Influence of Organic Matter on AM Colonization and Associated Rhizosphere Mycoflora in Vigna unguiculata subsp. unguiculata (L.) Walp

Abstract

A greenhouse investigation was undertaken to determine the influence of organic amendments on the colonization of arbuscular mycorrhizal (AM) symbiosis and rhizosphere microfungal population in Vigna unguiculata subsp. unguiculata (L.) Walp. grown in sandy loam. Pongamia glabra leaves (PL) and goat pellets (GP) were applied at the rates of 5, 10 and 15 g kg-1 soil either alone or with Acaulospora scrobiculata, Glomus aggregatum and G. etunicatum. Plant dry weights, nodulation and tissue nutrients differed with AM fungi, types of organic matter and their concentrations. Increased rates of PL amendment enhanced AM colonization; in contrast, higher rates of GP amendment suppressed AM fungi colonization. Among plant nutrients, potassium content increased profoundly with increasing rate of organic matter amendments with few exceptions at 90 d but at 45 d it showed a reverse trend at higher concentration. Microfungal populations were higher in PL amended soils than in GP-amended soils. Among the various types of microfungal genera isolated, Aspergillus had the most diverse species.