Arbuscular mycorrhizal fungal biodiversity for sustainable agroecosystems
Kuupäev
2021-07-02
Autorid
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Abstrakt
Doktoritöö käigus uuriti taimede ja seente vahelist vastastikku kasulikku kooselu, mükoriisat, moodustavate mullaseente ökoloogiat põllumajandusmaastikes. Kuna nende seente abil saavad taimed mullast vajaminevaid toitaineid, on nad oluline osa mulla elustikust ning panustavad ka põllumajanduse jätkusuutlikkusse. Töö üks põhieesmärke oli uurida, kuidas levinud põlluharimise praktikad mükoriisaseeni mõjutavad ning millised praktikad võiksid nende elurikkust suurendada. Uuringutes leidsime, et sarnaselt Lääne-Euroopaga on ka Eestis olenevalt põlluharimise viisidest mükoriisaseente elurikkuses suured erinevused – mitmekesisemate ja vaesemate põldude mükoriisaseente liigirikkuse vahe oli koguni kuuekordne. Olulisteks negatiivseteks teguriteks olid sünteetiliste väetiste ja pestitsiidide kasutamine, kuid positiivselt mõjusid orgaaniliste väetiste kasutamine ja maastikuelementide rohkus. Lisaks saime teada, et lühiajaliste rohumaade lisamine külvikorda soodustab mullaseeni ning külvikorra planeerimisel tasuks mõelda kasvatatavate sortide valiku peale. Näiteks selgus, et mõned ajaloolised nisusordid kasvavad paremini koos mahetootmise põllu mullast pärit seentega, samas kui mõni kaasaegne sort jällegi intensiivtootmise mulla seentega. Selle teadmise baasilt oleks võimalik tulevikus aretada näiteks mükoriisasõbralikke sorte nii mahe- kui tavaviljelusse. Lisaks eksperimenteerisime ka liigirikaste taimekoosluste taastamisega, luues liigivaestesse põlevkivikarjääridesse mükoriisaseente abiga kõigest mõne aastaga rohelised niidud. Sama metoodikat kasutades võiks tekitada elurikkuse tugipunkte ka intensiivselt majandatud põllumajandusmaastikesse, kus taimede, putukate ja mükoriisaseente elustik põllumajandustootjale kasu saaks tuua. Seega, kasutades rohkem orgaanilisi väetisi ja tõrjudes haiguseid ning kahjureid mitmekesise külvikorraga saab luua mükoriisaseeni soodustavad tingimused. Lisades maastikesse veel uusi ja hoides olemasolevaid elurikkuse tugipunkte, võiksime olla eeskujuks oma kodukandi kõrge elurikkuse ja sellega arvestava toidutootmisega.
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.
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.
Kirjeldus
Väitekirja elektrooniline versioon ei sisalda publikatsioone
Märksõnad
agriculture, soil fungi, soil biology, mycorrhiza, Estonia