Occurrence of arbuscular mycorrhizal fungi in different cropping systems at Cochabamba, Bolivia (Research Note)

Abstract

The occurrence of arbuscule-forming fungi in different cropping systems was investigated at Cochabamba in the province of Cercado, Bolivia. The cropping systems included grain and mixed pasture systems, with or without fertilization and agrochemicals. Geographically, the soils studied were situated at 17°23'9'' southern latitude and 66°9'35'' western longitude and a mean height of 2600 m above sea level. Spores of four arbuscular mycorrhiza fungi-forming genera were observed; Glomus Tul. & Tul., Entrophospora Ames & Schneider, Sclerocystis Berk. & Broome emend. Almeida & Schenck and Scutellospora Walker & Sanders. Glomus was the dominating genus, followed by Sclerocystis; Scutellospora and Entrophospora were observed occasionally. A cropping system consisting of a native pasture without any fertilization or other plant or soil treatments had the highest numbers of spores and the highest species richness, i.e. eight out of nine species identified. The mycorrhizal diversity measured with the Shannon-Wiener index did however not differ very much between cropping systems. ;