“…One way to achieve an increased spore density would be to shorten the period of bare ground (Isoi, 1997;Isobe and Tsuboki, 1999;Usuki and Yamamoto, 2003). However, because the density of AM fungi spores greatly varies with the species and cultivar of the crop, the crop type and the crop system (Troeh and Loynachan, 2003;Usuki and Yamamoto, 2003), it is necessary to understand the correlation between spore production and the type of crop. It is anticipated that the composition of the species of the AM fungi differs with the sampling site.…”