Participatory Implementation of Sustainable Vegetable Systems for Small and Limited Resource Farmers

Project Overview

Project Type: Research and Education
Funds awarded in 2002: $161,280.00
Projected End Date: 12/31/2005
Region: Southern
State: Alabama
Principal Investigator:
Joseph Kloepper
Auburn University

Annual Reports


  • Fruits: melons
  • Vegetables: peppers, tomatoes


  • Crop Production: conservation tillage
  • Education and Training: technical assistance, demonstration, extension, farmer to farmer, focus group, networking, on-farm/ranch research, participatory research
  • Farm Business Management: cooperatives
  • Pest Management: biological control, cultural control, integrated pest management, mulches - killed, mulches - living
  • Production Systems: agroecosystems, holistic management
  • Soil Management: green manures, organic matter
  • Sustainable Communities: partnerships, analysis of personal/family life, social networks


    Tuskegee University (TU): Weeds are a major problem in tomato production. Until now, methyl bromide has been used as a soil fumigant to control nematodes, weeds, insects, and diseases in tomato fields. However, methyl bromide (MB) has adverse effects on the environment and is due to be taken off the United States’ market in 2006. This makes it important to find an environmentally friendly alternative. Crop rotations that include legumes and grasses may be used as alternatives to methyl bromide. The objectives of this research were to: (1) evaluate yield of tomato in rotation with cover crops (crimson clover, black oat, and crimson clover-black oat mixture) under two tillage systems (conventional tillage and no-tillage) and (2) identify tomato pests and diseases under conventional and no-till systems.

    The experimental field is located at the George Washington Carver Agricultural Experimental Station in Tuskegee University.* Cover crops were planted early in spring 2004, plowed and incorporated into soil or mowed and left on the soil surface. Prior to establishment of the cover crops, eight core soil samples were collected at 0-15 cm depth using an auger. The soil samples were air dried and passed through a 2-mm sieve. Organic C, N, and S were analyzed by using an automated CHNS Analyzer. Total P was analyzed by the perchloric acid digestion method and the P in the digest was determined by the Murphy and Riley procedure. Inorganic N (NH4+ and NO2- + NO3- ) was determined by steam distillation after extraction of 10 g soil with 50 mL of a 2 M KCl solution. The mixture was shaken for 1 hour on a shaker and filtered through a membrane filter (<0.45μm). A Berlese Funnel was used to extract soil arthropods which were identified using appropriate guidebooks. Sticky traps were also used to sample flying insects. Insect damage to tomato fruits and foliage was assessed at harvest. Tomato yields following crimson clover, black oat, or black oat-crimson clover mixtures incorporated in soils were 9.23, 7.69 or 2.10 t/ha, respectively. The yield of the control plot without cover crop was only 1.00 t/ha.

    *The farm demonstration for spring 2005 was not successful. Consequently, land has been set aside and another cover crop has been planted both on the farmer’s field and at the Experiment Station for a re-trial in the spring. An amended report will then be filed.

    Auburn University (AU): The fundamental question we were addressing was if an integrated sustainable system can be developed as a substitute for the conventional system of growing tomato in Alabama. The conventional system uses plowing, creation of raised beds, and plastic cover. The integrated system uses winter and summer cover crops, biological treatments, and no-till transplanting. The answer to our fundamental question appears to be yes, based on economics of the yield differences.

    As expected, the first year that we used cover crops and minimum tillage, yields were markedly lower than in the conventional plastic system. The 2-site yield reduction in the first year was 26% less with the best integrated system than with the conventional plastic system. By the third year, yields in the best integrated system had increased and were 5% less than yields in plastic at Cullman and 20% less at Sand Mountain. Hence, the average lowest yield reduction with integrated systems at two locations was 12.5% in year 3.

    Another impact of the research is clarifying the impact of biological treatments consisting of PGPR in an integrated system. Overall, treatments with the biologicals did not increase cumulative yields. However, there were other benefits. For example, the PGPR treatments decreased transplant shock and increased plant growth early in the season. Under conditions of mid- to late-season plant stress, this early-season growth enhancement would be expected to result in increased yields. Also, speeding up plant growth can result in faster tolerance to diseases that impact young plants more. The other impact of the PGPR in our studies was on disease. In 2003, PGPR treatments resulted in reduced damage to root-knot nematodes, and in 2004, they resulted in a lower incidence of tomato spot disease. An additional benefit of the PGPR treatments was to increase nutrient uptake by the plants.

    Project objectives:

    AU and TU: The objectives for this project were as follows. 1) Maintain the viability and profitability of the grower participant farms by implementing an integrated sustainable production system. 2) Improve grower communication by facilitating networks of vegetable growers. 3) Remove marketing barriers by developing strategies to help growers gain the best price for their crop. 4) Secure the continuance of a systems approach in Alabama agriculture by developing classroom modules for increasing student knowledge of implementing sustainable agriculture.

    For Tuskegee University the objectives were the same as Auburn’s except in objective one, in which they sought to (1) evaluate yield of tomato in rotation with cover crops (crimson clover, black oat, and crimson clover-black oat mixture) under two tillage systems (conventional tillage and no-tillage) and (2) identify tomato pests and diseases under conventional and no-till systems. Auburn University met objective one through the experiments discussed under the sections Material and Methods and Impacts.

    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.