Shifts from conventional horticulture to agroecology impacts soil fungal diversity in Central Argentina

Abstract

Conventional agriculture generally relies on monocultures and external inputs, such as synthetic fertilizers and pesticides, which not only impact on farmer’s economy and health, but also lead to a reduction of soil biodiversity. The agroecological management is constituted by a series of alternative strategies that seek to increase the biodiversity of agroecosystems and rely on the ecosystem services that it provides. Fungi are key components in ecosystems, but few studies have examined how the agroecology affects soil fungal composition. Using meta-genomic tools, we studied the taxonomic and functional composition of fungi in soils subjected to conventional horticulture (CH) and transition to agroecology (TA) (7–10 years old), which mainly differ because the latter does not use synthetic agrochemicals and generally includes accompanying vegetation. We found that these crop soils were dominated by Ascomycota, in particular Sordariomycetes. The average taxonomic richness and the fungal guild abundance at the local scale did not differ between managements. The TA led to higher abundance and richness of soil fungi than CH at the regional scale, but the PERMANOVA revealed non-significant differences in the fungal community composition. These results could be explained by the number of years elapsed since the implementation of the TA management that might have not been sufficient to have a profound impact on the fungal communities and/or the persistence of relict DNA in soils that mask possible differences between managements. The differences observed at the regional scale may possibly be observed at the local scale in longer-term studies.