Determination of the relationship between soil nutrients, mycorrhizae, and plant health in organic blueberry production

Project Overview

Project Type: Graduate Student
Funds awarded in 2008: $9,900.00
Projected End Date: 12/31/2009
Grant Recipient: Michigan State University
Region: North Central
State: Michigan
Graduate Student:
Faculty Advisor:
Dr. Annemiek Schilder
Michigan State University

Annual Reports


  • Fruits: berries (blueberries)


  • Crop Production: biological inoculants, nutrient cycling, organic fertilizers, tissue analysis
  • Natural Resources/Environment: indicators
  • Production Systems: agroecosystems, organic agriculture, transitioning to organic
  • Soil Management: nutrient mineralization, organic matter, soil analysis, soil chemistry, soil microbiology, soil quality/health

    Proposal abstract:

    Organic blueberries represent less than 0.3% of the total blueberry acreage in Michigan. Despite rising interest, growers are limited by a lack of knowledge in organic practices, particularly nutrient management. Soil building practices utilized in other cropping systems may not be applicable to the highbush blueberry due to the plant’s adaptation to acidic, low-nutrient sand and muck soils. Ericoid mycorrhizal fungi, symbiotic inhabitants of blueberry roots, are able to mineralize and transfer a substantial amount of immobile soil nitrogen and phosphorus to the plant. This mutualism is crucial for nutrient uptake of ericaceous plants in native ecosystems, but is inhibited by high concentrations of inorganic nitrogen. In other cropping systems, organic production practices have been shown to stimulate mycorrhizal colonization, and the symbiosis often provides greater benefits to plants grown organically, but these phenomena have not been documented in field-grown blueberries. The objectives of this project are to: 1) Quantify mycorrhizae in organic and conventional Michigan blueberry fields, 2) Describe the interaction between mycorrhizal infection, soil characteristics, management system, and measures of plant health, and 3) Compare the effects of fertilizer type and mycorrhizal inoculation on growth and nutrient uptake of blueberry plants in a greenhouse study. Results will be disseminated via meetings, publications, extension articles, and online. Project outcomes will contribute to growers’ understanding of organic blueberry management, and have the potential to advance economic opportunities for farmers, reduce environmental impacts, and ultimately facilitate a more sustainable means of blueberry production.

    Project objectives from proposal:

    1) Determine mycorrhizal status of blueberry plants in eight organic and eight conventional fields paired by NRCS soil classification in Michigan and Northern Indiana.

    2) Measure soil biological properties, including enzyme activity, carbon and nitrogen mineralization, light fraction organic matter C and N, and cultivable bacteria and fungi at 0-5 cm and 5-30 cm soil depths in organic and conventional fields.

    3) Record disease incidence, leaf nutrient status, growth, and yield in organic and conventional fields.

    4) Compare the effects of organic and conventional fertilizer and mycorrhizal inoculation on growth, nutrient uptake, and mycorrhizal infection of blueberry plants in a greenhouse study.

    5) Disseminate results via meetings, research and extension publications, and online.

    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.