Summary
Mycorrhizal symbioses of the vesicular-arbuscular type are of great importance In the mineral nutrition of both economic and native plant species. In spite of much speculation about the role of these fungi in tropical environments, little Is known of their distribution or ecology in this region. In this study a survey was carried out to determine the effects of four soil management systems and three soil depths on proportion of roots infected by mycorrhizae, number of spores, and number of roots per unit area at a vertical surface of a soil profile. No difference was found between management systems in proportion of Infected roots or number of spores. Forest control area showed more roots per unit area of surface soil. There was a large effect of depth on proportion of infected roots and number of roots per unit area in all treatments.