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

    Proposal abstract:

    This project is designed to examine effects of organic weed management on crop productivity and soil and water quality variables. Two fundamentally different approaches are being attempted by North Carolina farmers: a conventional tillage, cultivation intensive approach, and a reduced tillage system utilizing weed suppressive cover crops and mulches. Conventional tillage is raising serious concerns over soil health, erosion and water quality. However, reduced organic tillage systems are unproven and the growers engaged in these practices are concerned about their ability to control weeds over the long-term. The use of strip-tillage and the arrival of new equipment that make light cultivation tillage a reality will energize this approach. When surveyed and in focus groups organic farmers cite weed pests as their most serious and intractable problem. Current weed management strategies in organic production systems are centered on cultivation. This has been shown to be effective in many cases, but loss of soil carbon, the importance of particulate organic matter fraction and the potential for soil erosion and water quality issues must be addressed if organic grain systems are to be sustainable. Quality data from infiltrating water collected below the root zone of organic systems is of particular interest do to the paucity of data in the literature associated with organic systems and because of the ability to directly compare these data with data collected from other systems located on the Farming Systems Research Unit at CEFS. Conservation tillage approaches that rely on allelopathic smother crops, and strategic, light, surface cultivation has the potential to drastically reduce reliance on tillage for weed control. These practices, combined with recent advance in conservation tillage implements and high residue cultivation tools, are redefining organic weed management.

    Project objectives from proposal:

    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 CEFS.

    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.