17.08.2021 - 15:00 to 17:30
On 17 August at 15:00 Tanel Vahter will defend his doctoral thesis “Arbuscular mycorrhizal fungal biodiversity for sustainable agroecosystems” (in Plant Ecology and Ecophysiology).
Professor Maarja Öpik, Tartu Ülikool
Professor James Bever, University of Kansas (USA)
This doctoral thesis provides a deeper understanding of the ecology of soil fungi that form mycorrhizas in arable landscapes. These fungi provide plants with much needed soil nutrients and are therefore a vital part of sustainable food production. One of the central aims was to understand how the common agricultural practices used in the fields affect these key fungi. In our studies we found that much like in the rest of Europe, there are large differences in the diversity of mycorrhizal fungi in arable field soils. Differences in mycorrhizal fungal richness between the most and least diverse fields were sixfold. The major factors decreasing mycorrhizal fungal diversity were the use of synthetic fertilizers and pesticides but also biodiversity impoverished agricultural landscapes. In addition, we learned that temporary grasslands within the crop rotations have important implications for sustaining soil fungal biodiversity. Furthermore, we found that the crop varieties sown can have an impact on mycorrhizal fungi, with some older varieties faring better in organically managed soils than newer breeds. Although the plants’ affinity to mycorrhizal fungi was not clearly dependant on the era a variety was bred, it does show that we should bear mycorrhizal associations in mind when breeding crops of the future. We also experimented with creating diverse vegetation assemblages in biodiversity impoverished landscapes, using depleted oil-shale quarries as a model system. We used native plants and sowed them onto the restoration sites together with the mycorrhizal fungi they naturally grow with. Using this methodology, we were able to bring dosens of plant species into a former biodiversity desert, highlighting the possibilities of restoring biodiversity hot-spots also in other areas. To conclude, we emphasize that safeguarding the biodiversity of vital mycorrhizal fungi is possible even with the measures available to farmers today. More organic fertilizers with diverse crop rotations for disease and weed control, accompanied by the biodiversity support of diverse landscapes is something that would pave the way for sustainable food production.
Senat hall (Ülikooli 18–204) and via video bridge