On-farm Cyanobacterial Bio-fertilizer Production to Reduce the Carbon Footprint of Organic Fruit and Vegetable Production

Project Overview

SW14-023
Project Type: Research and Education
Funds awarded in 2014: $293,599.00
Projected End Date: 02/28/2018
Grant Recipient: Colorado State University
Region: Western
State: Colorado
Principal Investigator:
Dr. Jessica Davis
Colorado State University

Annual Reports

Commodities

  • Fruits: peaches
  • Vegetables: beets, cucurbits, greens (lettuces), sweet corn

Practices

  • Crop Production: biological inoculants, fertigation, irrigation, organic fertilizers, tissue analysis
  • Education and Training: demonstration, display, extension, farmer to farmer, on-farm/ranch research, participatory research
  • Energy: solar energy
  • Farm Business Management: budgets/cost and returns
  • Natural Resources/Environment: carbon sequestration
  • Production Systems: organic agriculture
  • Soil Management: organic matter, soil analysis

    Abstract:

    Nitrogen (N) is the limiting factor for agricultural yields in most cropping systems. Nitrogen gas (N2) makes up approximately 78% of the Earth’s atmosphere, but in order to be useful for most microorganisms, plants, and animals, N must be in a “fixed” form such as ammonium or nitrate. Agriculture has become highly dependent on N fertilizers produced through a chemical N fixation process involving very high temperatures and pressures and, hence, requiring high fossil energy inputs. Some N-fixing bacteria are heterotrophic (e.g. Azotobacter and Azospirillum) and, thus, require a source of C for growth. In contrast, cyanobacteria are phototrophic N-fixers; they can fix nitrogen from the atmosphere and can power this process by fixing their own source of C via photosynthesis. Cyanobacterial bio-fertilizer (cyano-fertilizer) has the potential to become a new, sustainable source of N fertilizer; a fertilizer that can be produced on-farm, supplementing or replacing chemical fertilizers while decreasing fossil fuel consumption. Organic N fertilizer options are limited, often low in nutrient content, expensive, bulky, and transported long distances. In arid and semi-arid areas, water limitations can preclude common fertility improvement methods such as leguminous cover crops/green manures. In contrast, intensive culture of cyanobacteria in covered raceways allows resource-efficient production of N fertilizer on small amounts of land. On-farm cyano-fertilizer production is an entirely new and innovative approach to providing crop N requirements using high-N bacterial biomass, while greatly reducing fertilizer manufacturing and transportation needs. However, for cyano-fertilizer production technology to be applied broadly to domestic agriculture, it must be scaled up and tested on farms, especially in the challenging environments of the semi-arid West. In this project, on-farm cyano-fertilizer production and use is being tested on one university research farm and four private organic farms (two vegetable farms, two fruit orchards).

    Economic and environmental sustainability is being evaluated through yield impacts, cost/benefit analyses, and carbon footprint comparisons. Since cyano-fertilizer depends heavily on farmer knowledge and management, stakeholder input is guiding research and making cyano-fertilizer as easy to use as possible. Broad dissemination of educational materials (video, production manual, utilization factsheet, carbon footprint decision tool) are critical to widespread adoption. Field days, regional workshops, a webinar, and a website are being used for dissemination. Success of the project will result in working, profit-enhancing on-farm cyano-fertilizer systems and will lay the groundwork for further dissemination of the cyano-fertilizer approach. Cyano-fertilizer will eventually improve the profitability and sustainability of farms throughout the West and eventually the entire United States.

    Project objectives:

    1) Optimize the yield and efficiency of an on-farm cyano-fertilizer production system

    Task 1.1 – Determine if CO2 bubbling will enhance growth and N-fixation of cyanobacteria grown in outdoor raceways.

    Task 1.2 – Evaluate batch vs. semi-continuous growth of cyanobacteria.

    Task 1.3 – Explore methods to optimize light absorption.

    2) Evaluate the utilization of cyano-fertilizer in irrigated fruit (peaches) and vegetable (lettuce, sweet corn) systems

    Task 2.1—Compare cyano-fertilizer with commonly-used organic fertilizers (compost, fish emulsion, feather meal, and blood meal) in terms of impact on plant growth, yield, quality, and N recovery.

    Task 2.2—Assess the effectiveness of cyano-fertilizer in contrast to farmers’ current practice on two working vegetable farms and two orchards.

    Task 2.3–Evaluate the barriers to integration of cyano-fertilizer into current organic farming systems.

    3) Quantify the direct costs and benefits of on-farm production and utilization of cyano-fertilizer to optimize economic returns for farmers

    Task 3.1—Quantify the costs of cyano-fertilizer production as compared to commonly-used organic fertilizers.

    Task 3.2—Appraise the economic benefits of cyano-fertilizer use.

    Task 3.3 –Evaluate the economic feasibility of on-farm production and use of cyano-fertilizer.

    4) Determine the carbon footprint of cyano-fertilizer compared to other methods of fertilization

    Task 4.1—Monitor the N2O and CO2 emissions from cyano-fertilizer applied to land as compared to commonly-used organic fertilizers (compost, fish emulsion, feather meal, and blood meal).

    Task 4.2—Modify the Daycent model to include cyano-fertilizer and other organic fertilizers for use in quantifying and comparing the carbon footprint of those fertilizers.

    5) Impact farmer decision-making by sharing results through multiple methods

    Task 5.1—Develop educational tools including a manual, factsheet, video, C footprint decision tool, and website.

    Task 5.2—Disseminate educational tools and research results locally, regionally, nationally, and globally.

    Task 5.3—Quantify and maximize producer adoption through continuous communication and feedback.

    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.