By contrast, many studies have been reported that previous Brassica crop reduced AM root colonization and spore number in subsequent crop. Brassica rotation crop in India was reported by Harinkumar and Bagyaraj that previous crop with Indian mustard reduced AM spore number in the subsequent AM-host crop (Harinkumar and Bagyaraj, 1998). In wheat belt regime of southern NSW, Australia, which was studied by Ryan (2001), reported that previous Brassica (canola; B. napus L. and Indian mustard) crop reduced AM root colonization in the subsequent wheat crop. Similarly, pot experiment in Japan also reported decreasing in AM spore number and root colonization of sunflower and maize that grew after white mustard (B. alba L.) (Karasawa et al., 2001) Furthermore, a short reason of rotation crop could substantially alter the inherent AMF potential of soil to significantly influence the mycorrhizal status in the subsequent crop due to changing in the mycorrhizal root mass, and spore number under rotation crop (Panja and Chaudhuri, 2004). Therefore, including non-mycorrhizal plants in the rotation may reduce the AM spore number and the AM colonization in following crops.
In Thailand, there is little knowledge of AM community under different crops. It might be possible that AM community would be changed by plant crop. Therefore, this study aimed to examine AM community under two different crop regimes; maize and cabbage crop in Pak Chong soil series.