On-Farm Colonization of Tomatoes by AM Fungi

Final Report for ONE08-091

Project Type: Partnership
Funds awarded in 2008: $4,055.00
Projected End Date: 12/31/2010
Region: Northeast
State: Maine
Project Leader:
Frank Wertheim
UMaine Cooperative Extension
Expand All

Project Information

Summary:

On-farm use of mycorrhizal fungi has the potential to enhance host susceptible vegetable crops’ ability to mobilize and take up soil nutrients, particularly phosphorus, aid in water uptake, and reduce some soil-borne disease pressures. This past year saw rapidly fluctuating costs of fertilizers – at one point in the 2008 growing season farmers were reporting a tripling in prices. Therefore the potential for crops inoculated with mycorrhizal fungi to increase uptake of soil phosphorus could boost yields, and save farmers money by decreasing the need for off-farm inputs.

Introduction:

The purpose of this study was to explore on-farm production of mycorrhizal fungi, and their use as an innoculum to boost production in field grown tomatoes on a small organic Maine farm. An on-farm research project carried out at Wolf Pine Farm, a well established certified organic CSA located in Alfred Maine, working together with farm owner/operator Amy Sprague and in collaboration with the USDA-ARS Eastern Regional Research Center in Wyndmoor, PA.

Project Objectives:

Assess the feasibility of on-farm production of mycorrhizal fungi as inexpensive source of innoculum for use in vegetable production.

Assess whether use of on-farm produced innoculum can boost yields in field grown tomatoes on a small organic Maine farm.

Cooperators

Click linked name(s) to expand
  • Dr. David Douds
  • Dr. David Handley
  • Dr. Mark Hutton
  • Amy Sprague

Research

Materials and methods:

This research project essentially entailed a two step process: Step 1 conducted in 2007 was to produce our own source of mycorrhizal fungal innoculum on the farm with low inputs, using a method developed by David Douds, USDA-ARS Research Scientist at Wyndmoor, PA; Step 2 conducted during the 2008 growing season was to use our farm produced mycorrhizal fungal innoculum to assess their potential for improving production in field trials with tomatoes.

We produced our own source of mycorrhizal fungal innoculum in the greenhouse at Wolf Pine Farm in Alfred, ME in a compost vermiculite growing medium during the 2007 growing season. Bahiagrass seedlings pre-inoculated with 4 species of mycorrhizal fungi were provided to us by the USDA-ARS Eastern Regional Research Center in Wyndmoor, PA. The bahiagrass seedlings were grown in 5-gallon plastic grow bags through the summer season, and watered as needed. At the end of the 2007 growing season, samples from our bahiagrass seedling soil mixture were sent to David Douds, of the USDA-ARS Lab in Wyndmoor, PA to be assayed for viable spore levels. We confirmed we had produced high levels of viable spores in our growing medium, which we stored on the farm for use in our 2008 field research.

In the spring of 2008 in the greenhouse at Wolf Pine Farm, we grew moskvich tomato seedlings in flats to the cotyledon stage. At that point they were transplanted into 4-inch pots which containing Living Acres, KomPlete organically certified germination mix combined with our on-farm produced innoculum mix at a ratio of 1 part inoculum or control media to 9 parts potting mix. We transplanted the inoculated seedlings into the field in June of 2008. We grew the mycorrhizal infected tomatoes in the field in a Latin square experimental design and compared them to a control, non inoculated seedlings. Fruit from inoculated and control plants were weighed as they ripened data was logged and the fruit then went back into the farm Community Supported Agriculture market.

Research results and discussion:

The mean weight of the fruit, from each treatment replication per harvest date, from the mycorrhizal inoculated plants was higher 14.44 lbs compared to the non inoculated control 13.44 lbs. However, the results were not statistically significant with an LSD value of 3.99 indicating there was significant variation within the trial. The summer of 2008 was unusually cold and wet with long rainy periods extending from June through early August. We noted a significant amount of septoria leaf spot which appeared to stunt the overall growth of the crop and resulting yields, and probably contributed to the amount of variation in the trial.

Even though the results were not statistically significant we were encouraged that the inoculated seedlings out performed the control by approximately 7 % higher yields. This result is typical of a first year field study. Our research team plans to repeat the field study in 2009 and will also add an additional farm site which will be Highmoor Farm, the Maine Experiment Station Farm located in Monmouth, ME. It is our hope that a repeat study with a second farm site added will give us more and potentially significant data in 2009 which we will with agricultural professionals and farmers in the region.

Frank Wertheim will be shared the results to date of this research with both the Maine Organic Farmers and Gardeners Association and the Maine Vegetable and Small Fruit Growers Association during the January, 2009 Maine Agriculture Trade Show. Mr. Wertheim also spoke to the Northeast Organic Farmers Association at their annual meeting in Concord, NH on March 7, 2009. He has been invited to speak at the September, 2010 MOFGA Common Ground Fair.

Research conclusions:

The mean weight of the fruit, from each treatment replication per harvest date, from the mycorrhizal inoculated plants was higher 14.44 lbs compared to the non inoculated control 13.44 lbs. However, the results were not statistically significant with an LSD value of 3.99 indicating there was significant variation within the trial. The summer of 2008 was unusually cold and wet with long rainy periods extending from June through early August. We noted a significant amount of septoria leaf spot which appeared to stunt the overall growth of the crop and resulting yields, and probably contributed to the amount of variation in the trial.

Even though the results were not statistically significant we were encouraged that the inoculated seedlings out performed the control by approximately 7 % higher yields. This result is typical of a first year field study. Our research team plans to repeat the field study in 2009 and will also add an additional farm site which will be Highmoor Farm, the Maine Experiment Station Farm located in Monmouth, ME. It is our hope that a repeat study with a second farm site added will give us more and potentially significant data in 2009 which we will with agricultural professionals and farmers in the region.

Frank Wertheim will be shared the results to date of this research with both the Maine Organic Farmers and Gardeners Association and the Maine Vegetable and Small Fruit Growers Association during the January, 2009 Maine Agriculture Trade Show. Mr. Wertheim also spoke to the Northeast Organic Farmers Association at their annual meeting in Concord, NH on March 7, 2009. He has been invited to speak at the September, 2010 MOFGA Common Ground Fair.

Participation Summary
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.