Evaluation of Crop Rotation for High Value Cool Season Horticultural Crop Production in Organic and Sustainable Systems

Project Overview

Project Type: Research and Education
Funds awarded in 2010: $200,000.00
Projected End Date: 12/31/2014
Region: Southern
State: Georgia
Principal Investigator:
Dr. George Boyhan
University Of Georgia

Annual Reports

Information Products


  • Agronomic: potatoes
  • Fruits: berries (strawberries)
  • Vegetables: broccoli, carrots, onions, peas (culinary)


  • Crop Production: crop rotation, cover crops, nutrient cycling, organic fertilizers
  • Education and Training: extension
  • Farm Business Management: new enterprise development, budgets/cost and returns, agricultural finance, risk management
  • Pest Management: biological control, cultural control
  • Production Systems: organic agriculture
  • Soil Management: green manures, organic matter, soil analysis, nutrient mineralization, soil quality/health
  • Sustainable Communities: local and regional food systems


    This three-year study evaluated two vegetable rotations of cool season crops and warm season cover crops for their productivity, economic viability, disease management, and soil building potential. Crop yield and economic profitability were closely linked in that the crops that had good yields also were most profitable. The most profitable crops were onions and lettuce. To a lesser extend broccoli and potatoes were also profitable. Strawberries did well the first year, but yields and profits declined in years 2 and 3. Carrots, bush beans, and southernpeas all had little or no profits. There was little effect of either rotation on soil organic matter. Cover crops did not result in notable increases in organic matter and there was a net loss of labile nitrogen. Longer term work needs to be done to assess soil management strategies. As expected from what is observed in cool season organic vegetable production in Georgia, disease pressure was low.

    Project objectives:

    The overarching objective of the study is to evaluate the profitability and production characteristics of two cool-season vegetable crop rotations in the Piedmont and Coastal Plain physiographic regions. The research will be conducted at University Research and Education Centers that have certified organic land in each region.

    Objective 1 - Develop an econometric model to evaluate the profitability of the two rotations.

    Objective 2 - Evaluate changes in plant nutrient status, crop yield and quality in the two crop rotations. Data on harvest date, yield, and graded yield will be collected for all treatments. Tissue samples will be collected to evaluate plant nutrient status at critical growth stages.

    Objective 3 - Evaluate changes in soil quality in the two crop rotations. Changes in soil quality will be measured using total carbon and nitrogen, potentially mineralizable nitrogen, active carbon, pH, and Mehlich extractable P, K, Ca, Mg, and Zn.

    Objective 4 - Determine disease incidence in the two rotations and on the specific crops grown.

    Objective 5 - Evaluate the research and potential impact, and disseminate results.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.