Project BG06RDNP001-16.001-007 „Mycorrhization of saplings and fruit-bearing tree species for truffle production“ funded under submeasure 16.1 of the Rural Development Programme, within almost a year, has set prerequisites for the implementation of project goal.

The project goal was to obtain black truffle fruiting body by mycorrhization of orchard trees (plum) during fruit-bearingand saplings (hazelnut). The implementation of the project was intended to happen through onsite inoculation with selected strains of certain truffle species.

The greater portion of the scheduled works has been realised yet during the first year, and namely: optimization of the soil composition based on its assessment and the respective improvements; developing of methods for mycorrhization of saplings and fruit-bearing trees; analysis of the general phytosanitary condition prior to inoculation with truffle mycelium; developing mycorhhization technology for orchard trees of the Rosacae family; general phytosanitary analysis following inoculation with truffle mycelium; conducting informative meetings and releasing publications.

Within the scope of the project works, the following ones have been implemented pursuant to the scheduled phases:

– Soil examination for determining the parameters deviation from those necessary for the mycorrhization and according to the specific requirements for the truffles growth – this was accomplished in April/May 2021. Identified was the humus content, the mechanical composition, the presence of hydrogen and salts of phosphorus,  calcium, sodium, potassium, magnesium, moisture retention, acidity and volumetric density.

– Optimization of the soil structure in compliance with the conducted examinations and the scientific team requirements. What turned out to be necessary was investing in improvement of the soil fertility to meet the needs of truffle production. The actions included: soil pH increasing by treatment with lime; introducing argillaceous fractions and mixing them with the existing soil layers; adding humus because the soil in the plum orchard corresponded to the poorest among the productive lands; ploughing the upper layer to ensure volumetric density necessary for the better aeration properties of the soil; applying humus and carbon-rich plant biomass of high cellulose content.

– Identifying trough morphological examination and DNA analysis the natural mycorhhiza in the plum orchard soil – Vesicular-arbuscular mycorrhiza (VAM) and ectomycorrhiza;

– Mapping the plants by numbering each plant or sapling, identifying its health status and stage of deforestation. This was accomplished in the spring of 2021.

– Inoculation with mycelium. This had to be done in the second year of the project, but since the informative events became impossible from September/October due to the Covid 19 crisis, the team decided on performing this procedure as early as the first year. Inoculation of the root area (rhizosphere) of the trees with black summer truffle, as well as two other varieties (Italian truffle and white truffle) was performed. For the inoculation, mycelium was collected from the rhizosphere of other ectomycorrhiza tree plants. More specifically, the mycelium was gathered in natural environment, in close vicinity to fruiting bodies of black summer truffle (within 5 cm) found with the help of a trained dog. Middle age (40 – 60 year) plants of white and black pine growing on humus-calcareous soil were selected. These are completely suitable for growing the truffle mycelium. It is worth mentioning that an additional difficulty was the decontamination of the mycelium to prevent the potential risk of introducing together with it bacteria and other fungi into the soil. By the middle of October, nearly 100 kg of planting material was secured – black truffle vegetative mycelium. It was distributed in the truffle garden, and all works were reported in a log book by date, number of the sapling where inoculation was performed, quantity and scheme of the inoculation;

– Monitoring the course of mycorrhization.

Detailed description of the works performed under the project is given in the Performance reports as at 31 December 2021.

It has to be noted that at the beginning of 2022, the examination in the soil area of the plum trees intended to confirm the ectomycorrhiza and the DNA analysis of 10 samples of the mycelium inoculated trees showed that the mycelium not only did not survive but it was fully spoiled – the climatic conditions were unfavourable for its survival.

The scientific team conducted meetings and analises based on which it was proposed that the project should continue throughout 2022 by planting, between the rows of plum tress,  mycorrhized 5-year tilia saplings in order to ensure the mycelium preserving and survival. We have to note that this activity was not on the action plan and we consider this as significantly diverging from the initial innovative idea.

Based on the works accomplished by now and the need for new solutions, we find this project impossible for continuation as it is now despite of our conscientious performance by now of obligations under the signed Contract.