Utilization of Compost Made from Agricultural and Forestry Wastes for Improving the Economic and Ecological Sustainability of Agronomic Crop Production on Low Organic Matter Soils in the San Luis Valley of Colorado

Project Overview

Project Type: Research and Education
Funds awarded in 2000: $137,916.00
Projected End Date: 12/31/2004
Matching Non-Federal Funds: $129,676.00
Region: Western
State: Colorado
Principal Investigator:
Richard Zink
Colorado State University

Annual Reports


  • Agronomic: barley, potatoes, grass (misc. perennial), hay


  • Animal Production: feed/forage
  • Crop Production: continuous cropping, nutrient cycling, organic fertilizers, application rate management, tissue analysis
  • Education and Training: technical assistance, demonstration, extension, on-farm/ranch research, participatory research
  • Farm Business Management: new enterprise development, budgets/cost and returns, whole farm planning
  • Natural Resources/Environment: biodiversity, soil stabilization
  • Pest Management: biological control, cultural control, field monitoring/scouting, integrated pest management, weed ecology
  • Production Systems: holistic management
  • Soil Management: composting, organic matter, soil analysis, soil quality/health
  • Sustainable Communities: new business opportunities, partnerships, community services, employment opportunities, sustainability measures


    This study evaluated the efficacy of utilizing compost made from cull potatoes and woodchips in potato, barley, and alfalfa production. A comparison of the agronomic benefits of applying different rates of this compost was evaluated and did not have viable economic benefits. The sawdust/cull potato compost did not have the organic content and fertility benefits of other manure based composts. No differences were observed in soil nutrient retention, crop nutrient uptake, soil microbiological health and diversity, soil water holding capacity and crop water utilization, plant growth characteristics, the suppression of soil borne pathogens, and crop yield and quality.

    Project objectives:

    The main objective of this study is to improve water conservation and sustainability of crop production on the low organic matter soils of the San Luis Valley, Colorado. This will be accomplished through on-farm demonstrations that will examine the impact field incorporated compost made from agricultural and forestry wastes has on: 1) reducing the use of synthetic fertilizers and fungicides, by improving nutrient retention in the root zone and the health and diversity of the soil’s biomass, 2) improving water utilization, thereby reducing water and power use in center-pivot irrigation systems, 3) crop yields and costs of production for potatoes, barley, and alfalfa.

    Proposal Objectives

    1. Develop local end markets for agricultural and forestry wastes. Improve the sustainability of potato, barley, and alfalfa crop production in the San Luis Valley.

    Demonstrate the impact that field incorporation of compost has on production through:

    a. The change in the diversity of the soil’s microbiology and biomass.

    b. Variations in disease levels in the crops.

    c. The potential improvement in nutrient retention in the root zone.

    d. The potential reduction in the use of synthetic fertilizers and pesticides.

    e. The potential improvement in water utilization and associated reduction in water and electrical power use by center-pivot irrigation systems.

    f. The net economic value of compost applications.

    2. Dissemination of results to farmers in the San Luis Valley to demonstrate the economic and
    ecological value of using compost to the long term sustainability of their operations.

    Anticipated Schedule for Achieving Objectives

    We are now at the conclusion of the study. Baseline soil samples were taken in late summer, 2000 and analyzed to establish the nutrient level and microbial levels at each test site. A water sample was taken from each of the center pivot systems and analyzed prior to compost applications. Compost was applied in the fall of each year of the project. The normal farming practice of the area is to do field preparation in the fall for planting the following spring. In one of the fields, however, it was more practical to apply the compost in the spring of 2002 due to wind erosion during the fall and winter. During the growing season, disease levels, crop health, water utilization and nutrient uptake were measured. Three cuttings of alfalfa were harvested for yield during each growing year. Crop yield data were collected at the end of each growing season for potato and barley crops. All data collected were summarized at the end of each growing season. In Year 2 and Year 3, summary bulletins were published in print and on the Colorado State University Web site:


    Field days at each site were held in Year 2 and 3 during the growing season. A summary of results was reported each year at potato and grain grower conferences in the San Luis Valley.

    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.