Effect of the host and non host crops on arbuscular mycorrhizal propagules

Recent field studies have shown that fungal spores decrease when non host plants are used as a pre-culture. The objective of this study was to evaluate how host plant like oats (Avena sativa L.), and non host, as lupine (Lupinus albus L.), and rapeseed (Brassica napus L.) can influence on arbuscular mycorrhizal fungi (AMF) propagules diversity and phosphatase activity when growing in an Andisol and an Inceptisol. The trial was conducted from September 2006 through March 2007 in greenhouse conditions using 5 kg pots with in a completely randomized design with four replicates. The number of AMF spores was higher in the Andisol than the Inceptisol and highest when using oats than lupine or raps as plant host. Oats also showed a large enrichment of morphotypes, whereas lupine and raps were poor. The phosphatase activity (P-ase) in Inceptisol was lower than in Andisol and between crops increased in the order oats < rapeseed < lupine; while significant differences between lupines with other crops were registred. Again, our results reinforce the hypothesis that the mycorrhizae and phosphatase activity are complementary mechanisms developed by plants for a better P acquisition.