grazing has been shown to be useful way to control intestinal parasites although not a 100% effective control method. Small changes to this method such as adjustments to the rotation periods should allow for even better control in the future. Three growers are using the parasitic wasp Pediobius foveolatus to manage Mexican Bean Beetle population in green beans with much success. Our 2005 results on the WVU farm confirmed data collected in 2004 showing almost a doubling of green bean yields when P. foveolatus is used to control Mexican Bean Beetles. The results were presented at the annual American Society for Horticultural Science in Las Vegas in July of 2005.
Yields in the market garden plots, both in the low and high input system were in general lower than in 2004 due to disease pressure, climate, and rodent and deer damage. Both peas and spinach continue to suffer from extensive root rot problems. Lettuce and bean crops were severely damaged by rodents and deer. Tomato fruit set was poor due to dry weather conditions. Zucchini and peppers yielded normal crops and showed 25-50% lower yields in low input plots versus high input plots, a trend observed throughout the experiment, now in its 6th year.
In 2005, Dr. Moritz published his work from the first two years of our study (2003-2004) showing that methionine supplementation is not necessary for poultry production in organic farming systems. Experiments on poultry production continued in 2005 with a comparison of feeds containing oats instead of wheat with an eye on reducing feed costs.
The annual organic farm field day was held on July 14 and as in previous years featured workshops, demonstrations, and tours of the farm. Approximately 70 people attended, significantly fewer than previous years (200-2003, 180-2004). However, we attracted approximately the same number (20) of growers and farmers as in previous years.
Impacts and Contributions/Outcomes
In 2005 we made significant progress towards some of our objectives and performance targets.
Performance targets and milestones in which we met or exceeded our original goals include training undergraduate and graduate students and enrolling sheep producers in rotational grazing trials. We now have 12 sheep producers that have incorporated or are incorporating (or at least using it on a trial basis) rotational grazing as part of their farming system. We also have formally trained 11 undergraduate interns and 4 graduate students, 3 of which graduated in 2005. As part of graduate training one manuscript was published in 2005. At least 3 additional manuscripts were either submitted or are in preparation.
Participation in on-farm evaluations was good but did not meet performance targets for 2005. We have 3 actively participating growers, two less than our performace targets. We will continue our efforts to enroll more growers and farmers to meet this specific goal.
In 2005 a compost application decision tree tool for growers was finalized. The decision tree has seen little use so far both as a factor of grower/farmer interest and the time the decsison tree became available for use. Again we will continue our efforts in disseminating the organic practices and tools developed by the project.