Evaluation of Cover Crops and Conservation Tillage for Conventional and Organic Sweetpotato (Ipomoea batatas) Production in North Carolina

2001 Annual Report for GS00-006

Project Type: Graduate Student
Funds awarded in 2000: $9,927.00
Projected End Date: 12/31/2004
Region: Southern
State: North Carolina
Graduate Student:
Major Professor:
Dr. Nancy Creamer
North Carolina State University

Evaluation of Cover Crops and Conservation Tillage for Conventional and Organic Sweetpotato (Ipomoea batatas) Production in North Carolina


Three organic treatments (no cover crop, hairy vetch and rye incorporated prior to transplanting, hairy vetch and rye conservation tillage) and a conventional control (no cover) were examined using a systems approach. Although broadleaf weed biomass was lower in the conventional treatment, no differences in yield (No. 1 grade) were noted between treatments. A decline in crop vine weight was observed in conservation tillage treatments, perhaps due to an increase in grass weed biomass. Wireworm densities were lowest in conventional and organic conservation tillage plots, and highest in organic plots where the cover crop mixture was incorporated prior to transplanting.

Objectives/Performance Targets

  1. 1. To examine differences in soil dwelling insect densities, soil physical properties, crop growth parameters, and weed competition on crop yield among organic and conventional sweetpotato production systems.
    2. To investigate the impact of conservation tillage on sweetpotato quality and yield.
    3. To evaluate the influence of cover crop species to maximize their benefits on sweetpotato quality and to identify a suitable cover crop that will modify the soil environment for optimum crop growth and development.
    4. Evaluate the economics of conventional verses organic sweetpotato production in terms of cost effectiveness and product return to serve as a guide for growers who are interested in producing organic sweetpotatoes.
    5. To participate in outreach and education events for growers, buyers and extension agents.


The first year of a three-year study was completed, and much progress has been made. Data were collected on weed density and biomass, crop biomass and yield, soil nutrients, gravimetric water and temperature, wireworm density and species identification, and costs and returns of each system. An additional, separate study has been implemented to examine methods of cover crop management in an organic conservation tillage system. Species of cover crops include a mixture of hairy vetch and rye, 100% hairy vetch, and 100% crimson clover.

Impacts and Contributions/Outcomes

Results were disseminated to growers and university personnel at the Southeastern Vegetable and Fruit Expo in Greensboro, N.C. on December 12, 2001. A review of preliminary results will also be presented at the National Sweetpotato Collaborator's Meeting in Orlando, Florida on February 1, 2002.