Arbuscular mycorrhizal fungi in oat-pea intercropping
Arbuscular mycorrhizal fungal diversity can be altered by intercropping plant species, as well as N fertilizer applications. This study examined the effects of oat-pea intercropping and N fertilizer addition on the abundance and diversity of mycorrhizal species, as well as identified the most frequent genera for oats and peas in two growing seasons (2019 and 2020). Under drier conditions in 2019, arbuscular mycorrhizal abundance decreased with N fertilizer addition in sole peas and increased with N fertilizer addition in sole oats, but no significant change in abundance was observed in oat-pea intercropping. During the wetter growing season 2020, arbuscular mycorrhizal diversity increased when oat and pea were intercropped, compared to either sole oat or sole pea. The presence of Diversispora mycorrhizal genus in sole pea led to a rhizosphere community different than in sole oat. Claroideoglomus abundance increased in peas in 2020, thus this genus could be moisture dependent. Paraglomus abundance in oat-pea intercropping was similar to sole oat in 2019, while similar to sole pea in 2020. This can suggest that Paraglomus is an indicator of plant stress under intercropping, as based on the premise that stressed plants release more exudates, and the subsequent mycorrhizal associations favor these plants with higher exudation. Future investigations can further reveal the functions and benefits of these mycorrhizal genera in annual monocrop and intercropping systems.