Reduced tillage in organic systems: a soil and water quality imperative

Project Overview

Project Type: Research and Education
Funds awarded in 2008: $190,000.00
Projected End Date: 12/31/2011
Region: Southern
State: North Carolina
Principal Investigator:
Dr. J. Paul Mueller
North Carolina State University

Annual Reports


  • Agronomic: corn, sorghum (milo), soybeans, sunflower, wheat, grass (misc. perennial), hay
  • Animals: poultry, bovine


  • Animal Production: grazing management, grazing - rotational, watering systems, feed/forage
  • Crop Production: conservation tillage
  • Education and Training: demonstration
  • Natural Resources/Environment: riparian buffers, carbon sequestration
  • Pest Management: allelopathy, biological control, chemical control, competition, cultural control, field monitoring/scouting, mulches - killed, cultivation
  • Production Systems: organic agriculture, integrated crop and livestock systems
  • Soil Management: green manures, soil analysis, soil microbiology, organic matter, soil physics, soil quality/health


    To date we have found that total C and N were increased by 10-20% in systems using conservation tillage versus conventional tillage. Microbial respiration, microbial biomass N and net N mineralization were much lower in the conventional system than in other systems. Increased total N and microbial biomass N imply enhanced N holding potential in the systems, and improved net N mineralization means enhanced ability of the systems to meet plant N needs. All these findings suggest that compared to the conventional system all other systems show greater potential in improving water quality and sequestering carbon. We are documenting the weed seed bank in the various systems and monitoring weed seed emergence. Although the organic system had concentration of nitrate slightly exceeding 10ppm, drainage was lowest in this system. Soil water content differed between systems at soil depths below 60cm.

    Project objectives:

    General: To provide the preliminary data necessary for the implementation of effective weed control
    strategies based on conservation tillage practices and light, surface cultivation suitable for organic grain
    production systems in the southeastern USA. Based on initial experimental data, the most promising
    practices will be integrated into the existing long-term farming systems experiment located at The Center
    for Environmental Farming Systems (CEFS).

    1. To compare alternative organic weed management systems: one with major emphasis on cultivation and tillage and another with major emphasis on conservation tillage.

    2. To monitor the impacts of the weed management strategies in objective 1 on water quality (NO3, PO4,
    DOC), soil physical properties, soil C and N dynamics, microbial activities associated with the organic
    systems under comparison and with non-organic systems which are part of the existing experimental
    design at CEFS.

    3. Use The Organic Farm Panel comprised of farmers, county agents, non-profit partners and researchers
    and meets twice annually to set the agenda for organic research and extension activities conducted by

    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.