A clear understanding of how crop root proliferation affects
the distribution of the spore abundance of arbuscular mycorrhizal
fungi (AMF) and the composition of AMF communities
in agricultural fields is imperative to identify the potential
roles of AMF in winter cover crop rotational systems. Toward
this goal, we conducted a field trial using wheat (Triticum
aestivum L.) or red clover (Trifolium pratense L.) grown during
the winter season. We conducted a molecular analysis to
compare the diversity and distribution of AMF communities
in roots and spore abundance in soil cropped with wheat and
red clover. The AMF spore abundance, AMF root colonization,
and abundance of root length were investigated at three
different distances from winter crops (0 cm, 7.5 cm, and 15
cm), and differences in these variables were found between
the two crops. The distribution of specific AMF communities
and variables responded to the two winter cover crops. The
majority of Glomerales phylotypes were common to the
roots of both winter cover crops, but Gigaspora phylotypes
in Gigasporales were found only in red clover roots. These
results
also demonstrated that the diversity of the AMF colonizing
the roots did not significantly change with the three
distances from the crop within each rotation but was strongly
influenced by the host crop identity. The distribution of specific
AMF phylotypes responded to the presence of wheat and
red clover roots, indicating that the host crop identity was
much more important than the proliferation of crop roots
in determining the diversity of the AMF communities.