Project Overview
Information Products
Commodities
- Additional Plants: trees
- Miscellaneous: Truffles (Fungi)
Practices
- Crop Production: agroforestry
Summary:
To our knowledge, a large scale sustainable truffle orchard has never been established in Indiana. Truffles are highly prized for their umami aroma and flavor. A supply of fresh truffles would improve market opportunities, soil health, food systems and quality of life, culinary and gastronomic experiences, agroforestry and tourism in the region. Five acres of cropland in Parke County, Indiana was set aside to establish a Truffle-Hardwood Orchard in 2022.
Burgundy truffle inoculated oak seedlings (New World Truffles, Oregon) were selected for Indiana’s climate, its market value and vigor. Dr. Charles Lefevre, New World Truffles, our mycologist partner is experienced in successful establishment of truffle orchards.
Truffles are subterranean fungi that have critical functions in ecosystems. They recycle nutrients, improve soil texture and structure, nourish and network trees, and support wildlife food webs. Culinary truffles offer other ecological benefits. In Oregon, Douglas fir plantations on former pastureland, produced valuable truffles while improving habitat for struggling salmon, and provided carbon offsets reducing atmospheric CO2.
Wild truffles (Tuber canaliculatum, Michigan truffle) found in cold climates underscore the promise of truffle cultivation in the Midwest and specifically in Indiana. The burgundy truffle was selected because of the significant experience and success with its cultivation in cold climates. In 2021-2022, we asked if T. canaliculatum, the native Michigan truffle was available, however, New World Truffles had not successfully or consistently cultivated the native Michigan truffle.
A total of 24 tons per acre of lime was applied to the 5 acres in June-July 1, 2021 to raise the soil pH. Straw was mixed in with the lime.
In August 2021, a custom blend of forbs, grasses, and legumes were seeded in the 5 acres to improve the soil (see attached list of the custom blend, with ounces or pounds per acre shown). We requested the soil samples are ran and reported in metric system instead of English pounds per acre, as recommended by Dr. Charles Lefevre, as standardized in the soil community. The post-planting soil samples can be compared to the prior soil samples taken before planting on 3-24-21 and 7-7-21, and after the lime was deposited in June-July 1, 2021. The post-planting soil samples (4 different sites on the 5 acres were taken on 4-19-22 are attached).
A total of 667 bur oaks (Quercus macrocarpa) and 667 english oak (Quercus robur) inoculated with Burgundy truffle (Tuber aestivum) were received on March 16 & March 17. Of the initial 2,000 inoculated trees that were ordered, the chinkapin oaks (Quercus muehlenbergii) were not assessed as sufficient quality in the growing laboratory, and therefore were not sent to us. The planting began on March 17 and was completed on March 21, 2022. We used an 8” auger mounted on a Bobcat to drill holes into the soil (see diagram). The trees were planted in a 11’ equilateral triangular configuration with a vertical distance of 9’5” vertical (distance between rows) and a 416 trees per acre density. The benefit of this relatively higher planting density is to promote earlier closure of the canopy to minimize sunlight reaching the soil as in interior forest conditions to promote truffle growth.
We used a fixed measuring stick for placement of auger and planting holes. The auger and bobcat also served to fix the metal stakes into the ground. We learned a smaller diameter auger would be better since the tree roots were quite narrow and short relatively. A final planted tree mortality was assessed and tallied on 4-30-21. A total of 53 trees out of the 1,334 planted trees were not-viable, which was aligned with the approximately 3% expected mortality per Dr. Charles Lefevre.
Challenges post-planting included:
1. Bending of tree tubes due to high winds, which we had to unbend and secure to the posts as high on the tubes as possible or place a second post. We learned that if the metal stakes were embedded into the soil outside of the dug holes, it may facilitate a higher stake height and better vertical support of the 5’ tree tubes to reduce risk of bending.
2. Drought during June – September 2022 & 2023. We expected the risk of drought and therefore, we had a well and pump placed adjacent to the 5 acre field, with confirmed water pressure and good quality of water. We decided on a spray irrigation hose system that we used to water the trees.
3) Weeds grew significantly in July-August and had to be removed by herbicide around outside of the trees and tubes, and then by hand both within and around tubes. Leaf and coffee compost were placed at the base of trees inside and around tubes after weeding by hand, and tubes replaced and resecured. The weeds included types of grass weeds, Canadian thistle, and Cocklebur. The Cocklebur is the most problematic as its “fruit-seed” harbors prickles and toxic poisons for animals ingesting them. Therefore, goats or other type of animal cannot be used remove these invasive weeds. We learned these weeds were previously not as evident or problematic on the historically farmed land because a pre-emergent was applied prior to planting the corn and soy crops. We pulled Cockleburs by hand and disposed of plants. We learned that ridding the field of Cockleburs will require annual removal before any fruiting, and it will take several years because of the Cocklebur seeds that have previously fallen into the soil will likely remain viable. We also can anticipate the time period (June-September) when they will emerge and we can be more vigilant to reduce their burden.
In July 2023, Japanese beetles (Popillia japonica) descended onto the inoculated oaks resulting varying defoliation of some trees. After researching sustainable methods to control and eradicate the invasive insects, we applied Neem oil spray to the trees, which was clearly ineffective for immediate relief and damage control. After weighing risk-benfits, we then placed non-pesticidal Spectracide Bag-A-Bug, a pheromone attractant traps in July-September, which proved to be especially effective in capturing the flying stage of the insect with supreme specificity without any direct treatment to the trees. We plan to set these traps proactively in late June through September 2024, since we expect at least some infestation from Japanese Beetles in the upcoming year.
We received and planted the 53 replacement Burgundy inoculated oak trees in March 2023 to replace those that did not survive of the 1,334 trees (planted in March 2022). These replacement trees appear to be growing well.
In Spring 2024, we would like to plant 667 truffle inoculated trees on the remaining 1.67 acres of the previously prepared 5 acres. As such, a farmer rancher proposal for novel opportunity in native truffle cultivation has been submitted.
You can see photos, diagrams from soil sampling, and get a visual sense of how our project was designed and implemented on the Farming Matters YouTube Video Establishing a Truffle Orchard.
Project objectives:
1. Identify the truffle and symbiotic tree species ideal for cultivation of truffles in Indiana or similar regional conditions
2. Evaluate the soil texture, condition and health for supporting truffles and hardwoods
3. Establish the soil improvements necessary to support truffle and hardwood plantings
4. Develop the plan for water, weather and pest mitigation
5. Design the orchard planting and maintenance plan
6. Confirm viability of truffle fungi and oak saplings in the laboratory and prior to planting
7. Create educational materials and communications of the project experience and results for omnichannels (e.g. virtual, online powerpoint or pdf, youtube videos, and face-to-face field days or conferences)