Systems of Transition from Conventional to Organic Agricultural Production

Systems of Transition from Conventional to Organic Agricultural Production

Summary

Summary
Low-input transition systems for converting from conventional to organic production were established using green manure and cover crops. These are being compared to high-input systems that rely on compost amendments from off-farm sources. The systems are being assessed in a market garden vegetable production trial and a field crop/livestock trial at the West Virginia University Horticultural Research Farm. Data on soil quality, pest incidence, yields, and economic inputs are being compared. After one season of transition, most crop yields were comparable to national averages. Pest and disease incidence varied with crop, while compost improved certain soil quality indicators.

Objectives
To compare intensive cover cropping and use of compost as methods to convert market gardening and field crop/livestock farming from conventional to organic.

Methods
The WVU Horticulture farm has been managed for conventional fruit and vegetable production for over 80 years. In 1999, the entire farm began the transition to organic management and replicated plots for two experimental farming systems—market garden and field crop/livestock—were established. Each compares two treatments for managing soil quality during the transition: A low-input transition using cover crops only, and a high-input treatment using off-farm compost amendments with cover crops.

Low-input plots were cover cropped intensively in 1999 and 2000. Rye, sown in the fall of 1999, was followed by clover in the spring of 2000 and by rye and vetches in the fall of 2000. All cover crops were plowed in as green manure.

High-input plots were planted to rye in the fall of 1999, then treated with 10 T/acre compost in the spring of 2000. Field plots were cropped to wheat, potato, forage soybean, or Brussels sprouts while the cropping sequence in market garden plots included legumes (beans and peas), leafy vegetables (spinach and lettuce), solanaceous crops (tomato and pepper), and cucurbits (zucchini and pumpkin).

Detailed records were kept of all operations in each experiment so that enterprise budgets can be produced. Two small-plot experiments examined compost application rates and weed management alternatives in greater detail.

Grower outreach and student education projects included three internships for undergraduate students, a training session for organic certification inspectors, and weekly farm sales of organic farm produce to local restaurants as well as direct marketing to the public.

Results
Yields of most crops in the high-input treatments were near or above national averages; however, severe root rot reduced yields of spinach and deer damage affected yields of soybeans and Brussels sprouts. Fencing is under construction to limit damage to next year’s crops. Other pests included aphids, leafhoppers on potato, squash bugs, bean beetles, Colorado potato beetle, powdery mildew on cucurbits, root knot nematode on lettuce, and late blight and early blight on tomatoes.

Soil parameters assayed included soil pH, nutrient availability, plant parasitic nematodes, and earthworms. Results from this first year are preliminary, since the low-input treatment was cover cropped and will not produce cash crops until next year. However, compost treatments did enhance soil nutrient status as expected, and increased earthworm population densities compared to the low-input treatment.

Early season frosts destroyed much of the apple crop. Insect and disease monitoring in orchard crops produced baseline pest data that will be used to design an organic pest management program for the 2001 season.

Impacts and Potential Contributions
Factors affecting the transition from conventional to organic practices are often site-specific, and on-farm monitoring is essential to adapt management practices to developing problems. Results from the initial year of this research demonstrated successful establishment and production of most crops and highlighted aspects that will need to be monitored over the next two years of the project as we begin direct comparisons of crops grown under low- versus high-input treatments.

Since this project evaluates whole-farm systems over a three-year transition phase, the most appropriate comparisons will be the cumulative returns and soil quality improvements over the course of the entire experiment.

Reported November 2000