Arbuscular mycorrhizal fungi (AM fungi) diversity was investigated in 12 selected long-term soil observation sites in the canton of Bern. These consisted of nine soils farmed according to Proof of Ecological Performance (PEP) production guidelines, of which three were natural meadows, three were no-till (NT) or ploughed (PL) arable soils, and three were ploughed arable soils farmed according to organic farming guidelines (ORG). The AM fungal spores from soil samples taken from the top 20 cm were isolated and morphologically determined. Of the total 57 detected species, 40–45 were found in natural meadows, 33–40 in PEP-NT soils, 31–35 in ORG-PL and 28–35 species in PEP-PL soils. Generally speaking, the meadows exhibited higher spore densities than the croplands. Indicator species were identified for each cropping system. Conservation tillage and wide crop rotations with a temporary-grassland component encouraged the AM fungal communities in the agricultural soils of the Bernese Midlands. The numbers of AM fungal species in these soils of the Bernese Midlands are higher than those previously reported from similar arable regions in central Europe.
Cropping systems affect species diversity of mycorrhizal fungi