Mustard Green Manures for Potato Production

Project Overview

Project Type: Research and Education
Funds awarded in 2003: $45,653.00
Projected End Date: 12/31/2007
Matching Non-Federal Funds: $18,324.00
Region: Western
State: Washington
Principal Investigator:
Andrew McGuire
Washington State University Extension

Annual Reports


  • Agronomic: potatoes, wheat


  • Crop Production: cover crops, nutrient cycling
  • Education and Training: demonstration, extension, farmer to farmer, on-farm/ranch research, participatory research
  • Farm Business Management: budgets/cost and returns
  • Pest Management: allelopathy, biological control
  • Production Systems: integrated crop and livestock systems
  • Soil Management: green manures, soil analysis, organic matter, soil quality/health


    Over the course of this project, the use of mustard green manures in Washington potato production has held steady from an estimated 23,620 acres in 2003 to 24,400 acres in the fall of 2006. However, of the farmers using this practice, only a few are doing it to replace their use of metam sodium fumigant. The majority are using the practice to 1) improve their soils and control wind erosion, 2) supplement their normal pest management practices, including fumigation. This project’s research activities, including green manure variety trials, agronomic trials with mustard, and investigation into the soil quality effects of mustard green manures, have provided valuable information to farmers. This information was disseminated to them through field days, workshops, publications and a website. The on-farm research used in this project has proven valuable in rousing farmer’s interest and helping them adopt the practice. However, there are still many questions about the practice of using mustard green manures that will not be answered through on-farm research. The nature of these questions will require a team of researchers - soil microbiologists, plant pathologists, and horticulturists – doing research at research stations, greenhouses, and laboratories where factors can be better controlled than in farmer’s fields.

    Project objectives:


    Objective 1: Determine the measurable factors related to suppression or non-suppression of potato early dying in processing potatoes.

    Objective 2: Determine the species and variety of mustard, or other Brassica, that will most benefit Washington potato growers.

    Objective 3: Increase the adoption of mustard green manures by potato growers through an integrated program of on-farm research and education.

    Performance Targets

    Increasing the Producer's Knowledge Base: production of research summaries containing the results from +/- fumigant trials, wheat straw management trials, and green manure variety trials

    Dissemination of Information: records of website users/hits, number of articles published, and attendance at presentations and the field day.
    Number of Acres Impacted: increase acres planted to mustard green manures in Central Washington by 25% every year for the next five years (three covered by this proposal), from 9,260 acres in 2001, to 28,000 acres being planted the fall of 2006.

    Actual Positive Economic Impact: if we feel that a significant number of potato growers are replacing their fumigant with mustard green manures, we will conduct a survey to estimate this impact.

    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.