Effects of arbuscular mycorrhizae (AM) and effective microorganisms (EM) on various plants under allelopathic stress

Field and pot trials were conducted to investigate the effects of allelopathy on development of arbuscular mycorrhizal (AM) fungi and the role of AM association in alleviating the allelopathic stress on crop growth. In field studies, the allelopathic grasses [Imperata cylindrica (L) Beauv and Dicanthium annulatum (Forssk) Stapf.] decreased the mycorrhizal colonization of associated weeds. In pot trial the allelopathic stress of Melia azedarach L. leaf mulch on growth of maize (Zea mays L.) was significantly reduced by introducing AM fungi, Consequently, the root and shoot growth of mycorrhizal plants was improved than non-mycorrhizal plants. In another pot trial, AM inoculation significantly decreased the negative effects of aqueous leaf extract of Syzygium cumuni (L.) Skeels on growth, yield and N-content of chickpea (Cicer arietinum L.) plants. The potential to provide relief against allelopathic stress by AM fungi was found to be further enhanced by EM (Effective microorganisms) application.