Impact of Commercial Fungal Inoculant on Tomato Yield and Disease Resistance in Deep Composted Raised Beds

Project Overview

Project Type: Farmer/Rancher
Funds awarded in 2020: $8,907.00
Projected End Date: 01/31/2022
Grant Recipient: Liberty Prairie Foundation
Region: North Central
State: Illinois
Project Coordinator:
Shannon McBride
Liberty Prairie Foundation


  • Vegetables: tomatoes


  • Crop Production: biological inoculants, no-till
  • Production Systems: organic agriculture
  • Soil Management: composting


    In the Midwest, climate change has increased the difficulty of growing tomatoes through more frequent precipitation events, colder, wetter Springs, and colder Falls. These conditions leave tomatoes more susceptible to disease and shorten the harvest season, resulting in less yield and profit.

    Arbuscular mycorrhizas (AM) increase a plant’s ability to acquire nutrients from the soil, by increasing the plant roots’ absorptive surface area through hyphal extension (Cavagnaro et. al., 2014). If AM fungal partners are able to increase the nutrient absorption for plants, they may have a positive impact on disease resistance and yield.

    Commercial fungal inoculants have become readily available as an option for sustainable farmers. Products are touted to improve nutrient efficiency, root system growth, and water absorption; however, limited research is available as to the impact of these products on tomato production.

    Our study examined if commercial fungal inoculant can have an impact on yield or disease resistance in tomatoes. If fungal inoculants can impact the disease resistance and yield of tomatoes, farmers could further the ecological health of their farms by decreasing their fungicide usage, and increase their economic viability through increasing profits from their tomato harvests.

    From our research, we were unable to determine conclusively if the inoculant had an impact. From the trial tomatoes, there was no significant impact on disease resistance or yield between the test and the control tomatoes. However, in early root colonization assays, it was determined that the AMF had not colonized the roots. This was likely caused by high levels of phosphorus available to the plant through the deep composted raised beds. It would be beneficial to analyze the inoculant in standard, tilled raised beds to determine its impact when phosphorus levels are not high, and it would be more beneficial to the plant to allow the colonization of AMF. 

    However, from our application of deep composted raised beds through this experiment, we saw high increases in both yield and disease resistance in our tomatoes in 2020, and will continue this practice into the future. 

    Project objectives:

    1. Evaluate the impact of Arbuscular mycorrhizas (AM) fungal inoculant on yield and disease resistance on field tomatoes.
    2. Complete the project to the best of our ability despite COVID hindrances. 
    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.