Trials and Informing Regional Farmers about Organic Weed Control Methods

Project Overview

Project Type: Farmer/Rancher
Funds awarded in 2011: $13,163.00
Projected End Date: 12/31/2012
Region: Western
State: New Mexico
Principal Investigator:
Dale Rhoads
Rhoads Farm

Annual Reports


  • Agronomic: corn, potatoes


  • Crop Production: conservation tillage
  • Education and Training: demonstration, extension, farmer to farmer, networking, on-farm/ranch research, workshop, technical assistance
  • Energy: energy conservation/efficiency, energy use
  • Farm Business Management: whole farm planning, budgets/cost and returns, farm-to-institution, feasibility study
  • Natural Resources/Environment: soil stabilization
  • Pest Management: allelopathy, flame, mulches - killed, mulches - living, mulching - vegetative
  • Production Systems: agroecosystems, holistic management, organic agriculture, permaculture
  • Soil Management: green manures, organic matter, nutrient mineralization, soil quality/health
  • Sustainable Communities: local and regional food systems, employment opportunities, social networks, sustainability measures


    The field trials clearly demonstrated that crimping a winter cover crop into an in-place mulch suppresses weed growth significantly. In these trials we measured 70% less weeds and 50% less labor to manage a crimped cover crop than more conventional methods of weed management. Of the vegetables tested, corn and green chiles' yields were similar in the no-till crimped areas; summer squash yield was 30% less in the crimped areas; and tomato yield was 15% more in the crimped areas compared to the conventionally-tilled test areas.

    Through soil testing, it was seen that the amount of available nitrogen was higher and more consistent all season in the crimped and mulched treatment areas compared to the conventional tilled areas. Over the length of the season, 27% less water was needed in the crimped areas compared to the tilled areas. More water was saved early in the season; less later in the season due to larger plant size shading the soil. It was also noticed that after heavy winds the areas with a winter mulch and the crimped area held topsoil and collected wind blow dust. It was also observed that grasshoppers preferred the crimped areas as habitat over the tilled areas early in the season, and more grasshopper damage was seen on recently transplanted chiles in the crimped areas. Organic herbicides were also tested in these trials and had spotty performance in managing weeds on both the crimped and non crimped areas due to several weeds they were not able to kill and germination of weeds occurring over weeks instead of immediately after tilling or weeding, making for multiple passes needed and hence more time spent.


    These trials are to test several important weed management techniques and skills to regional farmers: crimping a overwintered cover crop into an in-place mulch and organic herbicides. Effective and sustainable weed control strategies are one of the most critical areas of concern for the economic and sustainable viability of local production of organic vegetables. For over ten years, Rhoads Farm has been experimenting in on-farm and formal trials with the use of organic herbicides, flaming, and more recently, the manipulation of cover crops, especially the creation of an ‘in-place’ soil building ‘crimp killed’ over-wintered cover crop mulch. This was the first or one of the first crimping tests in the southwest. This current project is aimed at testing five different techniques of managing weeds and fertility in longer season larger vegetable plants as part of an overall weed management for long season crops.

    Project objectives:

    Using seven treatments, measure five different performances with five different test plants.

    Data was gathered about the use of the most efficient organic weed control and data provided for farmers to chose among different techniques. The treatments, what was measured and the test plants are listed below.

    Seven Treatments

    *no cover crop/hand weed
    *cover crop turned under/hand weed
    *cover crop turned under and mulch applied
    *cover crop crimped in place mulch/no weeding
    *cover crimped/herbicides
    *cover crimped/a mulch

    What was measured

    *water use
    *harvest size
    *weed control
    *labor - install and plant
    *soil fertility tested monthly

    Five test plants

    *sweet corn

    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.