Influences of Alternative Vegetable Systems on Arthropods/Soil Biological Dynamics and Soil Quality Trajectory

Project Overview

Project Type: Research and Education
Funds awarded in 1995: $180,000.00
Projected End Date: 12/31/1999
Matching Non-Federal Funds: $28,842.00
Region: Western
State: Oregon
Principal Investigator:
Richard Dick
Oregon State University

Annual Reports


  • Agronomic: oats, wheat
  • Vegetables: beans, broccoli, cauliflower, sweet corn


  • Crop Production: conservation tillage
  • Education and Training: demonstration, extension, farmer to farmer, focus group, networking, on-farm/ranch research, participatory research
  • Natural Resources/Environment: biodiversity, indicators
  • Pest Management: biological control
  • Production Systems: agroecosystems, holistic management
  • Soil Management: earthworms, green manures, organic matter, soil analysis, soil quality/health


    This is an in-depth study in western Oregon of soil quality, soil biology and above ground arthropods in alternative vegetable systems that includes cover crops and reduced tillage. The work was conducted at two experiment station research sites (fully replicated with statistically valid experiments initiated in 1989 and 1993) and on 6 farmers’ fields who split their field into two management systems.

    We have identified that certain soil enzyme activities and increases in large aggregates fractions (1-2 mm) are early indicators of changes in soil quality due to improved soil management. A cotton strip decomposition method was tested as a simple measure of soil biology activity but it was concluded that it must be used under the same environmental conditions each year to give comparable results. These results are encouraging in that certain microbial and physical properties are sensitive to changes after only one year of a change in management which hold potential to guide farmers to manage soil for long-term sustainability. Furthermore, use of cover crop systems is improving soil quantity that is quantifiable. To date, there is evidence that suggests that microbial communities are affected by cover cropping practices.

    Earthworms appear to be stimulated by cover cropping even under conventional tillage, but more in-depth studies are needed to confirm this. Nutrient-mobilizing species such as fungus-feeding springtails and mites are conserved by cover crops and reduced tillage. Deposition of green manure cover crops on the soil surface supports high populations of a mite (Pergamasus) which is currently being developed as a bio-control agent of symphylans. The beneficial predator, P. melanarius (ground beetle) was conserved in cover crop systems.

    A major accomplishment of the project was the development of a soil quality card and an accompanying guide that was done at farmer focus sessions. Besides being now available as a tool for farmers to assess their own soil quality, the participating farmers in our study are using the card to evaluate the two systems they are testing. This is providing a rich data set that can be compared to the more rigorous lab based measurements.

    Although we have only preliminary results from the research, we have extended the results in various workshops and popular outlets. It has been well received and is providing information that will give farmers confidence that adopting certain sustainable practices can improve soil quality.

    Project objectives:

    1. To identify and explore sensitive early indicators of changes in soil quality useful to agroecosystem analysis and farm management.

    2. To identify and explore linkages between changes in vegetation/soil management and associated C Inputs with soil community structure and processes, and above ground arthropods dynamics.

    3. To test and adopt strategies for conducting participatory research and education programs.

    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.